Evaluation of the Histoplasma capsulatum 100-kilodalton antigen dot blot for the rapid diagnosis of progressive histoplasmosis in HIV/AIDS patients

Among people living with HIV (PLHIV), progressive disseminated histoplasmosis (PDH) represents an important cause of mortality. Since antigen detection allows a rapid diagnosis and the instauration of a specific treatment this study aimed to evaluate the analytical performance of the Hcp100 dot blot, an in-house assay that detects the Histoplasma capsulatum 100-kilodalton antigen in urine and compare it with 2 commercially available assays the Histoplasma Urine Antigen Lateral Flow Assay (MVD-LFA) (MiraVista® Diagnostics) and the Clarus Histoplasma Galactomannan EIA (Clarus HGM) (IMMY). Urine specimens from 23 PLHIV with PDH, 13 patients with other infectious diseases, and 20 healthy individuals were tested. The Hcp100 dot blot showed higher sensitivity (87.0%), specificity (97.0%) and accuracy (92.9%) than the MVD-LFA (73.9%, 78.8%, and 76.8%, respectively) and the Clarus HGM (78.3%, 90.9%, and 85.7%, respectively). The Hcp100 dot blot had high analytical performance and would be a valuable screening tool for diagnosing PDH among PLHIV.

Progressive disseminated histoplasmosis in an immunocompetent adult: A case report

Histoplasmosis is a systemic fungal infection caused by Histoplasma capsulatum which occurs endemically in some parts of the world like North and Central America particularly in Mississippi and Ohio River valleys, but is uncommon in India. Progressive disseminated form of histoplasmosis (PDH) usually occurs in the immune-compromised hosts especially in HIV positive population. In PDH any organ can be involved like lung, liver, spleen, brain, adrenals etc. Involvement of oral cavity and buccal mucosa in PDH is common but pharyngeal involvement is rare. We here report a case of progressive disseminated histoplasmsosis with pharyngeal involvement in an immunocompetent male from non-endemic area. This case presented to us with history of long duration fever and we found the etiology by giving due significance to a trivial symptom and thorough evaluation of the same. Etiology was found as disseminated histoplasmosis, which is not a common disease. We treated him initially with amphotericin-B then subsequently with itraconazole for one year. He recovered fully over the period of one year with the given treatment. This case report emphasizes that disseminated histoplasmosis should be considered one differential diagnosis in case of long duration of fever, even in an immunocompetent patient. It also emphasizes that in evaluation of a case of long duration of fever, even a trivial symptom is very crucial, which may direct towards the diagnosis.