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Departments of Medicine and Immunology, Mayo Clinic, Rochester, MN 55905
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Abstract |
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 Top Abstract IntroductionMaterials and MethodsResultsDiscussionReferences |
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, IL-1
, and TNF-
. In vivo
activity of adoptively transferred CD4 T cells required matching of
HLA-DRB1 alleles and also the presence of T cell/B
cell follicles. HLA-DRB1-matched synovial tissues that were
infiltrated by T cells, macrophages, and dendritic cells, but that
lacked B cells, did not support the activation of adoptively
transferred CD4 T cell clones, raising the possibility that B cells
provided a critical function in T cell activation or harbored the
relevant Ag. Dependence of T cell activation on B cells was confirmed
in B cell depletion studies. Treatment of chimeric mice with
anti-CD20 mAb inhibited the production of IFN- and IL-1,
indicating that APCs other than B cells could not substitute in
maintaining T cell activation. The central role of B cells in synovial
inflammation identifies them as excellent targets for immunosuppressive
therapy. |
Introduction |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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In most autoimmune syndromes, chronic inflammatory lesions are arranged as diffuse infiltrates of mixed cell populations. This is not the case in RA, in which cells invading the synovial membrane organize themselves into sophisticated microstructures. Most interesting is a subset of patients with RA in whom T cells and B cells form aggregates and eventually develop germinal centers (GCs) (7). As in lymph nodes, T cells and B cells are arranged around a network of follicular dendritic cells (8, 9). Mechanisms regulating this process of lymphoid neogenesis (10, 11) in RA synovium are not understood, but the topographical arrangement as well as the overall number and ratio of T cells and B cells are strictly controlled (12). GCs in RA synovitis are functionally competent, allowing for affinity maturation via IgG hypermutation (7). Analagous to normal secondary lymphoid tissue, extranodal GCs with surrounding T cell populations should be ideal sites for Ag capture. Ag presentation is most likely accomplished by interdigitating dendritic cells that activate Ag-specific T cells in the T cell-rich zones, followed by migration of these T cells into the GCs (8, 9, 13, 14, 15, 16).
In the current study, CD4+ T cells in synovial GCs were isolated by microdissection. Activation requirements for these follicle-derived CD4 T cells were analyzed in adoptive transfer experiments. Distinct GCs from the same patient contained identical CD4 T cell clones that, upon transfer into heterologous synovial tissues, were able to increase the production of proinflammatory mediators. Two factors were critical in determining the functional activity of follicular CD4 T cells, matching with the MHC class II polymorphism of the implanted synovium and the presence of B lymphocytes in the tissue. Several possible mechanisms could underlie the critical role of B cells in regulating the activation of tissue-invading CD4 T cells. Given the ability of B cells to specifically capture Ag with their Ig receptors and present it to T cells (17, 18), B cells may be uniquely situated to stimulate proinflammatory T cells in rheumatoid synovitis.
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Materials and Methods |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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Synovial tissue specimens were obtained from patients with RA
with active synovitis who were undergoing synovial biopsy, synovectomy,
or total joint replacement surgery. All patients had unequivocal
destructive RA, were seropositive for rheumatoid factor (RF), and
fulfilled the American College of Rheumatology (Atlanta, GA)
criteria for the diagnosis of RA (19). Clinical and
demographic data are given in Table I
.
Matching blood samples were collected before the surgical procedure.
The protocol was approved by the Mayo Clinic Internal Review Board, and
all patients provided written informed consent.
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NOD.CB17-Prkdcscid/J mice (nonobese diabetic (NOD)-SCID) were purchased from The Jackson Laboratory (Bar Harbor, ME) and used at age 6–8 wk. For tissue implantation, mice were anesthetized with 50 mg/kg pentobarbital (Abbott Laboratories, North Chicago, IL) i.p. and methoxyflurane (Medical Developments Australia, Springvale, Victoria, Australia) inhalation. Pieces of human synovial tissue with inflammatory infiltrates were placed into a s.c. pocket on the upper dorsal midline. In this model, complete engraftment is reached within 1 wk (20). At the completion of the experiment, the mice were sacrificed and the synovial tissue was harvested and embedded in OCT (Tissue-Tek; Sakura Finetek, Torrance, CA) for histological studies or was shock frozen in liquid nitrogen for RNA extraction.
