HTLV-1-associated diseases: a systematic review.

Human T-cell lymphotropic virus type 1 (HTLV-1) is a human retrovirus associated with a broad spectrum of clinical manifestations. While most people living with HTLV-1 remain asymptomatic, a proportion develops severe conditions such as adult T-cell leukemia/lymphoma or HTLV-1-associated myelopathy/tropical spastic paraparesis. Increasing evidence also indicates that HTLV-1 infection is related to multiple systemic complications involving different organ systems (including neurological, pulmonary, dermatological, rheumatological, and ophthalmological disorders) and opportunistic infections. Given the growing recognition of these diverse manifestations, this review aims to compile and synthesize the scientific evidence regarding clinical manifestations, co-infections, opportunistic diseases, and complications related to HTLV-1 infection.