FOLLOW-UP OF IMMUNOCOMPROMISED PATIENT WITH HUMAN PARVOVIRUS B19 INFECTION: A CASE REPORT

Human parvovirus B19 (B19V) infection is a common, highly contagious and usually mild disease, occurring in infancy. Parvoviruses are single-stranded, cubic DNA viruses of about 18-32 nm without an envelope. B19V infects only humans and has a selective tropism for erythroid progenitor cells of the bone marrow.  Persons infected with the virus develop lasting immunity that protects them against infection in the future. Although, common symptoms are mild, and unspecific, and may consist of fever, myalgia and rhinorrhea, parvovirus B19 infection can also cause serious illness in people with sickle-cell disease or similar types of chronic anemia, as well as in immunocompromised patients. Consequently, patients with impaired immune system and anemia should be closely monitored. We describe a case of a 26 year-old caucasian male, bearer of an acute lymphocytic leukemia diagnosed in March 2019. Patient had an allogenic stem cell transplant in 2019 from a non-related donor, under reduced intensity conditioning regimen with busulfan, cyclophosphamide and anti-thymocyte globulin. He received methotrexate and tacrolimus as graft versus host disease (GVHD) prophylaxis. After transplantation the patient persisted with low hemoglobin (ranging from 7,1 g/dL to 9,4 g/dL over a period of 6 months)  and diminished reticulocyte count (ranging from 62,9×109/L (2,3%) to 103,1×109/L (4,3%) during this period), which was compatible with a hypoproliferative anemia. Blood samples were collected for detection of B19V viremia and serology (whole blood collected in EDTA and human serum respectively) which were carried out by the Clinical Virology Laboratory. The viremia assay was performed by real-time amplification reaction (PCR) using the ELITe InGeniusTM (combining extraction and an amplification thermocycler) using Parvovirus B19 ELITe MGB® kit (qualitative and quantitative nucleic acids amplification assay) and revealed the amplification of B19V DNA higher than 2,5x107IU/mL. Serology was performed by enzyme-linked immunosorbent assay (ELISA) to detect IgG and IgM antibodies against B19V antigens. Samples were analysed by the Meditecno® Gemini, using Parvovirus B19 IgG ELISA NovaLisa® and Parvovirus B19 IgM ELISA NovaLisa® kits, considering as positive a cut-off above 11 Novatec Unit [NTU]. Results were positive for immunoglobulin G. After establishing the diagnosis of B19V reactivation, the patient was treated with intravenous immunoglobulin 400 mg/kg/day, for five days, and repeated the same treatment at least twice more. The patient is currently stable and monitored every two weeks for B19V viremia.