Prevalence of antibodies to parvovirus B 19 in Thailand

Infection with human parvovirus B 19, a single-stranded non-enveloped DNA virus of worldwide distribution, is rather common and displays a broad spectrum of clinical manifestations of varying severity, depending on the patient's immune response. As the target of infection are the erythroid precursor cells, patients can experience an aplastic crisis. Usually, at least in immunocompetent individuals, viremia ceases with the appearance of virus-specific antibodies in the patient's serum whereupon the patients retain lifelong immunity to reinfection. Since data as to the prevalence of this agent has not been established for Thailand, the purpose of the present study was to investigate its frequency among 3 distinct groups, comprising 30 healthy children. 64 children with acute unrelated illness, and 35 voluntary blood donors, respectively, by means of enzyme linked immunosorbent assay. Our results have shown that, as reported for other countries, anti-parvovirus IgG increases in an age-dependent manner and is established at an overall prevalence of 20.16%, inviting the conclusion that the local population is infected by this agent as frequently as those of other countries in the Far East. Further studies need to be undertaken in order to elucidate its prevalence among members of high-risk groups.     

Serological markers of hepatitis B virus and cytomegalovirus infections in Norwegians with coagulation factor defects

Summary The prevalence of serological markers for present and past hepatitis B virus (HBV) infection and antibodies against cytomegalovirus (CMV) among Norwegians with coagulation factor defects was examined in serum samples collected before virus-inactivated coagulation concentrates came into use. Sera collected in 1985/86 from 324 of 377 (86%) registered persons with such defects were available. Three persons were chronic carriers of HBsAg. The prevalence of HBV antibodies was 28% compared with about 5% in the general population. The highest prevalence rate was found among patients with severe haemophilia A (44%) and in patients with haemophilia B (39%). The prevalence of anti-CMV antibodies was 75% which is similar to that found in the general Norwegian population.     

Detection of human parvovirus B19 DNA in plasma pools and blood products derived from these pools: implications for efficiency and consistency of removal of B19 DNA during manufacture

The polymerase chain reaction (PCR) assay was used to detect human parvovirus B19 DNA in 38 blood products and start plasma pools from five different manufacturers. The products examined were albumin, factor VIII, intravenous (i.v.) and intramuscular (i.m.) immunoglobulin batches. The majority of pools from all the manufacturers had detectable B19 DNA (64/75: 85%; ranging from 60% to 100% for individual manufacturers). B19 DNA was found in 3/12 albumin samples, in 7/7 factor VIII samples, 3/15 IVIG samples and 3/4 IMIG samples. The levels of B19 DNA in pools varied from 10² to 10⁹ genome equivalents/ml, whereas the levels in products varied from 10² to 10⁶ genome equivalents/ml, but there was no clear relationship between the levels of B19 DNA in start pools and final products.   The levels of B19 DNA varied between different batches of the same product from a single manufacturer, possibly due to small variations in the processing parameters. In addition, there was some indication from the study of IVIG samples that treatment at low pH may result in removal of PCR-detectable B19 DNA.     

Prevalence of antibodies to human parvovirus B19 nonstructural protein in persons with various clinical outcomes following B19 infection.

Persistent infections with human parvovirus B19 (B19) associated with debilitating chronic disease have been described, although evidence linking B19 to these more unusual clinical outcomes has been inconclusive. Recent reports have suggested that the development of antibodies to the B19 nonstructural protein (NS1) following B19 infection might be linked to development of severe arthropathy and chronic infection. To confirm these findings, the C-terminal region of the NS1 protein was expressed for use in Western blot assays for detection of anti-NS1 IgG antibodies in human serum. Among 91 persons tested, 0 of 20 not previously infected with B19, 9(36%) of 25 with past B19 infection, and 5 (12.5%) of 40 with recent B19 infection, had detectable anti-NS1 antibodies. Of 6 persons with chronic B19 infection, 2 had detectable antibodies to NS1. The presence of anti-NS1 antibodies did not appear to correlate with unusual clinical outcomes or chronic B19 infection.     

Variability of parvovirus B19 to inactivation by liquid heating in plasma products

BACKGROUND AND OBJECTIVES: Previously, we reported that although human parvovirus B19 in albumin and intravenous immunoglobulin preparations was rapidly inactivated during liquid heating, in contrast to other parvoviruses such as canine parvovirus, sensitivity to heat was highly dependent on the composition of the solution. In this study, we aimed to further elucidate the sensitivity to heat of B19 in haptoglobin and antithrombin (previously named antithrombin III) preparations during liquid heating. MATERIALS AND METHODS: Two different solutions collected immediately before heat treatment of haptoglobin and antithrombin preparations were spiked with B19 and subsequently treated at 60 degrees C for 10 h. B19 DNA-positive, anti-B19 IgG/IgM-negative plasma was used as a source of B19. The residual infectivity in each sample was measured using a B19 cell-based infectivity assay with an mRNA polymerase chain reaction. RESULTS: B19 in different plasma preparations showed different heat-sensitivity patterns during liquid heating: (i) slow inactivation in haptoglobin preparations, and (ii) only limited inactivation in antithrombin preparations. The kinetics of inactivation was greatly different from that in our previous studies in which the virus was shown to be rapidly inactivated in albumin and intravenous immunoglobulin preparations. CONCLUSION: B19 has unique properties in terms of heat sensitivity, depending on the composition of the solution during liquid heating. This finding may indicate the need for caution when interpreting the sensitivity of B19 to heat.     

