Interleukin 8 and monocyte chemoattractant protein-1 in patients with juvenile rheumatoid arthritis. Relation to onset types, disease activity, and synovial fluid leukocytes

OBJECTIVE: To measure serum and synovial fluid (SF) levels of interleukin 8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) in patients with juvenile rheumatoid arthritis (JRA) and to compare them with adult rheumatoid factor-positive rheumatoid arthritis (RA). METHODS: IL-8 and MCP-1 were measured by immunoassay (1) in sera obtained from 55 children with JRA and from 16 adults with RA, and (2) in SF obtained from 30 children with JRA and 11 adults with RA. RESULTS: Patients with active systemic JRA had serum levels of IL-8 and MCP-1 higher than in controls (p<0.01) and in patients with active polyarticular or pauciarticular JRA (p<0.05). In patients with RA serum MCP-1 levels were higher than in patients with the 3 JRA onset types, while no difference was found for IL-8 levels. Patients with systemic JRA and with current systemic features had serum levels of IL-8 and MCP-1 higher (p = 0.03 and p = 0.04, respectively) than patients in which systemic features had subsided. No significant differences in SF IL-8 or MCP-1 levels were found among the 3 JRA onset types or adults with RA. In patients with JRA SF leukocyte counts were correlated with SF IL-8 levels (p = 0.002), but not with MCP-1 levels. Moreover, SF levels of both IL-8 and MCP-1 were correlated with those of IL-1beta (p<0.001) and IL-6 (p<0.01), but not with those of TNF-alpha. CONCLUSION: Elevated serum levels of IL-8 and MCP-1 in patients with systemic JRA with current systemic features at sampling suggest systemic production of the 2 chemokines during systemic phases of the disease. Similar SF levels of IL-8 and MCP-1 among the 3 JRA onset-types and RA suggest comparable local production of the 2 chemokines.     

Autoantibody studies in juvenile rheumatoid arthritis

Early studies showed few immunologic abnormalities in juvenile rheumatoid arthritis (JRA) patients. There were no specific laboratory markers useful for diagnosis and assessment of the course of disease in JRA. Previous work showed an association of antinuclear antibodies (ANA) with early-onset pauciarticular disease and iridocyclitis. Similarly, the presence of 19S immunoglobulin (Ig) M rheumatoid factors (RF) was associated with late-onset polyarticular disease in girls. More recent studies have detected many unique autoantibodies. Newer assays show 19S IgM RF in up to 35% of JRA patients, although still mainly in girls with late-onset polyarticular disease. Hidden 19S IgM RF can be shown in up to 75% of JRA patients using different procedures, primarily in those with active polyarticular-or pauciarticular-onset disease. Immune complexes have been detected in JRA patients by means of different techniques; their presence usually correlates with active disease. Studies on a specific ANA in JRA have shown no common extractable nuclear antigen, but antihistone antibodies have been found in up to 75% of cases, again mainly in those with pauciarticular onset and iritis. Finally, a variety of unusual immunologic proteins have also been detected, including anti-ocular, anti-cellular, anti-cardiolipin, anti-perinuclear factor, and anti-collagen antibodies. This review evaluates the significance of these antibodies that can now be found in JRA.     

Comparative sequence analysis of the human T cell receptor beta chain in juvenile rheumatoid arthritis and juvenile spondylarthropathies: evidence for antigenic selection of T cells in the synovium

OBJECTIVE: To identify features of the T cell receptors (TCRs) present on clonally expanded T cells in the joints of patients with similar types of childhood rheumatic disease. Vbeta8 and Vbeta20 TCRs were selected as prototypic for polyarticular juvenile rheumatoid arthritis (JRA) and pauciarticular/juvenile spondylarthropathy (SpA), respectively. METHODS: The portion of the TCR beta chain involved in antigen recognition in the synovial tissue, synovial fluid, and peripheral blood from patients with JRA and juvenile SpA was cloned and sequenced. The frequency of expanded clonotypes, size of expansions, the Jbeta region, and sequence motifs were determined for >2,000 sequences. RESULTS: The majority of Vbeta20 and Vbeta8 clonal expansions were found in the joint rather than the peripheral blood. While instances of both Vbeta8 and Vbeta20 clonal expansion were detected in all disease types, the features of these expanded clonotypes were specific for disease type and Vbeta family. For example, Vbeta20 clonal expansion was characterized by many small expanded clonotypes in samples from patients with pauciarticular JRA and juvenile SpA while single large Vbeta8-specific expansions were found only in patients with polyarticular disease. Motifs specific to individual patients were identified, and for Vbeta20 clonotypes, a motif was found in synovial tissue samples. CONCLUSION: Identification of common TCR features in oligoclonal expansions within individual patients and between patients with the same type of JRA suggests the recognition of a common or limited group of antigens in these diseases.     

