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Objective: To investigate the expression and release of HLA-G and HLA-E in JIA., Methods: Soluble (s)HLA-G and HLA-E were measured in sera from 58 JIA patients and 54 healthy donors. Surface expression of HLA-G, HLA-E and immunoglobulin-like transcript (ILT)2 and ILT4, two receptors for HLA-G, was assessed on T, B cells and monocytes from peripheral blood (PB) and SF of 12 JIA patients and from PB of 12 controls., Results: Serum sHLA-G concentration was significantly lower in patients than in controls. Both sHLA-G and sHLA-E were detected in SF and sHLA-E concentration in SF was higher in extended oligoarticular/polyarticular than in limited oligoarticular JIA. Patients compared with controls showed: (i) down-regulation of HLA-E and ILT2 expression on T cells; (ii) up-regulation of HLA-E expression on B cells and monocytes; and (iii) down-regulation of ILT4 expression on monocytes. Comparing JIA patients' SF and PB we found: (i) up-regulation of HLA-E and ILT2 expression in T and B cells and monocytes; and (ii) down-regulation of ILT4 expression in monocytes. ILT4 was up-regulated in monocytes from oligoarticular extended/polyarticular compared with oligoarticular limited JIA., Conclusions: A lower concentration of sHLA-G in sera may predispose to JIA, as observed for other autoimmune diseases. sHLA-E concentration in SF correlate with the number of affected joints. Higher ILT2 expression on SF cell populations compared with PB may be related to high sHLA-G concentration in SF. Higher HLA-E expression in SF than in PB cell populations may protect them from NK cytolysis.

The aim of the study was to characterise CCR7+ and CCR7- memory T cells infiltrating the inflamed joints of patients with juvenile idiopathic arthritis (JIA) and to investigate the functional and anatomical heterogeneity of these cell subsets in relation to the expression of the inflammatory chemokine receptors CXCR3 and CCR5. Memory T cells freshly isolated from the peripheral blood and synovial fluid (SF) of 25 patients with JIA were tested for the expression of CCR7, CCR5, CXCR3 and interferon-gamma by flow cytometry. The chemotactic activity of CD4 SF memory T cells from eight patients with JIA to inflammatory (CXCL11 and CCL3) and homeostatic (CCL19, CCL21) chemokines was also evaluated. Paired serum and SF samples from 28 patients with JIA were tested for CCL21 concentrations. CCR7, CXCR3, CCR5 and CCL21 expression in synovial tissue from six patients with JIA was investigated by immunohistochemistry. Enrichment of CD4+, CCR7- memory T cells was demonstrated in SF in comparison with paired blood from patients with JIA. SF CD4+CCR7- memory T cells were enriched for CCR5+ and interferon-gamma+ cells, whereas CD4+CCR7+ memory T cells showed higher coexpression of CXCR3. Expression of CCL21 was detected in both SF and synovial membranes. SF CD4+ memory T cells displayed significant migration to both inflammatory and homeostatic chemokines. CCR7+ T cells were detected in the synovial tissue in either diffuse perivascular lymphocytic infiltrates or organised lymphoid aggregates. In synovial tissue, a large fraction of CCR7+ cells co-localised with CXCR3, especially inside lymphoid aggregates, whereas CCR5+ cells were enriched in the sublining of the superficial subintima. In conclusion, CCR7 may have a role in the synovial recruitment of memory T cells in JIA, irrespective of the pattern of lymphoid organisation. Moreover, discrete patterns of chemokine receptor expression are detected in the synovial tissue.

Objective: CD27 is a member of tumour necrosis factor receptor family. Its expression is predominantly confined to mature lymphocytes and is strongly enhanced after cell activation. Shedding of the CD27 from the surface of activated cells is related to their effector phase. The aim of the present study was to evaluate the levels of soluble CD27 in sera and synovial fluids, together with its expression on circulating and synovial fluid (SF) memory T cells, in children with JIA., Methods: Sera from 40 patients with active JIA were studied for soluble CD27. Paired SF samples were available in 20 patients. Sera from 12 age-matched patients affected with various acute infectious diseases and 12 age-matched healthy subjects were used as controls. In 8 JIA patients freshly isolated circulating and SF lymphocytes were stained for CD27 in CD4+CD45 RO+ T cell subpopulation and analyzed by cytometry., Results: Soluble CD27 serum levels were significantly higher in patients with polyarticular JIA and acute systemic infectious diseases than in patients with active oligoarticular or healthy controls. Both polyarticular and oligoarticular JIA patients showed increased levels of soluble CD27 in SF when compared with paired serum samples (p = 0.01). In all the patients tested a significant enrichment of CD27- T cells was seen in the SF (median 39.5%, range 18-56%) when compared to paired CD4+CD45RO+ peripheral lymphocytes (median 19.5%, range 5-43%; p = 0.01)., Conclusions: A clear enrichment of CD4+ memory SF T cells with a CD27-phenotype is observed when compared to correspondent circulating T lymphocytes. This issue is conceivably related to re-activation and recruitment of memory T cells to the site of inflammation, and to the subsequent expansion of a subpopulation of "effector" memory T cells.

The aim of the present study was to investigate the patterns of cytokine production by T cell clones raised from in vivo activated synovial fluid (SF) mononuclear cells (MNC) of five patients with oligoarticular juvenile arthritis (JA). Freshly isolated SF T cells were cultured in vitro with low dose recombinant IL-2 and subsequently cloned by limiting dilution. Sixty-four clones were obtained from the five patients studied. Fifty-nine clones were TCR alpha/beta+, either CD4+ (n = 43) or CD8+ (n = 15). The remaining five clones were TCR gamma/delta+, CD4-, CD8-. Clone immunophenotypes differed in the individual patients. Forty-four T cell clones were stimulated with phytohaemagglutinin (PHA) and phorbol myristate acetate (PMA) and supernatants tested for the presence of IL-2, IL-4, IL-5 and interferon-gamma (IFN-gamma) by ELISA or bioassays. Cytokine mRNA accumulation was tested by reverse transcriptase-polymerase chain reaction (RT-PCR). Most of 44 clones tested released large amounts of IFN-gamma irrespective of the immunophenotype. Of these, 27 were classified as Th1-type and 17 as Th0-type based upon the IFN-gamma/IL-4 ratio in culture supernatants. Finally, when 10 representative T cell clones were tested for pro- and anti-inflammatory cytokines, gene expression by RT-PCR, all of them were found to express the granulocyte-macrophage colony-stimulating factor (GM-CSF), tumour necrosis factor-alpha (TNF-alpha), IL-10 and transforming growth factor-beta 1 (TGF-beta1) genes, and half of them IL-6 and IL-8 mRNA. In conclusion, T cell clones, that represent the progeny of in vivo activated SF T cells from oligoarticular JA patients, display heterogeneous immunophenotypes, but all share the ability to produce large amounts of IFN-gamma, with a predominant Th1/Th0 pattern. The expression of pro- and anti-inflammatory cytokine genes in these clones suggests that in vivo activated SF T cells modulate joint inflammation in a complex fashion.