Metabolic profiling of CD19+ cells in chronic lymphocytic leukemia by single-cell mass spectrometry imaging.

BACKGROUND AND AIMS: Modern mass spectrometry imaging (MSI) enables single cells' metabolism exploration. Aims of this study were development of the single-cell MSI of human CD19+ lymphocytes and metabolic profiling of chronic lymphocytic leukemia (CLL). MATERIALS AND METHODS: Blood donor (BD) samples were used for the optimization of CD19+ lymphocyte isolation and single-cell matrix-assisted laser desorption/ionization time-of-flight (MALDI TOF) MSI. Independent set of 200 CD19+ lymphocytes coming from 5 CLL patients and 5 BD was used for the CD19+ lymphocytes classification assessment and the untargeted metabolic profiling. CLL vs BD lymphocyte classification was performed using partial least squares-discriminant analysis (PLS-DA) using normalized single-cell mass spectra recorded in 300-600 and 600-950 Da ranges was applied. RESULTS: Accuracy assessed by 10-fold cross-validation of CD19+ lymphocyte PLS-DA classification reached >90.0 %. Volcano plots showed 106 significantly altered m/z signals in CLL of which 9 were tentatively annotated. Among tentatively annotated m/z signals formaldehyde and glutathione metabolites and tetrahydrofolate stand out. CONCLUSION: A method for single-cell MALDI TOF MSI of CD19+ lymphocytes was successfully developed. The method confirmed the significance of oxidative stress and single-carbon metabolism, pyruvate and fatty acid metabolism and apoptosis in CLL and it provided metabolic candidates for diagnostic applications.

Test results comparison and sample stability study: is the BD Barricor tube a suitable replacement for the BD RST tube?

INTRODUCTION: The aim was to evaluate the BD Barricor tubes by comparison with the BD Rapid Serum Tubes (RST) through measuring 25 analytes and monitoring sample stability after 24 hours and 7 days. MATERIALS AND METHODS: Samples of 52 patients from different hospital departments were examined. Blood was collected in BD RST and BD Barricor tubes (Becton, Dickinson and Company, Franklin Lakes, USA). Analytes were measured by Beckman Coulter AU 480 (Beckman Coulter, Brea, USA), Dimension EXL (Siemens Healthcare Diagnostics, Newark, USA) and ARCHITECT i2000SR (Abbott Diagnostics, Lake Forest, USA). Between-tube comparison for each analyte was performed, along with testing analyte stability after storing samples at 4 °C. RESULTS: BD Barricor tubes showed unacceptable bias compared to BD RST tubes for potassium (K) (- 4.5%) and total protein (4.4%). Analyte stability after 24 hours was acceptable in both tested tubes for most of analytes, except for glucose, aspartate aminotransferase (AST) and lactate dehydrogenase (LD) in BD Barricor and free triiodothyronine in BD RST sample tubes. Analyte stability after 7 days was unacceptable for sodium, K, calcium, creatine kinase isoenzyme MB, AST, LD and troponin I in both samples; additionally for glucose, alkaline phosphatase and albumin in BD Barricor. CONCLUSION: All analytes, except K and total protein, can be measured interchangeably in BD RST and BD Barricor tubes, applying the same reference intervals. For most of the analytes, sample re-analysis can be performed in both tubes after 24 hours and 7 days, although BD RST tubes show better 7-day analytes stability over BD Barricor tubes.