Heterogeneity of specific-IgE responses in workers sensitized to acid anhydride compounds.

Acid anhydride compounds cause IgE-mediated respiratory sensitization in the workplace. In this study reaginic responses in four workers sensitized to phthalic anhydride (PA), hexahydrophthalic (HHPA), or himic anhydride (HA) were determined by direct RAST by use of PA-human serum albumin (HSA), HPPA-HSA, and HA-HSA methylcellulose disc substrates. RAST inhibition of binding to anhydride-HSA substrates was done with various concentrations of sodium salts, lysine, and HSA conjugates of PA, HHPA, HA, and trimellitic anhydride (TMA) in order to characterize cross-reactivity and specificity of humoral responses in these workers. Molar concentrations of anhydride bound to lysine and HSA carriers were assayed by protein hydrolysis followed by gas chromatographic analysis. Significant direct RAST binding against PA-HSA, HHPA-HSA, and HA-HSA was found in all four workers. PA-HSA-IgE binding in one PA-sensitive worker (no. 1) was inhibited significantly by PA-HSA alone and not by sodium PA or PA lysine. In contrast, another PA-sensitized worker (no. 2) exhibited 50% inhibition of PA-HSA binding by PA-HSA (1 X 10(-9) M), PA-lysine (7 X 10(-8) M), and NaPA (1 X 10(-7) M); no inhibition of PA-HSA by heterologous HHPA-, HA-, or TMA-inhibitory reagents was found in either of the PA workers. RAST binding to HHPA-HSA in the HHPA-sensitive worker was inhibited by HHPA-HSA alone.(ABSTRACT TRUNCATED AT 250 WORDS)