Association of FOXP3 regulatory gene expression with systemic lupus erythematosus disease activity among Egyptian patients.

The concept that regulatory T cells (Treg) play a key role in both development and maintenance of autoimmune response in rheumatological diseases is well accepted. In recent years, several studies analyzed Treg cell phenotype and function in systemic lupus erythematosus (SLE), the prototypical systemic autoimmune disorder in humans. The forkhead family transcription factor FOXP3 currently represents the most specific marker molecule for T cells with suppressive/regulatory capacity (Treg). Using real-time polymerase chain reaction, we quantified messenger RNA (mRNA) expression of FOXP3 in peripheral blood mononuclear cells (PBMCs) of 19 subjects with active SLE, 16 with inactive lupus and 20 healthy subjects. Relative FOXP3 gene expression was assessed by the comparative CT method in which FOXP3 gene expression was normalized to GAPDH gene expression in each sample. Our preliminary investigations demonstrated higher FOXP3 expression in active SLE patients as compared to inactive SL E (median 8.83 and interquartile range 0.74-347.0 versus 0.426 and 0.04-3.93 respectively; P < 0.05). Compared to the control group (median of 0.01 and IQR 0.011-0.07), both active and inactive SLE patients showed increased expression for FOXP3 with P value < 0.01, respectively. In the active group, FOXP3 mRNA level correlated positively with disease activity as assessed with the SLEDAI index. However, this correlation did not reach statistical significance (r = 0.122; P = 0.08).