A single nucleotide polymorphism of FCGR2A is associated to higher severity in RSV infected infants

HOLGADO, MARÍA PÍA; RAIDEN, SILVINA; SANANEZ, INÉS; SEERY, VANESA; DE LILLO, LEONARDO; MALDONADO, LUCAS L.; KAMENETZKY, LAURA; GEFFNER, JORGE; ARRUVITO, LOURDES

Congreso; Reunión anual de sociedades de Biociencias 2020; 2020

BackgroundRespiratory syncytial virus (RSV) infection is the commonest cause for hospitalization in infants and it is not clear yet why some children with no apparent risk factors develop severe bronchiolitis. Genetic variation in the receptor for the Fc portion of IgG (FcγR) determines their affinity for IgG subclasses and has been linked to susceptibility and/or progression of several infectious diseases. Here we study the association between a polymorphism for FcγRIIa (H131R) and RSV disease. Methods Blood samples were collected from 182 infants ≤24-month-old (50 uninfected, 114 moderate RSV-infected with moderate progression and 18 with severe disease). FcγRIIa-H131R SNP genotypic frequencies (HH, HR, RR) and anti-RSV IgG1, IgG2 and IgG3 levels were studied. ResultsWe found no differences among genotypic frequencies for FcγRIIa-131H/R SNP between uninfected and RSV-infected infants. However, we observed a significant higher frequency of HH genotype in severe RSV-infected children versus moderate patients. HH RSV-infants from severe group presented more factors associated to severity than HR or RR patients. Furthermore, compared to moderate RSV-infected infants, severe patients showed higher levels of anti-RSV IgG1 and IgG3. Conclusions We found that FcγRIIa SNP is not related with a higher susceptibility for RSV infection. However, we did find an association between an FcγRIIa-H131 variant and progression to severe RSV disease once infected, which might support the involvement of IgG immune complexes in RSV pathogenesis. This genetic factor could also help to predict the worse outcome and identify healthy infants at risk at time of hospitalization.