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Abstract Neoplasms of mature lymphoid cells include the chronic lymphocytic leukemia and non-Hodgkin lymphomas. This group of diseases is recognized by an immunophenotype that is similar to normal mature lymphoid cells (eg, surface immunoglobulin on mature B cells) and lack of antigenic features of immaturity, such as expression of TdT, CD34, or weak intensity staining for CD45. According to the 4th edition of the WHO Classification, the diagnosis of major mature B-cell malignancies is usually based on a combination of morphology, immunophenotype & recurrent cytogenetic aberration . Some other B cell lymphomas still remain challenging for flow cytometrists, particularly where there is no single disease-specific phenotype which characterizes the entity, and there is great heterogeneity between cases . Purpose: o The purpose of this study was to categorize the unclassifiable mature B-cell lymphoid neoplasms using a broad panel of monoclonal antibodies against B-cell antigens & adhesion molecules, in addition to other characteristic molecular genetic abnormalities in a trial to develop an algorithm for testing those unclassifiable cases to reach a definite diagnosis (whenever possible) with the least laboratory workup. Patient and Methods: The study was performed on 119 newly diagnosed CLL and NHL patients. -Patients were 77 (64.7%) males and 42 (35.3%) females. Their ages ranged from 25-85 with a median of 60 years. 1. Immunophenotyping of BM or PB using cell coulter (Coulter EPICS-XL flowcytometer, USA). The following panel of monoclonal antibodies was used: CD5, CD19, CD20, CD22, CD23, CD79b, FMC7, CD10 as well as κ and λ light chains labeled with either fluorescin isothiocyanate (FITC) or phycoerythrin (PE). 2. Measuring of CD43, CD200, CD11a, CD11b, CD49d, CD49C, CD29, & Cyclin D1 expression by flow cytometry (Coulter EPICS-XL, USA) 3. Out of these patients, 67 were tested for Cyclin D1 mRNA expression ;t(11:14) by RT-PCR. The study was performed according to Helsinki declaration for studies on human subjects and approved by the Institution Review Board (IRB) of the National Cancer Institute, Cairo University. Results: Lymphadenopathy showed highest frequency in CLL, followed by Mantle cell; both were significantly higher than the unclassifiable group (p=<0.001). Splenomegaly and hepatomegaly were not significantly different between the 3 groups. Both Hb level and platelet count were significantly higher in CLL compared to MCL (p=0.008 and 0.03 respectively). The levels in the unclassifiable group were not significantly different from either. There was a trend for a higher TLC, % L and ALC in CLL though the difference did not achieve statistical significance (p=0.08, 0.06 and 0.09 respectively). Insignificant difference was found between the 3 groups as regards age and B.M. cellularity. As expected the scoring system markers were significantly more frequent in CLL (p=0.001 for CD5, CD23, FMC7 and dim sIg expression and 0.004 for dim CD22). CD5 showed high frequency also in MCL though less than CLL. CD20 was significantly higher in MCL in comparison to CLL (P 0.002), while levels in the unclassifiable group were not significantly different from either. CD200 was the most discriminative being positive in `94% of CLL cases (figure 3), versus 3.85% (one case only) in MCL, (P ˂0.001). The corresponding figure for the unclassifiable was 8/12 (66.66%). CD43 showed highest frequency in CLL (83.33% vs. 50% and 41.67% in the other two groups, p˂0.001. |