Interactome Based Identification and Validation of Prefoldin 5α for Prognosing CNS Leukemia in B-All Patients

BackgroundThe gold standard for central nervous system (CNS) B cell acute lymphoblastic leukemia (B-ALL) diagnosis is cerebrospinal fluid (CSF) cytology with poor sensitivity. Thus, prophylactic intrathecal chemotherapy is implemented, which has severe neurological consequences necessitating discovery of CNS leukemia prognostic markers. MethodsTwo-dimensional (2D) far-western interactome analysis was performed to identify CNS+ve/-ve B-ALL CSF reactivity to lymphoblastic proteins profiled on a 2D-western blot. Those specific CNS+ve reacting spots were identified using mass spectrometry. The identified proteins were further validated by both 1D western and ELISA. An ROC curve was generated to identify the cut-off value for prognostication of CNS leukemia in B-ALL patients. ResultsUsing interactome analysis with B-ALL CNS+ve/-ve CSF, we identified prefoldin 5α (PFDN5α), cytokine induced protein 29 (CIP29), enoyl CoA hydratase (ECH1) and peroxiredoxin 6 (PRDX6). Among these proteins, PFDN5α showed statistically significant consistent low reactivity to CNS+ve CSF compared to CNS-ve. Further validation of PFDN5α-CSF reactivity using 1D western and ELISA platform confirmed our interactome analysis. Receiver Operating Characteristic (ROC) curve analysis generated from B-ALL CNS +ve (n = 25) and –ve (n = 40) CSF samples identified PFDN5α-CSF reactivity cut-off value as 0.456. In contrast, CIP29, ECH1 and PRDX6 proteins did not show any differences in CSF reactivity as seen in interactome analysis. ConclusionsUsing far-western interactome approach, we identified the prognostic significance of PFDN5α in predicting CNS leukemia. Further validation by 1D western and ELISA confirmed the significance of differential CSF reactivity of CNS+ve/-ve B-ALL CSF to PFDN5α towards prognostication of CNS leukemia. ROC curve analysis identified the cut-off value for CNS leukemia prediction as 0.456. Values above or below 0.456 could discriminate B-ALL patients either not requiring or requiring intrathecal chemotherapy respectively. Considering the prophylactic chemotherapy associated neurological consequences, PFDN5α-CSF reactivity based prognosis of CNS leukemia is important in avoiding prophylactic intrathecal chemotherapy for the effective clinical management of patients.