OBJECTIVE To understand better the immunopathology of HTLV-I uveitis by investigating the clonality of HTLV-I-infected T-cell clones. METHODS Eleven T-cell clones were established from the aqueous humor (six clones) and the peripheral blood (five clones) of a patient with HTLV-I uveitis, and the clonality of the HTLV-I-infected T cells was investigated by sequencing the T-cell receptor (TCR) alpha gene after the amplification of TCR alpha cDNA using an adaptor-ligation method and reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS TCR alpha use was different for each of 11 T-cell clones, encompassing eight different HTLV-I-infected T-cell clones (four from the aqueous humor and four from peripheral blood) and three HTLV-I-negative T-cell clones. CONCLUSIONS This study demonstrated polyclonal use of TCR alpha for HTLV-I-infected T cells in the ocular lesion and the peripheral blood. Results suggested that these T cells are not precursors of the leukemic cells associated with malignant transformation. Instead, they might be randomly infected with HTLV-I in the process of HTLV-I uveitis.