Treatment with anti-CD20 mAb
Ab treatment was initiated 12 days after tissue implantation. Human synovium-SCID mouse chimeras were injected i.p. three times daily with anti-CD20 mAb (Rituxan; IDEC Pharmaceuticals, San Diego, CA) for 3 consecutive days. Mice received either 100 or 200 µg per injection (300 or 600 µg/day, respectively). Tissue grafts were explanted on day 20 and embedded in OCT for immunohistochemistry or shock frozen in liquid nitrogen for subsequent analysis of in situ cytokine transcription by PCR-ELISA.
Microdissection of GCs and TCR sequencing
Fractions of lymphoid aggregates were collected from 8-µm
cryosections with a 50-µm microcapillary under an inverted
microscope. cDNA from each pick was amplified by PCR with TCR -chain
variable region (BV) (21)- and nested -chain
constant region (BC)-specific primers
(5'-CTGTGCACCTCCTTCCCATTC-3' and 5'-GTGGGAGATCTCTGCTTCTG-3'),
cloned with the TA cloning kit (Invitrogen Life Technologies, Carlsbad,
CA), and sequenced. To select BV elements used by follicular CD4 T
cells, immunohistochemical staining with BV-specific mAb was performed
on serial tissue sections directly adjacent to the sections used for
microdissection. The panel of anti-BV mAb was specific against
BV3S1, BV5S1, BV5S2/S3, BV6S7, and BV8 (T Cell Diagnostics/Endogen,
Cambridge, MA). From each patient, material from two to three
independent follicular picks was subjected to sequence analysis.
Subsequently, 50–70 follicular picks were screened for specific TCR
sequences in hybridization experiments. In these experiments, cDNA was
amplified with the appropriate primers and hybridized with biotinylated
oligonucleotides representing the N-D-N region of TCR sequences that
were expanded in the follicles, using the hybridization protocol
described below for the cytokine semiquantification. Specificity and
sensitivity of the assay system have been described (22).
A signal was considered positive if it exceeded a nonspecific binding
signal by at least 10% of the positive control.
T cell cloning and adoptive transfer experiments
T cell clones were generated from synovial tissue by limiting
dilution cloning (21) and maintained by weekly polyclonal
restimulation and 20 IU/ml human rIL-2 (Proleukin; Chiron, Emeryville,
CA). Three T cell clones were identified that expressed a TCR -chain
nucleotide sequence also found in microdissected GCs from the same
patient. All three clones preferentially produced IFN- after in
vitro stimulation. Autologous control clones were generated from
anti-CD3-activated PBMC and maintained in parallel. Because
tissue-derived clones had a Th1 profile of cytokine production, control
clones were selected to also preferentially produce IFN-. For
adoptive transfer experiments, synovium-SCID mouse chimeras were
generated, and 12–14 days after tissue implantation, 5 x
106 T cell clones were slowly injected into the
tail vein. Synovial grafts were explanted on day 20–22 and embedded in
OCT for immunohistochemistry or shock frozen in liquid nitrogen for
tissue cytokine measurements.
Histopathological evaluation and immunohistochemistry
Hematoxylin-stained sections of the synovial tissue samples were examined for the organizational structure of the inflammatory infiltrate, paying particular attention to the topographical arrangement of T cells, B cells, and macrophages; the degree of angiogenesis and synovial hyperplasia; and the presence of plasma cells. GC reactions, diagnosed by histomorphology, were confirmed by immunohistochemical staining for CD23+ networks (12). Tissues were classified as having diffuse synovitis if neither granulomas nor T cell/B cell clusters could be detected in serial sections from multiple independent sites of the specimen.
