Lymphocytes Tγδ in clinically normal skin and peripheral blood of patients with systemic lupus erythematosus and their correlation with disease activity

HUMAN T gamma delta lymphocytes constitute from 1 to 15% of all peripheral blood lymphocytes. Recent work has demonstrated that this population plays a major role in the pathogenesis of Infectious and immune diseases. Increased numbers of gamma delta T cells have been found in affected skin from systemic sclerosis and chronic cutaneous lupus erythematosus patients. In our study, we have determined the numbers of T gamma delta lymphocytes and their subpopulations in peripheral blood from 29 patients with systemic lupus erythematosus (SLE) and in 19 healthy volunteers using flow cytometry and specific monoclonal antibodies. The same cells in uninvolved skin from SLE patients and human controls using immunohistochemical analysis were estimated. T-Cell receptor (TCR) delta chain gene rearrangement was identified with primers for V delta1, V delta2 and V delta3 by the polymerase chain reaction. Statistical analysis showed a significantly decreased number of gamma delta T cells in SLE patients (26.4 +/- 16.9/mul) compared with the control group (55.3 +/- 20.6/mul) (P<0.001). The number of V<delta>2 TCR+ and V gamma9 TCR+ subpopulations was also lower in SIE patients than in healthy persons. No statistical correlation between disease activity and the number of gamma delta T cells was demonstrated. The percentage of T gamma delta lymphocytes in clinically normal skin from SLE patients was twice (22.0 +/-9.4%) that found in the skin from healthy persons (11.1 +/-5.5%) (p<0.002). Higher percentages of the V<delta>2 TCR+ and V gamma9 TCR+ subpopulation of lymphocytes were found in the skin from SLE patients. We have also found positive correlation between the percentage of T gamma delta lymphocytes in skin and the activity of SLE (r=0.594, p<0.001), and between subpopulation V<delta>3 TCR+ and disease activity (r=0.659, p<0.001). In conclusion, the results of our studies demonstrate that, in patients with SIE, accumulation of T<gamma>delta lymphocytes can be seen in clinically normal skin, and the percentage of these cells correlates with the activity of the disease.