The determination and prevention of cytotoxic effects induced in human lymphocytes by the alkylating agent 2,2'-dichlorodiethyl sulfide (sulfur mustard, HD).

2,2'-Dichlorodiethyl sulfide (sulfur mustard, HD, 1,1'-thio-bis[2-chloroethane]) is a potent vesicant which can cause severe lesions to skin, lung, and eyes. There is no convenient in vitro or in vivo method(s) to objectively measure the damage induced by HD; therefore, a simple in vitro method was developed using human peripheral lymphocytes to study HD-induced cytotoxicity. The cytotoxicity of HD was measured using dye exclusion as an indicator of human lymphocyte viability. Exposure to HD resulted in both a time- and a concentration-dependent cytotoxic effect on human lymphocytes. Using this in vitro assay, the effectiveness of various therapeutics (niacin, niacinamide, and 3-aminobenzamide) in preventing HD-induced cytotoxicity was studied. Niacinamide and 3-aminobenzamide prevented the cytotoxic effects of HD for up to 2 days.