Cell populations in the synovial samples were identified by immunohistochemical staining of frozen sections. Tissues embedded in OCT were cut into 5-µm sections and mounted on slides (SuperFrost/Plus; Fisher Scientific, Pittsburgh, PA). Before staining, the slides were fixed in acetone for 10 min, air dried, and fixed in 1% paraformaldehyde/EDTA (pH 7.2) for 3 min. Endogenous peroxidase was blocked with 0.3% H2O2 in 0.1% sodium azide. Nonspecific binding was blocked with 5% normal goat serum (Invitrogen Life Technologies) for 15 min. Sections were stained with anti-human CD3 (1:100; BD Biosciences, San Jose, CA), anti-human CD4 (1:100), anti-human CD20 (1:100), or anti-human CD23 (1:100) mAb (all from DAKO, Carpenteria, CA) for 60 min at room temperature. After incubation with biotinylated rabbit anti-mouse Ig Ab (1:300; DAKO), the slides were developed with diaminobenzidine tetrahydrochloride substrate for 3 min, counterstained with hematoxylin for 5 s, and mounted in Cytoseal-60 (Stephens Scientific, Riverdale, NJ). Negative controls were stained in parallel without the primary Ab.
Cytokine semiquantification
Total RNA was extracted from synovial tissue specimens using
TRIzol reagent (Invitrogen Life Technologies). cDNA samples were
analyzed for -actin transcripts by semiquantitative PCR-ELISA and
were adjusted to contain equal numbers of -actin transcripts
(20, 23). The adjusted cDNA was amplified by PCR for 30
cycles under nonsaturating conditions with cytokine-specific primers.
Standard curves were generated by amplifying serial dilutions of known
concentrations of cytokine-specific sequences. Detailed procedures and
primer sequences for IFN-, IL-1, and TNF- have been reported
(23). Each PCR amplification cycle consisted of
denaturation at 94°C for 30 s, annealing at 55°C for 1 min,
and polymerization at 72°C for 1 min, with 10-min initial
denaturation at 94°C and a final 10-min extension at 72°C.
Amplified products were labeled with digoxigenin-11-dUTP (Roche
Molecular Biochemicals-Boehringer Mannheim, Indianapolis, IN) and
semiquantified in a liquid hybridization assay with biotinylated
internal probes (23) using a commercially available
PCR-ELISA kit (Roche Molecular Biochemicals-Boehringer Mannheim). In
this assay, the labeled PCR products were hybridized with 200 ng/ml
probe at 55°C for 2.5 h. Hybrids were immobilized on
streptavidin-coated microtiter plates and, after washing, were detected
with a peroxidase-labeled anti-digoxigenin Ab. Plates were
developed by a color reaction using ABTS substrate and quantitated
using a kinetic microplate reader (Molecular Devices, Sunnyvale, CA).
The number of cytokine-specific sequences was determined by
interpolation on a standard curve, and was expressed as the number of
cytokine sequences per 2 x 106 -actin
sequences. Data are given as mean ± SD of triplicate
PCR.
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Results |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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The population of CD4 T cells in synovial lesions is diverse
(24). Not knowing which Ag are critical in the disease
process, it has not been possible to isolate T cells relevant for
synovitis. To overcome this, we used synovial tissues with GCs. We
reasoned that CD4 T cells participating in these microstructures would
be specific for disease-relevant Ag. Tissues with follicles and
CD23+ follicular dendritic networks from five
patients bearing HLA-DRB1*04 were selected for analysis.
Synovial follicles were isolated by microdissection. cDNA was generated
from the dissected material and was amplified with TCR BV-
and BC-specific primers, cloned, and sequenced. From
all five patients, sequences derived from the follicular structures had
limited diversity, with sets of 25 sequences consistently containing
two to three sequences present in multiple copies. More importantly,
identical TCR sequences were demonstrated in distinct follicles from
the same patient. All of these shared sequences were identical at the
nucleotide and not only at the protein level, suggesting that they
derive from the same founder cell. TCR sequences expressed in at least
three independent follicles were considered to have derived from T
cells specifically activated in the lesions and were selected. Parallel
samples of synovial tissues from the same patients were used to
establish T cell clones that were screened for these relevant TCR
sequences. Three BV6S7+ T cell clones that
expressed nucleotide sequences identical to sequences in the follicular
picks (BV6S7-TTATTCGGGACAGACACAGAT-BJ2S3;
BV6S7-TTAGGGGTGCTAGCGCGGGAG-BJ2S3;
BV6S7-CCAACAGGGGTTGGCGCAGAT-BJ2S5) were retrieved
from an HLA-DRB1*0401/0403+ patient,
RA-4. These three T cell clones were phenotyped as
CD4+CD8nullCD28+.
