Background: Although patients with idiopathic CD4+ T-lymphocytopenia and serious opportunistic infections have been described previously, the clinical and immunologic features of this condition have not been well defined.
Methods: We studied in detail five patients with idiopathic CD4+ T-lymphocytopenia. The studies included serologic testing, culture, and polymerase chain reaction for the human immunodeficiency virus (HIV) types 1 and 2, serologic testing for the human T-cell lymphotropic virus (HTLV) types I and II, lymphocyte phenotyping, immunoglobulin quantitation, and lymphocyte-transformation assays, as well as attempts to isolate a retroviral agent. The results were compared with those in HIV-infected persons matched for CD4+ T-cell counts and with those in normal controls. We also studied the spouses of patients and the blood donors for one patient.
Results: In these five patients, there was no evidence of either HIV or HTLV infection. All the patients had both low percentages and low counts of CD4+ T cells, with relative increases in percentages, but not counts, of CD8+ cells. Numbers of B cells and natural killer cells were generally normal. As compared with HIV-infected persons, our patients had lower percentages and counts of CD8+ cells and more lymphopenia. CD4+ counts were relatively stable over time. Instead of the high immunoglobulin levels seen in HIV infection, these patients had normal or slightly low levels of immunoglobulins. The lymphocyte-transformation response to mitogens and antigens was depressed. Results in spouses and blood donors were normal.
Conclusions: Idiopathic CD4+ T-lymphocytopenia differs from HIV infection in its immunologic characteristics and in its apparent lack of progression over time. Nothing about the immunologic or viral-culture studies performed in these patients or about their family members or blood donors suggests that a transmissible agent causes this condition.