Gama Bianca E, Emmel Vanessa E, Oliveira-Silva Michelle, Gutiyama Luciana M, Arcuri Leonardo, Colares Marta, de Cássia Tavares Rita, Bouzas Luis F, Abdelhay Eliana, Hassan Rocio
Bone Marrow Transplantation Center (CEMO), Instituto Nacional de Câncer (INCA), Rio de Janeiro, Brazil.
Transplant Direct. 2017 Oct 2;3(11):e217. doi: 10.1097/TXD.0000000000000731. eCollection 2017 Nov.
Parvovirus B19 (B19V) is a common human pathogen, member of the family Parvoviridae. Typically, B19V has been found to infect erythroid progenitors and cause hematological disorders, such as anemia and aplastic crisis. However, the persistence of genomic deoxyribonucleic acid (DNA) has been demonstrated in tonsils, liver, skin, brain, synovial, and testicular tissues as well as bone marrow, for both symptomatic and asymptomatic subjects. Although the molecular and cellular mechanisms of persistence remain undefined, it raises questions about potential virus transmissibility and its effects in the context of allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients.
With this aim, we retrospectively screened allogeneic stem cell donors from 173 patients admitted for allo-HSCT from January 2008 to May 2013 using a seminested polymerase chain reaction approach.
We found 8 positive donor samples, yielding a 4.6% of parvovirus prevalence (95% confidence interval, 2.36-8.85). Pre- and post-HSCT samples (n = 51) from the 8 recipients of the positive donors were also investigated, and 1 case exhibited B19V DNA in the post-HSCT follow-up (D + 60). Direct DNA sequencing was performed to determine the genotype of isolates and classification, performed by phylogenetic reconstruction, showed a predominance of genotype 1a, whereas the rare genotype 3b was detected in 2 additional patients. By molecular cloning, different B19V 1a substrains polymorphisms were evidenced in the single case in which donor and its recipient were B19V+.
Our results suggest that HSCT allografts are not a main source for B19V transmission, pointing to potential events of reinfection or endogenous viral reactivation.
细小病毒B19（B19V）是一种常见的人类病原体，属于细小病毒科。通常，已发现B19V感染红系祖细胞并引起血液系统疾病，如贫血和再生障碍危象。然而，对于有症状和无症状的受试者，在扁桃体、肝脏、皮肤、大脑、滑膜和睾丸组织以及骨髓中均已证实存在基因组脱氧核糖核酸（DNA）的持续性。尽管持续性的分子和细胞机制尚不清楚，但这引发了关于潜在病毒传播及其在异基因造血干细胞移植（allo-HSCT）受者中的影响的问题。
为此，我们采用半巢式聚合酶链反应方法，对2008年1月至2013年5月因allo-HSCT入院的173例患者的异基因干细胞供体进行了回顾性筛查。
我们发现8份供体阳性样本，细小病毒患病率为4.6%（95%置信区间，2.36-8.85）。还对8例阳性供体受者的HSCT前后样本（n = 51）进行了调查，1例在HSCT后随访（D + 60）时出现B19V DNA。通过直接DNA测序确定分离株的基因型，并通过系统发育重建进行分类，结果显示基因型1a占主导，而在另外2例患者中检测到罕见的基因型3b。通过分子克隆，在供体及其受者均为B19V阳性的单例中，证实了不同的B19V 1a亚株多态性。
我们的结果表明，HSCT同种异体移植物不是B19V传播的主要来源，提示可能存在再感染或内源性病毒再激活事件。
