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

Abstract

Human Tγσ 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 γσ 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 Tγσ 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 Vσ1, Vσ2 and Vσ3 by the polymerase chain reaction. Statistical analysis showed a significantly decreased number of γσ T cells in SLE patients (26.4 Ī 16.9/μl) compared with the control group (55.3 Ī 20.6/μl) (p<0.001). The number of Vσ2 TCR+ and Vγ9 TCR+ subpopulations was also lower in SLE patients than in healthy persons. No statistical correlation between disease activity and the number of γσ T cells was demonstrated. The percentage of T γσ lymphocytes in clinically normal skin from SLE patients was twice (22.0 Ī 9.4%) that found in the skin from healthy persons (11.1 Ī 5.5%) (p<0.002). Higher percentages of the Vσ2 TCR+ and Vγ9 TCR+ subpopulation of lymphocytes were found in the skin from SLE patients. We have also found positive correlation between the percentage of Tγσ lymphocytes in skin and the activity of SLE (r=0.594, p<0.001), and between subpopulation Vσ3 TCR+ and disease activity (r=0.659, p<0.001). In conclusion, the results of our studies demonstrate that, in patients with SLE, accumulation of Tγσ lymphocytes can be seen in clinically normal skin, and the percentage of these cells correlates with the activity of the disease.