Evaluation of Urinary Tract Infection and Measurement of Interleukin 18 in Iraqi Patients with Rheumatoid Arthritis

Although the etiology of RA is complicated, infection with various microorganisms can activate several immune system pathways, potentially leading to an autoimmune response. Urinary tract infections were significantly more common in RA patients. Interleukin 18 is crucial in the pathogenesis of rheumatoid arthritis. A case-control study included 50 patients with rheumatoid arthritis indicating urinary tract infection symptoms, diagnosed by the rheumatologist according to the criteria of ACR/EULAR 2010, compared to 40 healthy subjects of the same age and sex who served as the control. For routine laboratory tests such as C-reactive protein(CRP), erythrocyte sedimentation rate (ESR), rheumatoid factor (RF), and anti-cyclic citrullinated peptide (anti-CCP), in addition to the estimation of serum concentration of IL18 by ELISA, to detect UTI, midstream urine samples were obtained aseptically, and samples were diagnosed using accepted techniques. The results of this study revealed that 44(88%)of patients with rheumatoid arthritis were found to have UTI, compared to the control group (88% vs. 17.5%), with an odd ratio (alternative for relative risk) of 34.571. In the investigation of the study groups, an equal proportion of gram-positive and gram-negative bacteria were identified among the case groups (each 50%). Among isolates, Escherichia coli (E.coli) was the predominant isolated bacteria (73%),and the gram-positive bacteria among the case groups were mainly Staphylococcus haemolyticus (41%). The mean values of IL18 compared to the control group were found to be considerably higher among the case group.