HPRT mutant frequencies and detection of large deletions by multiplex-PCR in human lymphocytes of vinyl chloride exposed and non-exposed populations

The frequency of hypoxanthine guanine phosphoribosyltransferase (HPRT) mutations was determined in human T-lymphocytes isolated from peripheral blood of three populations: (1) 24 employees occupationally exposed to vinyl chloride monomer; (2) 23 healthy non-exposed matched control individuals and (3) 41 regular blood donors. In addition, mutant clones of all studied groups were examined by multiplex-PCR for visible abnormalities of the gene (large deletions), Surprisingly, the mutation frequency of all three investigated populations was approximately the same (7-8 x 10(-6)). However, great differences occurred for the spectrum of mutants. Among the mutant clones of the non-exposed healthy individuals only 6% (blood donors) and 11% (matched control group) showed large deletions. The corresponding percentage of large deletions in the occupationally exposed group was, at 21%, much higher.