BACKGROUND: Idiopathic CD4 lymphocytopenia is a rare immunodeficiency syndrome characterized by a persistent reduction in CD4 lymphocyte count to fewer than 300 cells/µL or less than 20% of total T lymphocytes on multiple occasions. This diagnosis is made in the absence of HIV infection or other known immunodeficiencies. Herein, we present a case report of idiopathic CD4 lymphocytopenia in an adult patient, contributing to the limited literature on the management challenges of this rare immunodeficiency.

CASE REPORT: A 42-year-old male patient presented with shortness of breath, productive cough, subjective fever, night sweats, and unintentional weight loss of 6 kg over 1 month. Imaging showed a loculated right-sided pleural effusion with an air-filled cavity. The diagnosis of active pulmonary tuberculosis was confirmed based on positive tuberculosis diagnostic tests. In addition, his complete blood count showed marked lymphopenia; however, his human immunodeficiency virus (HIV) result test was repeatedly negative. In the context of investigations for lymphopenia, lymphocyte subset analysis showed a low CD4 lymphocyte count of 103.8 cells/µL, in the absence of known etiologies such as other immunodeficiencies, drug-induced leukopenia, or immunomodulatory therapy. The CD4 lymphocyte count remains below 200 cells/µL on consecutive analyses, even after successful completion of anti-tuberculosis therapy. Consequently, a diagnosis of idiopathic CD4 lymphocytopenia with pulmonary tuberculosis as an opportunistic infection was made.

CONCLUSIONS: This case highlights the importance of high clinical suspicion for idiopathic CD4 lymphocytopenia in patients presenting with lymphocytopenia and a negative history of HIV/AIDS. Further research is needed to formalize management guidelines for patients with idiopathic CD4 lymphocytopenia.

Keywords: Idiopathic CD4 Lymphocytopenia, Lymphocyte Count, Opportunistic Infections, Tuberculosis Disease