Parvovirus B19 infection in patients with hemophilia

BACKGROUND: The long-term consequences of parvovirus B19 infection in transfusion recipients are not known, and thus the value of B19 screening of blood donors remains unresolved. Hemophiliacs, at risk for B19 through their chronic exposure to clotting factor concentrates, have frequent, close medical follow-up and thereby constitute an ideal group in which to study the hematologic sequelae of B19 infection. STUDY DESIGN AND METHODS: An enzyme-linked immunosorbent assay was used to detect B19 IgG and IgM and the polymerase chain reaction was used to detect B19 DNA in frozen, stored plasma samples, obtained between 1987 and 1994, from 136 subjects with hemophilia, including 71 who were human immunodeficiency virus (HIV)-positive and 65 who were HIV- negative. Then the results of the tests were compared with clinical hematological data and blood product usage data. RESULTS: B19 seroprevalence in the hemophilic cohort was 81.6 percent (111/136), including 74.6 percent (53/71) of HIV-positive and 89.2 percent (58/65) of HIV-negative hemophiliacs. It was not affected by age, type or severity of hemophilia, HIV status, CD4 number, or yearly blood product usage. Only 1 (0.7%) of the 136 samples was positive for B19 IgM and none was positive in polymerase chain reaction for B19 DNA. After adjusting for HIV status, there were no differences between B19- positive and B19-negative hemophiliacs in hematologic values, CD4 counts, or blood product use. CONCLUSION: Although B19 IgG seroprevalence in this hemophilic cohort is high and indicative of past B19 infection, there is no detectable B19 viral activity or any associated long-term clinical or hematologic sequelae.     

Serologic and molecular detection of human Parvovirus B19 infection

Following its identification by Yvonne Cossart in 1975, human Parvovirus B19 has been recognized as the causative agent of a wide range of diseases. In childhood, the most common disease is a typical exanthema called "fifth disease". In adults, viral infection may be responsible for fetal loss and for aplastic anaemia in immuno-compromised patients. Because persistent viral infection may induce an autoimmune response, Parvovirus B19 is emerging as an environmental factor linked to the pathogenesis of autoimmunity. As a result of its expanding disease spectrum, Parvovirus B19 is the subject of intense efforts to clarify the pathogenesis of virus-related disorders as well as improve diagnostic laboratory testing including standardization of serological and nucleic acid-based detection assays. Enzymatic immunoassays based on conformational antigens have proven to be the most important tools for accurate diagnosis in the majority of cases. In other selected clinical cases, the detection of Parvovirus B19 infection can be complemented by PCR and, more recently, by the real-time PCR.     

Parvovirus B19 infections.

Infections caused by human parvovirus B19 can result in a wide spectrum of manifestations, which are usually influenced by the patient's immunologic and hematologic status. In the normal host, parvovirus infection can be asymptomatic or can result in erythema infectiosum or arthropathy. Patients with underlying hematologic and immunologic disorders who become infected with this virus are at risk for aplastic anemia. Hydrops fetalis and fetal death are complications of intrauterine parvovirus B19 infection.     

人微小DNA病毒B19与人类疾病

人微小ＤＮＡ病毒Ｂ１９是１９７４年偶然发现的一种不同于已知的动物微小ＤＮＡ病毒的病毒。这种平均直径为２３ｎｍ、单链线状ＤＮＡ病毒感染人后常呈隐性感染，故在发现后数年内并未引起人们的注意。直至检测该病毒特异性诊断方法的建立和应用才逐渐明确了Ｂ１９与人类疾病的关系，也才使我们对一些不明原因的疾病有了新的认识，目前已明确Ｂ１９感染可以造成:一些慢性溶血性贫血尤其是镰形细胞贫血病人发生再障危象；传染性红斑及其并发病──多发性关节炎或关节病；妊娠妇女流产、死胎或胎儿畸形。呼吸道是Ｂ１９最常见的传播途径。此外，经血和胎盘也可造成Ｂ１９感染。鉴于Ｂ１９感染范围广泛，且各国报告的流行情况无明显差异，考虑在我国也有可能存在Ｂ１９感染，故建议在我国开展该项调查。     

Parvovirus B19 transmission by heat-treated clotting factor concentrates

BACKGROUND: Human parvovirus B19 (B19) DNA can be frequently detected in plasma-derived coagulation factor concentrates. The production of some clotting factor products includes heat treatment steps for virus inactivation, but the effectiveness of such steps for B19 inactivation is unclear. Moreover, detailed transmission case reports including DNA sequence analysis and quantification of B19 DNA from contaminated heat-treated blood components have not been provided so far. Therefore, the correlation between B19 DNA in blood components and infectivity remains unclear. STUDY DESIGN AND METHODS: Asymptomatic B19 infections of two patients with hemophilia A were detected by anti-B19 seroconversion after administration of B19-contaminated heat-treated clotting factors. The suitability of nucleic acid sequence analysis for confirmation of B19 transmission was investigated. Furthermore, the B19 DNA level in blood components was determined and the drug administration was reviewed to calculate the amount of inoculated B19 DNA. RESULTS: Both B19 transmissions from clotting factor products could be confirmed by identical nucleic acid sequences of virus DNA from patients and blood components while sequences from unrelated controls could be differentiated. One patient received, for 4 days, a total of 180 mL vapor heat-treated prothrombin complex concentrate containing 8.6 x 10(6) genome equivalents per mL of B19 DNA. The other patient received 966 mL of low-contamination (4.0 x 10(3) genome equivalents/mL) dry heat-treated FVIII concentrate over a period of 52 days. CONCLUSION: B19 transmissions can be confirmed by nucleic acid sequencing. However, due to the low variability of the B19 genome, a large part of the B19 genome must be analyzed. The transmissions show that the applied heat treatment procedures were not sufficient to inactivate B19 completely.     

