SYMPTOMS AND IMMUNOLOGICAL MARKERS INDUCED BY EXPOSURE TO METHYLTETRAHYDROPHTHALIC ANHYDRIDE

A study was performed in 43 workers exposed to methyltetrahydrophth al ic anhydride (MTHPA) used as a hardener in an epoxy resin system. Ten workers sensitized to MTHPA (group SS; presence of serum IgE antibodie s against a conjugate of MTHPA and human serum albumin (HSA) detected by RAST) had significantly higher levels of tryptase in nasal lavage f luid than 19 nonsensitized workers with work-related nasal symptoms (g roup NS) and 14 nonsensitized workers without nasal symptoms (group NN ), This suggests an ongoing mast-cell-mediated reaction in the sensiti zed group. No statistically significant differences were found in the three groups concerning eosinophil cationic protein (ECP) and TAME-act ivity in lavage fluid. However, there was a significant increase in se rum ECP in the SS group, as compared with a group of unexposed control s. Nasal challenge with MTHPA-HSA, performed in a subsequent study in seven workers from the SS group, six from the NS group, and seven from the NN, caused a larger increase of symptom score and a more pronounc ed decrease in nasal inspiratory peak flow in the SS group than in the other two groups. No significant rise was recorded for tryptase and E CP in lavage fluid in any of the three groups after challenge. The com bined results of the two studies indicate that specific IgE antibodies play a pathogenetic role in at least some of the cases of work-relate d nasal symptoms associated with MTHPA exposure.