Comparison of Response to Rituximab Therapy in Adults with Refractory Symptomatic Immune Thrombocytopenia According to the Presence of Accessory Spleen.

No data exist for the association between the presence of accessory spleen after splenectomy and response to rituximab in immune thrombocytopenia (ITP). We investigated the relationship between accessory spleen presence and rituximab response in splenectomized ITP patients. Fifteen chronic refractory ITP patients were included. Four weekly doses of rituximab 375 mg/m were administered. All patients had undergone splenectomy before rituximab administration. Accessory spleen was detected in 5 of 15 patients (33.3%). Median age at diagnosis was significantly higher in patients with accessory spleen than those without accessory spleen (40 (range 25-68 years) and 26 (range 7-40 years), respectively; = 0.049). There was a trend for older age at time of rituximab initiation in patients with accessory spleen compared to the other group (median 51 (range 43-75 years) and 42.5 (range 30-60 years), respectively; = 0.066). Median follow-up duration was 96 months (range 40-98). We demonstrated a significant correlation between accessory spleen presence and older age. Accessory spleen presence correlated with higher platelet and WBC counts. We showed good inverse correlation between presence of accessory spleen and time to early response (ER) to rituximab while the rate of early response (ER), late response (LR), sustained response (SR) and overall response (OR) did not differ with respect to the presence of acessory spleen.