SECONDARY: To evaluate the effect of thalidomide on blood tumor necrosis factor (TNF) levels and to obtain pharmacokinetic data on the drug. Per 06/28/94 amendment, to evaluate the safety of thalidomide. Per 05/10/95 amendment, to explore in a substudy the effects of thalidomide on idiopathic genital aphthous ulcers in HIV-infected women.