Expression of PD-1hiCXCR5-CD4+ T cells in patients with systemic lupus erythematosus

Objective To investigate the expression of peripheral programmed death (PD)-1hiCXCR5- CD4+ T cells and its clinical significance in systemic lupus erythematosus (SLE). Methods Peripheral blood PD-1hiCXCR5-CD4+ T cells from 21 SLE patients and 16 healthy controls were examined by flow cytometry. The levels of serum anti-double-stranded deoxyribonucleic acid (dsDNA) antibodies were determined using immunoradiometric as-say. Data were analyzed with t test and Pearson's correlation test. Results The per-centages of PD-1hiCXCR5- cells within CD4+ T cell were significantly higher in SLE patients [(2.1±2.0)%] compared to normal controls [(0.3±0.3)%] (t=2.959, P<0.01). The percentages of PD-1hiCXCR5- cells within CD4+ T cells in moderate to severe active SLE patients (3.0±2.0)% was significantly increased compared to patients with mild or inactive (1.0±1.4)% (t=2.574, P<0.05) and normal controls (0.3±0.3)% (t=5.149, P<0.01). The percentages of PD-1hiCXCR5- cells within CD4+ T cells from SLE patients were positively related with systemic lupus erythematosus disease activity index (SLEDAI) (r=0.475, P=0.0297). SLE patients in serum anti-dsDNA antibodies positive group (2.7±2.1)% displayed a higher percentage of PD-1hiCXCR5- cells within CD4+ T cells than patients in serum anti-dsDNA antibodies negative group (0.6±0.5)% (t=2.303, P<0.05). The percentages of PD-1hiCXCR5- cells within CD4+ T cells from SLE patients were positively correlated with anti-dsDNA antibody titers. Conclusion The percentages of PD-1hiCXCR5- cells within CD4+ T cells from SLE patients are increased and are positively correlated with SLEDAI and anti-dsDNA antibody levels. Increased percentage of PD-1hiCXCR5- cells within CD4+ T cells might play an important role in the pathogenesis of SLE. Key words: Lupus erythematosus, systemic; Programmed death-1hiCXCR5-CD4+ T cells; Systemic lupus erythem-atosus disease activity index; Aanti-double-stranded deoxyribonucleic acid antibodies