Mondo Description Idiopathic CD4 lymphocytopenia (ICL) is a rare primary immunodeficiency disorder characterized by persistent CD4 T-cell lymphopenia (less than 300 cells/B5L on multiple occasions) not associated with any other underlying primary or secondary immune deficiency. Patients typically present opportunistic infections (with cryptococcal, mycobacterial, candidal, varicella zoster virus infections and progressive multifocal leukoencephalopathy being the most prevalent), malignancies (mainly lymphoproliferative disorders), or autoimmune disorders. Some individuals are asymptomatic and incidentally diagnosed.

Uniprot Description A rare and heterogeneous syndrome defined by a reproducible reduction in the CD4 T-lymphocyte count (less than 300 cells per microliter or less than 20% of total T-cells) in the absence of HIV infection or other known causes of immunodeficiency. IMD13 predisposes to infections and malignancy.