Immunocompromised patients suffer from prolonged viral infections often without detectable immune response. However, even if the immune response occurs, can it clear the virus completely?
To detect parvovirus B19 DNA and its antibodies in bone marrow cells and in serum by polymerase chain reaction (PCR) in children with acute lymphoblastic leukemia receiving chemotherapy to highlight the relation of humoral immune response to the presence of viremia. Also, to evaluate the optimal diagnostic test(s) for a correct diagnosis of parvovirus B19 disease in immunocompromised patients.
Forty-eight children with acute lymphoblastic leukemia receiving maintenance chemotherapy were included in the study in addition to 20 healthy children with matched age and sex. Study for parvovirus B19 was performed by serologic determination of specific immunoglobulin (Ig) M and IgG, and viral DNA was determined by PCR in both serum and bone marrow aspiration.
Parvovirus B19 DNA was detected in both serum and bone marrow in 20% of patients. Specific IgG was found in 40% and IgM in 26.7%. Two cases (10%) in the control group were positive for IgG. The agreement between IgG and positive results of PCR in the bone marrow was 33.3%, and the agreement for IgM and PCR in the serum was 33.3%.
Parvovirus B19 is considered a common viral infection in children with acute lymphoblastic leukemia receiving chemotherapy. We must use our full potential to exclude such infection, which can mimic the side effects of chemotherapy in these patients. In immunocompromised patients, there are immunologic discrepancies in humoral immune responses for both IgM and IgG between individuals with parvovirus B19 persistence and healthy individuals, findings that may reflect both failed immunity and antigenic exhaustion. The contemporaneous determination of parvovirus B19 DNA by PCR in both bone marrow and peripheral blood and specific serologic markers appears to be the most appropriate diagnostic protocol for the correct laboratory diagnosis of parvovirus B19 infection in these patients.