Clinical review of hidradenitis suppurativa

Summary Hidradenitis suppurativa is an uncommon disease that affects chiefly young male adults. It is characterized by an infection which begins in the skin and apocrine sweat glands and extends into the subcutaneous tissues. It may extend over wide areas and involve multiple sites. Milder forms of the disease respond to conservative surgical measures. Extensive lesions require wide surgical excision and reconstruction of the resultant defect. Owing to fecal contamination, perianal involvement presents an added difficulty which can be obviated by establishing a diverting colostomy prior to beginning surgical treatment.     

Expression of blood group antigens on red cell microvesicles

The purpose of this study was to determine whether epitopes of the A, B, D, Fya, M, N, S, s, and K blood group antigens are present on microvesicle membranes shed by red cells during storage. Vesicles were isolated from outdated units of blood having and lacking the specified antigens. Diluted antisera were absorbed with fixed quantities of vesicles from red cells with the test antigen and red cells lacking that antigen (controls). The adsorbed and unadsorbed antisera were titrated and scored by using panel cells from persons known to be heterozygous for all the non-AB antigens. The mean titration scores following adsorption with the vesicles from A, B, D, M+N-, M-N+, S+s-, S-s+, and Fy(a+b-) units were appreciably lower than the control scores (0, 0, 3, 2, 2, 0, 4, and 4 vs. 19, 23, 34, 13, 12, 16, 18, and 29, respectively), which indicated the presence of these epitopes on the membrane of shed vesicles. The results following adsorption with K:1,2 vesicles were equivocal.     

Effect of scleroderma serum on human fibroblast collagen production: possible selection through proliferation

The effects on cell proliferation and on collagen and protein synthesis of prolonged exposure of control and scleroderma skin fibroblasts to control and scleroderma serum were studied. The previously described mitogenic effect originally noted at 3 days was observed to a lesser degree at 21 days, at which time a doubling of protein synthesis and a 3-fold increase in collagen synthesis were noted. Since earlier studies of shorter exposure times did not show effects on protein or collagen synthesis, the prolonged exposure of heterogeneous mass cultures of dermal fibroblasts to the mitogenic effects of scleroderma serum may result in the emergence of high collagen producing cells.     

Effect of lymphotoxin and tumor necrosis factor on endothelial and connective tissue cell growth and function

In an approach to understand the immune basis of human vascular and fibrotic disorders, the effects of recombinant human tumor necrosis factor alpha (rTNF) and lymphotoxin (rLT) on the in vitro growth and function of vascular and connective tissue cells were studied. Both rTNF and rLT stimulated fibroblast growth and protein, fibronectin, and collagen synthesis in dose-dependent fashion. In contrast, endothelial cell (EC) growth was inhibited by both cytokines; true EC cytotoxicity was seen at high concentrations (greater than or equal to 500 mu/ml). Addition of recombinant interferon-gamma markedly enhanced EC cytotoxicity while the growth factor beta-transforming growth factor reversed EC growth inhibition. Both rTNF and rLT stimulated factor VIII-Ag synthesis by EC. These contrasting effects of rTNF and rLT on fibroblast and endothelial cell growth and function in vitro are intriguing because they are the same contrasting effects observed in vivo in connective tissue and vascular disorders, raising the possibility of a role for these cytokines in these disorders. Study of the in vitro and in vivo mechanisms of these diverse effects may contribute to the understanding of certain human disorders characterized by endothelial injury and fibroblast activation leading to fibrosis.