Elevated serum interleukin-34 level in juvenile systemic lupus erythematosus and disease activity

To determine the role of Interleukin-34 (IL-34) in the pathogenesis of juvenile systemic lupus erythematosus (J-SLE), by exploring the relationship between IL-34 concentration and the disease activity SUBJECTS AND METHODS: This study was carried out on 48 children with SLE, and 30 healthy control subjects. SLE disease activity was measured by systemic lupus erythematosus disease activity index (SLEDAI). Serum IL-34 was measured by enzyme-linked immunosorbent assay (ELISA). The collected data were statistically analyzed using SPSS program version 16.0.

There was a significant elevation in IL-34 concentration in J-SLE patients (52.25 ± 19.94 pg/ml) compared with control group (11.20 ± 6.40 pg/ml) (p < 0.001). The highest level was detected in patients with high SLEDAI score and with lupus nephritis (p = 0.005, 0.003, respectively). There was a statistically significant positive correlation between IL-34 levels and SLEDAI, ESR, CRP, and anti-ds DNA antibodies, but negative correlation with complement (C3, C4), and hemoglobin levels in J-SLE patients.

IL-34 could be a probable marker for J-SLE disease activity which is more aggressive than adult-SLE, and IL-34 blockage may suppress the expression of proinflammatory cytokines in patients' blood.Key Points•Juvenile SLE is more aggressive and of worse prognosis than adult-SLE.• Significantly elevated concentration of IL-34 in juvenile SLE patients when compared with controls.• Elevated concentrations of IL-34 in patients are correlated with SLEDAI, ESR, CRP, ds-DNA antibodies, hemoglobin, and complement levels.• IL-34 may play a role in SLE pathogenesis and disease activity.