Submitted June 27, 2006
Accepted October 13, 2006
Idiopathic CD4+ T lymphocytopenia is associated with increases in immature/transitional B cells and serum levels of IL-7
Angela Malaspina, Susan Moir*, Doreen G Chaitt, Catherine A Rehm, Shyam Kottilil, Judith Falloon, and Anthony S Fauci
National Institutes of Health, Department of Health and Human Services, United States
* Corresponding author; email: smoir{at}niaid.nih.gov.
Idiopathic CD4+ T lymphocytopenia (ICL) is a rare heterogeneous disorder defined by CD4+ T-cell counts below 300/µ1 in the absence of HIV infection or other known immune deficiency disorders. Here, we report the expansion of immature/transitional B cells in ICL patients that is associated with elevated serum levels of IL-7. Both the percentage of immature/transitional B cells and levels of IL-7 were inversely correlated with levels of CD4+ T cell counts and directly correlated to each other. Further analyses of B cells indicated that, in contrast to the activating effects of HIV disease on mature B cells, the expansion of immature/transitional B cells in ICL patients occurred at the expense of memory B cells. These findings extend previous reports on primary immunodeficiencies as well as HIV disease by suggesting that CD4+ T cell lymphopenia has an impact on human B cell development either directly or indirectly via the associated elevation of IL-7 levels.
