Concomitant augmentation of CD4⁺CD29⁺ helper inducer and diminution of CD4⁺CD45RA⁺ suppressor inducer subset in patients infected with human T cell lymphotropic virus types I or II

To examine the immunomodulatory effects of HTLV infection, lymphocyte subset analysis was performed on patients infected with human T cell lymphotropic virus type-I (HTLV-I, n = 6) or -II (HTLV-II, n = 12) and on normal blood donors (n = 16). The percentages of total B lymphocytes (CD 19), natural killer (NK) cells (CD 16), T lymphocytes and their subsets (CD2, CD3, CD4, CD5, CD7, CD8), and IL-2R (CD25) were found to be within the range found in normal donors. However, the expression of CD8⁺ HLA-DR⁺ increased significantly in patients with HTLV-I or HTLV-II infection (14.1 ± 3.9% and 9.7 ± 2.4% respectively; P < 0.01) when compared with controls (3.2 ± 1.1%). In addition, there was a significantly greater proportion of CD4⁺CD29⁺ T lymphocytes (29.3 ± 6.1% and 31.1 ± 9.0%; P<0.05) with concomitant diminution of CD4⁺CD45⁺ T lymphocytes (8.3 ± 3.3% and 11.4 ± 1.5%; P < 0.01) in patients infected with HTLV-I or HTLV-II respectively, when compared with controls. The increased percentage of CD4⁺CD29⁺ subpopulations showed a direct correlation (r(s) = 0.86; P < 0.001) with HTLV-specific antibody production. No difference in the CD8 population coexpressing CD29 and S6F1 (an epitope of LFA-1) were observed in the HTLV-infected group when compared with normal donors and functional analysis exhibited minimal cytotoxicity against lectin labelled heterologous target cells. Thus, the shift in the suppressor/cytotoxic to helper/inducer 'memory' CD4⁺ may be associated with immunoregulatory abnormalities often found in persons infected with HTLV-I or HTLV-II.