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Parvovirus B19 is the aetiological agent of erythema infectiosum, transient bone marrow aplastic crises, arthritis, non-immune hydrops fetalis, and chronic pure red cell aplasia in immunocompromised persons. More than 20 reports describe an association between acute lymphoblastic leukaemia (ALL) and persistent B19 infection which, until recently, has been assumed to represent an opportunistic infection, the chronicity of which results from immunosuppression. However, several reports describe B19 infection preceding and mimicking ALL. 1- 4 One published study examined serum from 65 patients with ALL for B19 DNA and specific IgG. 5 The results showed that although there was one positive case, which was also published separately, 1 serum anti-B19 IgG was positive in 30% of patients, which is consistent with the population prevalence adjusted for age.
"More than 20 reports describe an association between acute lymphoblastic leukaemia and persistent B19 infection"
We hypothesised that if B19 virus does play a role in the pathogenesis of acute leukaemia, the virus may no longer be present in the serum at the time of diagnosis, but may be present at other more cryptic sites because clearance from these areas may be delayed. One such site is the cerebrospinal fluid (CSF), 6 samples of which are commonly taken as part of routine investigations in new cases of leukaemia. In support of this approach, B19 virus is known to cause meningoencephalitis, 7 and one report describes chronic B19 meningitis in a child with ALL. 6
MATERIALS AND METHODS
As part of routine viral screening, we examined CSF from cases of ALL at diagnosis (two were of T cell origin) (n = 14), acute myeloblastic leukaemia (AML) at diagnosis (n = 2), benign intracranial hypertension (BIH) with ventriculoperitoneal shunt (n = 10), and hydrocephalus with ventriculoperitoneal shunt (n = 13) presenting during an outbreak of acute parvovirus B19 in the UK using nested polymerase chain reaction (PCR) specific for the B19 NS1 gene. 7 Positive samples were confirmed using a nested PCR specific for the B19 VP1 gene, as described previously. 7 The patients with leukaemia had an overall mean age of 46.9 months (range, 18-86 months). CSF was taken during routine diagnostic and therapeutic lumbar puncture. Anti-B19 IgM and IgG antibodies were detected in serum and CSF by western blot...