38 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Now, what are these cells, and where do they exist? Admittedly, no definitive statement can be made, but the evidence seems to point clearly to cells of the reticuloendothelial system as being the cells in which the altera- tion takes place. For a variety of reasons that I shall not go into here, it is thought that the primitive reticulum cell is a likely one in which the adapta- tion occurs. Of course, it is quite conceivable that the enzymatic adjust- ment can take place in several kinds of cells, but the primitive reticulum cell is the one I believe to be primarily responsible. This cell is rather ubiqui- tously distributed throughout the body and exists in the curls, as well as in the regional lymph nodes. There is circumstantial evidence to make one believe that the adaptation takes place in the curls or in the regional node or in both. An important point to realize about the enzymatic modification is that there is reason to believe that this type of adaptation is passed to the descendants of the cells in question. Consequently, the persistence of a sensitization over a period of time is explained. The next problem to be discussed is what happens to the cells in which the enzymatic adaptation has occurred? In the event that the adaptation has taken place in primi- tive reticulum cells situated either in the curls or in the regional nodes, there is, of course, no reason to believe that these cells move from their original locus but the primitive reticulum cell is the theoretical progenitor for the wide variety of cells, including many motile ones, such as macro- phages and lymphocytes. Such cells, when they are the descendants of a primitive reticulum cell with an adapted enzyme system, would then have the same modification and thus one would find cells with the specifically adapted system ubiquitously distributed throughout the body. When the eczematously sensitized individual is again exposed to the simple chemical in question, or to an immunologically equivalent material, there is reason to believe that, in order for a reaction to develop, the simple chemical has again to enter into the same sort of union that it did when the sensitizing application was originally done or, in other words, the same antigenic protein conjugate is formed in vivo as was formed initially. Just how the formation of this conjugate in the specifically sensitized in- dividual causes the development of the eczematous lesions is not known, but speculations which are at least in accord with the known facts can be advanced. First, in view of the fact that the conjugate is probably formed, as was already stated, within the epidermis, it would lie in proximity to the capillary loops coursing in the papillary bodies of the cutis. Theoretically, the in vivo formation of the conjugate would cause a trivial amount of damage which might mildly alter the permeability of the capillaries in ques- tion as a consequence of this alteration in permeability a few cells escape. In a person who possesses cells with an adapted enzyme system directed toward the antigenic conjugate which has been formed in the epidermis in

DEVELOPMENT OF AN ECZEMATOUS SENSITIZATION 39 proximity to the area in which these cells have escaped, there would be further interaction as the enzymatic adaptation in the cells in question has caused these cells to react in a different fashion when they again encounter the antigen to which they have become adapted. This further action would then be the basis of the eczematous alterations. In view of the fact that the essential lesion of the eczematous response is a primordial vesicle, it is reasonable to believe that a pyruvate-oxidase system may have been affected, inasmuch as this system is known to be affected in vesicular lesions caused by primary vesiculating agents. According to Andrew and Andrew (6), lymphocytes continuously invade the epidermis and there become transformed into epidermal cells. Un- fortunately, most anatomists and pathologists are in opposition to this theory it is, nevertheless, an extremely attractive suggestion from the point of view of pathogenesis of the eczematous lesions, for if it were true and the lymphocytes that invaded the epidermis and which became trans- formed into epidermal cells were descendants of cells with a specifically adapted enzyme system, it is easy to see how the epidermis in such persons acquired a specific sensitivity toward the antigen in question. For the epidermal cells right at the site of the formation of the antigenic conjugate within the epidermis would be specifically sensitized and consequently capable of reacting with the conjugate in question. BIBLIOGRAPHY (1) Landsteiner, K., and S. Jacobs, John, "Studies on the Sensitization of Animals with Simple Chemical Compound," II, 5 t. Exp. Meal., 64, 625 (October 1, 1936). (2) Gell, P. G. H., Harington, C. R., and R. P. Rivers, "The Antigenic Function of Simple Chemical Compounds: Production of Precipitin in Rabbits," Brit. 7. Exp. Path., 27, 267 (1946). (3) Cullumbine, H., "The Mode of Penetration of the Skin by Mustard Gas," Brit. 7. Dermatol & Syphilol., 58, 291 (1946). (4) Burner, F. M.,"The Edward Stirling Lectures. I. The Basis of Allergic Disease," Meal. 7. •lustralia, 1, 29 (January 10, 1948). (5) Rostenberg, A., Jr., and Brunner, M. J., "Remarks on the Theories of Antibody Forma- tion," •lnn. of •lllergy, 8, 108 (January-February, 1950). (6) Andrew, W., and Andrew, N. V., "Lymphocytes in the Normal Epidermis of the Rat and of Man," •.n_•t: Record, 104, 217 (1949). MEETING MAY 12, 1955 "Topical Uses of Antibiotics: Vehicles Employed," William B. Baker, S. B. Penick and Company "Acetylated Lanolin Derivatives," Lester I. Conrad, American Cholesterol Products, Inc. "Foam Transition and Foam Persistence," M. B. Epstein, Onyx Oil and Chemical Company "Film Properties and Compound Formation in the Sodium Lauryl Sulfate-Lauryl Alcohol-Water System," A. Wilson, Colgate-Palmolive Company 'Symposium on Skin Geriatrics "The Social and Economic Aspects of Skin Geriatrics," E. Anderson, Schering Corp. "The Anatomy and Histology of Aging Skin," Warren Andrew, Wake Forest College "The Chemistry of Aging Skin," Peter Flesh, University of Pennsylvania "The Structural Proteins in the Epidermis and Their Relation to Aging Skin," C. Carruthers, State of New York Department of Health