Clinical manifestations and outcomes of parvovirus B19 infection during pregnancy in Japan

Parvovirus B19 is a small DNA virus. Infection with parvovirus B19 during pregnancy may cause serious complications in the fetus, including hydrops fetalis and fetal death. The purpose of the present study is to clarify the clinical manifestations and outcomes of parvovirus B19 infection during pregnancy. This prospective study enrolled 478 women with suspected B19 infections during pregnancy between 1999 and 2004. One hundred cases (21%) of B19 infection were detected in 478 pregnant women who had been exposed to B19. Serological infection was confirmed by measurement of B19-specific IgM and IgG in sera. Forty-nine cases reported maternal clinical symptoms and 51 cases were asymptomatic. Facial rash was the most common symptom, with 51% (25/49) of the symptomatic patients complaining of either a facial, body or limb rash. The most common infectious source was children living in the home. Overall, the incidence of adverse fetal effects (including hydrops fetalis and fetal death) related to intrauterine B19 infection was 7% (7/100), and all seven cases were exposed to B19 infection before 20 weeks of gestation. Although half of the cases with parvovirus B19 infections during pregnancy were asymptomatic, patients with adverse fetal effects tended to be symptomatic including rash and fever. These clinical data may supply useful information to produce clinical guidelines for managing B19 infection during pregnancy.     

Parvovirus B19 transmission by a high-purity factor VIII concentrate

BACKGROUND: Parvovirus B19 (B19) is known to cause a variety of human diseases in susceptible individuals by close contact via the respiratory route or by transfusion of contaminated blood or blood products. In this study, whether a case of B19 transmission was causally related to the infusion of implicated lots of a solvent/detergent (S/D)-treated, immunoaffinity-purified factor VIII concentrate (antihemophilic factor [human][AHF]) was investigated. STUDY DESIGN AND METHODS: Anti-B19 (both immunoglobulin M [IgM] and immunoglobulin G [IgG]) and B19 DNA (by a nucleic acid testing [NAT] procedure) were assayed in two implicated product lots, a plasma pool, and a recipient's serum sample. Analysis of the partial B19 sequences obtained from sequencing clones or direct sequencing of the samples was performed. RESULTS: Only one of the two implicated lots was B19 DNA-positive. It contained 1.3 x 10(3) genome equivalents (geq or international units [IU]) per mL. The negative lot was derived from plasma screened for B19 DNA by NAT in a minipool format to exclude high-titer donations, whereas the positive lot was mostly from unscreened plasma. This high-purity AHF product had no detectable anti-B19 IgG. A 4-week postinfusion serum sample from a recipient, who received both lots and became ill, was positive for the presence of B19 antibodies (both IgM and IgG) as well as B19 DNA. The B19 sequences from the positive lot, its plasma pool, and the recipient's serum sample were closely related. CONCLUSION: These findings and the recipient's clinical history support a causal relationship between the implicated AHF product and B19 infection in this recipient. The seronegative patient became infected after receiving 2x10(4) IU (or geq) of B19 DNA, which was present in this S/D-treated, high-purity AHF product.     

2016-2017年武汉地区儿童细小病毒B19感染及流行情况分析

摘要：目的 了解武汉地区儿童细小病毒B19感染状况及流行病学特征。 方法 采集自2016年1月1日至2017年12月31日在我院门、急诊和住院部就诊或住院治疗的疑似细小病毒B19感染儿童静脉血,通过ELISA法检测血清细小病毒B19-IgM,并对抗体活性值在10 ~20 U/mL之间的标本进行细小病毒B19 DNA定量检测,综合分析武汉地区儿童细小病毒B19感染状况及流行病学特征。结果 武汉地区2017年儿童细小病毒B19感染率为2.83%,较2016年6.31%的感染率显著下降,两年平均总体感染率为4.34%;儿童细小病毒B19感染状况具有明显的年龄（2岁以上）及性别（女性高于男性）差异; ELISA法检测HPV-B19抗体活性值处于10~13 U/mL之间的标本与PCR检测结果一致性较好,阴性符合率为93.54%;抗体活性值处于13~17 U/mL之间的标本结果一致性较差,阳性符合率为43.21%。抗体活性值17~20 U/mL的标本,阳性符合率为74.81%。结论 武汉地区儿童细小病毒B19感染具有年龄、性别差异,同时对于经ELISA法检测抗体活性值处于13~20 U/mL之间的标本,有必要进行PCR检测确诊。     

