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Background: Bullous pemphigoid (BP) associated with milia lesions has been increasingly reported, but its prevalence has not been reported in a Brazilian BP population yet., Objectives: To describe the occurrence and clinical-laboratorial findings of BP-milia association in a southeastern Brazilian sample., Methods: A descriptive study based on the medical charts of 102 BP patients was accomplished. Clinical and laboratory data of BP-milia patients were compiled. Total serum IgE measurements, immunoblot assays based on basement membrane zone antigens, and HLA-DQ alleles typing were performed., Results: Milia was evident in 8 (7.8%) BP patients, five males, aged between 46 and 88 years. Increased total IgE levels were determined in 7 (87.5%) of the eight patients. In five of eight patients, immunoblotting showed IgG reactivity against the BP180-NC16a domain but not against collagen VII or laminin-332; it also revealed reactivity against the BP180 C-terminal domain or LAD-1, or both in four of them. The HLA-DQB1*03:01 and HLA-DQA1*05:05 alleles were identified in three of five BP-milia patients. Moreover, three of five cases presented the HLA-DQB1*06 allelic group., Study Limitations: HLA determination was performed in five patients., Conclusions: Milia formation in BP patients seems to be less uncommon than previously admitted. Laboratory data revealed increased IgE; autoantibodies against the BP180 C-terminal domain or LAD-1, or both; and the HLA-DQB1*06 allelic group, described for the BP-milia association. Careful determination of antibodies against basement membrane zone molecules and HLA characterization in different populations may provide further insights into this association., (Copyright © 2022 Sociedade Brasileira de Dermatologia. Published by Elsevier España, S.L.U. All rights reserved.)

Background: Besides Brazilian endemic pemphigus foliaceus (EPF), we have described another focus of EPF in Colombia. Our previous study suggested that Colombian EPF seemed to react various plakin family proteins, such as envoplakin, periplakin and BP230., Objective: To further characterize the Colombian EPF and study the difference from Brazilian EPF, we examined the antigen profile of the two types of EPF., Methods and Results: Immunoblotting using normal human epidermal extracts revealed that 38% Colombian EPF sera and 25% Brazilian EPF sera showed IgG antibodies reactive with desmoglein (Dsg) 1, pemphigus foliaceus antigen. The sera of both types of EPF showed protein bands co-migrating with plakin family proteins, particularly periplakin. Immunoblotting analyses using recombinant proteins of various domains of envoplakin, periplakin and BP230 revealed that a considerable number of Colombian EPF sera reacted with recombinant proteins of periplakin, while only few Brazilian sera reacted with some of the recombinant proteins of any plakins. Enzyme-linked immunosorbent assay (ELISA) for Dsg1 and Dsg3 showed that Dsg1 was reacted by almost all sera of both types of EPF. However, unexpectedly, while none of Colombian EPF sera reacted with Dsg3, about half of Brazilian EPF sera reacted with Dsg3., Conclusion: These results suggested that the Colombian EPF is basically similar to Brazilian EPF in terms that major antigen is Dsg1, but there were some different antigen profiles between the two types of EPF.

Human IgG possesses four main subclasses, namely IgG1, IgG2, IgG3, and IgG4, of these IgG1-IgG3 fix complement, but IgG4 does not. We have studied the IgG subclasses of intercellular antibodies in the sera from 20 patients with Brazilian pemphigus foliaceus by immunofluorescent staining using mouse monoclonal antibodies against human IgG1-IgG4. At the same time, the complement fixing capability of each antibody was examined by complement immunofluorescence. All of four subclasses were frequently detected in most cases with varying distributions. However, no specific pattern was observed. Complement fixing antibodies were found in four patients. However, the distribution of IgG subclasses was incompatible with their known characteristics in terms of complement activation. This discrepancy increases the controversy over the importance of the complement system in blister formation in pemphigus.