Summary. The response to high-dose intravenous immunoglobulin (IVIg) was recently reported to be predictive of outcome after splenectomy in patients with autoimmune thrombocytopenic purpura (AITP). We analysed the records of 75 adults with chronic AITP who received IVIg and subsequently underwent splenectomy. There was no significant difference in the response rate to splenectomy according to whether or not patients had responded to IVIg (81% v 67%, P ¼ 0·36). Age, the time from diagnosis to splenectomy, and the response to steroids were also not significantly associated with outcome after splenectomy. These results indicate that the response to IVIg or steroids is not predictive of the efficacy of splenectomy.Keywords: autoimmune thrombocytopenic purpura, splenectomy, intravenous immunoglobulins.Although alternatives have been proposed, splenectomy remains the best treatment for patients with chronic autoimmune thrombocytopenic purpura (AITP) (Blanchette et al, 1998). However, only 50-90% of patients respond to splenectomy, and 10% relapse after initial success (Karpatkin, 1997). Moreover, even if the operative mortality rate is now probably low, morbidity can be severe, particularly in older patients who, furthermore, do not respond to splenectomy as well as younger subjects (George et al, 1996). Splenectomized patients are also more at risk of life-threatening infections. Thus, it would be useful to have a means of predicting the response to splenectomy. Recently, Law et al (1997) found a close relationship between the platelet increase after high-dose intravenous immunoglobulin (IVIg) and the outcome of splenectomy. We sought to confirm these findings and evaluate the value of some other preoperative criteria in a larger series of adults with chronic AITP.
PATIENTS AND METHODSAll adults (age >17 years) with AITP followed in three centres who received IVIg and subsequently underwent splenectomy were included. AITP was diagnosed according to standard criteria, i.e. isolated thrombocytopenia, normal or increased megakaryocyte count in an otherwise normal bone marrow aspirate, and absence of other causes of thrombocytopenia. Patients with human immunodeficiency virus infection or systemic lupus erythematosus were excluded. Responses to IVIg, steroids and splenectomy were analysed; a positive response was defined as a platelet count increase to > 50 × 10 9 /l and at least twice the initial value. A response to splenectomy was recorded only if no relapses occurred (in such situations an accessory spleen was not found despite systematic search). Different IVIg treatment schedules were administered: one group of patients received a total IVIg dose of 2 g/kg body weight (b.w.) injected over 2-5 d, and another group received 0·5-1 g/kg b.w. infused in 1 d. In this latter group, IVIg was always reinfused if no platelet response was observed on day 3; thus, all non-responders received a total IVIg dose of 2 g/kg b.w. The response to steroids was assessable in 62 patients; the administered dose of steroids ranged from 1 ...