POTENTIALLY ALLERGENIC PROTEINS IN COCKROACHES Four allergenic proteins which are secreted by the common household cockroach have been recently cloned. One of these proteins belongs to the family of calycins which includes a number of other human allergens such as beta-lactoglobulin present in the cow’s milk, and two pheromone binding proteins in the rat urine. Calycins form cup like pockets that bind hydrophobic molecules such as pigments, animal phermones and fatty acids. These proteins contain conserved amino acid sequences which may be the binding site for the IgE or CD4+ T cells and therefore account for their allergenic potential. Martin et al report in the August 1994 issue of Clinical Experimental Allergy that peptides from the conserved region of beta-lactoglobulin possess such activity. These findings raise the important issue that some types of allergy in humans may be related to the proteins secreted by the common household cockroach (German cockroach).