Differential expression of cytokine genes in CD27-positive and -negative CD4 lymphocyte subsets from healthy humans and rheumatoid arthritis patients

Immunofluorescence analysis of CD27 expression by CD4 lymphocytes from the peripheral blood of healthy humans or rheumatoid arthritis (RA) patients and from the synovial fluid (SF) of RA patients was carried out, along with the estimation of cytokine gene [interleukin (IL) 2, IL-3, IL-4, IL-5, IL-6, IL-6R, IL-10 and interferon-gamma (IFN-gamma)] expression in these lymphocyte subsets by RT-PCR. Although no differences in CD27-positive and -negative peripheral blood CD4 cell subset distribution were revealed, marked differences in IL-3, IL-4, IL-5 and IFN-gamma mRNA expression were detected between these lymphocyte subsets and between control and disease states. These results showed that phenotyping of different cell subsets in disease cannot provide adequate information about lymphocyte functional status. To estimate differences in cytokine gene expression, CD4 lymphocytes from the peripheral blood and SF of RA patients were compared. In both cases, mRNAs for IL-2, IL-4, IL-10 and IFN-gamma were detected, but CD4 cells from SF failed to express detectable levels of IL-5 mRNA despite our findings of a CD27-cell accumulation within the synovial population of CD4 lymphocytes. These are the first data to demonstrate that expression of the IL-5 gene in RA SF CD27- lymphocytes is down-regulated and that IL-5 disregulation in RA cannot be ruled out.     

Chlorella virus NY-2A encodes at least 12 DNA endonuclease/methyltransferase genes

OBJECTIVE: To describe outcome and determine predictive factors in juvenile rheumatoid arthritis (JRA) and juvenile spondyloarthopathy (JSpA). METHODS: Seventy-two children with chronic arthritis were studied on first admission to the pediatric rheumatology clinic and after a mean of 9.7 +/- 1.8 yrs of disease duration. RESULTS: At followup, 53 patients had JRA and 19 had JSpA. Eleven (21%) of the patients with JRA did not meet the criteria for JRA on first admission, and 12 (22%) of 54 children diagnosed as having JRA on first admission were later reclassified as having another disease. Remission occurred in 43 (60%) of the 72 patients with JRA and JSpA. Forty-four patients (60%) reported no disability by the childhood or adult Health Assessment Questionnaire and 18 patients (25%) had developed joint erosions. Disease modifying antirheumatic drugs (DMARD) were given to 49 patients (68%) after a median of 0.8 yrs (range 0.2-10.8) disease duration. The patients who developed erosions and disability tended to have started treatment later than those who did not (NS). Active disease 5 years after onset was a predictor of disability in JRA and JSpA (OR 4.5, 95% CI 1.6-12.5). Predictors of joint erosions were long duration of elevated erythrocyte sedimentation rate (ESR) (OR 3.7/yr of elevated ESR, 95% CI 1.9-7.2), long disease duration before first admission (OR 1.5/yr of duration, 95% CI 1.1-2.1), long disease duration before treatment with DMARD (OR 1.8, 95% CI 1.0-3.3), and IgM rheumatoid factor (OR 12 x 10(4), 95% CI 0-1.2 x 10[52]). CONCLUSION: The longterm outcome in JRA and JSpA was more favorable than previously reported. This may be explained by less selection in favor of severely diseased patients and by the use of early aggressive treatment regimes.     

