Enes BASARAN, Senar ŞAN, Oznur Sadioglu CAGDAS, Emel Azak KARALI, Huseyin UZUNER, Aynur KARADENİZLİ, Neslihan GÖKÇEN, Duygu Temiz KARADAG, Ayse CEFLE, Ayten YAZICI
Rheumatology Quarterly - 2026;4(2):102-108
Objection: Data on the clinical course of COVID-19 and subsequent humoral immune responses in patients with rheumatic diseases remain limited. This study aimed to compare SARS-CoV-2 antibody responses between patients with rheumatic diseases and healthy controls and to identify clinical and treatment-related factors associated with antibody levels. Methods: This prospectively designed, single-center cross-sectional study included unvaccinated adults with rheumatoid arthritis, systemic lupus erythematosus, or ankylosing spondylitis who had a previous COVID-19 infection, along with age- and sex-matched healthy controls. COVID-19 was identified by PCR confirmation or compatible thoracic CT findings, and anti-spike and anti-nucleocapsid SARS-CoV-2 antibodies were assessed 1-6 months after infection using Elecsys immunoassays. Results: PCR-confirmed infection (P < .001) and several COVID-19-related symptoms, including headache, dyspnea, nausea/vomiting, fatigue, sore throat, and arthralgia, were significantly more frequent in the patient group (all P < .05). However, hospitalization and pulmonary involvement were each significantly more common in the control group (both P < .001). Intensive care admission was similarly low in both groups. Anti-S seropositivity was significantly higher in patients than in controls (P < .001), while anti-N seropositivity and anti-N/anti-S antibody titers were comparable between groups. Antibody levels did not differ significantly among rheumatic disease subgroups. However, both anti-N and anti-S titers were significantly higher in patients not receiving biologic therapy (both P < .001). Conclusion: Humoral immune responses following COVID-19 appeared to be largely preserved in patients with rheumatic diseases. Although anti-S seropositivity was higher in the patient group, antibody titers were lower among those receiving biologic therapy, suggesting a potential treatment-related effect on humoral immunity. Larger studies are warranted to confirm these findings.
