Pancytopenia with hemophagocytosis secondary to parvovirus B19 infection in a family with hereditary spherocytosis

Transient aplastic crisis triggered by parvovirus B19 in a family with hereditary spherocytosis

Acute parvovirus B19 infection may lead to erythroblastopenia crisis in patients with underlying red blood cells disorders. We report herein an uncommon concomitant transient aplastic crisis in a mother and her daughter, both affected by hereditary spherocytosis. The diagnosis was confirmed by the detection of a very high parvovirus B19 DNA load in both the mother’s and daughter’s sera, associated with the presence of parvovirus B19 specific immunoglobulin-M antibodies. This rapid etiologic diagnosis allowed to save bone marrow sampling, although blood transfusion was required regarding the severe anemia associated with pancytopenia. Our observation illustrates first line parvovirus B19 hypothesis in the context of transient aplastic crisis and that contagiousness in household contacts should be considered in family with a medical history of red blood cell pathology.

Parvovirus B19-induced hemophagocytic lymphohistiocytosis: Case report and review of the literature

HLH is a catastrophic and likely underdiagnosed pathology with multiple triggers including infection. PVB19 can cause persistent marrow infection leading to HLH despite negative acute serologic markers making timely diagnosis difficult. Increased awareness of PVB19-HLH is warranted given its potentially lethal nature and the careful interpretation required with serologic markers.

Quantitation of human parvovirus B19 DNA in erythema infectiosum and aplastic crisis

Several publications concerning the methods of real-time PCR for human parvovirus B19 (B19V) have appeared and some case reports mention B19V DNA loads. However, no large-scale study quantitating levels of B19V DNA in common or representative B19V manifestations such as erythema infectiosum and aplastic crisis has been performed. Consequently, using the TaqMan PCR assay, the B19V load in a large sample of subjects with erythema infectiosum or aplastic crisis was quantitated. Sixty-five subjects in the acute phase of erythema infectiosum were involved, and in addition 22 serum samples from seven subjects with B19V-associated aplastic crisis complicating chronic hemolytic anemia were also analyzed. In the acute phase of erythema infectiosum the median B19V DNA load in the serum samples from the acute phase of erythema infectiosum was 7.63 × 10(5)  genomes/ml, (range from 4.48 × 10(3) to 8.31 × 10(6)  genomes/ml). The serum B19V DNA load during the acute phase of aplastic crisis complicating chronic hemolytic anemia was extremely high, that is 10(10) -10(13)  genomes/ml, and decreased gradually to around 10(5) genomes/ml over 1-2 months. Although all subjects followed an almost uniform and typical clinical course of erythema infectiosum, there was a large individual variation of B19V DNA loads, that is differences of over 1,000 times. Extremely high B19V loads were observed in subjects with aplastic crisis. This study is the first large scale report of studies of the B19V DNA loads in subjects with erythema infectiosum and aplastic crisis, the most common and significant clinical manifestations by B19V infections.

[Acute erythroblastopenia due to Parvovirus B19 revealing hereditary spherocytosis]

Acute Parvovirus B19 infection is responsible for blocking the erythroblastic line, usually with no consequences on hematopoiesis except in patients with chronic hemolytic anemia in whom it can evolve to potentially serious acute anemia. We report 2 observations of acute erythroblastopenia revealing hereditary spherocytosis in 2 children (1 boy and 1 girl) of non-consanguineous parents.

Antibody-mediated opsonization of red blood cells in parvovirus B19 infection

Red blood cells (RBCs) express abundantly parvovirus B19 receptor, and their role in the dissemination or clearance of B19 infection is unknown. In this study, we report that in early, acute or persistent infection, B19 viremia is mostly associated with RBCs. The capacity of different patients' plasma or IgG to opsonize RBCs collected from patients with early B19 infection, was investigated. The highest opsonization activity was observed with plasma or IgG fractions from patients with past B19 infection. In contrast, IgG samples from patients with acute or persistent infection showed no or little opsonization activity. The depletion of antibodies specific to B19 VP1, but not VP2, from IgG samples, resulted in a significant suppression of opsonization. Furthermore, IgG samples preincubated with heated B19 particles exposing VP1-unique (VP1u) region were unable to opsonize RBCs. These observations clearly suggest a role for anti-VP1u IgG in the opsonization of RBC-bound B19 particles.

Human parvovirus B19

Parvovirus B19 (B19) was discovered in 1974 and is the only member of the family Parvoviridae known to be pathogenic in humans. Despite the inability to propagate the virus in cell cultures, much has been learned about the pathophysiology of this virus, including the identification of the cellular receptor (P antigen), and the control of the virus by the immune system. B19 is widespread, and manifestations of infection vary with the immunologic and hematologic status of the host. In healthy immunocompetent individuals B19 is the cause of erythema infectiosum and, particularly in adults, acute symmetric polyarthropathy. Due to the tropism of B19 to erythroid progenitor cells, infection in individuals with an underlying hemolytic disorder causes transient aplastic crisis. In the immunocompromised host persistent B19 infection is manifested as pure red cell aplasia and chronic anemia. Likewise, the immature immune response of the fetus may render it susceptible to infection, leading to fetal death in utero, hydrops fetalis, or development of congenital anemia. B19 has also been suggested as the causative agent in a variety of clinical syndromes, but given the common nature, causality is often difficult to infer. Diagnosis is primarily based on detection of specific antibodies by enzyme-linked immunosorbent assay or detection of viral DNA by dot blot hybridization or PCR. Treatment of persistent infection with immunoglobulin reduces the viral load and results in a marked resolution of anemia. Vaccine phase I trials show promising results.

[Acute transitory intrafamilial erythroblastopenia and hereditary spherocytosis: role of parvovirus B19]

INTRODUCTION

Acute parvovirus B19 infection induces a transient inhibition of erythroid cell formation, which may induce an erythroblastopenia crisis in patients suffering from chronic hemolytic anemia.

EXEGESIS

We report here an exceptional observation of acute erythroblastopenia crisis with good outcome, occurring at the same time in a mother and her son, both suffering from hereditary spherocytosis. Diagnosis of parvovirus infection is based on detection of serum parvovirus B19-specific immunoglobulin M antibodies in the mother and her son and by the positivity of parvovirus B19 DNA detected by PCR in serum in the mother. Outcome was good, with the end of the erythroblastopenia crisis obtained 7 to 10 days later, but requiring blood transfusion in the mother.

CONCLUSION

Our observation is a reminder that the contagiosity of parvovirus B19 is high in household contacts and that protection of family members should rapidly be considered in hereditary spherocytosis.