Parvovirus B19 Antibodies, IgG & IgM
Parvovirus B19 is associated with 5 syndromes including erythema infectiosum, arthropathy, transient aplastic crisis, pure red blood cell aplasia, and transplacental infection. The infectious phase begins 24 to 48 hours before onset of the viral prodome and lasts until the rash appears. Children are commonly infected first and then infection spreads to other family members by direct contact with respiratory secretions. Close contact between individuals increases the incidence of outbreaks in schools, daycare centers, and hospitals. Outbreaks most commonly occur during the spring.
Erythema infectiosum is commonly seen in children and is also called fifth disease or slapped cheek syndrome. Children present with a febrile influenza-like illness for 5 to 7 days followed by the classic slapped cheek rash on the face. An erythematous maculopapular rash may appear on the trunk 1 to 2 days later.
Symmetrical arthropathy is rare in children but common in adults. The small joints of the hands and feet are usually affected. Joint pain usually lasts for 1 to 3 weeks but may last for months in some individuals.
Parvovirus B19 preferentially replicates in human erythroid progenitor cells. Transient aplastic crisis is usually seen in patients with chronic hemolytic disorders such as sickle cell anemia. Infection causes an abrupt cessation of erythropoiesis and anemia that lasts up to 8 days. Severe anemia can be life threatening in these patients.
Pure red blood cell aplasia causes prolonged anemia in patients with congenital and acquired immunodeficiencies. Bone marrow biopsy reveals giant proerythroblasts with viral inclusions.
Transplacental fetal infection occurs in approximately 30% of women infected during pregnancy and is associated with fetal death in 2 to 6% of cases. Fetuses can develop nonimmune hydrops fetalis, intrauterine growth retardation or serositis.
Diagnosis of acute parvovirus B19 infection is confirmed by detection of IgM antibodies. More than 90% of individuals have detectable IgM antibody by the time the rash appears. IgM antibody level peaks at 30 days and remains detectable for up to 3 months.
IgG antibody appears during the first week of illness and remains detectable for life. The prevalence of parvovirus B19 IgG antibodies increases with age. Parvovirus IgG antibodies are detected in 2% to 9% of children under 5 years of age, 15% to 35% in children between 5 and 18 years of age, and 30% to 60% of adults.
As the following table indicates, the presence of IgM indicates recent infection while IgG antibodies is suggestive of past exposure.
| Parvovirus B19 IgM | Parvovirus B19 IgG | Interpretation |
| Negative | Negative | Not infected |
| Negative | Positive | Past exposure |
| Equivocal | Positive or Negative | Possible recent infection |
| Positive | Positive | Recent infection |
| Positive | Negative or Equivocal | Possible current infection |
Epstein Barr virus infections and antinuclear antibodies may produce equivocal or positive IgM results. Patients who are immunosuppressed may not produce detectable Parvovirus antibodies. In these cases, parvovirus DNA can be detected by polymerase chain reaction (PCR).
Antibody to parvovirus B19 is detected by a sandwich EIA for the detection of IgG or IgM class antibodies in serum or plasma. Reference value is negative for IgG and IgM.
Specimen requirement is one SST tube of blood.
