Association of anti-brucella antibodies with circulatory IL-17, IL-18 and INF-γ in patients with brucellosis in Diyala province-Iraq

Background: Brucellosis, caused by the intracellular pathogens brucellae, is one of the most prevalent bacterial zoonosis of worldwide distribution. The disease is highly prevalent in East Mediterranean region. Cytokines are key players in protection against brucellosis, mediating both innate and adaptive immune responses. Objective: The aims of this study are exploration the association of anti-brucella IgM and IgG antibody with the detection of circulatory IL-17, IL-18 and INF-γ. Patients and method: A total of 55 patients who were clinically suspected as having brucellosis were included as patients group and 35 apparently healthy individuals as control group. The highest age range was 20-29 years. The mean ± SD and the age range of the patients and control groups were 29.8 ± 10.1 (15-59) and 33.8 ± 11.0 (18-58) years respectively. 20% of patients were males and 80% were females, while, 37.1 % of controls were males and 62.9% were females. The study groups were allocated from Baquba Teaching Hospital and some Healthcare Centers. A questionnaire form was preconstructed including socio-demographic and clinical information. Blood samples were collected from both study groups, sera were separated and submitted for slide agglutination (Rose Benal) test (Spin-React, Spain), Anti-Brucella IgM and IgG (Demeditec - Germany) as well as for detection of serum Interleukin-17, Interleukin-18, and Interferon –γ (My biosource -USA). Human privacy was respected by obtaining verbal consent from all participants. Statistical analysis was done using SPSS version 25 and p values ≤ 0.05 were considered significant. Results: primarily, the clinical signs are highly associated in brucellosis patients. Moreover, consumption of milk and meat, intrafamilial clustering of cases and disease history are associated with brucellosis. The results found that 18 (32.7%) of the patients and 2 (5.7%) of the control were positive for anti-brucella IgM with statistically significant difference (P= 0.003). The anti-brucella IgG positivity rate among patients was 31(56.4%) while that of the control group was 4 (11.4%), with statistically significant difference (P= 0.0001). The IL-17 positivity rate among brucella patients was 32(58.2%) versus 15 (42.9%) among controls, with statistically insignificant difference (P= 0.156). the IL-18 positivity rate among patients was 27(49.1%) which is insignificantly higher than that of controls 11(31.4%), (P= 0.098). The positivity rate of INF-γ in patient group was 52(94.5%) which is highly significant compared to controls 12(34.3%), (P= 0.0001). The IL-17 and INF-γ were higher among IgM positive patients while the IL-18 was significantly higher among patients with IgG positivity. Conclusion: Patients with acute brucellosis had higher Iinterleukin-17, and interferon-γ positivity, while the IL-18 was highly associated in patients with persistent brucellosis