The association between antinuclear antibody and response to rituximab treatment in adult patients with primary immune thrombocytopenia

Abstract

<b>Background:</b> Antinuclear antibodies (ANAs) can be detected in about 30% of patients with primary immune thrombocytopenia (ITP), yet their relationship with treatment response to rituximab remains elusive.<b>Methods:</b> we retrospectively reviewed the clinical records of hospitalized adult ITP patients who were treated with rituximab from three medical centers across China. Rituximab was given intravenously at 100 mg weekly for 4 weeks, or at a single dose of 375 mg/m². All included patients had their ANAs tested before rituximab treatment.<b>Results:</b> A total of 287 patients fulfilled the inclusion criteria and were eligible for analysis. ANAs were positive in 98 (34.1%) of the included patients. The incidence of overall response and complete response (CR) in ANA-positive patients was significantly higher than that in ANA-negative patients (overall response: 76.5% vs. 55.0%, <i>P</i> < 0.001; CR: 46.9% vs. 29.1%, <i>P</i> = 0.003). However, sustained response (SR) rates in ANA-positive patients at 6, 12 and 24 months were all lower compared with ANA-negative patients (all <i>P</i> < 0.05). The overall duration of response (DOR) estimated by Kaplan-Meier analysis in ANA-negative patients was greater than that in ANA-positive patients (<i>P</i> < 0.001).<b>Conclusion:</b> ITP patients with positive ANA test were likely to achieve a better initial response to rituximab treatment, while their long-term outcome was unfavorable. Therefore, ANA test could be useful for predicting rituximab response in ITP.