The impact of Parvovirus B19 on hereditary haemolytic anaemias

Parvovirus B19 is a small single-stranded DNA virus, generally causing an asymptomatic infection in 25–50% of the general population. Seropositivity increases with age (15% preschool children, 50% young adults and 85% elderly), transmission most commonly horizontally by respiratory secretions, but also vertically from mother to foetus during pregnancy. The clinically relevant cellular receptor parvovirus globoside or P antigen, which present on several cell types, particularly erythrocytes haematopoietic precursors. Since its discovery more than 40 years ago, has been associated diseases. Erythema infectiosum (‘fifth disease’) common self-limiting clinical manifestation acute immunocompetent hosts. However, chronic forms are increasingly described immunocompromised patients, such as those haematologic cancers, autoimmune diseases solid organ transplant recipients.1-3 prevalent form pure red-cell aplasia, characterized recurrent anaemia reticulocytopenia, may be serious life-threatening. In addition, includes myocarditis, dilated cardiomyopathy arthritis, due tropism virus for myocytes synovial tissues. haemoglobinopathies already investigated recently reviewed.4 beta-thalassaemia, positivity IgG, IgM reported up 81%, 40% 15% cases, respectively. sickle disease (SCD), seropositivity was less (IgG varied 37–66%, 3–30%) while detection rate greater (4–54%). both thalassaemia SCD, can cause transient potentially severe aplastic crises. this complicated splenic hepatic sequestration chest syndrome. Less known about other hereditary haemolytic anaemias, heterogeneous group conditions including defects erythrocyte membrane proteins, enzymes defective erythropoiesis. They variable degrees haemolysis, increased turnover, splenomegaly, jaundice, biliary lithiasis iron overload. typical examples spherocytosis (HS), elliptocytosis stomatocytoses. Glucose-6-phosphate dehydrogenase (G6PD) pyruvate kinase (PK) enzyme deficiencies, congenital dyserythropietic type II best-studied erytropoiesis. These rare sometimes difficult diagnose their phenotype need specialized work-up genetic testing. HS, case reports showed that induce crisis, first undiagnosed disease.5-7 Moreover, complications, glomerulopathy microangiopathy, encephalopathy haemophagocytic lymphohistiocytosis.8-10 G6PD deficiency, crisis presentation previously unknown disease, misinterpreted Diamond-Blackfan anaemia.11, 12 PK crises course initial manifestation, often complicating differential diagnosis. abrupt onset profound requiring blood transfusions, pancytopenia, again challenging diagnosis.13 paper Mahmoud I. Elbadry14 offers comprehensive evaluation large cohort 244 patients different types anaemias (HHA), namely HS deficiency. From February 2018 2020 all admitted symptoms at Shoag Assiut University Hospitals Egypt were simultaneously screened HHA infection; positive underwent extensive clinical, laboratory radiological damage long follow-up (12–32 months). Of note, 67 (27%) received diagnosis admission event study period, highlighting early still haematological disorders if screening newborns not place, frequently occurs emergency admissions.15 Acute symptomatic diagnosed 33 (13·5%). All presented cytopenia (pancytopenia 27, bicytopenia 6); fever musculoskeletal pain common, interestingly manifestations differed according type. Adolescents had lymphadenopathy, kidney injury (AKI) pancytopenia. General (skin rash lymphadenopathy) extreme direct hyperbilirubinaemia (EDHB) frequent AKI SCD compared thalassaemia. One death occurred multiorgan failure (AKI, hepatitis, failure, encephalopathy) patient vaso-occlusive crisis. Compared previous single shows 82% multiple impairment AKI, EDHB neurological sequelae, well widely bone marrow failure. Interestingly, only resolved steroid therapy plasma exchange. authors describe depth overall phenotypes management evolution particular cases involvement. Their detailed experience guide clinicians routine approach settings prompt awareness complications B19, especially SCD.