Idiopathic CD4 Lymphocytopenia at 30 Years

To the Editor: In the article by Lisco et al. (May 4 issue), 1 the authors report that five cases of sarcoidosis were diagnosed among the 44 autoimmune diseases identified in their study patients. Because CD4 lymphocytopenia (also called lymphopenia) is a well-established disease manifestation of sarcoidosis, we think that these patients do not belong in the cohort of patients with idiopathic CD4 lymphopenia. The CD4 lymphopenia in sarcoidosis is strongly linked to tumor necrosis factor alpha (TNFα), a promoter of granuloma formation. 2 Other reported mechanisms include enhanced CD4 chemotaxis to sites of granuloma formation 3 and increased apoptosis. 4 Hence, we believe . . .