title: Lymphocyte toxicity and T cell receptor excision circles in workers exposed to benzene.
abstract: 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.
authors.affiliation: 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
authors.forename: Qing
authors.initials: Q
authors.lastname: Lan
authors.forename: Luoping
authors.initials: L
authors.lastname: Zhang
authors.forename: Fran
authors.initials: F
authors.lastname: Hakim
authors.forename: Min
authors.initials: M
authors.lastname: Shen
authors.forename: Sarfraz
authors.initials: S
authors.lastname: Memon
authors.forename: Guilan
authors.initials: G
authors.lastname: Li
authors.forename: Roel
authors.initials: R
authors.lastname: Vermeulen
authors.forename: Martyn T
authors.initials: MT
authors.lastname: Smith
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Rappaport
authors.forename: Richard
authors.initials: R
authors.lastname: Hayes
authors.forename: Martha
authors.initials: M
authors.lastname: Linet
authors.forename: Songnian
authors.initials: S
authors.lastname: Yin
authors.forename: Nathaniel
authors.initials: N
authors.lastname: Rothman
authors.forename: Charles S
authors.initials: CS
authors.lastname: Rabkin
mesh_terms: 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
chemical_list: D000395:Air Pollutants, Occupational; D004270:DNA, Circular; D011948:Receptors, Antigen, T-Cell; D001554:Benzene