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[A case with petechiae due to human parvovirus B19]
Summary
Human parvovirus B19 infection caused petechiae in a child with normal platelet counts. The virus may directly damage endothelial cells expressing P antigen, leading to this symptom.
Area of Science:
- Virology
- Hematology
- Immunology
Background:
- Idiopathic thrombocytopenic purpura typically presents with low platelet counts.
- Human parvovirus B19 (B19) is a common virus, but its role in petechiae with normal platelet counts is less understood.
Observation:
- A 10-year-old girl presented with petechiae and normal platelet counts.
- Bone marrow examination revealed reduced erythroblasts and giant proerythroblast-like cells.
- B19 DNA was detected, with significant changes in B19-specific IgM and IgG antibody titers.
Findings:
- Petechiae resolved within 8 days of admission.
- Reticulocyte counts increased, and bone marrow smears normalized by day 17.
- B19 infection was confirmed as the cause, with potential direct endothelial cell injury.
Implications:
- This case suggests B19 can cause petechiae through direct endothelial cell damage, independent of thrombocytopenia.
- The P antigen, present on endothelial cells, may be the cellular receptor for B19, mediating this effect.
- Understanding B19's mechanism in petechiae broadens its clinical spectrum beyond typical presentations.