Haemoglobin adducts and specific immunoglobulin G in humans as biomarkers of exposure to hexahydrophthalic anhydride

The aim of this study was to determine whether haemoglobin adducts Hb of hexahydrophthalic anhydride HHPA and HHPA specific immunoglobulin G IgG can be used as biomarkers of exposure to HHPA. The exposures of HHPA in 10 workers were determined from the mean urinary hexahydrophthalic acid HHP acid levels range 76-3300 nmol HHP acid mmol-1 creatinine during a period of 4 weeks. Blood was collected at the end of the period and Hb-HHPA adducts were analysed by gas chromatography mass spectrometry. The Hb-HHPA adduct levels ranged from 0.45 to 24.7 pmol g-1 Hb. There was a close correlation between the urinary HHP acid levels and the amount of Hb-HHPA adducts r = 0.87 . One day exposures to HHPA and methylhexahydrophthalic anhydride MHHPA in 142 workers were determined from analysis of urinary HHP acid range 0-3300 nmol HHP acid mmol-1 creatinine and methylhexahydrophthalic acid MHHP acid; range 0-1700 nmol MHHP acid mmol-1 creatinine. HHPA specific IgG were analysed in the 142 workers with an ELISA method. The optical density for HHPA specific IgG varied between 0 and 1.25. There was no statistically significant correlation between the sum of the urinary HHP acid and MHHP acid and the HHPA specific IgG r = 0.12; p = 0.14 . Thus, Hb-HHPA adducts seem to be applicable as biomarkers of exposure to HHPA while the possible role of HHPA specific IgG as an indicator of exposure has to be further evaluated.