Electron microscopic identification of parvovirus virions in erythroid and granulocytic-line cells in a patient with human parvovirus B19 induced pancytopenia

Increased Numbers of CD4+CD25+ and CD8+CD25+ T-Cells in Peripheral Blood of Patients with Rheumatoid Arthritis with Parvovirus B19 Infection

AIM

To investigate T-cell subpopulations in peripheral blood of human parvovirus B19 DNA-positive (B19⁺) and -negative (B19^-) patients with rheumatoid arthritis (RA) and healthy persons.

PATIENTS AND METHODS

Blood samples were collected from 115 patients with RA and 47 healthy volunteers; 27 patients with RA and nine controls were B19⁺ Cluster of differentiation (CD) 4, 8, 25 and 45RA were analyzed on blood cells. CD25 expression on CD4⁺CD45RA⁺, CD4⁺CD45RA^-, CD8⁺CD45RA⁺, CD8⁺CD45RA^- subsets were analyzed by flow cytometry.

RESULTS

The percentage of CD25^low and CD25^hi cells was increased on CD4⁺CD45RA⁺, CD4⁺CD45RA^- T-cells and the percentage of CD25⁺ cells was increased on CD8⁺CD45RA⁺, CD8⁺CD45RA^- T-cells of B19⁺ patients with RA in comparison with B19^- patients and controls.

CONCLUSION

Raised levels of CD4 and CD8 regulatory T-cells in B19⁺ RA patients could cause down-regulation of antiviral clearance mechanisms and lead to activation of persistent human parvovirus B19 infection in patients with RA.

Frequency and significance of parvovirus B19 infection in patients with rheumatoid arthritis

The present study aims to clarify the possible involvement of parvovirus B19 (B19V) infection in rheumatoid arthritis (RA) pathogenesis by investigating the presence of B19V infection markers (genomic sequences and virus-specific antibodies) in association with the level of cytokines and RA clinical activity and aggressiveness. A total of 118 RA patients and 49 age- and sex-matched healthy volunteers were enrolled in the study. Nested PCR was used to detect B19V sequences in whole blood and cell-free plasma DNA, ELISA to detect virus-specific antibodies and cytokine levels in plasma and recomLine dot blot assay for antibodies to separate B19V antigens. The detection frequency of B19V DNA was higher in patients with RA (25.4 %) in comparison with healthy persons (18.4 %). B19V DNA in cell-free plasma (B19⁺p) was detected significantly often in RA patients in comparison with healthy controls (13.6 vs 2 %; P=0.0002). RA B19⁺p patients had higher disease activity and aggressiveness, decreased haemoglobin and increased erythrocyte sedimentation rates. IL-6 plasma levels were significantly higher in RA patients than in controls. Within the RA patients’ group the IL-6 level was significantly increased in B19⁺p patients with disease activity scores of DAS28>5.2, high C-reactive protein and low haemoglobin. Contrary to the healthy controls, the majority of RA B19⁺p patients did not have antibodies to VP-1S (VP1u) and VP-N (N-terminal half of structural proteins VP1 and VP2), which correspond to the epitopes of neutralizing antibodies. These results indicate that B19V infection at least in some patients is involved in RA pathogenesis.

Parvovirus B19 causing leucopenia and neutropenia in a healthy adult

A 27-year-old healthy female presented with a prolonged and intermittent febrile illness. She was found to have leucopenia, neutropenia and thrombocytopenia, but a normal haemoglobin. The patient recovered spontaneously and convalescent serology 1 month later was positive for specific parvovirus B19 IgM and IgG. Parvovirus B19 infection was confirmed by detection of viral DNA by dot blot hybridization in a specimen of blood taken during the acute illness. A review of the previously reported cases of parvovirus B19-induced leucopenia in normal adults is presented. Parvovirus B19 should be considered in the differential diagnosis of leucopenia and neutropenia in healthy adults.

Diverse hematologic effects of parvovirus B19 infection

Human parvovirus B19 is linked with a broadening spectrum of hematologic disorders, including aplastic crises in the context of hemolytic anemias, neutropenia, thrombocytopenia, and hemophagocytic syndromes. Children with any of these cytopenias should be screened for the presence of B19 because treatment with intravenous gamma globulin may provide resolution of abnormal blood counts if other therapeutic options, such as transfusion, are not adequate or desired.