Comparative flow cytometric study of clonal excess in leukaemic peripheralblood from patients suffering from chronic lymphocytic leukaemia (B-CLL) by different antibodies, staining techniques and the effects of blood storage

This investigation studied the effects of cell preparation methods, differe nt antibody panels and blood storage on antigen expression of abnormal B ly mphocytes from patients with B-CLL. Blood specimens collected in Heparin de novo were processed by using conventional Hypaque-Ficoll density gradient centrifugation and whole blood lysis. These were stored for 3 days at 4 deg rees C, 24 degrees C and 30 degrees C, Although clonal excess was detected by all antibody panels, significant differences could be observed in terms of molecules of equivalent fluorochromes (MEF/MESF units), Evaluation of 'w eak and strong' staining is dependent on the antibody panel used, Immunoflu orescent values for CD19 and CD45 were unchanged at 4 OC and 24 degrees C b ut immunoglobulin staining showed best results when blood was stored at 4 d egrees C. Storage at 30 OC produced unreliable results. Abnormal B lymphocy tes should be analysed immediately after the specimen is obtained, If shipm ent is necessary they should be kept at 4 degrees C. Surface immunoglobulin s are the 'antigens' most sensitive to storage alterations. Sample alterati ons alone are sufficient to the correct classification of NHL, especially i n the case of low-grade NHL.