Assessment of Proinflammatory Th1 Cytokines (IL18-IFN ) and Th2 Cytokine (IL13) Concentrations in patients with Autoimmune Rheumatic Diseases (Systemic Lupus Erythematosus, Rheumatoid Artharitis and Systemic Sclerosis)

Abstract

Objective: Several cytokines play a role in the production of autoantibodies and the pathogenesis of rheumatic diseases including systemic lupus erythematosus (SLE), rheumatoid arthritis (RA) and systemic sclerosis (SS). This study investigated serum concentration of the proinflammatory Th1 cytokine; IL18 and its inducer IFNg, the study also investigated serum concentration of proinflammatory Th2­ cytokine; IL13, to explain the role of Th1 and Th2 in the pathogenesis of autoimmune rheumatic diseases (SLE, RA and SS) Patients and methods: IL18, IFNg and IL13 levels were evaluated by enzyme linked immunosorbent assay (ELISA). Four groups were included in this study. Group I: Comprised (15) patients of SLE. Group II: Comprised (15) patients of RA. Group III: Comprised (15) patients with SS. Group IV: Control group consisted of (15) sex and age matched healthy controls. Results: Serum levels of IL18 was significantly higher in SLE (3138.200± 1413.096 pg/ml)& RA(3336.667± 921.839 pg/ml) than control group(86.647± 35.370 pg/ml ), while IL18­ in SS had no statistically significant difference between patients (103.634± 50.593 pg/ml) and control group (86.647± 35.370 pg/ml).The cut off level was 257.75 pg/ml . IFNg was significantly higher in SLE patients (5.439±1.430 IU/ml) and RA patients (2.973± 0.598 IU/ml ) than control group(0.580 ± 0.234 IU/ml) ,while IFNg in SS had no statistically significant difference (0.592± 0.245IU/ml) than control group (0.580 ± 0.234 IU/ml) .The cut off level was1.2 IU/ml . As regard IL13 it was significantly higher in SLE patients (55.673±6.892 pg/ml) ,RA patients (59.587±12.183 pg/ml) and SS (61.550± 12.047 pg/ml) than control group (21.427± 7.274 pg/ml ) .The cut off level was 44.4 pg/ml .There was significant positive correlation of IL18/ IL13 and IFNg / IL13 ratio in SLE and RA , while significant negative correlation of IL18/ IL13 and IFNg / IL13 ratio in SS. Conclusion: There was a significant increase of both Th1 cytokines (IL18 and IFNg) and Th2­ cytokine (IL13) in SLE and RA with Th1 predominance,while predominance of Th2­ cytokine (IL13) in SS than Th1 cytokine (IL18 and IFNg). This result suggests that IL18, INFg and IL13 could be involved in the pathogenesis of autoimmune rheumatic diseases.