Their distribution in multiple follicles of the donor tissue is
described in Table II.
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, TNF-, and IL-1 cytokines,
all previously implicated in the disease process (1). The
transfer of the control clone did not affect baseline IFN-
transcription in the engrafted synovium. In contrast, infusion of
follicle-derived T cell clones resulted in a 3- to 4-fold increase in
tissue IFN- production (Fig. 1).
Similar increases were obtained in two additional experiments using the
same synovial T cell clones and two different control clones. Also, the
number of IL-1- and TNF--specific transcripts increased 2- to
3-fold over baseline following transfer of autologous follicular CD4 T
cell clones, but remained unaffected when the control clones were
injected. The selective activation of follicular T cells is most
consistent with the model that these cells recognize a local Ag,
although additional differences between control and follicular T cells
(such as differences in homing receptors) may contribute. The T cell
clones did not produce TNF- or IL-1 in vitro. Therefore, the
increased production of these cytokines must be considered a downstream
event, documenting that T cell activation and increases in IFN-
transcripts were of functional importance. There was a trend for T cell
clone ST52 to boost synovial cytokines most efficiently, but all three
synovial T cell clones had strong proinflammatory properties. These
data suggested that CD4 T cell clones isolated from follicular centers
are effective regulatory cells in rheumatoid inflammation.
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To investigate whether the activation of adoptively transferred
CD4 T cells was restricted by HLA class II molecules, adoptive transfer
experiments were performed with SCID mouse chimeras carrying
HLA-DRB1-matched and -mismatched tissues. Donor-recipient
combinations included matches for both HLA-DRB1 alleles
(RA-6), matches for one HLA-DRB1 allele (RA-8 and RA-9), and
mismatching for both (RA-7 and RA-10). Results of representative
experiments are shown in Fig. 2. All
three T cell clones, ST52, ST57, and ST59, which had been shown to
function in autologous tissue grafts, were able to act as
proinflammatory cells in heterologous tissue. Transfer into human
synovium-SCID mouse chimeras implanted with tissue matched for both
HLA-DRB1 alleles resulted in a 3- to 4-fold increase in the
transcription of IFN-, IL-1, and TNF- (Fig. 2, upper
panel). Similar results were obtained when the T cell clones and
the recipient tissue were matched for only one HLA-DRB1
allele, HLA-DRB1*0401 (Fig. 2, middle panel).
Mismatch of both HLA-DRB1 alleles resulted in the loss of T
cell clone function, with none of the inflammatory cytokines responding
to the transfer of cloned follicular T cells. These experiments
demonstrated that the necessary components to trigger the activity of
follicle-derived CD4 T cell clones are present in heterologous synovial
tissues, suggesting that Ags driving the inflammation are shared by
different patients.
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Experiments shown in Fig. 2
were performed with tissues containing
GCs. To address the question as to whether T cell activation is
dependent upon the presence of these microstructures, we made use of
the observation that not all patients with rheumatoid synovitis form
classical GCs. In a subset of patients with RA, no T cell/B cell
aggregates were found in the synovial membrane. Instead, T cells were
dispersed throughout the tissue and CD20+ B cells
were essentially absent (Fig. 3). In both
follicular and diffuse synovitis, CD83+
interdigitating dendritic cells were present as possible APC (data not
shown). The pattern of synovitis was consistent within patients, and
synovial tissues from distinct joints showed the same type of
inflammatory lesion. Also, longitudinal studies have demonstrated that
diffuse synovitis does not convert into follicular synovitis or vice
versa (data not shown).
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. Synovial tissues lacking B cells were
not able to support the activation of any of the three follicle-derived
CD4 T cell clones. Levels of tissue IFN- transcripts were
indistinguishable between control mice, mice injected with a
PBMC-derived CD4 T cell clone, and mice injected with the follicular
CD4 T cell clones. Data shown in the upper panel of Fig. 4
are derived from experiments using recipient tissue that typed
HLA-DRB1*0401/0403 (RA-11), and thus, was matched for both
alleles. Despite this perfect match, the transferred CD4 T cell clones
remained nonfunctional. Tissue concentrations for TNF- and IL-1
transcripts also remained unaltered. These experiments suggested that B
cells were critical in inducing activation of selected CD4 T cells.
