Editorial: Frontiers in Autoimmune Disease: Rheumatic Fever and Rheumatic Heart Disease

Rheumatic fever (RF) and rheumatic heart disease (RHD), its most clinically consequence, resulting from untreated throat Streptococcus pyogenes infection in susceptible children, are considered as models of autoimmune post-infectious disease. This Research Topic compiled clinical and scientific data and brings interesting viewpoints of clinicians and basic researchers. The ensemble of data and ideas certainly makes a new portrait of the mechanisms leading the autoimmune reactions. On the other hand, the clinical data contributes with the diagnosis and prevention of the disease. Rheumatic fever and RHD are still prevalent in diverse regions of the world (1–3). The correct diagnosis is very important as well as the clinical treatment. Briefly, in Brazil, both RF and RHD are still important diseases in different regions (4). A RF prevention program involving more than 700 children with RF/RHD was performed. This program evaluated the long-term evolution and outcomes after the control of recurrences. These data are presented and discussed by Mota et al. (5). Another interesting article, done by Spina et al., discusses the clinical diagnosis of acute rheumatic myocarditis in asymptomatic RHD patients (6). As RF and RHD are autoimmune diseases, the mechanisms leading to autoimmune reactions involve several molecules that play a role in the immune response against the bacteria (7, 8). As we know, protective response involves several molecules that are genetically controlled, from both innate and adaptive immune response, in order to eradicate an infection (8). Among these molecules, complement plays an important role in the immune response against S. pyogenes. The lectin pathway of complement and RHD is discussed by the group de Messias-Reason (9). Another interesting article on autoimmune targets is presented by Root-Bernstein. In his article, a parallel between molecular mimicry reactions on RHD and autoimmune myocarditis is established (10). Rheumatic fever and RHD are considered as prototypes of human autoimmune diseases, and no animal models could reproduce accurately the disease. In the past few years, however, experiments on Lewis rat showed some similar autoimmune reactions in the myocardium of S. pyogenes immunized mice. The article by the group of Ketheesan presented a historical overview of animal models that were used to investigate the pathogenesis of RF/RHD (11). I hope the readers enjoy this collection, and I and my co-editors are grateful of having the opportunity to prepare this Research Topic for Frontiers in Pediatrics.