Do high sensitivity C-reactive protein and serum interleukin-6 levels correlate with disease activity in systemic lupus erythematosuspatients?

INTRODUCTION Systemic Lupus Erythematosus (SLE) is an inflammatory autoimmune disease where an interplay between acute phase proteins and cytokines are involved in disease activation. AIM AND OBJECTIVES This case control study was performed to investigate interrelationship between high sensitivity C-reactive proteins (hs-CRP), Interleukin-6 (IL-6) levels and disease activity among SLE patients. MATERIALS AND METHODS One hundred forty one clinically diagnosed SLE cases were included and disease activity was noted by SLE Disease Activity Index (SLEDAI). Serum IL-6 levels were measure by cytokine multiplex assay. Serum hs-CRP, C3 and C4 levels were measure by nephelometer. The Pearson correlation test was used for correlation between hs-CRP, Il-6 and SLEDAI. RESULTS Based on SLEDAI, 126 patients (89.4 %) had active disease and 15 patients (10.6%) had inactive disease. Mean hs-CRP levels in SLE patients were significantly higher (12.1+ 11.5 mg/L) than controls (2.41+ 1.37 mg/L) (P < 0.0001). Hs-CRP levels among active SLE were significantly higher (13.5+ 11.4 mg/L) as compared with inactive SLE (4.4 + 2.9 mg/L) (P=0.0002). Similarly, IL-6 levels in SLE patients were significantly higher among active SLE (26.9 + 15.5 pg/ml) as compared with inactive SLE (13.9+ 10.2 pg/ml) (P=0.0001). An inverse correlation between Il-6 and hemoglobin levels between active and inactive SLE was noted (r=-0.46, P <0.0001). CONCLUSION This study suggests a good correlation between hs-CRP, IL-6 and SLE disease activity indicating their direct involvement in inflammatory conditions associated with disease.