Lymphocyte toxicity and T cell receptor excision circles in workers exposed to benzene.
We have previously reported that benzene decreases peripheral white blood cell and platelet counts and specifically lowers subsets of several blood cell types, including CD4+-T cells, B cells, NK cells, and granulocytes. Diminished thymus function has been implicated as a mechanism for CD4+-T cell loss in other conditions such as AIDS by assays of T cell receptor excision circles (TRECs), a marker of naive T cells that have recently emigrated from the thymus. To evaluate alteration of thymic function as a mechanism for benzene's effects on CD4+-T cell counts, we measured total TREC levels in 45 benzene-exposed workers and 45 unexposed controls. There was no significant difference in TREC levels per 10(6) peripheral blood leukocytes in the benzene-exposed workers compared to the controls. Although our study does not rule out counterbalancing alterations of TREC levels in specific T cell subsets, benzene's lymphotoxicity does not appear to be mediated through diminished thymus function.
Lan
Qing
Q
Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, 6120 Executive Blvd., EPS 8109, Bethesda, MD 20892-7240, USA. qingl@mail.nih.gov
Zhang
Luoping
L
Hakim
Fran
F
Shen
Min
M
Memon
Sarfraz
S
Li
Guilan
G
Vermeulen
Roel
R
Smith
Martyn T
MT
Rappaport
Stephen M
SM
Hayes
Richard
R
Linet
Martha
M
Yin
Songnian
S
Rothman
Nathaniel
N
Rabkin
Charles S
CS
D000328:Adult; D000395:Air Pollutants, Occupational / Q000032:analysis / Q000633:toxicity*; D001554:Benzene / Q000032:analysis / Q000633:toxicity*; D001772:Blood Cell Count; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects / Q000276:immunology; D002681:China; D004270:DNA, Circular / Q000032:analysis* / Q000097:blood; D004784:Environmental Monitoring; D005260:Female; D006801:Humans; D007962:Leukocytes / Q000276:immunology; D008297:Male; D016273:Occupational Exposure; D011948:Receptors, Antigen, T-Cell / Q000235:genetics* / Q000276:immunology; D011995:Recombination, Genetic; D012775:Shoes; D013950:Thymus Gland / Q000187:drug effects / Q000276:immunology
D000395:Air Pollutants, Occupational; D004270:DNA, Circular; D011948:Receptors, Antigen, T-Cell; D001554:Benzene