Environmentally-induced malignant pleural mesothelioma and HLA distribution in Turkey.

SETTING

A large university hospital in Ankara, Turkey.

OBJECTIVE

To investigate the potential links, if any, between the occurrence of malignant pleural mesothelioma (MPM) and the presence and distribution of human leukocyte antigens (HLA) in patients environmentally exposed to asbestos and erionite in rural Anatolia, Turkey.

DESIGN

A case-control study design was used to compare the relative frequency and distribution of HLA among 31 MPM patients originating from the fibrous zeolite (erionite) and asbestos villages in central Anatolia, and two sets of controls. The cases represented all of the MPM cases diagnosed between 1995 and 1997 in our clinic at the Hacettepe University Hospital. One control group of 119 healthy individuals was drawn from Tuzköy, which has the largest population of three erionite villages, a very high prevalence of mesothelioma due to environmental exposure to erionite, and accounted for 16 of the MPM cases in the study. A second control group composed of 118 renal transplant donors was formed for external comparison.

RESULTS

A significant relation was found with the HLA-B41 antigen in 19.4% of the patients compared to 0.8% of the Tuzköy inhabitants (odds ratio [OR] 28.3; 95% confidence interval [CI] 3.1-652.5) and 1.7% of the referent renal donor population (OR 13.9; 95% CI 2.3-106.7). The frequency of the HLA-B58 and -DR16 antigens was also observed to be significantly higher in patients with MPM compared to the two control groups. The odds ratios of MPM in those with HLA-B58 were 8.6 (95% CI 1.2-72.4) and 8.5 (95% CI 1.2-71.8), respectively, compared to those of the Tuzköy inhabitants and renal donors.

CONCLUSION

The predictive role of the HLA antigens -B41, -B58 and -DR16 for MPM needs to be further investigated. This will help in screening the population at risk, and facilitate preventive measures such as family counselling and gene therapy.