Positive anti-neutrophil antibodies test in autoimmune neutropenia experience from single center cohort.

Background Autoimmune neutropenia (AIN) characterized by presence of anti-neutrophil antibodiesand exclusion of other diagnosis. In contrast to pediatrics, data in adults is limited. We aimed to assess the basic characteristics of the disease, outcomes, and clinical impact in that group. Methods We performed a retrospective cohort study of 180 adults with isolated neutropenia tested for anti-neutrophil antibodies at our center (2017-2023). Patients were classified as antibody-positive or negative. a second comparison was conducted with a matched healthy control group for comparison. Clinical outcomes like infections, hospitalizations, antibiotic treatments, and mortality were analyzed. Results Of 180 patients, 134 (74.4%) were antibody-positive. No significant differences were found between antibody-positive and negative groups in baseline characteristics and clinical outcomes. Compared with the healthy control group (3600 patients), antibody-positive patients had higher rates of hospitalizations (29% vs. 15%, p<0.001) and ER visits (50% vs. 32%, p=0.002), but similar infection and death rates (0.7% vs 2.4%, p=0.4). Discussion Our findings suggest that adult AIN follows a benign course, similar to that of matched healthy cohort. We also didn't find any major difference between antibody-positive and negative patients, a fact that raises questions about the utility of anti-neutrophil antibody testing in adults.