Immunophenotyping of Chronic B-Cell Neoplasms in correlation with Morphological Diagnosis

Chronic B-cell neoplasms include a number of disease entities arising from mature B lymphocytes and which involve primarily the blood, bone marrow and lymphoid organs such as the lymph nodes and spleen. Chronic lymphocytic leukemia (CLL) is a disease of older adults. It is characterized by absolute lymphocytosis in the peripheral blood and bone marrow at the time of diagnosis. Non-Hodgkin lymphomas (NHL) also may have extensive bone marrow (BM) and peripheral blood involvement at initial presentation. NHL that most frequently exhibit circulating lymphoma cells include follicular lymphoma (FL), mantle cell lymphoma (MCL) and splenic marginal zone lymphoma (SMZL). Although there are difficulties in separating CLL from some NHL, the distinction is important because prognostic and therapeutic differences exist.
Immunophenotyping (IPT) has become an essential tool to confirm the diagnosis and to separate CLL from other lymphoid malignancies. Aims of the study: 1: To evaluate the role of immunostained CD5, CD10, CD20, CD23 and light chains Kappa and Lambda in the subclassification of chronic B-cell neoplasms.
2: To confirm the significance of these markers as a complementary test to morphological features of chronic B-cell neoplasms using BM aspirate and biopsy. Patients, materials and methods: BM biopsies of fifty five adult patients with CLL and leukemic phase of NHL were collected from December 2010 to April 2011; fifty of them were retrospectively collected from archive files of the Department of Hematology of the Medical City Teaching Laboratories while five of them were prospectively collected from private laboratories. Clinical and laboratory information regarding age, gender, PCV, Hb, WBC count, platelet count, percentage of lymphocyte in the blood and bone marrow and the pattern of bone marrow infiltration were obtained from patients recording file at diagnosis For each case, one section was stained with hematoxylin and eosin and six other sections were stained immunohistochemically for CD5, CD10, CD20, CD23 and light chains (Kappa and Lambda), each section with 4 micron thickness. The slides were examined by light microscope and scanned on low and high powers. Results: The diagnosis of twenty six CLL patients out of 29 were confirmed by IPT while 3 cases were in favor of NHL rather than CLL and twenty five NHL cases out of 26 were confirmed by IPT and only one case was diagnosed as CLL. Current study revealed that CLL cases (27) showed positive IPT reaction with CD5 (100%), CD23 (100%), CD20 (96%) weak positive reaction while no reaction with CD10 (0%) and either with Kappa (52%) or Lambda (48%). While NHL (28) cases showed positive reaction with CD20 (100%), CD10 (71.5%), CD5 (14%) and either with Kappa (46.5%) or Lambda (53.5%) and no reaction with CD23. According to IPT findings, the NHL cases can be classified into FL in 20/28 (71.5%), MCL in 4/28 (14%) and other B-cell NHL 4/28 (14%). Furthermore, FL showed positive reaction (100%) with CD10 and CD20 and no reaction with CD5 and CD23 while MCL showed positive
reaction (100%) with CD5 and CD20 and no reaction with CD23 and CD10. This study revealed significant statistical difference between morphology and IPT diagnosis at the level of P.value <0.05. Conclusions:
1. This study revealed that the immunophenotyping has important diagnostic role in the subclassification of chronic B-cell neoplasms. 2. This study revealed that the immunophenotyping technique in conjunction with morphology have more precise role than morphology alone in the diagnosis of chronic B-cell neoplasms.
3. Characterization of LPD is not possible without the use CD markers, which help define the cell lineage (B or T), whether clonal or polyclonal, and the maturation stage.