SCREENING OF BLOOD-DONORS FOR IDIOPATHIC CD4+ T-LYMPHOCYTOPENIA

Background: The recent recognition of idiopathic CD4+ T-lymphocytopenia (ICL) has led to concern that an unknown immunodeficiency virus may be transmissible by transfusion. Study Design and Methods: To evaluate the prevalence and significance of low CD4+ values among blood donors, CD4, data on 2030 blood donors who were negative for antibody to human immunodeficiency virus type 1 (HIV-1) were compiled. Those with CD4+ values below ICL cutoffs (<300 CD4+ T cells/muL, or <20% CD4+ T cells) were recalled for follow-up investigations. Serial CD4+ data on 55 homosexual men who seroconverted during prospective follow-up and data on 139 anti-HIV-1-positive blood donors initially evaluated in 1986 were reviewed as well. Results: Five seronegative donors (0.25%) had absolute CD4+ counts <300 cells per muL and/or <20 percent. On follow-up, all five donors had immunologic findings within normal ranges, lacked HIV risk factors, and tested negative for HIV types 1 and 2 and human T-lymphotropic virus type I and II infections by antibody and polymerase chain reaction assays. Four of five donors reported transient illnesses shortly after their low CD4+ count donations. The median interval from HIV-1 seroconversion to an initial CD4+ value below ICL CD4+ cutoffs was 63 months for infected homosexual men. Of 139 HIV-1-infected blood donors studied 1 to 2 years after seropositive donations, 34 (24%) had CD4+ counts <300 cells per muL and/or <20 percent. Conclusion: Low CD4+ counts are rare among anti-HIV-1 -negative volunteer blood donors and are generally associated with transient illnesses. If any unknown virus progresses similarly to HIV-1, CD4+ count donor screening would be a poor surrogate for its detection.