- Combined alveolitis and asthma due to hexamethylene diisocyanate (HDI), with demonstration of crossed respiratory and immunologic reactivities to diphenylmethane diisocyanate (MDI). Malo, J.L., Ouimet, G., Cartier, A., Levitz, D., Zeiss, C.R. J. Allergy Clin. Immunol. (1983)