Low CD4+ Counts in a Study of Transfusion Safety

To the Editor: Laurence and coworkers, 1 as well as others, 2 , 3 have reported that the depletion of CD4+ T lymphocytes may be associated with AIDS-defining or other severe illnesses in persons without identifiable human immunodeficiency virus (HIV) infection (those with idiopathic CD4+ T-lymphocytopenia) 4 . Although obviously uncommon, this event and the possibility that a new virus could be transmitted by blood transfusion or clotting-factor concentrates have caused great concern. Data concerning CD4+ counts have been collected by the Transfusion Safety Study at six-month intervals for persons at risk for HIV infection and for control populations since August 1985. Six sites . . .