Prevalence of ZAP-70, LAT, SLP-76, and DNA methyltransferase 1 expression in CD4+ T cells of patients with systemic lupus erythematosus

T cells from systemic lupus erythematosus (SLE) patients exhibit defective function of CD4(+) T cells that can be responsible for improper activation of B cells and antibody biosynthesis against host antigens. We compared the level of ZAP-70, LAT, and SLP-76, transcripts and proteins in CD4(+) T cells from SLE patients (n=22) and healthy individuals (n=15). We also determined DNA methyltransferase 1 (DNMT1) protein content in CD4(+) T cells of SLE patients. The CD4(+) T cells were isolated by positive biomagnetic separation technique. The quantitative analysis of messenger RNA (mRNA) was performed by reverse transcription and real-time quantitative polymerase chain reaction (RQ-PCR) SYBR Green I system. The protein level in the CD4(+) T cells was determined by Western blotting analysis. We found that the LAT protein level was significantly higher in SLE CD4(+) T cells than in controls (P=0.006). Western blot analysis revealed that ZAP-70 protein content in SLE CD4(+) T cells may be reciprocally correlated with disease activity expressed in SLEDAI scale (R=-0.623, P=0.002) or number of affected organ systems (R=-0.549, P=0.008). We also observed reciprocal correlation between DNMT1 protein content in CD4(+) T cells and disease activity scored with SLEDAI scale (R=-0.779, P=0.001) or number of affected organ systems (R=-0.617, P=0.019), respectively. Our findings might indicate that LAT, ZAP-70, and DNMT1 protein levels in CD4(+) T cells can be associated with SLE disease.