Retrospective evaluation of "Rods and Rings" pattern detected in the anti-nuclear antibody (ANA) indirect immunofluorescence (IIF) test.

Introduction: Anti-rods and rings (anti-RR) antibodies have recently been described as a cytoplasmic pattern in IIF-based screening of autoantibodies on HEp-2 cells and ICAP has named it as AC-23. It is most frequently related to drug-induced antibody generation. This study aimed to investigate the clinical significance of AC-23 positivity and its relevance to the diagnosis and/or follow-up of the associated diseases and/or drug use. Methods: A multicenter retrospective study was conducted among 10 hospitals from six different provinces in Türkiye from January 2017 to December 2021. The laboratory data and clinical information of 600 patients with positive anti-RR antibodies out of 547.558 HEp-2 IIF ANA samples were analyzed. Results: The distribution of AC-23 positive patients by year indicated a steady increase between 2017-2021. Anti-RR prevalence in post-COVID-19 period was significantly higher than that of pre-COVID-19 period (p=0.00). Concomitant ANA positivity was detected in 56.5% of patients, the most common patterns being AC-4 and AC-5 (41.1%). The most frequent pathology among the anti-RR positive patients was an autoimmune disease (19.83%); 28.57% of which had rheumatoid arthritis and 17.65% autoimmune liver disease. Among the 600 patients, 65 (10.83%) were diagnosed as hepatitis C virus (HCV) infection. Available data for 38 of the HCV patients revealed that 71.05% of them had a history of interferon alfa+ribavirin and 28.95% of them had a history of NS3/4/5A/5B polymerase inhibitor or protease inhibitor drug use. Significant increase in the rate of anti-RR positivity was observed in the post-COVID-19 period when compared to pre-COVID-19 period (p:0.00). Discussion: This is the first multicenter study in Türkiye about the clinical association of anti-RR antibodies which may be ignored during routine HEp-2 IIF testing. Pathologies other than HCV should be taken into consideration in terms of the possible role of anti-RR in autoimmune diseases and other pathologies. The preliminary data obtained in this study suggest that anti-RR antibody development might also be associated to COVID-19, supporting the several previous data related to the potential of viruses triggering the formation of autoantibodies. Large-scale prospective studies should elucidate the clinical significance of RR pattern and determine its role in patient diagnosis and follow-up.

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.

The clinical significance of anti-DFS70 autoantibodies and its correlation with Vitamin D levels.

OBJECTIVE: This study aims to investigate the clinical significance of anti-dense fine speckled 70 (DFS70) autoantibodies and its association with systemic autoimmune rheumatic diseases (SARD) related autoimmune markers and Vitamin D levels. METHODS: The study group consisted of 281 (mean age±SD: 45.31±15.89 years; 88.3% female) anti-DFS70 autoantibody-positive patients. All patients' sera in the study group were tested by ANA HEp-2 indirect immunofluorescent antibody (IIF) and immunoblotting (IB) methods (Euroimmun AG, Lübeck, Germany). Anti-DFS70 antibody-positive patients were divided into two subgroups. Anti-DFS70 antibody-positive patients with SARD were assigned as Group 1 (n=43), anti-DFS70 antibody-positive patients without SARD were assigned as Group 2 (n=238). A control group with anti-DFS70 negative patients with SARD were assigned as Group 3 (n=49, mean age±SD: 49.86±12.08; 79.6% female). The clinical characteristics, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), neutrophil/lymphocyte ratio, thrombocyte/lymphocyte ratio (TLR), rheumatoid factor (RF), anti-cyclic citrullinated peptide (anti-CCP), and 25-hydroxyvitamin D3 (25OHD3) levels were compared between three groups. RESULTS: The majority (61.9%) of anti-DFS70 antibody positive patients had no specific diagnosis. Other systemic diseases were detected as allergic diseases (10.0%), hematological abnormalities (5.0%), thyroid diseases (3.6%), gastrointestinal system diseases (1.8%), malignancies (1.4%), and infections (1.1%). ESR, CRP levels, and TLR were lower in Group 2 than Groups 1 and 3 (p<0.05). RF and anti-CCP positivity rates were lower in Group 2 when compared with Groups 1 and 3 (p<0.05). 25OHD3 levels did not differ between three groups (p=0.103). CONCLUSION: We observed that anti-DFS70 autoantibody may be associated with organ-specific autoimmune diseases, allergic diseases, and hematological disorders. Therefore, it is essential to evaluate these pathologies in patients positive for anti-DFS70 antibodies.