Idiopathic CD4+ Lymphocytopenia (ICL) is a rare disorder affecting the number of circulating CD4+ T-lymphocytes of unknown etiology.
Clinical features:
(1) (absolute CD4+ lymphocyte count < 300 per mL) OR (CD+ lymphocytes are less than 20% of the total T cell population)
(2) defining lymphocytopenia noted on more than 1 occasion
(3) exclusion of known causes (HIV, chemotherapy, known immunodeficiency syndrome)
Other lymphocyte populations (B cells, NK cells, CD8+ T-cells) may also be decreased in number.
Complications:
(1) opportunistic infection (nontuberculous mycobacteria, Cryptococcosis, Pneumocystosis, other)
(2) autoimmune disease (SLE, ulcerative colitis, autoimmune thyroiditis, psoriasis, AIHD, antiphospholipid antibody syndrome, etc)