Juvenile rheumatoid arthritis in African Americans

OBJECTIVE: To examine racial differences in disease expression in African American and Caucasian children with pauciarticular and polyarticular juvenile rheumatoid arthritis (JRA). METHODS: A retrospective chart review was conducted of 35 African American and 137 Caucasian children with pauciarticular and polyarticular JRA. RESULTS: African American children were significantly older than Caucasian children at the time of presentation. This was true both for the group as a whole and for each of the disease onset subtypes. African American children were less likely to have positive antinuclear antibody tests than Caucasian children. This finding paralleled a low incidence of uveitis in African American children. African American children were also more likely to have IgM rheumatoid factors (detected by latex agglutination) than Caucasian children. This was true even for African American children with pauciarticular JRA. CONCLUSION: There are significant phenotypic differences between African American and Caucasian children with JRA.     

Synovial fluid interleukin-8 and neutrophil function in rheumatoid arthritis and seronegative polyarthritis

The relationships between synovial fluid (SF) interleukin-8 (IL-8) and neutrophil turnover as measured by cytidine deaminase (CD), and SF metabolites were studied in 28 patients, 16 with rheumatoid arthritis (RA; median age and disease duration 62 and 14 yr, respectively) and 12 with seronegative polyarthritis (SNP; median age and disease duration 32 and 5 yr, respectively). Knee SF samples were aspirated using indwelling cannulae following a period of rest for 1 h. SF IL-8 levels (measured by an ELISA) were significantly elevated in RA compared to SNP (median 2.35 vs 0.22 ng/ml, P < 0.001), as were median levels of CD (55.8 vs 8.11 U/ml, P < 0.01), lactic acid (29.6 vs 16.6 mg/dl, P < 0.001), glucose (57.9 vs 84.5 mg/dl, P < 0.05) and the lactate to glucose ratio (0.85 vs 0.19, P < 0.001). Measures of disease activity, C-reactive protein, plasma viscosity and articular index were also elevated in RA compared to SNP (P < 0.05). SF IL-8 levels correlated strongly with CD, lactate, glucose and the lactate to glucose ratio when both disease groups were considered together (P < 0.001). These parameters also showed some association with the measures of disease activity (P < 0.05). All these associations were less marked when the individual disease groups were analysed separately. These results suggest that factors responsible for neutrophil accumulation and priming (probably IL-8) are present in SF, and these coincide with products of their activation (CD). The degree of neutrophil turnover is linked to the anaerobic metabolism of the synovial cavity.     

Long-term health outcomes and quality of life in American and Italian inception cohorts of patients with juvenile rheumatoid arthritis. I. Outcome status

OBJECTIVE: To assess the long-term health outcomes and quality of life of patients with juvenile rheumatoid arthritis (JRA) using health and functional assessment questionnaires in 2 populations, one from the USA and one from Italy. METHODS: Patient eligibility criteria: (1) first examined in our units between 1958 and 1990 during the first 6 months after onset of symptoms, (2) diagnosis of JRA by the American College of Rheumatology criteria, (3) disease duration of at least 5 years at the time of assessment of outcome. Instruments used: (1) the Health Assessment Questionnaire (HAQ, short form, or childhood HAQ (CHAQ), and (2) Quality of Life Scales (QOLS, adults only). Eligible patients were identified by computer search and chart review and were then mailed a packet containing a consent/assent form and the assessment instruments. RESULTS: Of 346 patients who met the eligibility criteria were able to locate 301, and 290 verbally agreed to participate and were mailed packets. Signed consent and complete information were received from 227 of the 290 (78%), 178 from the USA and 49 from Italy. Mean duration of disease at the time of outcome assessment was 15 yrs. 127 had pauciarticular, 55 polyarticular, and 45 systemic onset disease. Mean and (median) scores of the outcomes are shown in the table. [table: see text] CONCLUSION: Long-term outcome, as assessed by the instruments used, is very favorable in most patients with JRA 5 years or more after onset of symptoms.     