南宁地区育龄妇女人类微小病毒B19流行病学调查

目的 了解南宁地区育龄妇女人微小病毒B19(B19)感染状况及特点.方法 用酶联免疫吸附法检测2008～2010年南宁地区育龄妇女血清B19-IgM抗体,比较不良妊娠结局、妊娠和婚检妇女感染率及各年、季度感染情况.结果 10 125例育龄妇女,B19感染率为13.04%,不良妊娠结局组、妊娠组和婚检组感染度分别为17.69%,12.61%和10.82%,三组间感染率差异有统计学意义(P<0.01).各年感染率分别为12.20%,13.18%和13.68%,各年、季度感染率差异无统计学意义(P>0.05).感染组与非感染组不良妊娠结局发生率差异有统计学意义(P<0.01).结论 南宁地区育龄妇女B19感染率较高,应加强育龄妇女B19感染监测.     

应用PCR法对临床血标本中人微小病毒B19的检测分析

目的探讨PCR法检测临床血标本中人微小病毒B19(HPV B19)的应用价值。方法根据序列比对结果,在HPV B19核苷酸相对保守区设计引物进行PCR扩增。应用双脱氧链末端终止法对HPV B19阳性PCR产物进行克隆测序。结果应用该法最终检出HPV B19的血清稀释度为10^3。序列比较表明,用本法检出的1株HPV B19阳性标本与标准株(Au株)核苷酸序列同源性为92％。检测肝癌和肝硬化患者血清标本各14例,结果HPV B19阳性分别为8例和5例。结论本法可用于HPV B19的临床诊断和流行病学调查。     

Parvovirus B19 DNA in Factor VIII concentrates: effects of manufacturing procedures and B19 screening by nucleic acid testing

BACKGROUND: Parvovirus B19 (B19) is a common contaminant, especially in coagulation factors. Because of B19 transmission by pooled plasma, solvent/detergent treated in 1999, some fractionators initiated minipool nucleic acid testing (NAT) to limit the B19 load in manufacturing pools. In this study, the extent of B19 DNA contamination in commercial Factor VIII concentrates, that is, antihemophilic factor (human) (AHF), manufactured before and after B19 NAT screening was implemented, was determined. STUDY DESIGN AND METHODS: A total of 284 lots representing six AHF products made during 1993 to 1998 and 2001 to 2004 were assayed for B19 DNA by an in-house NAT procedure. Anti-B19 immunoglobulin G (IgG) was also measured. RESULTS: Most lots made during 1993 to 1998 had detectable B19 DNA. The prevalence ranged from 56 to 100 percent and appeared to differ between manufacturers. The highest level of B19 DNA found was 10(6) genome equivalents (geq or international units [IU]) per mL. Forty percent of the lots tested contained 10(3) geq (IU) per mL. In comparison, both prevalence and levels in source plasma-derived AHF products made in 2001 to 2004 were lower. Both, however, remained unchanged in the recovered plasma-derived product because B19 NAT screening had not been implemented. Only an intermediate-purity AHF product was positive for the presence of anti-B19 IgG. CONCLUSION: The prevalence and levels of B19 DNA in AHF prepared from B19 NAT unscreened plasma were high but varied among products with different manufacturing procedures. B19 NAT screening of plasma effectively lowered the B19 DNA level in the final products and in the majority of cases rendered it undetectable and hence potentially reduced the risk of B19 transmission.     

Prevalence of Parvovirus B19 and Hepatitis A virus in Portuguese blood donors.

INTRODUCTION: In recent years, concern about the safety of blood in regard to the transmission of blood-borne viruses has been decreased. Safety has been achieved with a combination of different strategies, such as careful selection of donors, screening for relevant virological markers and viral inactivation/removal methods. More recently, the implementation of the nucleic acid amplification technologies for the detection of HIV-1, HCV and HBV, has increased safety by reducing the "window period" of the infections. Other viruses, such as Parvovirus B19 (PB19) and Hepatitis A virus (HAV), can cause problems for blood safety. These infections could provoke serious complications in some risk groups, such as pregnant women, patients with hematological problems, children and patients with immunodeficiencies. MATERIALS AND METHODS: An observational study was performed to determine the prevalence of PB19 and HAV in Portuguese blood donors. We gathered, during four months, 5025 plasma donations and made them into 505 pools with no more than 10 donations each. The nucleic acids were isolated using MagNA Pure LC (Roche, Mannheim, Germany). A "Real Time PCR" (LightCycler, Roche) was used to perform the nucleic acid amplification and detection, using kits from the manufacturer. RESULTS: We found a prevalence of 0.12% for PB19 and 0% for HAV. Viraemia levels found in the positive donations range from 7.1x10(4) to 2.1x10(12)IU/ml. DISCUSSION: This study demonstrates the possibility of performing these tests in routine blood banks. We found a similar prevalence of PB19 when compared with other European and USA countries. In the case of HAV, we predict a maximum risk of 0.06% for a donor to be infected. It is necessary to perform other studies, including cost/benefit analysis to evaluate the risks and profits of implementing these methodologies in Transfusion Medicine.