Nucleotide sequence analysis of human T-cell lymphotropic virus type I pX and LTR regions from patients with sicca...

Human T-cell lymphotropic virus type I (HTLV-I) is associated with adult T-cell leukemia (ATL) and tropical spastic paraparesis/HTLV-I-associated myelopathy (TSP/HAM). Other inflammatory disorders may occur in HTLV-I-infected patients, such as sicca syndrome resembling Sjögren's syndrome. The sicca syndrome may be the unique clinical manifestation of HTLV-I infection, but is associated frequently with TSP/HAM, which could suggest that sicca syndrome might be an early event in disease progression to TSP/HAM in some cases. We investigated whether peculiar pX and LTR mutations could be related to sicca syndrome, or might argue the existence of clinical progression to TSP/HAM. pX, especially pX(I), pX(II), and pX(IV) ORFs corresponding to Tax cytotoxic T-lymphocyte epitopes, and LTR regions from Caribbean patients who have sicca syndrome with or without TSP/HAM, ATL patients, and healthy carriers were sequenced. The sequences were aligned and compared with ATK-1 prototype and published sequences. LTR sequences exhibited 1.5-2.4% of divergence with ATK-1. pX-sequenced regions showed a lower homology within p12(I) encoding sequences. Only few mutations were found within functionally important regions, but were not associated specifically with the clinical status. Finally, no mutations that could be related to sicca syndrome or argue the existence of clinical progression to TSP/HAM were found. It would be of interest to study the clinical evolution of HTLV-I-sicca syndrome in patients and to determine HTLV-I sequences from peripheral blood and salivary glands at different stages.