A Simple, Highly Sensitive, and Highly Specific Dot-Blot-Based Immunoassay for Serodiagnosis of HTLV-1 in Resource-Limited Settings

Human T-cell leukemia virus type 1 (HTLV-1), the first identified human retrovirus, is associated with adult T-cell leukemia (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The lack of effective antiviral therapies or vaccines highlights the critical importance of early diagnosis in managing HTLV-1-associated diseases. However, current commercial immunoassays, including enzyme immunoassays, line immunoassays, particle agglutination tests, and Western blots, are often limited by the need for specialized equipment and high costs, which restrict their accessibility in resource-poor regions. To address these challenges, we developed a novel dot-blot immunoassay using HTLV-1 P19 and GP46 synthetic peptides in combination with a precipitating tetramethylbenzidine (TMB) substrate. This innovative approach enables instrument-free visual detection through the formation of distinct blue-brown precipitates. Validation of this immunoassay with 179 clinical serum samples demonstrated 100% specificity and 91% sensitivity. Our assay offers a simple, cost-effective, and field-applicable diagnostic solution for HTLV-1 screening in resource-limited settings, potentially enhancing global surveillance of this neglected pathogen.