Scrub typhus association with autoimmune biomarkers and clinical implications

BACKGROUND: Scrub typhus, a disease caused by Orientia tsutsugamushi, triggers systemic vasculitis and is prevalent in Eastern and Southern Asia. This study aimed to uncover the relationship between scrub typhus and autoimmune responses, focusing on antinuclear antibodies (ANAs) and the implications of elevated ANA titers during infection. METHOD: Data from a total of 139 patients diagnosed with scrub typhus and 30 healthy controls were retrospectively analyzed through serum samples to assess the levels of ANAs and related autoantibodies. The study further examined the temporal variation of these antibody titers in relation to post-symptom progression and evaluated their association with clinical and laboratory parameters. RESULTS: The study results detail significant differences in autoimmune responses between scrub typhus patients and healthy controls. ANA titers above 1:80 were detected in 71.2% of patients; these titers were elevated in only 13.3% of the healthy controls. High-titer positivity (1:640 or higher) was observed exclusively in the scrub typhus group. The distribution of ANA titers revealed a progressive increase in mean ANA and double-stranded deoxyribonucleic acid Immunoglobulin M (anti-dsDNA IgM) titers as the duration after symptom onset increased, indicating an augmented immune response over time. This trend was observed along with a systematic elevation in median anti-dsDNA IgM titers, highlighting the dynamic nature of immune responses in scrub typhus infection. CONCLUSION: Our findings conclude a substantial autoimmunological reaction in scrub typhus patients, suggesting potential mimicry of autoimmune conditions like Systemic Lupus Erythematosus. These results underline the complex interplay between infectious diseases and autoimmunity, emphasizing the necessity for further research into these mechanisms and their clinical implications.