Transient Red Cell Aplasia Following Acute Human Parvovirus B19 Infection in a Sickle Cell Disease Patient in Aplastic Crisis

Abstract

Parvovirus B19 (PVB19) is a DNA virus, non-enveloped, with icosahedral nucleocapsid symmetry and measures 22-24 nm in diameter. Transmission is via blood transfusion being one of the transfusion transmissible viruses though infection can occur spontaneously. It is a major disease patients and Thalassemia patients, with clinical manifestation ranging from asymptomatic disease in immunocompetent to symptomatic disease in the immunocompromised. At risk group include children, pregnant women, immunocompromised and those with chronic haemolytic anemia. Clinical features include erythema infectiosum (fifth disease) in children, arthropathy, aplastic anemia/crisis and fetal hydrops.
Acute parvovirus B19 infection can be diagnosed by demonstrating the presence of HPV B19 IgM, with or without positive IgG using enzyme immunoassays (EIAs). Evidence of past infection is the presence of HPVB19 IgG. Red cell aplasia can be defined as a fall in haemoglobin concentration to below steadyƒ?state levels of more than 30g/l associated with a very low reticulocyte count.
This was a case report of a 15 year old girl, a known sickle cell anemia patient (HbSS) diagnosed a year after birth and has been stable on folic acid. Routine follow-up clinic visit has been irregular as patient had been clinically stable and crisis free on till about 15 months prior to presentation at our centre. Her steady state PCV hence could not be ascertained. She however started having extreme fatigue, tiredness and easy fatigability about 15months prior to her referral to our centre. On examination she was found to be severely pale with PCV of 6%. This necessitated her been transfused with whole blood at the peripheral health centre where she was been managed. PCV improves post transfusion for a few days after which the patient starts having dark coloured urine, jaundice, bone pains and generalized body pains. subsequently, the PCV drops to pre-transfusion level or below necessitating her frequent transfusion, atleast twice a month for upto 8 months before her referral to a tertiary health centre for further investigation. Investigations done include CBC, PBF, BMA, repeat haemoglobin genotyping using HPLC G6PD assay and Human Parvovirus B19 screening. Findings were in concordance with aplastic anaemia, negative for G6PD deficiency but was positive on screening for HPVB19 with a high persistent fetal hemoglobin of upto 31%.