Programmed death 1 (PD-1) serum level and gene expression in recent onset systemic lupus erythematosus patients

Aim of the work: To investigate the potential association of protein programmed death 1 (PD-1) serum level and its gene expression inrecent onset systemic lupus erythematosus (SLE) patients and study its association with the disease activity. Patients and methods: The study included 80 recently diagnosed SLE patients and 80 healthy controls. SLE disease activity index (SLEDAI) was assessed. The serum level of soluble (sPD-1) was assessed by enzyme linked immunosorbent assay (ELISA) and its gene expression level was evaluated by real time-polymerase chain reaction (RT-PCR). Results: They were 68 females and 12 males (F: M 5.7:1) with age 30.8 +/- 8.7 years and disease duration of 3.2 +/- 1.7 months. The sPD-1 and PD-1 gene expression level (folds) were significantly elevated in patients (1280.6 +/- 1448.1 pg/ml and 0.3 +/- 0.06 folds) than controls (109.1 +/- 11.9 pg/ml and 0.03 +/- 0.008 folds) (p < 0.001). A significant correlation was found between sPD-1 and hematuria, pyuria, fever and C3 level (p = 0.01, p = 0.001, p = 0.02, and p = 0.03 respectively), and between PD-1gene expression and psychosis and fever (p = 0.03, p = 0.014). No significant correlation was found between SLEDAI and PD-1 gene expression or sPD-1 level (p = 0.1, p = 0.23 respectively). No significant correlation was found between sPD-1 and PD-1 gene expression levels and the autoantibodies. Conclusion: PD-1 gene expression as well as the serum level of sPD-1 are elevated significantly in recent onset SLE patients denoting that they may have a role in the pathogenesis of the disease while there was no relation to the disease activity. This biomarker may be potentially promising for the development of a novel lupus immunotherapy by targeting the PD-1 pathway. (C) 2021 Egyptian Society of Rheumatic Diseases. Publishing services provided by Elsevier B.V.