Prevalence of TT virus in plasma pools and blood products

A high prevalence of TT virus (TTV), a novel virus recently identified in the serum of a patient with post-transfusion hepatitis of unknown aetiology, has been reported in blood donors worldwide. We investigated the presence of TTV DNA in several lots of blood products and in the corresponding plasma pools. In the process, we determined, from three sets of primers, the one which was most efficient in detecting the viral nucleic acid. This set amplifies the region closest to the 3'-end of the TTV genome which was proved, by sequence analysis, to be more conserved than the other two regions. Whereas all 10 intravenous immunoglobulin and 21 albumin batches were TTV negative, 4/5 factor VIII concentrates and 4/10 intramuscular immunoglobulin batches were TTV positive. A high prevalence of TTV DNA (70%) was found in the plasma pools that were collected from four different countries. These results confirm the worldwide distribution of this virus and show that TTV is removed with a varying efficiency during the manufacture of blood products.     

Prevalence of parvovirus B19 DNA in bone marrow of patients with haematological disorders.

Patients with haematological disorders (n = 100) were examined for prevalence of parvovirus B19 DNA in the bone marrow and serum, irrespective of B19-related symptoms. B19 DNA was studied using 2 nested PCRs and the serum samples were further analysed with B19-specific IgG, IgM and avidity as well as seroreactivity against linear and conformational epitopes of the B19 VP2 antigen. The latter assays specify whether the IgG antibody response represents acute or past B19 infection. B19 DNA was detected in 4 of the 100 bone marrow samples, whereas all the serum samples were B19 DNA negative. None of the 4 B19 DNA positive patients had symptoms typical of B19 infection and serology showed past infection. Furthermore, 2 were still B19 DNA positive in bone marrow more than 1 y after the first sample indicating virus persistence. The seroprevalence for B19 IgG was 59% and 2 patients were B19 IgM positive. Thus, presence of B19 DNA in bone marrow from patients with haematological disorders is not a general finding in seropositive patients. B19 DNA can persist in bone marrow, but in our material this finding showed no clear correlation with symptomatic B19 infection.     

Prevalence of parvovirus B19 infection in Thai young adults

The prevalence of antibody to human parvovirus B19 in 128 Thai healthy young adults was measured. Antibodies of the immunoglobulin G (IgG) class were investigated in serum samples of 51 males and 77 females aged 18-24 years (mean 19.83; SD 1.07) by a commercial enzyme-linked immunosorbent assay (ELISA) using high specific recombinant parvovirus B 19 antigen. Only 14 out of 128 (10.94%) sera were found positive, including 6 males and 8 females. No sex preponderance was observed. The amount of antibody calculated as antibody index was not statistically significant difference between genders.     

Prevalence of antihuman parvovirus B19 IgG antibodies in patients with refractory rheumatoid arthritis and polyarticular juvenile rheumatoid arthritis

We investigated the prevalence of antihuman parvovirus B19 immunoglobulin G (IgG) antibody in 108 Japanese patients with rheumatoid arthritis (RA) and 11 patients with polyarticular juvenile rheumatoid arthritis (JRA). Seropositivity of anti-B19 was significantly higher in patients with refractory RA (57.6%, 38/66) compared with patients with remittent RA (19.0%, 8/42; P>0.001) or age-matched controls (24.3%, 19/78; P>0.001). Patients with refractory polyarticular JRA had a significantly higher frequency of anti-B19 seropositivity (71.4%, 5/7) than age-matched controls (8.3%, 5/60; P>0.001), while none of the remittent group was positive for the antibody (0/4).     

Variability of parvovirus B19 genotype 2 in plasma products with different compositions in the inactivation sensitivity by liquid-heating

Background and Objectives Our previous report showed that parvovirus B19 genotype 1 in different solutions derived from plasma preparations showed different heat‐sensitivity patterns during liquid‐heating. In this study, we similarly examined B19 genotype 2. Materials and Methods Two plasma samples one containing B19 genotype 1 and the other genotype 2 DNA were used. Four process samples collected immediately before the heat treatment step in the manufacture of albumin, immunoglobulin, haptoglobin and antithrombin preparations were spiked with B19 and subsequently treated at 60°C for 10 h. A low pH immunoglobulin solution was also spiked with B19 and treated at room temperature for 14 days. Infectivity was then measured. Results B19 genotype 2, similar to genotype 1, showed three patterns of inactivation: (i) a rapid inactivation in the albumin and immunoglobulin preparations, (ii) a slow inactivation in the haptoglobin preparation and (iii) only limited inactivation in the antithrombin preparation. Its sensitivity in the low pH immunoglobulin solutions also resembled that of genotype 1. Conclusion Both genotypes 1 and 2 of B19 varied in sensitivity to liquid‐heating and low pH among different plasma preparations.     

