T-cell molecular mimicry between streptococcal and heart proteins has been proposed as the triggering factor leading to autoimmunity in rheumatic heart disease (RHD). We searched for immunodominant T-cell M5 epitopes among RHD patients with defined clinical outcomes and compared the T-cell reactivities of peripheral blood and intralesional T cells from patients with severe RHD. The role of HLA class II molecules in the presentation of M5 peptides was also evaluated. We studied the T-cell reactivity against M5 peptides and heart proteins on peripheral blood mononuclear cells (PBMC) from 74 RHD patients grouped according to the severity of disease, along with intralesional and peripheral T-cell clones from RHD patients. Peptides encompassing residues 1 to 25, 81 to 103, 125 to 139, and 163 to 177 were more frequently recognized by PBMC from RHD patients than by those from controls. The M5 peptide encompassing residues 81 to 96 [M5(81-96) peptide] was most frequently recognized by PBMC from HLA-DR7 ؉ DR53 ؉ patients with severe RHD, and 46.9% (15 of 32) and 43% (3 of 7) of heart-infiltrating and PBMC-derived peptide-reactive T-cell clones, respectively, recognized the M5(81-103) region. Heart proteins were recognized more frequently by PBMC from patients with severe RHD than by those from patients with mild RHD. The similar pattern of T-cell reactivity found with both peripheral blood and heart-infiltrating T cells is consistent with the migration of M-protein-sensitized T cells to the heart tissue. Conversely, the presence of heart-reactive T cells in the PBMC of patients with severe RHD also suggests a spillover of sensitized T cells from the heart lesion.Rheumatic fever (RF) is a sequel of group A streptococcal throat infection and remains an important health problem in developing countries. About 30% of RF patients develop rheumatic heart disease (RHD), with high morbidity and cost to the public health system. Molecular mimicry between streptococcal antigens, mainly the M protein, and heart tissue proteins is proposed as an important factor leading to the heart lesions found in RHD patients. Several studies have been performed with human peripheral blood mononuclear cells (PBMC) showing reactivity against the streptococcal cell wall and tissue antigens (20,25). CD4 ϩ T cells are the predominant population at the site of heart lesions (23, 16).Yoshinaga et al. (30) reported that T-cell lines derived from heart valve specimens and PBMC from RF patients react with cell wall and membrane streptococcal antigens. These lymphocytes did not cross-react with M protein or mammalian cytoskeletal proteins. Autoreactivity to heart antigens caused by streptococcal infections was also suggested by results of immunization in which peripheral T lymphocytes from RHD patients stimulated in vitro with streptococci were able to recognize a 50-to 54-kDa myocardial protein fraction (7). Our group previously reported intralesional T-cell clones, from surgical fragments of patients with severe RHD, capable of recognizing immunodominant...
BACKGROUND
The incidence of rheumatic heart disease is great in Brazil. We analyzed the distribution of human leukocyte (HLA) antigens in a Brazilian population sample with rheumatic fever or rheumatic heart disease, with the aim of better understanding the mechanisms involved.
METHODS AND RESULTS
HLA class I (A, B, and C) and class II (DR and DQ) antigen distribution was studied in 40 patients with diagnosis of rheumatic fever or rheumatic heart disease and compared with a control group of 617 healthy individuals for class I typing, from which 118 were drawn for class II typing. A strong correlation between rheumatic fever and rheumatic heart disease and HLA-DRw53 (72.9% in the disease group versus 39% in the control group: p = 0.00061, relative risk, 4.2; etiologic fraction, 0.43) was found. We also found an increase in the frequency of HLA-DR7 (57.5% in the disease group versus 26.3% in control group: p = 0.00715; relative risk, 3.8; etiologic fraction, 0.56). HLA class I and HLA-DQ typing did not point to any association with these diseases.
CONCLUSIONS
HLA-DR7 and HLA-DRw53 are markers for susceptibility to rheumatic fever and rheumatic heart disease in Brazil. These results could be explained by genetic differences resulting from racial or geographical diversity.
MRI appears unnecessary as a routine method in the diagnosis of SS; US examination is suitable both for the diagnosis and follow-up of SS. The above combination of the seemingly contradictory US and MRI findings is highly characteristic of lymphoma which has developed in the course of the disease.
A 43-year-old woman developed annular and pustular cutaneous lesions preceded by tiny yellow pustules coating the surface of the oral mucosa. The clinical, histological and immunopathological evidence clearly showed that the patient had pyodermatitis-pyostomatitis vegetans. It is suggested that this disease is a distinct entity which should be differentiated from pemphigus vegetans.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.