Figure 3

Validation Flow cytometry-based quantification of CD34⁺/CD19⁺ cells in the CSF following initial gating with CD45⁺ and the extent of CSF reactivity of the same samples to PFDN5-α by ELISA quantification. Note that with increasing number of CD34⁺/CD19⁺ cells (A), there is gradual decrease in reactivity of CSF to PFDN5-α identified by ELISA (B). More importantly, the CSF samples in which > 3% blast cells seen are statistically significant compared to CNS leukemia negative samples identified by flow (less than 1% CD34⁺/CD19⁺ cells) and that the average CSF reactivity to PFDN5-α is 0.448 ± 0.092, a value below the cut off value of 0.456 identified by ROC curve analysis.