A pilot study on parvovirus B19 infection in paediatric haematological malignancies

BACKGROUND & OBJECTIVES: Leukaemia and lymphoma are common paediatric haematological malignancies acquiring human parvovirus B19 (B19) infection. In some studies anaemia has been found in children with acute lymphoblastic leukaemia (ALL) during maintenance therapy and rarely in lymphoma. We studied frequency of B19 infection and its implications in new onset acute leukaemia (mostly ALL) and lymphoma in children. METHODS: Seventy serum samples from 35 children (age <12 yr, 29 males) newly diagnosed with haematological malignancies (on induction therapy) were collected together with 34 controls (solid tumours). Children were examined clinically and for anti-B19 IgM antibodies by quantitative ELISA and B19 DNA by PCR (VP1-VP2) and nested-PCR (VP1 unique). Bone marrow aspirates were examined histopathologically, whenever possible. RESULTS: Of the 35 children, 22 had acute leukaemia while 13 had lymphoma. B19 infection was seen in six (17.1%) of 35 children (5 ALL, 1 NHL), two at diagnosis and four during follow up compared to none in the control. Among five B19 IgM positive ALL (n=18) children, two had B19 genome and two had giant pronormoblasts (lantern cells; but one lacked B19 DNA). Of the 70 serum samples tested, eight (11.4%) had anti-B19 IgM as two children had persistent B19 infection and one showed atypical maculopapular rashes (lower limbs) while 12 (34.3%) had anti-B19 IgG antibodies. B19 infected children had unexplained anaemia (80%), required more blood transfusions (6.6 ± 4.8 Units vs 3.0 ± 2.6 Units) besides induction chemotherapy was delayed (60%) and required longer duration of therapy (29.2 ± 20 vs 6.3 ± 7.8 days) (P<0.02). Five children (2 ALL, 2 AML, 1 NHL) died but none were infected with B19. INTERPRETATION & CONCLUSIONS: B19 infection should be considered in children with ALL as it frequently caused unexplained anaemia and delay in induction chemotherapy.