Immune Cell Profiles of Patients with Sickle Cell Disease during Parvovirus B19–Induced Transient Red Cell Aplasia

Parvovirus B19 frequently infects children and targets cells of the erythroid lineage. Although healthy children rarely suffer severe disease, children with sickle cell disease (SCD) can experience transient red cell aplasia (TRCA), hospitalization, and life-threatening anemia upon first virus exposure. Given that children with SCD can also suffer chronic inflammation and that parvovirus B19 has been associated with autoimmune disease in other patient populations, we asked if parvovirus B19 infections contributed to acute and chronic immune abnormalities in children with SCD. Nineteen hospitalized patients with SCD and parvovirus B19-induced TRCA were evaluated. Blood tests included CBC, flow cytometry, and total antibody isotype analyses. Cytokine/chemokine analyses were performed on nasal wash (NW) samples, representing a common site of viral entry. Unusually high white blood cell count (WBC) and absolute neutrophil count (ANC) values were observed in some patients. A correlation matrix with Day 0 values from the 19 patients then identified two mutually exclusive phenotype clusters. Cluster 1 included WBC, ANC, absolute reticulocyte count (ARC), absolute lymphocyte count (ALC), lactate dehydrogenase (LDH), NW cytokines/chemokines, % naïve cells among B cell and T cell populations, and parvovirus-specific IgG. This cluster was negatively associated with virus load, suggesting a signature of successful adaptive immunity and virus control. Cluster 2 included virus load, % CD38