Lymphocyte subsets in HTLV-II-infected former blood donors: relationship to spontaneous lymphocyte proliferation.
Previous studies showed that over 70% of HTLV-seropositive blood donors from the Los Angeles area are infected with HTLV-II; further, mononuclear cells from about half of these HTLV-II+ donors exhibit spontaneous lymphocyte proliferation (SLP) during in vitro culture. To determine if HTLV-II+SLP+ donors exhibit more marked immune system changes than HTLV-II+SLP- donors, lymphocyte subsets for these two HTLV-II+ groups were compared to an uninfected control group. The percentage of lymphocytes expressing CD3 was significantly increased and the percentage expressing a CD16/56+CD3- phenotype (natural killer cells) was significantly decreased in the HTLV-II+SLP+ group (N = 34) versus the control group (N = 49). On the basis of absolute numbers, the lymphocyte number was significantly higher in the HTLV-II+SLP+ group than in the control group and reflected significant increases in the numbers of both CD4 and CD8 subsets of T cells. Analysis of proportional changes in CD4 and CD8 cell subsets revealed significant increases in the proportions of CD4 cells expressing HLA-DR, CD8 cells expressing HLA-DR, and CD8 cells expressing CD45RO for the HTLV-II+SLP+ group versus the control group. For all phenotypic parameters measured, no significant differences were noted when comparing the HTLV-II+SLP- group (N = 21) and the control group. Cell culture experiments utilizing purified CD4 cells and CD8 cells from a subset of each study group revealed that in vitro spontaneous proliferative capacity resides within both the CD4 cell and CD8 cell populations from SLP+ individuals. These findings show that changes in circulating lymphocyte subsets in HTLV-II infection are found only in association with SLP, and that the capacity to exhibit SLP characterizes both CD4 and CD8 lymphocyte subsets.
Prince
H E
HE
Cellular Immunology Laboratory, American Red Cross Blood Services, Southern California Region, Los Angeles 90006.
Jensen
E R
ER
York
J
J
D001782:Blood Donors; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D016827:CD8 Antigens / Q000276:immunology; D002469:Cell Separation; D006684:HLA-DR Antigens / Q000032:analysis; D015491:HTLV-II Infections / Q000097:blood*; D006801:Humans; D017493:Leukocyte Common Antigens / Q000276:immunology; D008213:Lymphocyte Activation; D016131:Lymphocyte Subsets / Q000276:immunology*
D016827:CD8 Antigens; D006684:HLA-DR Antigens; D017493:Leukocyte Common Antigens