The European Myeloma Network (EMN) organized two flow cytometry workshops. The first aimed to identify specific indications for flow cytometry in patients with monoclonal gammopathies, and consensus technical approaches through a questionnaire-based review of current practice in participating laboratories. The second aimed to resolve outstanding technical issues and develop a consensus approach to analysis of plasma cells. The primary clinical applications identified were: differential diagnosis of neoplastic plasma cell disorders from reactive plasmacytosis; identifying risk of progression in patients with MGUS and detecting minimal residual disease. A range of technical recommendations were identified, including: 1) CD38, CD138 and CD45 should all be included in at least one tube for plasma cell identification and enumeration. The primary gate should be based on CD38 vs. CD138 expression; 2) after treatment, clonality assessment is only likely to be informative when combined with immunophenotype to detect abnormal cells. Flow cytometry is suitable for demonstrating a stringent complete remission; 3) for detection of abnormal plasma cells, a minimal panel should include CD19 and CD56. A preferred panel would also include CD20, CD117, CD28 and CD27; 4) discrepancies between the percentage of plasma cells detected by flow cytometry and morphology are primarily related to sample quality and it is, therefore, important to determine that marrow elements are present in follow-up samples, particularly normal plasma cells in MRD negative cases.

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HEMATOPATHOLOGYOriginal Article I m p r o v e m e n t o f t h e C h r o n i c L y m p h o c y t i c L e u k e m i a S c o r i n g S y s t e m W i t h t h e M o n o c l o n a l A n t i b o d y S N 8 ( C D 7 9 b )ELISABETH J. A scoring system, based on the immunophenotypic analysis of a panel of five membrane markers (CD5, CD22, CD23, FMC7, Smlg) was shown to be useful in the distinction between chronic lymphocytic leukemia (CLL) and other B-cell lymphoproliferative diseases (non-CLL). We investigated whether the monoclonal antibody SN8 (CD79b) could improve our previous scoring system. Peripheral blood samples of 298 patients with CLL and 166 patients with non-CLL were analyzed by flow cytometry. Using the five standard markers, the accuracy of the scoring system was 91.8%, using a cutoff of 4The use of cell markers in the diagnosis of B-cell lymphoproliferative disorders has an important role in the distinction between chronic lymphocytic leukemia (CLL) and other chronic B-cell disorders. 1-2We have proposed 3 a scoring system based on flow cytometry analysis of five membrane markers: CD5, CD22, CD23, FMC7, and Smlg. A value of 1 or 0 was given for each marker to represent whether it is typical or atypical, respectively, for CLL. The most common immunophenotype profile observed in CLL is the following: CD5, positive; CD22, weak or negative; CD23, positive; FMC7, negative; and Smlg, weak. While most CLL cases have a score of 4 or 5, most non-CLL cases have a score of less than 3. points or higher, to distinguish CLL from non-CLL. This was increased to 96.6% if SN8 was added and a cutoff of 4 points or higher was also used. A similar accuracy, 96.8%, was observed if CD22 was excluded and a cutoff of 3 points or higher was used. Thus, the replacement of CD22 by SN8 in the original scoring system significantly increases its potential to discriminate between CLL and other B-cell lymphoproliferative diseases.

We describe the clinical and laboratory findings of 78 adult patients with T-prolymphocytic leukemia (T-PLL) studied over the last 12 years. The main disease features were splenomegaly (73%), lymphadenopathy (53%), hepatomegaly (40%), skin lesions (27%), and a high leukocyte count (greater than 100 x 10(9)/L in 75%) with nucleolated prolymphocytes. A variant form with small, less typical cells was recognized in 19%. Membrane markers defined a postthymic phenotype TdT- , CD2+, CD3+, CD5+, CD7+; in 65%, the cells were CD4+ CD8-, in 21%, they coexpressed CD4 and CD8, and, in 13%, they were CD4- CD8+. Serology for human T-cell leukemia/lymphoma virus Type-I (HTLV-I) was negative in the 27 cases investigated. Cytogenetic analysis in 30 cases showed a consistent abnormality of chromosome 14, usually inv (14), with breakpoints at q11 and q32 in 76% of cases. Trisomy 8, including iso8q, was shown in 53%; t (11;14)(q13;q32) was documented in one case; and one had a normal karyotype. The clinical course was progressive with a median survival of 7.5 months. Thirty-one patients were treated with 2′ deoxycoformycin and 15 responded (3 complete remissions and 12 partial remissions); the response rate (48%) increased to 58% in patients with a CD4+ CD8- phenotype. The median survival of responders was 16 months and of nonresponders 10 months; other treatments were less effective. T-PLL is a distinct clinico-pathologic entity with aggressive course and characteristic chromosome abnormalities. A subgroup of patients may benefit from deoxycoformycin.