EVOLUTIONARY STUDY OF A G3P[4] STRAIN OF GROUP A ROTAVIRUS OVER A YEAR IN THE SAME PATIENT IN AN UNUSUAL IMMUNE ENVIRONMENT

MANDILE, M.G.; PERI IBÁÑEZ, E.S.

Bali

Simposio; 14th International Rotavirus Symposium; 2023

Comité de organizadores del 14th International Rotavirus Symposium

Resumen:Background and aimsGroup A rotaviruses (RVA) are the most frequent etiological agents causing severe diarrhea in infants and thanks to genotype surveillance, and genetic characterization of circulating strains in human populations it is possible to detect common and rare RVA strains in different environments. RVA infection could persists in immunosuppressed individuals for indeterminate periods of time, and host and viral factors affecting persistence and virus clearance are poorly understood. The aim of this study is to analyze virus modifications in a collection of samples from a persistent RVA infection in a one-year-old child undergoing bone marrow transplantation due to Severe Combined Immune Deficiency (SCID) in the Ricardo Gutierrez Children's Hospital located in Buenos Aires, Argentina. We hypothesize that changes would be related to T or B epitope modifications during the “co-evolution dialog” between replicating virus variants and the newly developing immune system.MethodsThe strain persistently infecting an immunosuppressed individual was analyzed by RT-PCR with specific primers, and by sequencing of the different genomic segments. With this generated data phylogenetic trees were made to look for variations in the nucleotide sequences along the 12 months that we could detect this strain in the same child.ResultsAnalyzing the phylogenetic trees of the vp7 and vp4 genes of the G3P[4] strains, that persisted for a year, it was observed that there were changes at the nucleotide level that have accumulated over time. This effect is observed first in time for the vp4 gene and then for the vp7 gene. Despite this, in this last gene the effect is observed more clearly.ConclusionsThis study is remarkably interesting since it is an unusual environment in which an uncommon strain of group A rotavirus is evolving, and it is an important objective to keep on with the analysis of as many genes as possible in these samples to obtain a better understanding of the RVA biology in this setting. Changes in structural and nonstructural proteins in the context of a recovering immune system from the time of the transplant to infection clearance are intended to be described. If these changes could be linked to B or T epitopes, the study can contribute to the understanding of cellular and humoral responses to clear RVA infections in humans.