Study of blood and renal Janus kinase 3 expression in pediatric systemic lupus erythematosus: a potential therapeutic target

Background: Janus kinase 3 (JAK3) is a member of the JAK family which plays an important role in cytokine signal transduction. Dysregulation of JAK pathway has been linked to several autoimmune disorders including systemic lupus erythematosus (SLE). This study aimed to evaluate the expression of JAK3 among pediatric SLE (pSLE) patients.Patients and Methods: Forty-six children and adolescents with active SLE were recruited from the Pediatric Rheumatology Unit, Assiut University. All patients were subjected to clinico-laboratory evaluation as well as assessment of SLE status using SLE disease activity index (SLEDAI). Blood and renal JAK3 expression were assessed using quantitative polymerase chain reaction (q-PCR) and enzyme-linked immunosorbent assay (ELISA) in all patients as well as 20 age-and gender-matched healthy controls and in 26 patients with biopsy-proven lupus nephritis (LN) respectively. Results: The mean (SD) age of the studied patients was 12.2 (2.4) years, they were 34 females (74%) and 12 males (26%). Blood JAK3 expression both by ELISA and q-PCR were significantly higher among pSLE patients as compared to healthy controls (p<0.000). Both blood and renal JAK3 expression were significantly positively correlated with anti-double stranded-DNA and SLEDAI and were significantly negatively correlated with serum complement 3 (p <0.000). Renal JAK 3 expression was significantly positively correlated with 24-hour urinary proteins and urinary RBCs (p<0.000).Conclusion: The increased JAK 3 expression among pSLE patients and its strong association with validated parameters of SLE activity could make it a potential therapeutic target for pSLE patients especially those with LN.