normal lymphopoiesis Flashcards
lymphocytes evolve from….
pluripotent stem cells
B lymphocyte do what?
- humoral immune system
- make antibodies
two types of T cells
- cytotoxic
- helper/suppressor
what do cytotoxic T cells do?
- direct killing
what do helper/suppressor T cells do?
- fine tuning via cell-cell interaction and secretion of cytokines
what are the primary lymphoid tissues and what is found there?
- bone marrow - B cells
- thymus - T cells
what are the secondary lymphoid tissues and what is found there?
- lymph nodes
- spleen
- MALT (mucosal associated lymphoid tissue) lining respiratory and GI tracts
- antigen driven differentiation and replication into committed effector cells
explain lymphoid variation
in the cortex of the lymph node, primary lymphoid follicles can change to secondary lymphoid follicles with germinal centers under immune stimulation
in what part of the lymph node do B cells reside?
primary and secondary follicles of the cortex
in what part of the lymph node to T cells reside
paracortex
in what part of the lymph node do plasma cells reside?
medulla, release immunoglobulins into the efferent limb
what are the three parts of the splenic follicle from outside to inside?
marginal zone
mantle zone
germinal center
what B cell stages of development happen in the bone marrow?
pluripotent stem cell -> B cell progenitor -> pro B cell -> pre B cell
what B cell stages happen in the peripheral blood/secondary lymph tissues?
naive mature B cell -> antigen activated B cell -> plasma/memory cells
what is the ratio of B cell light chain proteins
2:1, kappa:lambda
when is a B cell mature?
in bone marrow once it can express IgM and IgD along with the B cell receptor complex
surface antigens in early B cell development
CD79 Bruton tyrosine kinase CD10 CD20 CD22 TdT
what happens to mature B cells in the germinal center?
somatic hypermutation (SHM) - an error prone proliferation ending in high affinity antibody producing B cells
class switching
what antigens are expressed by plasma cells
CD38+ and CD138+
what happens to activated B cells that do not interact with T cells?
become short-lived plasma cells and secrete IgM
what does a memory cell do and how long does it live
- makes specific plasma cells faster than simply an activated B cell
- years to decades
percentages of T cell receptors (TCRs) in T cells
- > 95% have alpha/beta TCR (TCR2)
- rest have gamma/delta TCR (TCR1)
cytotoxic T cells express…
CD8
helper T cells express….
CD4
differential diagnosis for adenopathy
Infections Reactive hyperplasias Sarcoidosis Connective Tissue Disorders Metastatic tumors Malignant lymphomas
3 examples of non-malignant lymph node pathology
- follicular hyperplasia
- interfollicular hyperplasia
- sinus histiocytosis
what happens in follicular hyperplasia?
- increase in number and size of germinal centers, spread into paracortex, medullary areas
- “typical” for bacterial infections
what happens in inter follicular hyperplasia?
- expansion of paracortex
- “typical” for viral infections
what happens in sinus histiocytosis?
- expansion of the medullary sinus histiocytes
- occurs with adjacent cancer or with tattoos
histology of reactive follicular hyperplasia in bacterial infections
- caseating = necrotizing
- caveating or non-caseating granulomas
characteristics of cells in a malignant lymphoma
- derived from a single mutated cell
- cells have lost ability to differentiate to the full range, frozen at an early stage
human B cell malignancies at their locations
marrow - ALL
blood - CLL
post germinal center - MM (multiple myeloma), MZL (marginal zone lymphoma), HCL (hairy cell leukemia), PL (plasmablastic lymphoma), WM (waldenstrom macroglobulinemia)
germinal center - FL (follicular lymphoma), DLBCL (diffuse large B-cell lymphoma), BL (burkitt lymphoma), HL (hodgkin lymphoma)
primary follicle - SLL (small lymphocytic lymphoma), MCL (mantle cell lymphoma)
lymphomas are categorized as either….
hodgkins or non-hodgkins
characteristics of classic hodgkins lymphoma
- Nodular sclerosing
- Lymphocyte predominant
- Mixed Cellularity
- Lymphocyte depleted
non-hodgkins categorized as either….
B cell or T/NK cell
