Occupational Epidemiology Study On Benzene Exposed Workers And The White Blood Cell Counts Influenced By MDR1 Gene Polymorphysim

Benzene poisoning is a common occupational disease.《Diagnostic criteria of occupational benzene poisoning》(GBZ 68-2002) was promulgated in 2002 which was amended in 2008. Defining the platelet counts reduction as the starting point of the diagnostic criteria was the amendment description of the new diagnostic criteria. To investigate the mechanism of platelet counts reduction in benzene poisoning, we designed a unified questionnaire with occupational epidemiology method, estimated the cumulative exposure benzene doses, measured the blood routine examination and the platelet associated antibodies PAIgG,PAIgA,PAIgM with ELISA and explored the changes of platelet associated antibodies in benzene exposed workers. In this operating environment, benzene concentrations were from 0.25 to 15.70mg/m3. Cumulative exposure doses of exposed group were from 1.71 to 74.2 mg/(m3. a). The WBC,Hb,PLT of exposed workers were not significantly different from those of controls. The PAIgG,PAIgA,PAIgM and the proportion of elevated of PAIgA in exposed group were significantly higher (P<0.05) than those of the controls. PAIgA,PAIgM tended to elevate when the cumulative exposure doses of benzene were increasing in a dose-effect dependent manner. After stratification by smoking,drinking, the changes were still significant in smoking,drinking group or male, but not in non-smoking,non-drinking group or female. (P>0.05). Even though the low benzene concentration in operating environment, platelet associated antibodies may be changed before blood routine become abnormal, and smoking or drinking may interact with these changes.In order to explore a new genetic suseptibility biomarker and a novel mechanism to hematotoxicity from benzene, PCR-RFLP and HRM were utilized to detect the polymorphism of MDR1 in 110 healthy controls and 121 workers occupationally exposed to benzene and the influence on WBC produced by this polymorphism in benzene exposed workers. The frequency of MDR1 3435 C/C, C/T, T/T in healthy controls respectively was 37.27%,46.36%,16.36%, which in wokers exposed to benzene respectively was 38.84%,39.67%,21.49%. The frequency of the MDR1 gene polymorphism was also not significantly different between benzene exposed workers and controls. Subjects exposed to benzene with MDR1 3435 mutation genotype (T/T) had the significantly lower WBC(5.46±1.51×109/L) than those carring wild type (C/C) and heterozygous (C/T), whose WBC were 6.08±1.28×109/L (P=0.044). The results analyzed respectively by HRM and PCR-RFLP were consistent, while the former was easier to operate and had the lower costs than the latter.