Gamma/delta T cells in placenta and skin: their different functions may support the paradigm of microchimerism in systemic sclerosis.

Increased amounts of foetal cells persisting after pregnancy could be involved in the pathogenesis of systemic sclerosis (SSc) and other autoimmune diseases. Evidence suggests a specific role for a subset of T lymphocytes showing the gamma/delta T cell receptor (TCR) at the foetal/maternal interface. gamma/delta T cells significantly increase in the early pregnancy decidua and recognize trophoblast antigens, probably a highly evolutionarily conserved molecule such as Hsp60 or Hsp60-derived peptides, and are likely to suppress the maternal anti-foetal immune response via TGFbeta production, thus contributing to pregnancy maintenance. The similarity between the presence of host gamma/delta T cells in pregnancy decidua and in SSc skin suggests that the functional activities of these cells can be differentially modulated by several mechanisms including the nature of the antigen and the involved organs. To support pregnancy, the decidual microenvironment might induce a Th2 activity of host Vdelta1 + T cells. On the contrary, either the presence of foetal cells in the skin of SSc patients or an as yet unidentified stimulus (i.e. infections), may trigger Vdelta1 + T cells toward the Th1 phenotype with the subsequent activation of cytotoxicity and modulation of the cytotoxic alpha/beta acquired T cell response. On these grounds, understanding the mechanisms which prevent the maternal immune system from rejecting a semiallogenic foetus could be helpful to understand the development of some autoimmune diseases, and potentially to develop new targeted therapeutic strategies.

Infliximab in spondyloarthropathy associated with Crohn's disease: an open study on the efficacy of inducing and maintaining remission of musculoskeletal and gut manifestations.

OBJECTIVE: To evaluate the efficacy and tolerability of anti-tumour necrosis factor alpha (TNFalpha) monoclonal antibody (infliximab) in the treatment of spondyloarthropathy (SpA) associated with active and inactive Crohn's disease (CD). METHODS: Twenty four patients with SpA associated with active or inactive CD (16 active, 8 quiescent) were treated with anti-TNFalpha monoclonal antibody (infliximab) with repeated infusions for a period of 12-18 months. The treatment aimed at ameliorating the general musculoskeletal and spinal pain, controlling peripheral arthritis and enthesitis, decreasing the BASDAI score, modifying acute phase reactants, and reducing CD activity. RESULTS: Infliximab improved both gastrointestinal (p<0.01) and overall articular symptoms (BASDAI, p<0.01; general musculoskeletal and spinal pain, p<0.01; peripheral arthritis, p<0.01) in patients with active CD. Additionally, infliximab effectively controlled not only axial involvement and peripheral arthritis but also enthesitis (p<0.01) and prevented inflammatory bowel disease reactivation in patients with inactive CD and low inflammatory markers. Amelioration of gut and musculoskeletal involvement persisted for up to 12 months. CONCLUSION: Infliximab may act on the inflammation of entheses and of periarticular structures, which usually does not cause a change in the haematological markers that are the main indicators of pain and joint ankylosis in SpA. Infliximab induces and maintains remission of CD while at the same time treating active and severe SpA, suggesting that it should be the preferred drug for the treatment of active and severe SpA associated with active or quiescent CD.

Combination therapy with cyclosporine and methotrexate in patients with early rheumatoid arthritis soon inhibits TNFalpha production without decreasing TNFalpha mRNA levels. An in vivo and in vitro study.

OBJECTIVE: To evaluate the ability of two different combination therapies with prednisone (PDN), methotrexate (MTX) and cyclosporine (CSA) to modulate both TNFalpha transcription and production in early rheumatoid arthritis (RA). METHODS: 24 patients with early RA received a step-down bridge therapy with MTX and PDN (group A). Twelve patients out of the 24 randomly received also CSA (group B). Blood samples and peripheral blood mononuclear cells (PBMC) were collected at different times. TNFalpha levels were measured both in sera and in PBMC supernatants. TNFalpha mRNA was assessed by use of RT-PCR. RESULTS: 10 patients in group A and 9 in group B improved. At baseline, RA patients serum TNFalpha levels were increased compared to controls (p < 0.001) and did not correlate with clinical and serological parameters. These levels decreased within the first month of therapy in both groups, the lower levels being observed in the sera of CSA treated patients. After 30 days of therapy, TNFalpha levels in group B supernatants were significantly lower than those observed in group A, both after 24 and 48 hours of PHA stimulation (p < 0.03 and p < 0.05 respectively). TNFalpha mRNA levels never differed between patients and controls, independently of both the clinical picture and the assigned therapy. CONCLUSION: The addition of CSA to a treatment regimen of PDN + MTX lowers TNFalpha production in vitro without decreasing TNFalpha mRNA expression. This effect could help to induce early immunosoppressive and therapeutic effects during RA.

Circulating gamma/delta T lymphocytes from systemic sclerosis (SSc) patients display a T helper (Th) 1 polarization.

Systemic sclerosis (SSc) is a connective tissue disease in which immune system activation is evidenced by high levels of different cytokines in the sera and/or in the supernatants of cultured peripheral blood mononuclear cells (PBMC) and by the presence of specific autoantibodies. gamma/delta T cells accumulate in the lung and the skin of SSc patients suggesting their potential role in the development and maintenance of the disease. The aim of this study was to assess cytokine production and cytotoxic activity of circulating gamma/delta T lymphocytes obtained from SSc patients and to evaluate their potential role during this disorder. Our results showed that both the proportion and the absolute number of IFN-gamma gamma/delta-producing cells (i.e. displaying a Th1 polarization) in SSc was significantly higher than either the proportion and the absolute number of IL-4 gamma/delta-producing cells in SSc or the proportion and the absolute number of IFN-gamma gamma/delta-producing cells in healthy controls (P < 0.05 for both groups). Furthermore, the cytotoxic activity of enriched gamma/delta T cells was significantly increased in SSc patients compared with controls. The results concerning the Vdelta1+ T cell subset paralleled those of total gamma/delta T lymphocytes. In contrast, alpha/beta T cells from SSc and control subjects displayed Th2 cytokine production. All these findings were independent of both disease subset and clinical status. Our data demonstrate that, although SSc is generally considered a Th2 autoimmune disease, Th1 polarization of gamma/delta T cells and an increase in their cytotoxic activity is observed in SSc, suggesting that gamma/delta T cells could have a relatively autonomous role in the pathogenesis in this disease.