Prevalence of IgG antibodies to human parvovirus B19 in haemophilia children treated with recombinant factor (F)VIII only or with at least one plasma-derived FVIII or FIX concentrate: results from the French haemophilia cohort

Human parvovirus B19 (B19) has been transmitted by some brands of virally attenuated plasma-derived factor VIII (FVIII) or IX (FIX) concentrates. To quantify the differences of human parvovirus B19 risk transmission between albumin-stabilized recombinant factor and plasma-derived factor, we studied the prevalence of IgG antibodies to B19 (anti-B19) in 193 haemophiliac children between 1 and 6-years of age who had previously been treated with albumin-stabilized recombinant FVIII only (n = 104), and in children previously treated with solvent/detergent high-purity non-immunopurified and non-nanofiltered FVIII or IX concentrates (n = 89). Association between the prevalence of anti-B19 and the treatment group was analysed using multivariate logistic regression. Age, severity and type of haemophilia, number of cumulative days of exposure to factor VIII or IX, previous history of red blood cells or plasma transfusion were considered as potential confounding variables. A higher prevalence of anti-B19 was found in children previously treated with solvent/detergent high-purity non-immunopurified and non-nanofiltered FVIII or IX concentrates than in children treated with albumin- stabilized recombinant FVIII only (OR: 22.3; CI: 7.9-62.8), independently of the other factors studied.     

Prevalence of HIV infection in a cohort of patients with congenital coagulation defects of the prothrombin complex factors.

Twenty-seven patients suffering from congenital coagulation defects of the prothrombin complex factors were investigated: six had haemophilia B; 14, factor VII defect; four, factor X defect; and three, factor II defect. Nineteen patients (70.3%) had previously received plasma and/or clotting factors concentrates. Among these, markers of hepatitis B infection (HBV) were present in five cases (26.3%) and hepatitis C (HCV) antibodies were found in seven cases (36.8%). The HIV1 prevalence was similarly high. In fact, five patients (26.3%), previously infused with factor IX or prothrombin complex factors concentrates, developed HIV1 infection. No patient with factor VII deficiency became HIV1 positive, despite the administration of unheated factor VII concentrates and the consequent HBV and HCV contamination. In the HIV1 positive group, three patients showed a false positivity for HIV2 antibodies. Five years after seroconversion, three patients developed AIDS (stage IV) and died, one had persistent generalized lymphadenopathy (stage III), and one with post-hepatitis liver cirrhosis was asymptomatic (stage II) for HIV infection. The significant decrease in total white cells, T4 lymphocytes and platelet counts and increase of beta 2-microglobulin and neopterin levels confirmed the prognostic value of these markers for the progression of HIV1 disease. Only one HIV1 negative transfused patient developed anti-HTLV-I p19 antibodies.     

Human parvovirus B19-induced aplastic crisis in a patient treated with fibrin sealant

A 42-year-old woman underwent a myomectomy on March 31, 1998. On the 10th postoperative day, leukopenia and reticulocytopenia were observed. Bone marrow aspiration revealed severe erythroblastopenia with giant proerythroblasts, suggesting a recent parvovirus infection. Both anti-parvovirus B19 IgM antibody and IgG antibody seroconversion was observed, and human parvovirus B19 DNA was detected by polymerase chain reaction (PCR) methods. The hematologic data on the patient rapidly improved thereafter. It was determined that acute-phase serum had inhibited CFU-E and BFU-E derived colony formation. Based on these findings, parvovirus B19-induced aplastic crisis was diagnosed. Fibrin sealant, which is a typical hemostatic agent produced from blood, had been during the operation. Human parvovirus B19 DNA was detected in the fibrin sealant by PCR. Our case report documents the transmission of human parvovirus B19 by fibrin sealant.     

Seroprevalence of antibodies to parvovirus B19 among children in Papua New Guinea

Parvovirus B19 (B19) is a common childhood infection that has recently been found to be associated with severe anemia in Papua New Guinean children. Population surveys were performed in 15 villages in Maprik district, East Sepik Province, Papua New Guinea in 2005. Plasma samples collected from children less than 10 years of age were tested for IgM and IgG antibodies to B19 by enzyme immunoassay. The prevalence of IgG antibody to B19 was 53.8% and ranged from 20% in those less than one year of age to 85.5% in those nine years of age. Considerable variation in IgG prevalence was observed between study areas, indicating complex patterns of transmission. Prevalence of IgM antibody to B19 was 1.5%. This study confirms that B19 infection is common among children in this tropical area. With 19.5% of children one year of age showing evidence of previous infection, any preventive measures should be targeted at the very young.