Autoreactivity to human heat-shock protein 60 predicts disease remission in oligoarticular juvenile rheumatoid arthritis

OBJECTIVE: To determine whether T lymphocyte reactivity to endogenous human hsp60 plays a regulatory role in the course of oligoarticular juvenile rheumatoid arthritis (JRA). METHODS: A prospective, longitudinal study of T cell reactivity to HSP in 15 patients with newly diagnosed HLA-B27 negative oligoarticular JRA was performed. Results were compared with those in a group of 20 patients with newly diagnosed polyarticular or systemic JRA or with acute arthritis caused by other systemic diseases or viral infections, as well as with those in a group of 9 healthy control subjects. RESULTS: In 86% of the patients with oligoarticular JRA (13 of 15), significant T lymphocyte proliferative responses to hsp60 were found in peripheral blood mononuclear cells and/or synovial fluid mononuclear cells within 3 months after the onset of arthritis. Only 5% of the patients in the rheumatologic disease control group (1 of 20) showed such positivity. All patients with oligoarticular JRA and positive responses to human hsp60 developed a remission of their disease within 12 weeks. During this period of remission, blood samples were taken from 8 patients and showed significantly lower and even negative responses to hsp60, compared with active disease, when all 8 patients had good responses. CONCLUSION: The results show that significant proliferative responses to human hsp60 can be found early in the course of oligoarticular JRA. Furthermore, these responses correlate with disease activity in such a manner that T cell reactivity to human hsp60 seems to be associated with disease remission.     

Induction of invasive and degradative phenotype in normal synovial fibroblasts exposed to synovial fluid from patients with juvenile rheumatoid arthritis: role of mononuclear cell population

OBJECTIVE: To investigate the effect of synovial fluid (SF) from patients with juvenile rheumatoid arthritis (JRA) on proliferation and induction of degradative and invasive phenotype in normal synovial fibroblasts, and to elucidate the contribution of SF cells to this activity. METHODS: SF and/or conditioned medium (CM) from SF cells were evaluated for their ability to (1) stimulate a proliferative response, (2) induce the "activated phenotype" capable of invading cartilage matrix, and (3) promote the release of key matrix metalloproteinases (MMP) in normal synovial fibroblasts. RESULTS: Proliferation of normal synovial fibroblasts exposed to SF or CM from SF cells of patients with JRA was up to 3 times greater than untreated controls. Concomitant with induction of an activated phenotype in the treated synovial fibroblasts, the activated form exhibited up to 250% invasiveness of cartilage matrix compared to untreated synovial fibroblasts (100%), in addition to releasing increased MMP activity, not normally associated with these quiescent cells. This induction was not solely due to tumor necrosis factor-alpha, transforming growth factor-beta, interleukin 1beta (IL-1beta), and IL-6, as SF and/or CM depleted of these cytokines sustained about 40% of their invasive and inducing ability. We observed that the mononuclear cell (MNC) population that infiltrated into the joint cavity secretes this "inducing activity," which can be maintained in culture up to several weeks. CONCLUSION: Our data suggest that the cellular component of SF releases soluble factor(s) that directly or indirectly contribute to (a) proliferation of synovial fibroblasts, and (b) production and release of extracellular MMP by synovial fibroblasts, thereby inducing a degradative and invasive phenotype culminating in cartilage and bone destruction.     

Association of methotrexate treatment with a decrease of double negative (CD4-CD8-) and gamma/delta T cell levels in patients with juvenile rheumatoid arthritis

OBJECTIVE: It has been suggested that double negative (CD4-CD8-) (DN) and gamma/delta T cells may be involved in some autoimmune diseases. We investigated peripheral blood DN and gamma/delta T cell levels in patients with active juvenile rheumatoid arthritis (JRA). METHODS: DN and gamma/delta T cell levels were measured in 42 patients with active JRA and in 10 healthy controls comparable for age by an immunofluorescence double staining procedure. RESULTS: All 3 JRA onset types had DN and gamma/delta T cell levels not significantly different from those of controls, although a wide scattering of data was present. No correlation was found between DN or gamma/delta T cell levels and erythrocyte sedimentation rate values or the number of active joints. When patients were divided according to treatment, we found that DN and gamma/delta T cell levels were significantly lower (p = 0.001, p = 0.02, respectively) in patients receiving methotrexate (MTX) than in patients not receiving MTX. The association of MTX treatment with a decrease in DN and gamma/delta T cell levels was also confirmed in a followup study of individual patients. Among patients not receiving MTX, patients with systemic JRA presented DN T cell levels significantly higher than those of controls. In 5 patients with pauciarticular JRA DN and gamma/delta T cell levels were higher in synovial fluid than in the peripheral blood. CONCLUSIONS: We found an increase in peripheral blood DN T cell levels in systemic JRA; treatment with MTX appears to be associated with a decrease in DN and gamma/delta T cell levels.     

