Clinical significance of interleukin-36 alpha and gamma in systemic lupus erythematosus patients: Potential relation to disease activity and subclinical arthritis

Abstract

Aim of the work

To assess serum of interleukin-36 alpha (IL-36α) and interleukin-36 gamma (IL-36γ) levels in systemic lupus erythematosus (SLE) patients and to explore their association with clinical and laboratory features of SLE and with ultrasound evidence of subclinical hand arthritis.

Patients and methods

The study included 84 SLE patients without overt arthritis and 84 matched controls. The serum levels of IL-36α and IL-36γ were measured and compared between patients and controls. The hands and wrists of all patients underwent musculoskeletal ultrasound evaluation for evidence of subclinical arthritis and tenosynovitis. The SLE disease activity score was assessed for all patients.

Results

The mean of serum IL-36α (65.5 ± 38.9 pg/ml) and IL-36γ (468.9 ± 315.9 pg/ml) were significantly higher in SLE patients compared to controls (37.9 ± 17.2 pg/ml and 151.1 ± 73.4 pg/ml; p < 0.001 each). IL-36α and IL-36γ had the ability to discriminate between SLE patients and controls with an AUC of 0.69 and 0.83 respectively. Serum IL-36α was significantly correlated with SLEDAI score (p = 0.04), synovitis (p < 0.001),Us erosion score (p = 0.01) and PD signals score (p = 0.002). Serum IL-36γ was significantly correlated with serum creatinine level (p = 0.04). SLE patients with arthralgia had significantly higher IL-36α serum level than patients without (p = 0.04). SLE patients with proteinuria had significantly higher IL-36γ than those without (p = 0.04). The linear regression analysis model revealed that the US evidence of synovitis was the strongest factor associated with the serum level of IL-36α meanwhile proteinuria was the strongest factor associated with the serum level of IL-36γ.

Conclusion

IL-36αserum level was significantly associated with SLEDAI score, arthralgia and US evidence of subclinical arthritis. IL-36γ serum level was significantly associated with proteinuria.