We have carried out a retrospective, multicentre, chart-review trial, in which all the patients meeting pre-established inclusion criteria and treated in the three participating centres with either splenectomy or low-dose splenic irradiation were enrolled. Inclusion criteria were: long-lasting, symptomatic, severe thrombocytopenia (<25 x 10 super(9)/l), refractory to previous treatments (zidovudine; corticosteroids; vincristine; danazol; high-dose intravenous IgG; high-dose dexamethasone or IFN- alpha ) and a CD4 cell count higher than 50 x 10 super(6)/l. Exclusion criteria were: reduced bone marrow megakaryocytes; liver cirrhosis; granulocytes lower than 3 x 10 super(9)/l or haemoglobin lower than 110 g/l; allergy to pneumococcal vaccine or to cephalosporins. Patient records were analysed for a follow-up of 6 months by independent reviewers.