Human T-Lymphotropic Virus 1 (HTLV-1)-Associated Lichenoid Dermatitis Induced by CD8+ T Cells in HTLV-1 Carrier, HTLV-1-Associated Myelopathy/Tropical Spastic Paraparesis and Adult T-Cell Leukemia/Lymphoma

The study reviewed 50 patients with HTLV-1-associated diseases, including adult T-cell leukemia/lymphoma (ATLL), HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), and HTLV-1 carriers, who presented with skin lesions between 2002 and 2012. The researchers identified cases with lichenoid tissue reactions predominantly involving CD8+ T cells, rather than CD4+ tumor cells. These cases included conditions such as erythroderma, lichen planus, alopecia areata, chronic actinic dermatitis, and discoid lupus erythematosus. The study introduced the term HTLV-1-associated lichenoid dermatitis (HALD) to describe these conditions, suggesting that HALD may result from heightened immune responses against HTLV-1-infected CD4+ T cells, similar to the immune mechanisms seen in HAM/TSP.