Peripheral blood quantitation of CD26 positive leukemic stem cells as a predictor of tyrosine kinase inhibitor response in chronic myeloid leukemia.

INTRODUCTION: Leukemic stem cells (LSCs) are the transcriptionally low/silent cells which are resistant to the tyrosine kinase inhibitor. These have been found to play a pivotal role in disease relapse in chronic myeloid leukemia (CML) cases. The present study evaluated the correlation of absolute CML-LSC count in the peripheral blood (PB) at diagnosis and achievement of major molecular response (MMR) at 12 months in patients of CML-CP. METHODS: This was a prospective, observational, non-interventional single center study including newly diagnosed adult (>18 yrs) CML-CP patients. Absolute CD26 + CML-LSC quantification was done by multiparametric flow cytometry. Patients were treated with Imatinib treatment and subsequently monitored at 3-month intervals for BCR::ABL transcript levels. MMR was defined as a BCR::ABL1 transcript level of less than 0.1% on international scale. RESULTS: A total of 89 patients were enrolled in the study out of which 40.5% achieved MMR at 12 months. There was a significant difference in the median absolute CML-LSC count of the patients who achieved MMR at 12 months as compared to those who did not (58.5 vs 368.1 cells/µL; p value <0.001). Using a ROC analysis, a count of <165.69 CML LSC/µL was identified to have a sensitivity of 83.8% and specificity of 72.4%, in predicting the MMR at 12 months. CONCLUSION: Absolute CML-LSC count at diagnosis in the PB predicts the MMR achievement at 12 months. An absolute count of less than 165 cells/µL is highly predictive of achieving MMR at 12 months.

CD26 expression on circulating CD34+/CD38- progenitor population is a specific and reliable tool for the rapid flow cytometric diagnosis of chronic myeloid leukemia-A single-center validation study.

BACKGROUND: Recently, CD26 have been identified as one of the promising and specific marker for the identification of leukemic stem cells (LSCs) in chronic myeloid leukemia (CML). METHODS: This was a prospective, observational validation study. Peripheral blood (PB) samples from suspected cases of CML and other hematolymphoid neoplasm were evaluated for the expression of CD26 on stem cells (SC) (CD45 dim/CD34+/CD38-) fraction by flow cytometry (FCM) using a single tube four-color antibodies cocktail: CD45-V500 /CD26-PE/CD34-PerCPcy5.5/CD38-APC-H7. The diagnosis of CML was confirmed using cytogenetics and/or molecular studies. Additionally, 12 paired PB and bone marrow (BM) samples of CML cases were compared for the proportion of CD26+ LSCs. RESULTS: Expression of CD26 on the SC fraction was invariably noted in all cases (116/116) of CML, irrespective of the disease phase and transcript type. None of other neoplasm (0/26), including the Ph + ALLs expressed CD26. Proportion of SCs expressing CD26 was variable with a median (range) proportion being 61.3% (7.6%-98.6%). Evaluation of paired PB and BM samples showed similar proportion of CD26 + LSCs (R2 : 0.969). CONCLUSION: We confirmed that FCM evaluation of CD26 expression in the PB LSCs is a rapid and specific tool for CML diagnosis. Its utility as a marker for residual disease evaluation can also be explored in the future.

Clinicopathological and immunophenotypic features of early T cell precursor acute lymphoblastic leukaemia: A flow cytometry score for the initial diagnosis.

OBJECTIVE: To assess the prevalence of early T precursor-acute lymphoblastic leukaemia (ETP-ALL), study its clinicopathological features and devise a 'flow score' based on immunophenotypic profiles. MATERIAL METHODS: This was a retrospective study where clinical and laboratory data of all consecutive T-ALL cases were analysed to identify features differentiating ETP from non-ETP-ALL. The utility of a flow score based on the five commonly used markers in leukaemia panels for T-ALL (CD34, CD8, CD5, CD13 and CD33) was evaluated to differentiate ETP from non-ETP-ALL. RESULTS: Early T precursor-acute lymphoblastic leukaemia constituted 24.2% (n = 29) of all T-ALL cases. It was significantly more common in adults (30.2%) as compared to paediatric (17.5%) patients (P = .046). The median age of presentation was significantly higher than the non-ETP group. (24 vs 19 years; P = .01). Patients with ETP-ALL usually presented with organomegaly, lymphadenopathy, lower levels of haemoglobin, total leucocyte count, peripheral blood blast proportion and LDH levels as compared to non-ETP-ALL. The majority of ETP-ALL cases had L2 morphology with a moderate amount of cytoplasm showing frequent blebbing. A flow score cut-off value of ≥3 on ROC curve analysis had a sensitivity and specificity of 100% and 94.6% respectively. CONCLUSION: Early T precursor-acute lymphoblastic leukaemia had unique clinical and laboratory features. The prevalence of this entity is more common in the adult population. A flow score based on a minimum of five widely used markers can confidently identify ETP-ALL and should be included in the primary panel of markers used for flow cytometric analysis.

Utility of CD157 as a Common Leukocytes Marker for Paroxysmal Nocturnal Hemoglobinuria Screening in a Single Tube Five Color Combination.

To study the utility and advantage of CD157 in the paroxysmal nocturnal hemoglobinuria (PNH) screening along with its ability to replace CD24 and CD14. This was a confirmatory study to analyse the role and advantage of CD157 in a single tube five color combination to identify the PNH clones. A serial tenfold dilution experiments was carried out for sensitivity assessment. Reproducibility was checked in the intra-assay and inter-assay experiments. The results obtained with CD157 based assay were compared with the routinely used single tube six color CD24/CD14 based assay. CD157 showed a high degree of sensitivity at the level of 10-4. PNH positive clone sizes were precise with CVs of inter-assay and intra-assay precision analysis for polymorphs/monocytes ranging from 2.94 to 4.31/2.52 to 8.93, and 0.91 to 3.23/1.65 to 5.33%; respectively. The results were similar to those obtained from CD24/CD14 based assay (R2 > 0.993). There was no false positive or false negative result. CD157 was found better in delineating the type II clones. CD157 can be used as a common PNH leucocyte marker with high degree of sensitivity and precision. It can replace CD24 and CD14 from the currently used assays and thus bring down the cost of PNH screening.

Decalepisarayalpathra (J. Joseph & V. Chandras.) Venter, an endemic and endangered ethno medicinal plant from Western Ghats, India.

Decalepis arayalpatra is an endemic and critically endangered plant of India. May 2014 issue of Natural Products Research publishes the findings of R. S. Verma et al. on the chemical composition of D. arayalpatra. This study was conducted to characterise the root aroma of this plant for possible industrial applications. The authors suggest that due to its peculiar vanilla flavour, the plant could be explored as a potential substitute of vanillin-aroma in the flavour industry. Owing to the fact that D. arayalpatra is a critically endangered plant species, and its habitat is now limited to only the protected areas and reserve forest in southern part of India, and that collecting any plant from such reserve forests for commercial activities is illegal as per the law of the country, this specific conclusion of the authors is totally un-substantiated by the law of land, hence, calls for further review.