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To examine the role of B cells in the activation of
tissue-residing T cells, NOD-SCID mice were implanted with synovial
tissue containing GCs and were then injected with anti-CD20 mAb for
3 consecutive days. Tissues from eight different patients, four with
GCs and four with only diffuse infiltrates, were used. Grafts were
harvested and analyzed for tissue histomorphology and cytokine
production. The cell diversity of the infiltrate was semiquantified by
counting CD4 T cells in 20 high powered fields per tissue. As shown in
Fig. 5, treatment with anti-CD20 mAb
resulted in the dissociation of the follicular structures. Not only
were the follicles dissipated, the overall density of the infiltrates
was decreased with a concomitant loss of CD4+ T
cells. Upon treatment, the average number of CD3+
T cells per high powered field declined to 
25% in controls.
Functional studies demonstrated that the production of IFN- in the
tissue with GC decreased markedly (Fig. 6). In grafts retrieved from chimeras
treated with 300 µg anti-CD20 mAb per day, the concentration of
IFN- mRNA in the tissue was reduced by 60–80%. In synovial tissues
explanted from chimeras injected with a daily dose of 600 µg
anti-CD20 mAb, IFN- transcription essentially ceased. In
parallel to the suppression of T cell activation and IFN-
production, the transcription of the proinflammatory monokine IL-1
decreased by 80% in comparison with the controls (Fig. 6).
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Discussion |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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Several mechanisms could account for the critical position of B cells
in supporting the activation of synovial CD4 T cells. A direct
involvement of secreted Ab is unlikely. B cells, however, are highly
efficient in Ag presentation because they accumulate and incorporate Ag
by specifically capturing them with their Ig receptors. This mechanism
is particularly important for B cells with RF reactivity because
RF-positive B cells bind immune complexes and process them for Ag
presentation (18, 25). They could, therefore, function as
APCs in a cognate interaction. Alternatively, B cells could regulate T
cell homing and survival and, thereby, facilitate T cell activity.
Recent studies have clearly identified B cells as critical mediators of
lymphoid organogenesis, in part through their ability to express
lymphotoxin- on their cell surface (11, 14). Finally, B
cells could be the source of the relevant Ag, requiring their presence
for effective T cell activation.
Direct relevance of B cells in disease pathogenesis has been shown for several experimental models of autoimmunity, including murine models of lupus erythematosus and diabetes mellitus (26, 27, 28, 29, 30). Persistence of lupus nephritis in mice with B cells deficient in secreting Ig has excluded the simple explanation that B cells influence the disease process through the production of autoantibodies (31). In MRL/lpr mice, B cells have been implicated in inducing a highly activated phenotype of CD4 and CD8 T cells (26). Taken together, B cells influence autoimmunity through multiple pathways, thereby representing important therapeutic targets in autoimmune diseases.
The precise role of B cells in RA is not well understood. RA was
originally considered an Ab-driven disease (32, 33) with
immune complex-mediated tissue injury (34, 35, 36). The
failure to correlate disease activity to the levels of autoantibodies
and the realization that RA exists in individuals not expressing RF
focused interest on T lymphocytes and T cell-dependent effector
mechanisms. The current paradigm proposes that T cell-derived
cytokines, released upon T cell recognition of Ag in the synovial
membrane, induce activation of macrophages and synovial fibroblasts,
causing the formation of tissue-invasive pannus. Indirect evidence for
an important contribution of B cells in rheumatoid synovitis could be
inferred from the finding that the synovial membrane can be a site of
lymphoid neogenesis. Synovial GCs have the morphological and functional
characteristics of GCs in lymph nodes, with the exception that T cells
account for a higher proportion of the cells contributing to the core
(12). The formation of extranodal GCs is uncommon in
Ag-driven immune responses and has only been described for a very few
nonmalignant syndromes (37). In RA, 20% of all
patients have the ability to generate these complex microstructures in
the joint (38). The current study provides direct evidence
that in this subset with GCs, macrophages, synovial fibroblasts, or
interdigitating dendritic cells are not sufficient for sustaining T
cell activation, but that B cells are critical. The adoptive transfer
data are based on experiments with T cell clones from only one patient.
