الفهرس 
COVEROnly 14 pages are availabe for public view
 |  | from | 143 |  |  |
| | | from | 143 | | |
Abstract
Hairy cell leukemia (HCL) is an indolent lymphoproliferative
malignancy characterized by infiltration of the bone marrow,
liver, spleen and occasionally lymph nodes with a malignant Bcell
with hair-like cytoplasmic projections (Kraut, 2003). These
hairy cells co-express CD11c, CD19, CD20, CD22, CD25 and
CD103 (Goodman et al, 2003). Recent studies have indicated
that it is not uncommon for HCL to display an unusual
immunophenotype, including negativity for CD103 or CD25.
Recognizing the variability of immunophenotype and correlating
with morphologic and clinical features are essential for
establishing an accurate diagnosis of HCL (Chen et al, 2006).
HCL is usually readily diagnosed by seeing typical hairy cells
(HCs) in the blood film. The diagnosis is then confirmed by
tartrate-resistant acid phosphatase (TRAP) staining, marker
analysis, and bone marrow examination (Allsup and Cawley,
2004).
HCL has long been recognized as distinct from other chronic
B-cell malignancies, but several questions remain unanswered.
What is the HCL cell of origin? Why does HCL lack the
hallmarks of most mature B-cell tumours (for example,
xv
Introduction
chromosomal translocations and consistent lymph node
involvement) and show unique features like ’hairy’ morphology
and bone marrow fibrosis? Gene expression profiling and other
studies have recently provided new insights into HCL biology
and have the potential to affect clinical practice (Tiacci et al,
2006).
The involvement of the reticulo-endothelial system leads to
splenomegaly. The common hematological complications of
anemia, neutropenia and thrombocytopenia are due not only to
the enlarged spleen but probably also to HCs in the bone marrow
inducing cytokine mediated suppression of hematopoiesis.
Hepatic involvement is also frequent and infections are a
major cause of morbidity and mortality in patients with HCL
(Kraut, 2003).
The development of extremely effective therapy for HCL
results in a high incidence of complete remission. However, a
significant percentage of patients continue to harbour minimal
residual disease that can be revealed with immunohistochemical
and flow cytometric studies (Bethel and Sharpe, 2003).