Juvenile rheumatoid arthritis in affected sibpairs

OBJECTIVE: To describe the demographics and clinical disease in affected sibpairs (ASPs) with juvenile rheumatoid arthritis (JRA), and to compare JRA as it occurs in ASPs with that from non-ASP JRA populations described in the literature. METHODS: A rare disease research registry was established with a focus on JRA ASPs to facilitate accrual of patients for genetic, epidemiologic, and clinical studies. Physicians likely to care for patients with JRA were made aware of the registry and its goals by a variety of methods and asked to refer patients for entry. RESULTS: To date, 71 ASPs have been registered and complete information has been obtained. These affected sibs differed in age by a mean of 4.1 years (SD 3.4) and in age at disease onset by 2.8 years (SD 3.0). The actual time difference between onset in sib 1 versus sib 2 averaged 4.4 years (SD 4.2). Sixty-three percent of the sibpairs were concordant for sex, and 76% for JRA onset type. Onset type within sibpairs did not appear to be random, based upon comparisons with non-ASP populations. Greater than expected concordance was seen among those with pauciarticular-onset and polyarticular-onset JRA. Seventy-nine percent of the pairs were concordant for course type. Seven sets of twins were included (approximately 10% of the total), all were concordant for onset and course type (6 sets with pauciarticular, 1 set with polyarticular), and disease onset was separated by a mean of only 3.3 months. Within the onset and course types, the clinical disease, such as the female:male ratio, age at onset, and serologic findings, in ASPs resembled that which has been described in the literature. CONCLUSION: A higher than expected degree of concordance for onset type of JRA exists between sibpairs, indicating that genetic influences play a role. Affected sibs do not tend to develop their disease at approximately the same point in time, except for the twin sets. Clinical features of the disease within the various subtypes appear similar to those in non-ASP populations.     

Analysis of type 1 and type 2 T cells in synovial fluid and peripheral blood of patients with rheumatoid arthritis

OBJECTIVE: It has been reported that CD4+ helper T cells play an important role in the pathogenesis of rheumatoid arthritis (RA). We evaluated the presence of intracellular cytokines interleukin 4 (IL-4) and interferon-gamma (IFN-gamma) produced by CD4+ and CD8+ T cells in the synovial fluid and peripheral blood of patients with RA at the single cell level. METHODS: We used 3 color flow cytometric analysis. Synovial fluid mononuclear cells (SFMC) and peripheral blood mononuclear cells (PBMC) were stimulated with phorbol myristate acetate (PMA) and calcium ionophore. The stimulated SFMC and PBMC were triple stained with conjugated mononuclear antibodies (Mab) against cytokines and surface antigens after fixation and permeabilization with a saponine buffer solution. The cells were analyzed for intracellular cytokines (IFN-gamma, IL-4) and surface antigens (CD3, CD4, CD8) using a flow cytometer. RESULTS: The CD4/CD8 ratio was significantly lower in SFMC than in PBMC. The positive rates of IFN-gamma producing cells among CD4+ T cells were significantly higher than those of IL-4 producing cells in both the SFMC and the PBMC of patients with active RA. In the SF of these patients, we also found CD8+ T cells that produce IL-4 alone, or both IL-4 and IFN-gamma. CONCLUSION: In the SF of patients with RA, CD4+ type 1 T cells, which may infiltrate into the synovium and cause pathogenic immune responses in the tissue, are predominant. We believe this cell type also induces migration and activation of CD8+ type 2 T cells into the active site of inflammation, which appears to downregulate the activity of CD4+ type 1 T cells, modulating the excess immune response.     

