Serum IgE and lung function in workers exposed to phthalic anhydride.

A total of 23 phthalic anhydride (PA)-exposed workers (air levels up to 17 mg/m3) showed significantly (P less than 0.01) more workrelated symptoms in their eyes (48% vs 6%) and nose (39% vs 0) than did 18 unexposed control subjects. Two of the exposed workers had PA-associated asthma. Surprisingly, the control group exhibited significantly (P less than 0.05) more symptoms of nonspecific bronchial hyperreactivity (44% vs 13%). The exposed workers showed significantly higher levels of total serum IgE (medians, 32 vs 15 kIU/l, P less than 0.05), although values for specific IgE against PA did not differ. This may indicate that such exposure can facilitate the entry of common allergens. There was a significant difference in PA-specific IgG [enzyme-linked immunosorbent assay (ELISA) ratios 0.21 vs 0.12; P less than 0.01]. There were no differences in lung function with regard to vital capacity (VC) and forced expiratory volume (FEV1), closing volume expressed as a percentage of VC (CV%), volume of trapped gas (VTG) before and after inhalation of metacholine, or carbon monoxide transfer factor (TLCO), whereas exposed workers displayed significantly higher late expiratory flow rates (MEF50 and MEF25). In a [99mTc]-diethylenetriamine penta-acetate (DTPA) clearance test, there was no difference between exposed subjects and controls. In summary, exposure to PA did not cause subclinical effects of the lungs. Subjects with lower-airway symptoms showed lower FEV1, MEF50, and MEF25 values and higher VTG (after metacholine) than did those without symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)