Anti-lymphocyte antibodies and circulating immune complexes in the sera of patients with myelopathy associated with human T lymphotropic virus type-I.

We measured levels of circulating immune complexes in the human T-lymphotropic virus type I (HTLV-I)-associated myelopathy (HAM) by Raji cell assay and C1q binding assay using an enzyme-linked immunosorbent assay (ELISA). The levels of anti-lymphocyte antibody were also measured using normal donor peripheral blood T-lymphocytes. The levels of anti-lymphocyte antibodies were significantly higher in the sera of patients with HAM compared to controls (P < 0.01). The concentrations of immune complexes measured by Raji cell assay were also significantly higher in the HAM patients' sera than in controls. However, when levels of immune complexes were measured by C1q binding assay, there was no significant difference between HAM patients and controls. There was no significant difference in the levels of anti-lymphocyte antibodies and immune complexes between HTLV-I carriers and controls. Circulating immune complexes detected by the Raji cell assay did not include HTLV-I p-19 as detected by the indirect immunofluorescent method. Levels of anti-lymphocyte antibody were correlated with levels of circulating immune complexes as detected by the Raji cell assay in the sera of patients with HAM. These findings indicate that anti-lymphocyte antibodies and circulating immune complexes are present in the sera of HAM patients, and that the levels of complexes detected by Raji cell assay may reflect anti-lymphocyte antibody levels.