Immunologic specificity of IgG against trimellityl-human serum albumin in serum samples of workers exposed to trimellitic anhydride.

The specificity of immunoglobulin G (IgG) against trimellityl-human serum albumin (TM-HSA) in serum samples from 11 workers exposed to trimellitic anhydride (TMA) was characterized in this study. Levels of IgG against TM-HSA and HSA-conjugates of other acid anhydrides, phthalic anhydride (PA), maleic anhydride (MA), hexahydrophthalic anhydride (HHPA) and tetrachlorophthalic anhydride (TCPA) were estimated by enzyme-linked immunosorbent assay index. Inhibition studies using each of 5 HSA acid anhydride conjugates were performed on all 11 serum samples with IgG against TM-HSA, and on the three serum samples with highest IgG binding to P-HSA and M-HSA. The only conjugate capable of inhibiting TM-HSA was TM-HSA. Both P-HSA and TM-HSA were able to inhibit IgG bound to P-HSA, and all other anhydride conjugates were able to inhibit IgG bound to M-HSA to some degree. When using TM-HSA and the other anhydride-HSA conjugates to inhibit IgG against TM-HSA, cross-reactivity was not apparent. However, when using those same conjugates to inhibit IgG against P-HSA or M-HSA, cross-reactivity could be demonstrated in some serum samples. Thus TMA workers may have antibody that has some affinity for other anhydride-HSA conjugates, but this antibody cannot be demonstrated by inhibition studies of IgG against TM-HSA when using other acid anhydride-HSA conjugates. Further studies are needed to define the biologic relevance of these immunologic observations.