Human T-lymphotropic virus type I tax polymorphisms in a transmission cohort: No association between sequence variation and disease manifestations

Objective: To determine whether a unique human T-lymphotropic virus type I (HTLV-1) transmission cohort containing multiple disease manifestations cou ld be used to establish a relationship between tax gene sequence and HTLV d isease expression. Methods: DNA was extracted from the peripheral blood mononuclear cells (PBM C) of the HTLV-infected persons in the cohort. A 1.1-kb fragment of tax was amplified by polymerase chain reaction (PCR) and cloned. Six to 12 individ ual clones were sequenced per person. Results: Comparison to a reference ATK strain showed numerous differences; however, consensus tax sequences from all persons within the transmission c ohort were identical. Intraperson variation was 0.1% to 0.3%. Tax:sequences from the index case did not differ from those obtained from a transfusion recipient who developed tropical spastic paraparesis/HTLV-1-associated myel opathy (TSP/HAM). The sequences from the same index case did not differ fro m sequences obtained from the asymptomatic or ATL phases of a second recipi ent. Conclusions: In this cohort there dill not appear to be tax genotypes assoc iated with specific disease manifestations of HTLV infection.