Critical parameters in blood processing for T-cell assays: Validation on ELISpot and tetramer platforms

Assays detecting antigen (Ag)-specific T-cell responses in immune-mediated processes are increasingly employed to understand disease pathogenesis and "immune staging". The quantity and quality of starting peripheral blood mononuclear cell (PBMC) preparations are important factors in the performance of such assays. We therefore compared final PBMC yield and function by modifying parameters at the blood drawing, storage and processing steps. While drawing blood in vacuum-driven tubes or syringes and separating PBMCs on density gradients using standard or membrane (Leucosep (R)) tubes made no difference, storing tubes for 18 h without any agitation led to PBMC preparations contaminated with granulocytes and decreased interferon (IFN)-gamma enzyme-linked immunospot (ELISpot) responses. Even agitated blood showed a trend towards reduced ELISpot responses and increased human leukocyte Ag (HLA) multimer readouts when stored for 18 h compared to 3 h. These changes were reduced by diluting blood prior to storage. Washing PBMCs with media containing 10% human serum increased PBMC yields by 40.5%, without affecting ELISpot responses and multimer counts. However, washes with >10% human serum decreased multimer counts, with no additional improvement in PBMC yields. These findings may be relevant for optimizing and harmonizing PBMC processing procedures for T-cell assays. (C) 2010 Elsevier B.V. All rights reserved

Deferasirox in iron-overloaded patients with transfusion-dependent myelodysplastic syndromes: Results from the large 1-year EPIC study

The prospective 1-year EPIC study enrolled 341 patients with myelodysplastic syndromes (MDS); although baseline iron burden was >2500. ng/mL, ∼50% were chelation-naïve. Overall median serum ferritin decreased significantly at 1 year (p=0.002). Decreases occurred irrespective of whether patients were chelation-naïve or previously chelated; changes were dependent on dose adjustments and ongoing iron intake. Sustained reductions in labile plasma iron were observed. Discontinuation rate (48.7%) and adverse event profile were consistent with previously reported deferasirox data in MDS. Alanine aminotransferase levels decreased significantly; change correlated significantly with reduction in serum ferritin (p<0.0001). This large dataset prospectively confirms the efficacy and well characterizes the safety profile of deferasirox in MDS. © 2010 Elsevier Ltd