On May 3, 2023, National Institutes of Health (NIH) scientists announced that they had uncovered new details on idiopathic CD4 lymphocytopenia (ICL), a rare immune deficiency that leaves people vulnerable to infectious diseases, autoimmune diseases and certain types of cancer.

ICL is a condition marked by too few CD4+ T cellsﾗa type of white blood cell. There is no evidence that ICL is transmitted from person to person, and it has no known cause. The study was published in the New England Journal of Medicine.