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Introduction: Parvovirus B19 transmitted by umbilical cord blood (UCB) products may cause severe disease in allogenic hematopoietic stem cell transplant recipients. Thus, commercially available nucleic acid test (NAT) assays for highly sensitive detection of parvovirus B19 DNA validated for the specimen cord blood plasma (CBP) are required to avoid parvovirus B19 transmission by umbilical hematopoietic stem cell preparations. Methods: The multiplex cobas DPX NAT assay was validated for detection of parvovirus B19 DNA in CBP derived from citrate anticoagulated UCB units which have been processed by the Rubinstein method. In total, 363 retained CBP samples pretested negative for parvovirus B19 DNA were prepared for analyzing sensitivity, specificity, and interference of that NAT assay. The 3rd WHO International Standard for parvovirus B19 DNA was used for determining the 95% limit of detection (LOD95) by probit analysis. Results: The validation of the parvovirus B19 NAT assay for CBP demonstrated high sensitivity, specificity, intra- and inter-assay precision. Dilution series and replicate analyses showed a high linearity of the assay with a coefficient of determination above 0.99 and revealed a LOD95 of 17 International Units (IU)/mL (95% confidence interval, 14–44 IU/mL) for parvovirus B19 DNA in CBP samples. Conclusion: The validation of a commercially available parvovirus B19 NAT assay for the specimen CBP demonstrated a high assay performance fulfilling German guidelines and international regulations. [ABSTRACT FROM AUTHOR]

Parvovirus B-19 (B19V) is a common infection in children, occasionally complicated by ocular manifestations. In patients infected with severe acute respiratory syndrome virus (SARS-CoV-2), many cases of bacterial, fungal, and viral co-infections have been described. We report on a case of bilateral conjunctivitis, keratitis, and anterior uveitis that occurred in a patient co-infected by B19V and SARS-CoV-2. A young nurse developed, 20 days after the onset of asthenia and fever, a maculopapular rash and, in the following month, B19V-related arthritis. Shortly after a course of antibiotics and corticosteroids and the resolution of the arthritis, she began to complain of hearing loss and tinnitus. A polymerase chain reaction for SARS-CoV-2, previously negative, turned out positive; IgM for B19V decreased while IgG increased and antinuclear autoantibody and rheumatoid factor test results were positive. Ear symptoms disappeared after a course of prednisone, but eye burning and itching appeared 2 weeks after the coronavirus disease 2019 (COVID-19) positive swab. Bilateral conjunctivitis, keratitis, and anterior uveitis were diagnosed, which responded completely to a topical corticosteroid and mydriatic therapy. No relapses were observed in the following 12 months. The onset and progression of the symptoms, along with the laboratory findings, suggest a double pathogenesis of the ocular manifestations: keratitis and uveitis, along with the ear symptoms, seem to be the expression of an autoimmune reaction to B19V infection, while the conjunctivitis was likely related to direct infection of the conjunctiva by SARS-CoV-2. [ABSTRACT FROM AUTHOR]