BK polyomavirus genotypes Ia and Ib1 exhibit different biological properties in renal transplant recipients

• Published in: Virus research Vol. 243; pp. 65 - 68
• Main Authors: Varella, Rafael B., Zalona, Ana Carolina J., Diaz, Nuria C., Zalis, Mariano G., Santoro-Lopes, Guilherme
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 02-01-2018
• Subjects: Adult; Aged; BK polyomavirus; BK Virus - classification; BK Virus - genetics; BK Virus - isolation & purification; BK Virus - physiology; Genotype; Humans; Kidney - surgery; Kidney - virology; Kidney Transplantation - adverse effects; Male; Middle Aged; NCCR; Phylogeny; Polyomavirus Infections - etiology; Polyomavirus Infections - virology; Renal transplant; Transplant Recipients - statistics & numerical data; Tumor Virus Infections - etiology; Tumor Virus Infections - virology; Viral Load; VP1; NCCR; Renal transplant; Viral load; VP1; BK polyomavirus
• ISSN: 0168-1702; 1872-7492
• DOI: 10.1016/j.virusres.2017.10.018

•BKV Ia genotype exhibited higher viral loads in urine and mutations at VP1 region.•The few patients who developed BKV nephropathy were infected with genotype Ia.•The NCCR architecture was similar between BKV Ia and Ib1 genotypes.•The possible association between genotype Ia and BKVAN should be further investigated.
BK polyomavirus (BKV) is an opportunist agent associated with nephropathy (BKVAN) in 1–10% of kidney transplant recipients. BKV is classified into genotypes or subgroups according to minor nucleotidic variations with unknown biological implications. Studies assessing the possible association between genotypes and the risk of BKVAN in kidney transplant patients have presented conflicting results. In these studies, genotype Ia, which is highly prevalent in Brazil, was less frequently found and, thus, comparative data on the biological properties of this genotype are lacking. In this study, BKV Ia and Ib1 genotypes were compared according to their viral load, genetic evolution (VP1 and NCCR) – in a cohort of renal transplant recipients. The patients infected with Ia (13/23; 56.5%) genotype exhibited higher viral loads in urine [>1.4 log over Ib1 (10/23; 43.5%); p=0.025]. In addition, genotype Ia was associated with diverse mutations at VP1 loops and sites under positive selection outside loops, which were totally absent in Ib1. Although the number of viremic patients was similar, the three patients who had BK nephropathy (BKVAN) were infected with Ia genotype. NCCR architecture (ww or rr) were not distinctive between Ia and Ib1 genotypes. Ia genotype, which is rare in other published BKV cohorts, presented some diverse biological properties in transplanted recipients in comparison to Ib1.