Immune response prevalence to formaldehyde-human serum albumin molecular adduct in a healthy population

Formaldehyde (F) covalently binds human serum albumin (HSA), giving rise to the molecular adduct, F-HSA, with F as a hapten. Humoral immune response to the adduct provides a biological marker of F exposure. A new indirect competitive enzyme immunoassay (displacement assay) using an in vitro conjugate F-HSA adduct with a 10:1 ratio was developed to titrate serum anti-F-HSA antibodies. 219 healthy subjects were examined using this assay. Examination of the data using multivariate regression analysis revealed a significant association between the F exposure marker and smoking variables in both smokers (p < 0.001) and ex-smokers (p < 0.01). No association was found between F exposure marker values and age, sex, residence, or profession. Except for the fact that the smoking variable subdivided the population into smokers, ex-smokers, and non-smokers, a significant association was found in non-smokers concerning professional exposure (p < 0.03). Results confirm that the Displacement Assay (sensitivity 96% and specificity 71%) is a useful method of evaluating F exposure, especially in large-scale public health monitoring. In order to evaluate the importance of other exposure sources, such as F pollution in indoor and outdoor air, an interesting follow up to our study would be an evaluation of a possible increase of anti-F-HSA immune response in non-smokers.