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.
Cellular Immunology Laboratory, American Red Cross Blood Services, Southern California Region, Los Angeles 90006.
H E
HE
Prince
E R
ER
Jensen
J
J
York
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