Diffuse Large B-Cell Lymphoma Flashcards
what is diffuse large B-cell lymphoma?
large B-cell lymphoma (DLBCL) is an aggressive form of lymphoma
it is the most common form of non-Hodgkin’s lymphoma (NHL), accounting for 35% of all NHL
DLBCL arises from B lymphocytes
what does the microscope view of DLBCL look like?
the normal architecture of the lymph nodes is lost and replaced by the random pattern of growth of malignant B cells - hence the name “diffuse”
also the B cells are at least twice the size of normal lymphocytes
what populations does DLBCL effect?
usually seen in adults, with an average age of 60-65 years at time of diagnosis
but also occurs in children
often develops in immunocompromised patients and it is the most common HIV-related lymphoma
What is the most common non-Hodgkin lymphoma?
Diffuse large B-cell lymphoma is the most common non-Hodgkin lymphoma. It is also the most common HIV-related lymphoma.
where are B cells found in the lymph node?
cortex
specifically, they populate an area called the germinal follicle and they remain there until they get exposed to antigens, a turning point that dramatically changes their lives
where are plasma cells found in the lymph node?
medulla
where are T-cells found in the lymph node?
paracortex
what is anergy?
migrant naïve (baby) B cells are confronted with limited options: fight back or enter an unresponsive state called anergy
the naïve B cells that rise to the challenge and fight back form the germinal center (GC)
what happens to B-cells in the GC?
GC= germinal center of the lymph node
B cells in the GC proliferate, undergo somatic hypermutation, and differentiate into plasma cells before they migrate to the medullary cord
what are the two parts of the GC?
dark zone
light zone
what are centroblasts?
the B-cells that inhabit the dark zone of the germinal center
whencentroblasts migrate to the light zone and express their membrane-bound
immunoglobulins, they become centrocytes
what are centrocytes?
when centroblasts migrate to the light zone and express their membrane-bound
immunoglobulins, they become centrocytes
what are immunoblasts/plasmablasts?
B-cells destined to plasma cell
differentiation
once fully differentiated and mature, plasma cells leave the
germinal center to the medullary cords
what are memory B cells?
they develop from centrocytes in the GC and then migrate to the bone marrow, their hometown
well-known for their longevity
What subpopulation of B cells is found in the light zone of the germinal center?
Centrocytes are found in the light zone of the GC
when centroblasts migrate from the dark zone to the light zone and express their membrane-bound immunoglobulins, they become centrocytes
what do centroblasts look like?
large centrofollicular cells with pale, round nuclei with coarse chromatin and two or more nucleoli