Pleural effusion due to Histoplasma capsulatum and idiopathic CD4 lymphocytopenia

Acute histoplasmosis is usually a benign, self-limited infection in endemic areas. Since protection against Histoplasma capsulatum infection requires specific, cell-mediated immunity, histoplasmosis is well documented in patients with acquired T cell deficiencies e.g. due to HIV infection. We report here for the first time a case of pleural effusion due to H. capsulatum infection in a patient with idiopathic CD4 lymphocytopenia (ICL). A 25-year-old woman presented with chest pain, dyspnea on exertion and a moderate weight loss. Chest X-ray showed a large left pleural effusion, and thoracentesis yielded an exudate. Histologic examination of pleural biopsies identified H. capsulatum. Laboratory tests revealed lymphocytopenia with low CD4+ T cell counts (<100/microl) and a decreased CD4/CD8 ratio. Serology, including HIV, was repeatedly negative. The diagnosis of pleural effusion due to H. capsulatum infection in a patient with idiophatic ICL was established. There was no evidence of any other opportunistic infection. Treatment with itraconazole was initiated and pleural effusion resolved within 2 weeks of treatment. Moreover, the patient was found to have idiopathic thrombocytopenic purpura, as confirmed by the detection of autoantibodies against thrombocytes. In a 1-year follow-up, the patient remained asymptomatic without relapse or any new infection. Treatment with itraconazole was given for 12 months. Because of persistent CD4+ T cell counts below 100/microl, prophylactic antibiotic treatment is continued.