الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 190 |  |  |
| | | from | 190 | | |
Abstract
B-cell chronic lymphoproliferative disorders (B-CLPDs) are biologically heterogeneous group of malignant diseases characterized by accumulation of mature B lymphocytes in the bone marrow, peripheral blood, and lymphoid tissues.
Flow cytometry immunophenotyping is crucial for the diagnosis of B-CLPD due to its cost-effectiveness and capability of characterizing multiple parameters simultaneously that enhance the accuracy of the diagnosis. However, overlapping immunophenotypes exist. Recently, differential expression of CD200 in different CLPDs has been reported.
Assessment of CD200 is not basic in the diagnostic criteria for chronic lymphocytic leukemia (CLL) by the WHO; however, CD200 is implemented in the EuroFlow guidelines
CD200 delivers immunosuppressive signals through its receptor CD200R, which is expressed on monocytes/myeloid cells and T-lymphocytes. Moreover, interaction of CD200 with CD200R has been reported to play a role in regulation of tumor immunity. Overexpression of CD200 has been reported in CLL and hairy cell leukemia (HCL) but not in mantle cell lymphoma (MCL).
The aim of the study is to assess CD200 usefulness in diagnosis and differential diagnosis of different B-CLPDs in different types of samples and its role as prognostic marker using 8 color flowcytometry at South Egypt Cancer Institute.
This study was conducted on 100 B-CLPDs cases, after approval of the medical ethics committee of Faculty of Medicine Assiut University. It was
133
found that there was a male predominance (60%) over females (40%). The age range among enrolled cases was from 32-84 years.
Different types of samples were collected (peripheral blood, bone marrow aspirate and fine needle aspiration of lymph nodes) after taking complete history from patients and preforming complete blood count with differential count. Each sample was processed and analyzed on 8 color flow cytometry.
According to the diagnosis of B-CLPDs, there was a prevalence of CLL cases (70%), followed by small lymphocytic leukemia (9%), (MCL) (6%), HCL (5%), splenic marginal zone leukemia (3%) with only two cases of follicular lymphoma.
The role of CD200 was markedly evident in diagnosis of different types of B-CLPDs with 100% sensitivity and considerable accuracy (78%) in diagnosis of CLL. In concordance with previous studies, CLL cases in this study showed a consistent manner of CD200 positivity in all types of samples while all MCL cases show negative CD200 expression. Also, Hairy cell leukemia cases show significantly higher Median fluorescence intensity (MFI) in comparison to other CD200 positive cases (either CLL or other lymphomas).
As a prognostic marker, MFI of CD200 showed significant statistical correlation with Rai stage of CLL cases and CD38 positivity. Also, among CD200 positive group 73.2% of cases showed stable disease (not satisfactory response to therapy) which support the possible role of CD200 as a prognostic marker for CLL. However, there was no statistically significant relation between CD200 positive and CD200 negative cases due to limited number of follow up cases of CD200 negative cases.
133
This study concluded that in all types of samples CD200 expression helps in discrimination between different B cell malignancies and is essential in better classifying B-cell CLPDs. The addition of CD200 to flow cytometry marker panels for diagnosis of this heterogenous group of B cell neoplasms is particularly helpful in distinguishing some disease entities as CLL and MCL,
whose clinical behavior and prognosis are quite different. Also, the role of CD200 as prognostic marker for CLL cases was supported by the results of this study.