The Biology of Hairy Cell Leukemia 11
Table IV. Pathological features of HCL.
with HCs, and T-cell dysfunction contributes to the
Pathognomonic HC
well-known immune defect of the disease.
BM infiltration and fibrosis
Invasion of splenic red pulp and pseudosinus formation
Hepatic infiltration with sinusoidal and portal tract involvement
Unanswered questions
Lymph nodes relatively spared
The major outstanding question in HCL biology is
Cytopenias (especially monocytopenia), T-cell dysfunction and
immune defects
the nature of the causative oncogenic event(s).
Closely-related problems relate to the source of the
HCL, hairy cell leukemia; HC, hairy cell; BM, bone marrow.
intrinsic activation of HCs and the cause of the block
in their differentiation. Perhaps, answers to these
related issues will point the way to the finding of the
holy grail of HCL biology – the transforming
accumulate in modest numbers along the hepatic oncogenic event(s) in the disease.
plates, but do not synthesize FN because the
sinusoids do not contain HA. In contrast, HA is Declaration of interest: The author reports no
abundant in portal tracts and, as a result, the HCs are conflict of interests. The author alone is responsible
stimulated to produce FN. Consequently, extensive for the content and writing of this paper.
fibrosis is observed within the portal tracts, but not
within the sinusoids.
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