Acute Chest Syndrome Is Strongly Associated Parvo Virus B19 Seroconversion in Patients with Hemoglobin SC Disease.

Parvovirus B19 replicates principally in human erythrocyte precursors resulting in temporary cessation of erythropoiesis. In patients with sickle hemoglobinopathies, parvovirus B19 infection has been associated with acute chest syndrome and may lead to transient aplastic crisis. Evidence of prior infection with parvovirus B19 is found in 50 to 60% of adults. Infection appears to be followed by lifelong immunity. The objectives of the Study of Seroprevalence and Incidence of Parvovirus B19Infection in Children with Sickle Hemoglobinopathies are to determine the prevalence of parvovirus B19 antibodies in children less than 16 years old; determine the rate of parvovirus B19 seroconversion; and determine whether parvovirus B19 seroconversion is associated with the occurrence of aplastic crisis or acute chest syndrome. Between April 2000 and June 2002 a total of 1039 children from eight Comprehensive Sickle Cell Centers (CSCC) were enrolled in the study and 898 had at least one follow up visit. Participants ranged in age from <1 month to 16 years at enrollment (mean age 7.2, + 4.5 years), 47% were female, 53% were male. 67% had homozygous Hb SS disease, 24% had Hb SC disease, 6% had Hb SB+ disease, 3% had Hb SB0 disease, and <1% had other S sickle cell disease. The seroprevalence of parvovirus B19 in the cohort was 35%. Prevalence varied significantly by age, ranging from a low of 8% for children 1–2 years of age to 69% for children 13+ years of age (p<0.0001). The greatest increase in seroprevalence occurred between 6 and 7 years of age. Adjusted for age, there were no significant differences in seroprevalence by gender, clinical center, geographic area of residence (northeast, southeast, midwest, and west) sickle hemoglobinopathy, number of siblings, hemoglobin level, reticulocyte %, or among recipients of treatment with transfusion or hydroxyurea. Parvovirus B19 seroconversion was strongly associated with an increased risk of aplastic crisis in both SS (odds ratio of 29, 95% CI (11.3, 74.4)) and SC patients (odds ratio of 110, 95% CI (9.6, 1270.4)), even when controlling for age. Seroconversion was associated with an increased risk of acute chest syndrome in SC patients, (odds ratio of 6.4, 95% CI (1.9, 21.9)) but did not reach statistical significance in SS patients.

These data show a clear causal relation between parvovirus B19 seroconversions and acute chest syndrome in subjects with hemoglobin SC disease and confirm the previously known association aplastic crisis.