Analysis for Plasma Protein Biomarkers Following an Accidental Human Exposure to Sulfur Mustard

Following an accidental human exposure to a vesicating agent, plasma samples were analyzed for specific biomarkers of sulfur mustard. One individual suffered chemical burns over 6.5% of the body surface area and required hospitalization; the second individual developed a single, small blister. Plasma specimens from both individuals were examined using two different assays. The first assay targeted sulfur mustard adducts to cysteine-34 of albumin using affinity chromatography, enzyme digestion, and analysis of the alkylated peptide fragment using liquid chromatography-tandem mass spectrometry. The second assay targeted alkylation sites of glutamic and aspartic acids of plasma proteins. Following precipitation of plasma proteins, the sulfur mustard adducts were cleaved from the protein using base, derivatized, and analyzed using gas chromatography-mass spectrometry. Samples obtained over a 42-day period from the individual requiring hospitalization produced positive results for sulfur mustard adducts using both assays. Observed levels of the sulfur mustard biomarker decreased by approximately 75% between days 2 and 42 for both assays. Samples obtained over a six-day period from the individual with a single, small blister produced positive results for the albumin adduct assay. Observed levels were much lower than levels from the hospitalized patient. Blood samples from suspected human exposures to sulfur mustard have only rarely been made available for analysis by sensitive and specific laboratory assays. The data presented here add significantly to the small database of information that currently exists on human biomarkers of sulfur mustard exposure, linking a well-documented exposure event with levels of plasma protein adducts.