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The article presents a case study of a seven-year-old boy with Langerhans cell histiocytosis (LCH) who experienced severe myelosuppression during chemotherapy with oral 6-mercaptopurine (6-MP). Topics discussed include the association of NUDT15 polymorphisms with fatal myelosuppression, the risk of human parvovirus B19 (HPV-B19) infection during myelosuppression, and the recommendation for genotyping NUDT15 before initiating thiopurine-containing therapy to avoid excess toxicity.

Background: Human parvovirus B19 (B19) is a pathogen that threatens the quality of plasma products. Therefore, health authorities have mandated measures against B19 contamination of plasma pools. The US FDA has recommended a B19 genome level of 104 IU/ml or lower in pooled plasma lots. Therefore, the B19 nucleic acid amplification test (B19‐NAT) has been introduced in many plasma fractionators. However, in the Japanese Red Cross, which is the only approved blood collector in Japan, the B19 antigen test has been introduced for screening donated blood in Japan. Therefore, to clarify whether the antigen test is robust enough to screen blood samples according to the FDA recommendation, we evaluated B19 genome levels in each pooled plasma lot from 2003 to 2020. Study Design and Methods: Data of 5576 pooled plasma lots from factories A and B, which were derived from plasma bags and passed the B19 antigen‐based tests, receptor‐mediated hemagglutination assay (B19‐RHA), or chemiluminescent enzyme immunoassay (B19‐CLEIA), during 2003 to 2020, were evaluated. The amount of B19 genome in each lot was determined using quantitative or semiquantitative B19‐NAT. Results: The B19 genome levels in pooled plasma lots screened using B19‐RHA did not meet the FDA recommendation, whereas the lots derived from B19‐CLEIA fulfilled the FDA recommendation, even during the B19 epidemic in Japan. Discussion: The results suggest that the B19‐CLEIA donor screening for plasma pools is also useful in light of the US FDA recommendation. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the long-term changes in awareness of and knowledge about mother-to-child infections across 6 years in Japan. A questionnaire survey was conducted at our facility from October 2012 to January 2018, and the study periods were divided into 4 phases comprising 16 months each. A multiple-choice questionnaire assessed participants' awareness of the following 13 pathogens of mother-to-child infections: cytomegalovirus (CMV), Toxoplasma gondii (T. gondii), hepatitis B virus, rubella virus, herpes simplex virus, parvovirus B19, hepatitis C virus, human immunodeficiency virus, human T cell leukemia virus type-1, measles virus, varicella-zoster virus, Chlamydia trachomatis, and Treponema pallidum. For the selected four pathogens (i.e., CMV, rubella virus, T. gondii, and parvovirus B19), the questionnaire also evaluated participants' knowledge of transmission routes, the most susceptible time of infection that could yield severe fetal disease during pregnancy, the maximum frequency of fetal infection in cases of maternal infection, and methods to prevent maternal infection. In total, 1433 pregnant Japanese women were included in this study. There was no secular change in awareness of the pathogens concerning mother-to-child infections over time, and we also clarified that the detailed knowledge of the four pathogens of typical mother-to-child infections did not improve. Since knowledge about methods to prevent maternal infection is still insufficient for all pathogens, further advocacy is required to prevent mother-to-child infections. [ABSTRACT FROM AUTHOR]

Background To reduce the risk of human parvovirus B19 ( B19 V) transmission through contaminated blood for transfusion and plasma-derived products, the Japanese Red Cross ( JRC) Blood Centers introduced B19V antigen screening by chemiluminescent enzyme immunoassay ( CLEIA- B19V) in 2008. Study Design and Methods Donor samples that were positive by CLEIA- B19V screening were tested for B19V DNA. The sensitivity of CLEIA- B19V was tested using samples of all three genotypes and B19V DNA-positive donations. B19V DNA-positive donations and pooled plasma were quantitatively assayed for B19V DNA. B19V DNA-positive donations were phylogenetically analyzed by polymerase chain reaction direct sequencing. Results The sensitivity of CLEIA- B19V was inferred to be approximately 6.3 log IU/ mL with the genotype samples and 6.4 log IU/ mL with B19V DNA-positive donor samples. Of 417 CLEIA- B19V-positive samples from 1,035,560 donations in Hokkaido, Japan, 101 were positive for B19V DNA. The 198 strains of B19V DNA-positive donations in Hokkaido over the past 15 years clustered exclusively with Genotype 1. After introduction of CLEIA-B19V, the viral load for B19V DNA in all 772 pooled plasma for fractionation from donors in nationwide Japan did not exceed 4 log IU/ mL. Conclusion CLEIA- B19V can detect all three genotypes of B19V (viral load >6.3 log IU/ mL) and limit the viral load (<4 log IU/ mL) in pooled plasma, and thus such screening has further reduced the risk of transfusion-transmitted B19V infection. These results show that CLEIA- B19V screening at the JRC Blood Centers can be an alternative approach to comply with recommendations regarding B19V in the United States and Europe. [ABSTRACT FROM AUTHOR]

To relate the clinical findings of parvovirus B19 infection to the phase of the disease, we performed a retrospective chart review of 30 adult patients who tested positive for IgM antibody against parvovirus B19 at our hospital from March 2003 to November 2008. Median patient age was 38 years, with 86.7% aged between 26 and 45 years. The male-to-female ratio was 4:26 (86.7% female). Symptoms in the first phase were mainly flu-like, including fever, headache, or myalgia. Symptoms in the second phase were arthralgia in 24 (85.7%) and rash in 23 (82.1%). Fever was observed in 21 (70.0%), and 22 (75.9%) were found to be lymphopenic. The onsets in 73.3% of cases were concentrated within 10.1% of the study period, an observation nearly consistent with an outbreak of erythema infectiosum. Three patients had symmetrical swelling of joints, all of whom also had rash. Most patients visited the hospital within a week of onset and prognosis was favorable. In the parvovirus B19 infection, flu-like symptoms were frequent in the first phase, while rash and arthralgia were common in the second. Female sex, age between 26 and 45, and presence of rash, arthralgia, fever, and lymphopenia were clinical findings with a high frequency (≥70%), and these factors may contribute to diagnosis. In an era when early diagnosis and therapy is required in rheumatoid arthritis, it is important to recognize the parvovirus B19 infection with a presentation of acute arthritis and a favorable prognosis. [ABSTRACT FROM AUTHOR]