A partial nucleated differential cell count of the bone marrow aspirate that is independent of peripheral blood dilution.

In the bone marrow (BM) nucleated differential cell count (NDC), myeloblasts are enumerated as a percentage of total nucleated cells, which are inevitably diluted with peripheral blood nucleated cells (PBNC) during BM aspiration. We propose a partial NDC (PNDC) comprising only immature haemopoietic cells capable of division, i.e. myeloblasts, promyelocytes, myelocytes and erythroblasts. We show that the myeloid : erythroid (M : E) ratio of the PNDC remains approximately constant in progressively dilute aliquots of BM aspirates. We determined the PNDC in 22 healthy subjects and investigated the effect of peripheral blood dilution on disease stratification of 66 BM aspirates with myelodysplastic syndromes (MDS). NDC and PNDC myeloblast counts were compared and the equivalent PNDC myeloblast counts for NDC myeloblast threshold counts of 5, 10 and 20% were derived. Reclassification of MDS samples with the PNDC resulted in a change in disease category in 33.3% of 51 MDS samples with NDC myeloblast counts ranging from 3 to 26%. The PNDC is independent of PBNC dilution and can be determined in dilute BM samples. It alters the disease category in a significant proportion of BM aspirates with MDS and has the potential to better stratify MDS to improve clinical outcomes and treatment.

Antibodies against prM protein distinguish between previous infection with dengue and Japanese encephalitis viruses.

BACKGROUND: In Southeast Asia, dengue viruses often co-circulate with other flaviviruses such as Japanese encephalitis virus, and due to the presence of shared antigenic epitopes it is often difficult to use serological methods to distinguish between previous infections by these flaviviruses. RESULTS: Convalescent sera from 69 individuals who were known to have had dengue or Japanese encephalitis virus infection were tested by western blotting against dengue, Japanese encephalitis and West Nile virus antigens. We determined that individuals who had been infected with dengue viruses had IgG responses against the premembrane protein of dengue viruses but not Japanese encephalitis, whereas individuals who had been infected with Japanese encephalitis had IgG specific for the premembrane protein of Japanese encephalitis virus but not the dengue viruses. None reacted with the premembrane protein of West Nile virus. Using the Pearson Chi Square test, it was determined that the difference between the two groups was highly significant with a p value of <0.001. CONCLUSION: The use of flavivirus premembrane protein in seroepidemiological studies will be useful in determining what flaviviruses have circulated in a community.