Distinct clinical patterns in AQP4-IgG- positive NMOSD patients vs. Seronegative: Insights from a single-center study in Argentina

Background: Distinct clinical course patterns have been identified between AQP4-IgG-positive and AQP4-IgG-negative NMOSD patients.

Objectives: This study aimed to evaluate the differences between AQP4-IgG-seropositive and AQP4-IgG-seronegative NMOSD patients in a single centre in Argentina.

Methods: We performed a retrospective cross-sectional study of 108 NMOSD patients in the city of Buenos Aires, Argentina.

Results: We selected 94 for analysis. 77 patients (82 %) were AQP4-IgG positive. In the AQP4-IgG positive group, the ratio of male to female was 1:10 vs. 1:1.2 in the seronegative group (p = 0.001). Relapses were observed in 76 out of 77 (99 %) AQP4-IgG positive patients versus 3 out of 17 (17.6 %) AQP4-IgG negative patients (p = 0.01). In the seropositive group, other autoimmune diseases were present in 34/77 patients (44 %) vs. 2/12 (12 %) in the seronegative patients, a statistically significant difference (p = 0.009). 81 % of the seropositive group had an early adulthood onset (EAO-NMOSD) compared to 35 % in the seronegative group. All AQP4+ patients positive received treatment with monoclonal antibodies. In AQP4-IgG- NMOSD patients the use of immunosuppressive treatment was more common.

Conclusion: Female predominance, EAO-NMOSD, recurrence course and a high prevalence of autoimmune disease in AQP4-IgG-positive patients demonstrated a more pronounced autoimmunity profile.