Immune function and anti-HTLV-I/II status in anti-HIV-1-negative intravenous drug users receiving methadone.
OBJECTIVE
The study objective was to evaluate the effects of long-term methadone use and human T-cell leukemia virus (HTLV) types I and II seropositivity on the distribution of lymphocyte subsets and on lymphocyte function as measured in vitro in intravenous drug users seronegative for human immunodeficiency virus type 1 (HIV-1).


METHODS
Anti-HIV-1-negative intravenous drug users receiving methadone maintenance therapy (n = 24) were studied in a Veterans Administration drug abuse treatment center. These subjects were compared to 38 age- and sex-matched control subjects who did not abuse drugs. HIV-1 and HTLV serostatus was determined by repetitive enzyme-linked immunosorbent assay and confirmed by immunoblot. Lymphocyte subsets were determined by two-color flow cytometry. Lymphocyte function was measured by proliferative response to plant mitogens and by natural killer (NK) cell-mediated cytotoxicity to a tumor cell target.


RESULTS
Significant differences were seen in lymphocyte phenotype in the methadone-treated group, with elevations in the T-cell helper subset CD4+CD26+; in CD8 and CD8+I2+ cells, suppressor/cytotoxic T lymphocytes, and activated suppressor/cytotoxic T cells; and in CD2+CD26+ cells and activated total T lymphocytes. Lymphocyte function was suppressed in the methadone group, with poor responses to pokeweed mitogen and phytohemagglutinin in culture. Moreover, NK-cell cytotoxicity was significantly reduced in the methadone group. None of these immunologic differences were attributable to HTLV serostatus.


CONCLUSIONS
The immune abnormalities seen suggest that a clinically significant degree of immune impairment exists in methadone-treated intravenous drug users. However, these abnormalities could not be explained by the presence of other retroviruses in this HIV-1-negative study group, as there was no significant difference in immune function when HTLV-seropositive patients were compared to HTLV-seronegative subjects treated with methadone.
Klimas
N G
NG
Center for the Biopsychosocial Study of AIDS, Miami, Florida.
Blaney
N T
NT
Morgan
R O
RO
Chitwood
D
D
Milles
K
K
Lee
H
H
Fletcher
M A
MA
D000328:Adult; D001402:B-Lymphocytes / Q000276:immunology; D015480:Deltaretrovirus Antibodies / Q000032:analysis*; D015483:HIV Antibodies / Q000032:analysis*; D006679:HIV Seropositivity / Q000276:immunology*; D006801:Humans; D013287:Illicit Drugs; D007694:Killer Cells, Natural / Q000502:physiology; D007958:Leukocyte Count; D016131:Lymphocyte Subsets / Q000737:chemistry; D008297:Male; D008691:Methadone / Q000627:therapeutic use*; D015819:Substance Abuse, Intravenous / Q000188:drug therapy* / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology
D015480:Deltaretrovirus Antibodies; D015483:HIV Antibodies; D013287:Illicit Drugs; D008691:Methadone