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