Serological Interpretation of Rheumatic Manifestations in Brucellosis.

OBJECTIVES: To investigate the profile of autoimmune markers and to evaluate the status of vitamin D in the autoimmune process in brucellosis. STUDY DESIGN: Descriptive study. PLACE AND DURATION OF STUDY: Department of Rheumatology and Microbiology-Basic Immunology, Balikesir Ataturk City Hospital, Turkey, between June 2017 and December 2020. METHODOLOGY: Brucella seropositive patients (mean age 46.58 ± 15.43 years, 43.7% females) were investigated retrospectively in terms of clinical manifestations, rheumatoid factor (RF), anti-cyclic citrullinated peptide (anti-CCP), antinuclear antibody (ANA), and vitamin D (25OHD) levels. Patients were grouped as low Brucella (<1/160), high Brucella (≥1/160) titers, and the control group consisted of Brucella negative patients. Clinical manifestations, RF, anti-CCP, ANA, and 25 OHD levels were compared among the three groups. Correlation analysis was performed between autoimmune markers and 25OHD levels. RESULTS: The most common symptom among all Brucella seropositive patients was polyarthralgia (57.7%). RF positivity was found higher in two patient-groups than the control group (p = 0.008). Anti-CCP positivity was found higher in patient-groups than the control group (p <0.001). ANA levels were similar among the three groups (p = 0.077). Median 25OHD levels were found significantly lower in patient-groups than the control group (p <0.001). No correlation was found among vitamin D, RF, anti-CCP, and ANA levels (p = 0.501, p = 0.613 and p = 0.616, respectively). CONCLUSIONS: Increased rates of RF, anti-CCP; and decreased 25OHD levels in Brucella seropositive patients. It is important to consider brucellosis in the differential diagnosis of patients with rheumatologic manifestations in the presence of autoimmune markers. KEY WORDS: Anti-nuclear anti-body, Anti-cyclic citrullinated peptide, Brucella, Rheumatoid factor, Vitamin D.