Spectrum of Parvovirus B19 infection and its pathogenesis

人细小病毒B19 （B19）被认为只有一种免疫血清型。我们遇到了一位在初次感染3年后再次感染的患者。分析其原发性感染和继发性感染时血清B19 DNA基因组型，并与同期流行的感染性红斑患者血清B19 DNA基因组型进行比较。检测长巢式PCR扩增的DNA产物。通过限制性内切酶切割模式分析基因组类型。感染性红斑患者的菌株在3年内发生了变化。当分析和比较似乎有再感染的患者的血清样本时，原发感染和继发感染之间的基因组类型没有差异。潜伏的B19感染在初次感染后可能持续存在。B19 IgM和DNA的二次检测被认为是由于潜伏感染后的再激活。B19可通过输血和血浆衍生产品传播。我们于1992年1 - 5月对我院输注的血液制品进行了B19的大规模筛选。3342份冻存血浆标本中，22份经酶免疫测定细小病毒B19 (B19) IgM阳性。22份样品中，11份（0.33%）B19 IgG和B19 DNA聚合酶链反应均阳性，提示受B19污染。其发生率明显高于敏感的受体介导血凝试验（0.012%）。研究结果表明，报告的方法具有足够的灵敏度和特异性来检测人血浆中的B19，并且它的使用可能有助于预防易感人群（如免疫功能低下的患者或孕妇）输血介导的病毒感染。

Human parvovirus B19 (B19) is believed to have only one immunoserotype. We encountered a patient who appeared to have reinfection 3 years after the primary infection. The genome type of B19 DNA obtained from his serum in the primary infection and during the secondary infection was analyzed and compared with those from patients with erythema infectiosum which was prevalent during the same time period. DNA products amplified by long nested PCR were examined. Genome types were analyzed by restrictive endonuclease cleavage pattern. The strain obtained from erythema infectiosum patients changed during the 3 years. There was no difference in genome type between the primary and the secondary infection when serum samples from our patient who seemed to have a reinfection were analyzed and compared. Latent B19 infection may persist after a primary infection. The secondary detection of B19 IgM and DNA was assumed to be due to reactivation after a latent infection.B19 can be transmitted through blood transfusion and plasma-derived products. We attempted a large-scale screening of B19 in blood products transfused in our hospital from January to May in 1992. Among 3,342 plasma samples kept frozen from packed red blood cells, 22 samples were positive for parvovirus B19 (B19) IgM by enzyme immunoassay. Of these 22 samples, 11 (0.33%) were positive for both B19 IgG and B19 DNA by polymerase chain reaction indicating contamination with B19. The incidence was obviously higher than in those (0.012%) tested by the receptor-mediated haemagglutination assay considered as a sensitive method. The findings suggest that the method reported has enough sensitivity and specificity to detect B19 in human plasma and its use might help prevent transfusion mediated viral infection in those susceptible such as immunocompromised patients or pregnant women.