Expression of macrophage markers by a population of T cells obtained from synovial fluid of a subgroup of patients with juvenile rheumatoid arthritis

OBJECTIVE: To characterize distinctive lymphoid cell populations in the synovial fluid (SF) of patients with juvenile rheumatoid arthritis (JRA) that have the specific ability to display monocytic markers when cultured in vitro. METHODS: Mononuclear cells obtained from SF of patients with JRA and depleted of adherent macrophages were cultured in vitro in RPMI 1640 medium supplemented with only fetal calf serum (FCS). Phenotypic evaluation of these cells was by flow cytometry and immunohistochemical analysis was by specific fluorochrome labeled antibodies. RESULTS: T cells from a JRA subgroup displayed some typical macrophage attributes, i.e., abundant cytoplasm, adherence to plastic, and phagocytosis of latex beads when cultured in vitro. These cells have the ability to survive in culture for several weeks in RPMI 1640 medium containing only 10% FCS. The macrophage-like T cells rosetted with sheep red blood cells and proliferated when stimulated with phytohemagglutinin or anti-CD3, indicating functional T cell responses. CONCLUSION: Our data indicate that a population of T cells obtained from the SF of a subgroup of patients with JRA exhibited characteristics of macrophages, yet retained their CD3 and T cell receptor expression. Whether this promiscuous behavior is caused by malignant transformation of lymphoid precursor cells or is induced by the concerted effect of a myriad of cytokines and growth factors present in the SF remains unknown. The presence of these cells in the SF of 2 patients with JRA with different onset types raises the question of their function and significance in an autoimmune disorder such as JRA.     

Imaging approaches to the correlation of structure and function in the kidney

OBJECTIVES: To translate into Argentine Spanish and cross-culturally adapt the Childhood Health Assessment Questionnaire (CHAQ) and validate the adapted instrument in Argentine patients with juvenile rheumatoid arthritis (JRA). METHODS: Five bilingual Argentine pediatric rheumatologists translated into Argentine Spanish and cross-culturally adapted the United States English CHAQ. Pretesting was done in a sample of 23 parents using a probe question technique. Parents of 70 patients with JRA and 21 healthy children (controls) participated in the validation phase. All were from Argentina. RESULTS: The mean disability index (DI) scores for patients with systemic, polyarticular, or pauciarticular onset JRA were 0.64, 0.32, and 0.1, respectively. Healthy controls averaged 0.2. Intercomponent correlations were between 0.4 and 0.9, suggesting internal consistency, but also some redundancy. Test-retest reliability, studied at a 1-week interval, was moderate (mean DI 0.44 [in clinic] and 0.29 [one week later], Pearson's correlation = 0.82). We compared CHAQ scores from 15 parents with those of their children > 10 years of age. Significantly higher DI scores were given by patients than their respective parents (P > 0.019), but the pairwise scores (parent-patient) were highly correlated (r = 0.986). CONCLUSIONS: Cross-cultural adaptation of the US CHAQ to Argentina required few changes. Although DI scores for all patient subgroups were higher than for controls subjects, the scores were low, particularly for those with pauciarticular disease. Prospective studies designed to examine the sensitivity to change and predictive validity will help to assess further the usefulness of the adapted CHAQ in the Argentine population.     

Functional analysis of rheumatoid factor-producing B cells from the synovial fluid of rheumatoid arthritis patients

OBJECTIVE: To understand the regulation of rheumatoid factor (RF) production in rheumatoid arthritis (RA), we studied IgM-RF production by B cells isolated from the synovial fluid (SF). METHODS: Highly purified SF and peripheral blood (PB) B cells were isolated by negative selection in a fluorescence-activated cell sorter (FACS) and then cultured with either L cells, CD40 ligand (CD40L)-transfected L cells, or type B synoviocytes in the presence or absence of interleukin-2 (IL-2), IL-4, or IL-10. Total IgM and IgM-RF were detected after 14 days by enzyme-linked immunosorbent assay. Enzyme-linked immunospot assays were performed to detect cells that spontaneously produced immunoglobulin. SF B cells were also phenotypically characterized by FACS analysis. RESULTS: Terminally differentiated CD20-,CD38+ synovial plasma cells (PC) present in the SF of RA patients secreted IgM-RF in the absence of a stimulus. IgM-RF production markedly increased when SF B cells were cultured in the presence of type B RA synoviocytes together with IL-10, but independently of CD40-CD40L interaction. Although CD20-,CD38+ PC could also be demonstrated in SF B cells from patients with other forms of arthritis, IgM-RF production was restricted to the SF B cell cultures of patients with seropositive RA. The frequency of IgM-RF-producing cells among IgM-producing PC in patients with seropositive RA was estimated to be as much as 50%. CONCLUSION: These data demonstrate that terminally differentiated CD20-,CD38+ IgM-RF-producing B cells are specifically present in the inflamed joints of patients with seropositive RA. There is evidence that the local environment in the rheumatoid joint favors RF production. The relatively high frequency of IgM-RF PC in the SF B cell population provides evidence of a dominant RA-specific antigen-driven response in the development of the synovial PC repertoire.     

