Effect of long-term administration of beta-carotene on lymphocyte subsets in humans.
To examine whether or not beta-carotene alters immune indexes, we performed a single-blind trial in healthy male nonsmokers. Lymphocyte subsets were assessed by double labeling with monoclonal antibodies before and after 44 wk of administration of either beta-carotene (60 mg/d; n = 10) or placebo (n = 10). In addition, we measured the beta-carotene concentrations in plasma, mononuclear cells (MNC), platelets, and red blood cells (RBCs), as well as the plasma alpha-tocopherol concentration. An increase of plasma and MNC beta-carotene concentrations to four and three times the baseline value was noted after 2 and 4 wk, respectively. The CD4-CD8 ratio increased after 9 mo of beta-carotene administration whereas natural killer cells, virgin T cells, memory T cells, and cytotoxic T cells remained unaltered throughout the study. No side effects or toxicities were detected by a questionnaire survey and routine laboratory tests.
Murata
T
T
Department of Pediatrics, Osaka Medical College, Japan.
Tamai
H
H
Morinobu
T
T
Manago
M
M
Takenaka
H
H
Hayashi
K
K
Mino
M
M
D000328:Adult; D000911:Antibodies, Monoclonal; D001402:B-Lymphocytes / Q000166:cytology; D001792:Blood Platelets / Q000378:metabolism; D016516:CD4-CD8 Ratio / Q000187:drug effects; D002338:Carotenoids / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D004912:Erythrocytes / Q000378:metabolism; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D016131:Lymphocyte Subsets / Q000187:drug effects*; D008297:Male; D016037:Single-Blind Method; D013601:T-Lymphocytes / Q000166:cytology; D014810:Vitamin E / Q000097:blood; D019207:beta Carotene
D000911:Antibodies, Monoclonal; D019207:beta Carotene; D014810:Vitamin E; D002338:Carotenoids