Measurement of natural (CD4+CD25high) and inducible (CD4+IL-10+) regulatory T cells in patients with systemic lupus erythematosus

<jats:p>Abnormalities of regulatory T cells may play an important role in the loss of self-tolerance, which is a major characteristic of lupus. The objective of this study was to determine the ratio and the number of natural CD4+CD25highFoxp3+ and inducible CD4+IL-10+ regulatory T cells in lupus patients and to search correlation with disease activity. Seventy-two Hungarian lupus patients were enrolled in the study. Fourty-one age- and sex matched healthy donors served as controls. Flow cytometry was used for the quantification of CD4+CD25high Foxp3+ (nTreg) and CD4+IL-10+ (iTreg) cells. The ratio (3.06 ± 1.45%) and the number (0.019 ± 0.012 × 109/L) of nTreg cells decreased in lupus significantly ( P < 0.001 in both) as compared to normal controls (4.26 ± 1.01% and 0.039 ± 0.017 × 109/L). The ratio of iTreg cells were significantly higher in patients than in controls (20.92 ± 14.02% versus 15.49 ± 11.65%, P < 0.03), but the number of these cell type did not differ in significant manner (0.314 ± 0.236 × 109/L versus 0.259 ± 0.183 × 109/L). The 19 active patients were characterised by significantly higher disease activity index (SLEDAI 8.63 ± 2.95 versus 1.74 ± 1.68, P < 0.001) and anti-DNA concentration (117.85 ± 145.89 versus 37.36 ± 68.85 IU/mL, P = 0.001) as compered to the 52 inactive patients. Furthermore, active patients required higher dose of methylprednisolon than inactive ones (14.8 ± 10.6 versus 4.8 ± 3.4 mg/day, P < 0.001). However, we did not find statistical significant difference in the number and ratio of the examined cell populations regarding to disease activity. Altered ratio and number of both natural and inducible regulatory T cells may play a role in the pathogenesis of lupus. There are small but appreciable difference in the number of regulatory T cells between inactive patients and healthy controls. It suggests that immunoregulatory deficiencies are present in the inactive stage of the disease also. Lupus (2007) 16, 489—496.</jats:p>