Patterns of cytokine production in psoriatic synovium

OBJECTIVE: To determine patterns of cytokine production and mRNA expression in synovium from patients with psoriatic arthritis (PsA) and to compare the profile of cytokine production in PsA explants with those derived from rheumatoid (RA) and osteoarthritic (OA) synovia and psoriatic skin. METHODS: Cytokine levels were measured in supernatants from synovial and dermal explant cultures at Day 10 by ELISA. Cytokine mRNA expression in PsA whole tissue was determined by multi-gene assay. Cytokine levels in explant supernatants were compared between PsA, RA and OA, and psoriatic skin. Synovial tissues were scored histologically by a pathologist blinded to the clinical diagnosis. RESULTS: PsA explants released elevated levels of interleukin (IL)-1beta, IL-2, IL-10, interferon (IFN)-gamma, and tumor necrosis factor (TNF)-alpha, but not IL-4 or IL-5. A similar pattern of gene expression was detected in whole synovial tissue. These cytokine levels were greater in PsA than RA, despite higher histopathologic scores in RA explants. Production of IL-1beta, IFN-gamma, and IL-10 were strongly correlated. Levels of IFN-gamma, IL-1beta, and IL-10 were higher in psoriatic synovium than psoriatic dermal plaques. CONCLUSION: The cytokine profile in PsA is characterized by the presence of Th1 cytokines and the monokines TNF-alpha and IL-1beta and very elevated levels of IL-10. The higher levels of these cytokines in PsA compared to RA suggest the presence of different underlying mechanisms.     

High expression of V gamma 8 is a shared feature of human gamma delta T cells in the epithelium of the gut and in the inflamed synovial tissue

We have analyzed the V-gene usage in gamma delta T cells of the human gut and joint by using a new mAb (B18) specific for V gamma 8 of human TCR-gamma delta+ T cells. The B18+ population constituted a minor subset of the gamma delta T cells in peripheral blood (PB) of healthy persons (6 +/- 5%) and only 1 of 35 gamma delta T cell clones analyzed was positive. In contrast, the B18+ subset was a dominant gamma delta T cell population among intraepithelial lymphocytes (IEL) derived from the human intestine (74 +/- 29, p < 0.002), and two of three IEL clones from patients with coeliac disease were B18+. Interestingly, a higher proportion of B18+ gamma delta T cells was found in the synovial fluid of patients with rheumatoid arthritis (RA) (21 +/- 18%, 0.02 < p < 0.05) compared with normal PB. Furthermore, the B18+ subset was more frequent among IL-2-expanded gamma delta T cells (42 +/- 20%) derived from synovial tissue than among IL-2-expanded cells derived from synovial fluid (p < 0.002) and PB from RA patients (p < 0.02) as well as normal PB (p < 0.002). The V-gene usage of 13 gamma delta T cell clones from the synovial fluid of arthritic patients was analyzed. All B18+ clones (n = 7) expressed mRNA for V gamma 8 together with mRNA for V delta 1 (n = 5) or mRNA for V delta 3 (n = 2). None of the B18- clones expressed V gamma 8 (n = 6). We conclude that the gamma delta T cell that expresses V gamma 8, together with mainly V delta 1, is a major gamma delta T cell subset among the IEL of the gut and a highly frequent subset in the synovial tissue of patients with RA. This subset may correspond to the mouse V gamma 7+ IEL, which has a high degree of amino acid sequence homology with the human V gamma 8 protein.