However, similar results were found in chimeric mice implanted with
tissues from different donors, and the conclusion is further supported
by the B cell depletion experiments with tissues from different
patients. Recent data in a TCR transgenic mouse model have emphasized
that Ab produced by autoreactive B cells can have a direct role in
inducing synovial inflammation, indicated by the transfer of joint
inflammation from affected to unaffected animals by serum
(39). In contrast, B cell functions distinct from the
release of Ab must be underlying the critical involvement of B cells in
human rheumatoid synovitis. The property of B cells in controlling
stimulation of CD4 T cells in the lesion cannot be explained by
autoantibody production. Rather, it indicates a different contribution
of B cells to the RA process.
An interesting finding of the current study relates to the distribution of CD4 T cells able to boost synovial inflammation. Based on the reasoning that CD4 T cells participating in the GC reaction would almost certainly represent Ag-reactive T cells undergoing in situ activation, a microdissection approach was developed. TCR sequences isolated from the GC were restricted in diversity. More importantly, T cells with identical TCRs were isolated from different, nonadjacent T cell/B cell follicles. This finding supports the notion that the same Ag is driving the GC reaction in different follicles. TCR sequences isolated from microdissected follicular structures are only infrequently found outside of the clusters (data not shown). The restriction of the TCR and the sharing of T cells among different GCs strongly support a role for few Ag driving the formation of tertiary lymphoid tissue and subsequent tissue destruction in the rheumatoid joint. These Ag are obviously shared among patients because the follicular CD4 T cell clones underwent stimulation in the autologous as well as heterologous tissues. The restriction to HLA-DRB1 molecules is in line with the recognition of a classical peptide Ag. The possibility has to be considered that the failure of follicular CD4 T cells to function in B cell–poor tissues is a reflection of a lack of the relevant Ag. In this model, follicular and diffuse synovitis would be different diseases. The Ag recognized in the synovium would be shared between different patients with follicular synovitis, but would be different in diffuse synovitis. It was proposed that CD8 T cells in the joints of patients with RA are triggered by EBV-related Ag (40, 41), but subsequent studies did not confirm a pathogenic role of EBV infection in RA (42, 43, 44). The CD4 T cell clones used in the current study did not respond to autologous EBV-transformed lymphoblasts (data not shown). Synovial B cells could also harbor other Ag and, thus, hold a critical position in the synovial immune response.
Although this interpretation cannot be excluded, a B cell-derived Ag presented by B cells as well as other APCs would not explain the rapid decline in CD4 T cell activity after the elimination of CD20+ B cells. The mAb treatment had profound effects. Not only did the follicles disappear, but the frequency of tissue-infiltrating T cells and macrophages decreased markedly, to the extent of abrogating synovial inflammation. This observation supported a direct contribution of B cells in maintaining stimulation of proinflammatory T cells. Synovial B cells could have specialized Ag-presenting function, superior to all other accessory cells in the inflamed tissue. Several cell populations in the inflamed synovial membrane have been suspected to serve as APCs, including dendritic cells, synoviocytes, and macrophages (45, 46, 47, 48, 49). It is unlikely that primed T cells would be exclusively restricted to recognize Ag on B cells, especially when considering that GC T cells are thought to make their first Ag contact by interacting with dendritic cells in the T cell-rich zones. Anti-CD20 mAb treatment spared dendritic cells, but their presence was insufficient to sustain synovitis. Also, synovial tissues with diffuse infiltrates contain CD83+ dendritic cells and are able to promote T cell activation (20). However, in both experimental systems, the adoptive transfer experiments in follicular and diffuse synovitis and in the B cell depletion experiments, B cells proved to be critical for the functional activity of proinflammatory CD4 T cells. B cells may be superior to dendritic cells in capturing Ag, in particular, if Ag concentrations are limiting. B cells expressing Ig with RF activity could take up immune complexes presented by the follicular dendritic cells and thereby enrich for an infrequent Ag included in these complexes (18, 25).
