Flowcytometric study of expression of perforin and CD134 in patients with systemic lupus erythematosus

Perforin is a membrane-disrupting protein that allows the entry of granzymes into a target cell inducing degradation of target substances in the cytoplasm and nucleus thus leading to programmed cell death or apoptosis. CD134 was originally described as an activation antigen found on activated T cells. In this work Flowcytometry was used to evaluate the expression of perforin and CD134, as a costimulatory molecule on T cells, in patients with Systemic Lupus Erythematosus (SLE) to elucidate their role in the pathogenesis of SLE and disease severity. The study was conducted on 15 patients with SLE, 6 patients out of the 15 patients were suffering from lupus nephritis, 10 healthy subjects were included as controls. The results revealed that absolute number of circulating CD3+ lymphocytes in the patients was significantly lower than the controls (P = 0.013). The percentage of CD8+ CD3+ T cells was significantly increased in the SLE group when compared to that of CD4+ CD3+ T cells in same group (P = 0.001) Perforin expression on both CD4+ and CD8+ cells was significantly increased in patients compared to controls. (P = 0.002 & P = 0.001, respectively). In addition, a significant increase was observed in the percent of pf+CD8+CD3+ in the patient group compared to that of pf+CD4+CD3+ in the same group (P = 0.001). There was a significant increase in the expression of CD134 on CD4+ and CD8+ cells (P = 0.001 & P = 0.001 respectively). Also, in the same group of patients a significant increase was detected in the frequency of CD134+CD4+CD3+ T cells compared to that of CD134+CD8+CD3+ T cells (P = 0.032). A significant positive correlation was detected in the patient group between CD134 and perforin expression on both CD4+ and CD8+ T cells (p = 0.045, r = 0.523). Moreover, CD134+CD4+CD3+ was also correlated positively with urinary proteinuria (P = 0.023, r = 0.524). Our data suggest the role of Perforin + cytotoxic T lymphocytes and CD134+ cells in the pathogenesis of autoimmunity of SLE. Thus, inhibition of perforin could be beneficial for SLE patients. Targeting pf and CD134 could be a new therapeutic approach in patients with SLE.