1. Eight of 13 sera from patients with pemphigus vulgaris were found to contain antibodies to a substance at the surface of the cells of stratified squamous epithelium, particularly in the stratum spinosum, as demonstrated by indirect immunofluores-cent (I.I.F.) staining. The reactions of 4 of these 8 sera were deemed to be weakly positive or doubtful while the remaining 4 sera yielded titers of 1:30 to 1:120 by I.I.F. staining. The reactive antigen was found only in stratified squamous epithelium. Other types of epithelial tissue studied to date do not appear to contain the antigen. None of the 88 sera of normal individuals, patients with other skin diseases, or patients with other immunologic disturbances that have been tested to date appear to contain such antibody activity. However, 2 of the sera of patients with other chronic bullous skin diseases appeared to contain an antibody to the basement membrane of the skin and other stratified squamous epithelia. 2. A skin biopsy of one of the antibody producing patients with pemphigus vulgaris revealed the presence of bound gamma globulin on the surface of the epithelial cells in an apparently normal portion of the skin adjacent to a vesicle. This localization was identical to that obtained by I.I.F. staining with the patient's serum.

The authors gratefully acknowledge instruction and suggestions in the field of immunology by Dr. Ernest Witebsky, suggestions of Dr. James Jordon which stimulated the initiation of this study as well as his supply of the first 3 sera, the supply of one serum and skin biopsies by Dr. Joseph Aquilina, and the critique of the manuscript and supply of some additional sera by Dr. Walter Lever.