title: Increased lymphocyte replicative index following 2,4-dichlorophenoxyacetic acid herbicide exposure.
abstract: OBJECTIVE
  Evaluate peripheral blood lymphocyte proliferation (replicative index:RI) and micronuclei frequency (MF) among 2,4-D herbicide applicators.
  
  
  METHODS
  Twelve applicators spraying only 2,4-D provided a blood and urine specimen upon enrollment, several urine samples during the spraying season, and a blood specimen at the study's end. Nine controls provided blood and urine specimens upon enrollment and at the study's end. Gas chromatography/tandem mass spectroscopy determined urinary 2,4-D levels and standard in-vitro assays determined RI and MF scores. Applicator RI and MF were compared before and after spraying and with controls.
  
  
  RESULTS
  Applicators contributed 45 urine specimens with concentrations ranging from 1.0 to 1700 (microg 2,4-D/g creatinine/L urine) that logarithmically (In) increased as spraying time increased. Applicator RI increased after spraying (p = 0.016), independent of tobacco and alcohol use, and demonstrated a weak dose-response with increasing urinary 2,4-D levels (p = 0.15). Among 2,4-D applicators, pre-exposure complete blood counts and lymphocyte immunophenotypes were not significantly different from post-exposure measurements.
  
  
  CONCLUSIONS
  Urinary 2,4-D concentration, an exposure biomarker, may be associated with lymphocyte replicative index, a cell proliferation biomarker.
authors.affiliation: School of Public Health, St Louis University, MO 63108-3342, USA. figgslw@slu.edu
authors.forename: L W
authors.initials: LW
authors.lastname: Figgs
authors.forename: N T
authors.initials: NT
authors.lastname: Holland
authors.forename: N
authors.initials: N
authors.lastname: Rothmann
authors.forename: S H
authors.initials: SH
authors.lastname: Zahm
authors.forename: R E
authors.initials: RE
authors.lastname: Tarone
authors.forename: R
authors.initials: R
authors.lastname: Hill
authors.forename: R F
authors.initials: RF
authors.lastname: Vogt
authors.forename: M T
authors.initials: MT
authors.lastname: Smith
authors.forename: C D
authors.initials: CD
authors.lastname: Boysen
authors.forename: F F
authors.initials: FF
authors.lastname: Holmes
authors.forename: K
authors.initials: K
authors.lastname: VanDyck
authors.forename: A
authors.initials: A
authors.lastname: Blair
mesh_terms: D015084:2,4-Dichlorophenoxyacetic Acid / Q000009:adverse effects* / Q000097:blood / Q000652:urine*; D000293:Adolescent; D000328:Adult; D000428:Alcohol Drinking; D015415:Biomarkers / Q000652:urine; D016022:Case-Control Studies; D008401:Gas Chromatography-Mass Spectrometry; D006540:Herbicides / Q000009:adverse effects* / Q000097:blood / Q000652:urine*; D006801:Humans; D008213:Lymphocyte Activation / Q000187:drug effects*; D008297:Male; D048629:Micronuclei, Chromosome-Defective / Q000187:drug effects; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects* / Q000032:analysis; D010865:Pilot Projects; D012907:Smoking; D011795:Surveys and Questionnaires
chemical_list: D015415:Biomarkers; D006540:Herbicides; D015084:2,4-Dichlorophenoxyacetic Acid