Pulmonary thromboembolism in thalassemia intermedia patients.

hybrid (myeloid-erythroid) blasts has been proposed to be a characteristic bone marrow feature in EL, but has not as yet been emphasized as a morphologic feature of the disease.4 Erythroblasts with peripheral chromatin condensation are sufficiently characteristic for a provisional diagnosis of B 19 infection to be made on the histology5 and rare erythroblasts with this morphologic feature could be observed (Figure 1e). While we can firmly correlate the infectious phase of the disease to HPV B19, the association with the neoplastic phase is only hypothetical because of the absence of the virus in the marrow cells when searched for by in situ hybridization.6 An alternative interpretation is that the patient had already subclinical EL which was unmasked by HPV B19 infection. If the virus hit compromised marrow, in which a shrunken compartment of normal hemopoiesis coexists with a still subclinical competing leukemia clone, pancytopenia may follow. Resolution of the virus infection might have given the normal marrow a chance to re-establish normal blood counts transiently, but EL finally exapanded and took over. Since this is a case report it would be inappropriate to draw general conclusions. Nevertheless interesting speculation arise from this report: is there an association between HPV B19 and EL and can cell fusion play a role in the cytogenesis of giant multinucleated erythroblasts?