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Apoptosis of lymphocytes in SLE: the level, correlation with prednisolone dosage and lymphocyte phenotypes
Abstract
Patients and methods: The study included 34 Russian children patients with SLE in age between 6-17 years old. Lymphocytes were isolated from venous blood by method of gradient centrifugation of all the blood through a Ficoll-pak solution. The quantity apoptotic cells was determined in leukocytes by flow cytometry Epics XL-2 (“Beckman Coulter”, USA). Analysis of lymphocyte subpopulations was carried by using two fluorescent labels: FITC conjugated monoclonal antibodies (CD-25 and CD-20) and phycoerythrin conjugated monoclonal antibody (CD-3, CD-4 and CD-8).
Results: After in vitro incubation in CO2 incubator for 36hr; the percentage of apoptotic lymphocytes from patients with SLE was significantly higher than from healthy donors (7.2* ± 4.7 % vs. 5.5 ± 3.2% respectively). This was found to be depending upon the SLE disease activity. Moreover, observed correlations between level apoptosis lymphocyte in SLE and the titer of antibodies to dsDNA (r = 0.5) and dosage prednisolone (r = 0.6). By analyzing lymphocyte phenotypes; there was no significant difference in percentage of CD3+T-cells from SLE compared to normal donors (62.4±7.2 vs. 68.7±9.9.); the same had been observed in CD8+ T-cells (20.9±5.5 vs. 25.3±5.6); and in CD20+ B-cells (9.7±8.9 vs. 13.7±8.0). However, the percentage of CD4+T cell was significantly decreased (P = 0,001) in patients with SLE compared to normal donors (25.5*±7.3 vs. 40.6±8.7). The immunoregulatory index was decreased in SLE compared to normal donors (1.2 vs 1.6 respectively). This phenotypes disbalance was associated with significant increased in the level of activated CD25+ lymphocytes in SLE compared to normal healthy donors.
Keywords: SLE, apoptosis, lymphocyte phenotypes, prednisolone, dsDNA autoantibodies, flow cytometry
Sudan Journal of Medical Sciences Vol. 1(1) 2006: 14-19