Differential HLA class I and class II associations in pemphigus foliaceus and pemphigus vulgaris patients from a prevalent Southeastern Brazilian region Maria Jos  e Franco Brochado a , Daniela Francisca Nascimento b , Wagner Campos c , Neifi Hassan Saloum Deghaide d , Eduardo Antonio Donadi d, ** , Ana Maria Roselino a, *, 1 a Division of Dermatology, Department of Clinical Medicine, Ribeir~ ao Preto Medical School, University of S~ ao Paulo, Ribeir~ ao Preto, S~ ao Paulo, Brazil b Post-Graduate Clinical Medical Area, Ribeir~ ao Preto Medical School, University of S~ ao Paulo, Ribeir~ ao Preto, S~ ao Paulo, Brazil c Laboratory of Biochemistry and Phytopathology, Biological Institute, S~ ao Paulo, S~ ao Paulo, Brazil d Division of Clinical Immunology, Department of Clinical Medicine, Ribeir~ ao Preto Medical School, University of S~ ao Paulo, Ribeir~ ao Preto, S~ ao Paulo, Brazil article info Article history: Received 26 March 2016 Received in revised form 23 April 2016 Accepted 24 April 2016 Available online xxx Keywords: Haplotypes HLA class I HLA class II Pemphigus Pemphigus foliaceus Pemphigus vulgaris abstract Genetic factors, particularly those concerning HLA class II, have been associated with the pathogenesis of pemphigus. Taking advantage of an area where pemphigus foliaceus (PF) and pemphigus vulgaris (PV) are prevalent in the northeastern region of the state of S~ ao Paulo, Southeastern Brazil, we have studied the HLA class I (A, B and C) and class II (DRB1 and DQA1/DQB1) profiles in 86 and 83 patients with PF and PV, respectively, as compared with 1592 controls from the same region. Among all the HLA alleles described herein, the more prevalent susceptibility alleles for PF were HLA- A*11, 33, -B*14; -DRB1*01:01, *01:02; -DQA1*01:02; and -DQB1*05:01. In PV patients, the HLA-B*38; -C*12; -DRB1*04:02, *08:04, *14:01, *14:04; -DQA1*03:01; and -DQB1*03:02 and *05:03 alleles were associated with susceptibility. The HLA-DRB1*01:02 allele and the HLA-DRB1*01-DQA1*01-DQB1*05 haplotype in PF patients and the HLA-DRB1*04:02 and *14:01 alleles and the HLA-DRB1*14-DQA1*01- DQB1*05 haplotype in PV patients were related with the highest etiologic fraction values. Distinct genetic patterns and not yet described HLA susceptibility/protection alleles/haplotypes pro- files have been observed in this series. Our findings corroborate the differential genetic markers in PF and PV in an area where pemphigus is prevalent but not yet reported. © 2016 Elsevier Ltd. All rights reserved. 1. Introduction Pemphigus is a group of diseases characterized by the presence of autoantibodies against desmogleins (DSG). DSG originate from the cadherin family. They diminish adhesion among keratinocytes, culminating in intraepidermal blister formation and acantholysis. The commonest clinical forms of pemphigus are pemphigus folia- ceus (PF) and pemphigus vulgaris (PV). While PF affects the skin only and presents anti-DSG1 antibodies, PV can affect the skin and mucous membranes through production of autoantibodies against DSG1 and DSG3, respectively [1,2]. The etiology and the pathogenesis of the pemphigus blistering diseases deserve to be studied, since they were no fully determined until the moment [3]. While environmental features have been related to HLA genetic associations in this pathogenesis, the etiol- ogy of pemphigus has not been determined. Important studies on Brazilian PF have been conducted mainly with the Terena indige- nous population from the Lim~ ao Verde reserve in the state of Mato Grosso do Sul [4]. PF is endemic in the northeastern region of the state of S~ ao Paulo state [5]. In the last decades, PV has been diag- nosed in this same area, in younger patients as compared with the usual PV cases. In fact, PV incidence has surpassed PF incidence in this location [6]. Genetic associations with the pathogenesis of pemphigus have been broadly studied. The association of this pathogenesis with the major histocompatibility complex (MHC) genes, especially HLA class II, has been highlighted. Population studies have revealed that * Corresponding author. University Hospital, Ribeir~ ao Preto Medical School, University of S~ ao Paulo, S~ ao Paulo, Brazil. ** Corresponding author. E-mail addresses: eadonadi@fmrp.usp.br (E.A. Donadi), amfrosel@fmrp.usp.br (A.M. Roselino). 1 Avenida Bandeirantes, 3900, Ribeir~ ao Preto, SP, CEP: 14049-900, Brazil. Contents lists available at ScienceDirect Journal of Autoimmunity journal homepage: www.elsevier.com/locate/jautimm http://dx.doi.org/10.1016/j.jaut.2016.04.007 0896-8411/© 2016 Elsevier Ltd. All rights reserved. Journal of Autoimmunity xxx (2016) 1e6 Please cite this article in press as: M.J.F. Brochado, et al., Differential HLA class I and class II associations in pemphigus foliaceus and pemphigus vulgaris patients from a prevalent Southeastern Brazilian region, Journal of Autoimmunity (2016), http://dx.doi.org/10.1016/j.jaut.2016.04.007