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

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 IFN, 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, IFN 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 . IFN was significantly higher in SLE patients (5.4391.430 IU/ml) and RA patients (2.973 0.598 IU/ml ) than control group(0.580 0.234 IU/ml) ,while IFN 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 (55.6736.892 pg/ml) ,RA patients (59.58712.183 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 IFN / IL13 ratio in SLE and RA , while significant negative correlation of IL18/ IL13 and IFN / IL13 ratio in SS. Conclusion: There was a significant increase of both Th1 cytokines (IL18 and IFN) and Th2 cytokine (IL13) in SLE and RA with Th1 predominance,while predominance of Th2 cytokine (IL13) in SS than Th1 cytokine (IL18 and IFN). This result suggests that IL18, INF and IL13 could be involved in the pathogenesis of autoimmune rheumatic diseases.