Quantitation of human parvovirus B19 DNA by real-time polymerase chain reaction.

Background: There have been no reports on either the serial quantification of genomic copies in the various parvovirus B19 infections or the comparison of the viral amount in erythema infectiosum, unlike with that in other parvovirus B19 infections.

Methods: A total of 19 children with parvovirus B19 infection were classified into a group of seven (group A) with erythema infectiosum and a group of 12 (group B) without erythema infectiosum, and their serum levels of parvovirus B19 DNA were quantified by real-time polymerase chain reaction. A total of 30 boys and girls with some symptoms but no parvovirus B19 infection served as a control group (group C).

Results: The amount of parvovirus B19 DNA differed significantly between groups A and C (P < 0.01) and between groups B and C (P < 0.01). The amount of viral DNA was significantly higher in group B than in group A (P < 0.01). Sequential determination showed that the amount of viral DNA in group B rapidly decreased over several days. Erythema infectiosum developed in two patients of group B on the 6th and 29th days after onset when the amount of viral DNA was similar to that in group A.

Conclusions: The amount of parvovirus B19 DNA correlated well with the stage of infection, and its quantitation was useful for determining disease status and prognosis. In parvovirus B19 infection, the viremia is associated with rare but varied pathological states different from erythema infectiosum, such as transient aplastic crisis, hemophagocytic syndrome, lupus-like syndrome, and papular-purpuric gloves and socks syndrome.