Finally, it should be considered that the dependence of T cell
stimulation on CD20+ B cells is a reflection of
the complexity of the microenvironment. In situ activation of
tissue-infiltrating CD4 T cells may not only depend on the presence of
Ag and APCs, but it may be critically modulated by the spatial
arrangement of the cells, local gradients of cytokines and mediators,
and the competition of cells for space and resources. This model would
predict that T cell triggering in the synovial lesions is optimized in
follicular centers, and that the disease process in diffuse tissues is
low grade and smoldering. Evidence has been provided that small
concentrations of Ag are more effectively recognized when presented in
the specialized microenvironment of lymphoid tissue (50).
Indeed, previous studies have shown higher IFN-, IL-1, and
TNF- production in RA tissues with follicular synovitis than in
tissues with diffuse synovitis (23).
The data reported in this work have potential clinical applications.
Based on the finding in the human synovium-SCID mouse chimera model
that T cell activation and its downstream effects, such as production
of the proinflammatory monokines, TNF- and IL-1, were suppressed
by depleting CD20+ B cells, elimination of B
cells in patients could be developed into a potent immunosuppressive
therapy. Anti-B cell reagents have been generated for treatment of
patients with lymphoproliferative disorders and have been shown to be
relatively safe (51, 52, 53). Edwards and Cambridge
(54) have recently reported five RA patients who responded
to anti-CD20-mediated B cell depletion in combination with cytoxan
and prednisone. Three of the five patients had sustained improvement
for more than 1 year. Because this study used a combination therapy,
the relative contribution of B cell depletion to the treatment success
is unclear. It is known how many of these five patients had synovial
GCs. Our study suggests that B cell-depleting Abs or reagents
interfering with B cell stimulation pathways, such as BLyS, may
directly influence the synovial inflammation in the subset of RA
patients that generate tertiary lymphoid microstructures in the
synovium.
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Acknowledgments |
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Footnotes |
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2 Address correspondence and reprint requests to Dr. Cornelia M. Weyand, Mayo Clinic, Guggenheim 401, 200 First Street S.W., Rochester, MN 55905. E-mail address: weyand.cornelia{at}mayo.edu
3 Abbreviations used in this paper: RA, rheumatoid arthritis; BV, TCR -chain variable region; GC, germinal center; NOD, nonobese diabetic; RF, rheumatoid factor.
Received for publication April 17, 2001. Accepted for publication August 14, 2001.
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References |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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inhibits dendritic cell-T lymphocyte interactions in patients with chronic arthritis. Arthritis Rheum. 42:507.[Medline]
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K. Yanaba, Y. Hamaguchi, G. M. Venturi, D. A. Steeber, E. W. St. Clair, and T. F. Tedder B Cell Depletion Delays Collagen-Induced Arthritis in Mice: Arthritis Induction Requires Synergy between Humoral and Cell-Mediated Immunity J. Immunol., July 15, 2007; 179(2): 1369 - 1380. [Abstract] [Full Text] [PDF]
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J. D Canete, B. Santiago, T. Cantaert, R. Sanmarti, A. Palacin, R. Celis, E. Graell, B. Gil-Torregrosa, D. Baeten, and J. L Pablos Ectopic lymphoid neogenesis in psoriatic arthritis Ann Rheum Dis, June 1, 2007; 66(6): 720 - 726. [Abstract] [Full Text] [PDF]
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 S Wohrer, M Troch, J Zwerina, G Schett, C Skrabs, A Gaiger, U Jaeger, C. Zielinski, and M Raderer Influence of rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone on serologic parameters and clinical course in lymphoma patients with autoimmune diseases Ann. Onc., April 1, 2007; 18(4): 647 - 651. [Abstract] [Full Text] [PDF]
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 A. Kuek, B. L Hazleman, and A. J K Ostor Immune-mediated inflammatory diseases (IMIDs) and biologic therapy: a medical revolution Postgrad. Med. J., April 1, 2007; 83(978): 251 - 260. [Abstract] [Full Text] [PDF]
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