The authors do not hold and are not applying for any patents relating to the content of the manuscript. antibodies, and PSGN in Mumbai populace despite low point prevalence of M1, M12, M55 and M57. In addition we prolonged the study to GAS-pyoderma and non-GAS pyoderma instances. To our surprise, we found a positive association between the seroprevalence to SIC and DRS antibodies, and GAS-pyoderma owing to illness with varied M types. The mechanism of improved predisposition to pyoderma owing to illness by varied GAS among SIC or DRS antibody-positive populace is not obvious. Nonetheless, our findings could be explained by a trend akin to antibody-dependent enhancement (ADE). Conclusions This is the first report showing a small number of GAS M types conferring predisposition to pyoderma by varied types. Implications of this ADE-like trend are discussed in the light of evolutionary advantage to GAS, vaccine design and control of renal diseases. Keywords: Streptococcus pyogenes, Post streptococcal glomerulonephritis, Pyoderma, Streptococcal inhibitor of match Background (group A streptococcus; GAS), a human-specific pathogen, is responsible for varied diseases such as pharyngitis, Rabbit Polyclonal to TRPS1 pyoderma, cellulitis, necrotising faciitis, harmful shock syndrome and life-threatening immune sequelae including rheumatic heart disease and post-streptococcal glomerulonephritis (PSGN) [1,2]. Pharyngitis and pyoderma caused by some GAS strains (types) are associated with PSGN, of which types communicate a major secretory antigen called Streptococcal Inhibitor of Match (SIC; in and and type which was claimed to be unique from subtypes, isolates of both and are clonally related. Both SIC Phthalic acid and DRS elicit high antibody reactions during natural infections and the antibodies are prolonged [7,8]. Serological reactions to several GAS antigens have been observed subsequent to PSGN [9]. In an earlier community-based study seropositivity to DRS, but not to SIC, was found to be associated with history of PSGN among the Indigenous Australians [8]. Subsequently a Swedish hospital-based study found an association between acute PSGN instances and IgM antibodies to SIC in sera from pediatric instances [10]. The apparent variations in the above results could be because of variations in the distribution of types in these two geographical regions, to the variations in study design or both. Even though prognosis of PSGN is generally superb, many studies suggest that PSGN is definitely a strong risk element for chronic kidney disease (CKD) and end-stage renal disease (ESRD) [11-14]. Interestingly we recently showed [15] that SIC antibody seroprevalence is definitely higher in CKD and ESRD individuals than in control subjects in Mumbai, a region endemic for streptococcal diseases. Furthermore we found that anti-SIC seropositivity in CKD individuals may result in poor prognosis, the disease progressing to ESRD. These findings warranted a hospital-based investigation of association between SIC and DRS antibody-prevalence and PSGN in Mumbai area. We now show that acute PSGN pediatric individuals possess high seroprevalence for SIC and DRS antibodies. We Phthalic acid also prolonged this Phthalic acid study to pyoderma individuals going to outpatient wards of the same hospital. To our surprise we found that significantly greater proportion of GAS pyoderma individuals are positive to SIC and DRS antibodies than those with non-GAS pyoderma individuals, or age-matched healthy control subjects. Despite this observation, SIC or DRS positive types were not overly displayed among the isolates from your GAS pyoderma instances. This startling getting clearly highlights improved predisposition to GAS pyoderma in Mumbai region among the subjects seropositive to SIC or DRS antibodies due to past illness with types expressing these Phthalic acid antigens. We attribute this to a trend akin to antibody-dependent enhancement (ADE) of pores and skin illness. However, only a limited quantity of GAS strains seem to confer ADE of illness by varied GAS types. Such ADE may have a role in the development of GAS as a highly successful human being pathogen. We discuss implications of our findings in relation to the management of CKD individuals and vaccine strategy. Methods Subjects,.