Case-control study on concentrations of organohalogen compounds and titersof antibodies to Epstein-Barr virus antigens in the etiology of non-Hodgkin lymphoma

A rapid increase in incidence of non-Hodgkin lymphoma (NHL) has been report ed from many countries. Exposure to certain pesticides and organochlorines has been shown to be risk factors. Epstein-Barr virus (EBV) is a human herp esvirus that has been associated with some subgroups of NHL, such as Burkit t lymphoma and lymphomas related to severe immunosuppression. In this study , we measured lipid adjusted blood concentrations of 36 congeners of polych lorinated biphenyls (PCBs), p,p ' -dichlorodiphenyl-dichloroethylene (p,p ' -DDE), hexachlorobenzene (HCB), four different subgroups of chlordanes (tr ans-nonachlordane, cis-nonachlordane, MC6 and oxychlordane) and 2,2 ' ,4,4 ' -tetrabrominated diphenyl ether (TBDE) in incident cases of NHL and contr ols from the general population. Titers of antibodies to the Epstein-Barr e arly antigen (EA) were correlated to concentrations of organochlorines. We found a significant difference in lipid adjusted blood concentrations of to tal PCBs and TBDE between cases and controls. Titers of antibodies to EA Ig G > 80 were correlated to an increased risk for NHL with odds ratio (OR) = 1.9, 95% confidence interval (CI) = 0.94-3.8. This risk was further increas ed in those with a level above the median value of "sum of PCBs" (OR=4.0, C I=1.2-14), HCB (OR=5.3, CI=1.6-19), sum of chlordanes (OR=4.0, CI=1.2-14) a nd TBDE (OR=21, CI=4.6-124), suggesting an interaction between EBV and a hi gher concentration of these chemicals. Also for the "sum of immunotoxic PCB s" increased risk was found in that group (OR=6.4. CI=1.9-24). Subdivision of NHL in histological types yielded highest risks for low-grade B-cell NHL .