Discordance between phenotype and function of Japanese adult T cell leukemia cells.

Phenotypes of cells from 12 patients with ATL were analysed by means of a fluorescence-activated cell sorter by utilizing a panel of monoclonal antibodies. A majority of the cells from peripheral blood coexpressed the antigens against MAbs CD2, CD3, CD4, CD5, Ti (WT31), CD25, CD38, CD45, and CD29, but did not express the antigens against CD1, CD13, CD14, CD33, CD36, CD10, CD19, CD20, CD21, CD24, CD41, CD42, CD45RA, CD56, and CD57. The expression of antigen for TQ-1 or Leu8 was variable. Surface immunoglobulins were not detected. Phenotypes of cultured cells established by utilizing recombinant interleukin II were similar to those of the uncultured peripheral blood lymphoid cells except for the lack of expression of CD8. By means of two-color fluorescence, the ATL cells possessing CD4 in peripheral blood and culture coexpressed CD29, but did not express CD45RA. The suppression of PWM-induced B-cell immunoglobulin synthesis by normal T and B cells was found in five cases in the presence of ATL cells. The ATL cells demonstrated helper T-cell phenotypes (CD4+, CD29+) with suppressor function, paradoxically. We conclude that the phenotype of the ATL cells was CD4+, CD29+, and CD45RA- but that the function of these cells was of suppressor T-cells. Our results inevitably suggest the possible existence of suppressor T-cells with CD4+, CD29+ phenotype in persons without evidence of any underlying hematologic disorder.