A probable association between HTLV-1 and endemic mycosis in Latin America

We have read with interest the case report of severe gastrointestinal histoplasmosis in a patient infected with Human T lymphotropic virus-1 (HTLV1) by Canelo Aybar and colleagues [1]. In this case report, a possible link between these entities is suggested, but no conclusive evidence of a true association is provided. HTLV-1 causes clinical manifestations by three main mechanisms: autoimmune processes, malignant conditions, and infectious complications [2]. Infectious dermatitis, crusted scabies and strongyloidiasis are wellrecognized infectious diseases associated with HTLV-1, while the association with tuberculosis is still debatable [2,3]. We have recently reported four cases of patients co-infected with HTLV-1 and paracoccidioidomycosis [4]. These four patients presented with severe and unusual manifestations of paracoccidiodomycosis, including two patients with chronic diarrhoea and colonic ulcers. Taking these two reports together, it seems that HTLV-1 infection could modify the host response to endemic mycosis and can additionally contribute to the high severity and mortality rate observed in co-infected patients. Systematic studies are needed to determine an epidemiological and biological association between HTLV-1 and endemic mycosis. Comparison of the prevalence of HTLV-1 infection among patients infected with histoplasmosis and paracoccidiodomycosis with that of control groups is lacking. Additionally, studies to evaluate the immune status of co-infected patients are clearly necessary to link HTLV-1 induced immunosupression and increased risk of either acquiring de novo these infections or reactivating past infections. In the meantime, clinicians should be alert of a possible association between HTLV-1 and both histoplasmosis and paracoccidioidomycosis.