Haem 5 - Lymphoma 1 Flashcards
Type of cell giving rise to
Hodgkin’s lymphoma - HL
Non-Hodgkin’s lymphoma - NHL
HL - B cell
NHL - B cell or T cell or NK cell
Lymphoma RF
Most lymphoma subtypes/cases are sporadic with no known RF
Some lymphoma subtypes have specific risk factors
- immune diseases acquired or iatrogenic
- Associated specific infections or inflammation
Key enzyme involved in class switch recombination and somatic hypermutation
Adenosine induced deaminase
What problem can arise as a result of a mutation during class switch recombination? Give examples
- Normal recombination Ig/immunoglobulin molecules brought under the promotor => promotor drives AB production
- Problem mutation occurs oncogene brought under the promotor
• Oncogenes = anti-apoptotic or proliferative o Bcl2 o Bcl3 o (C-)MYC o CyclinD1
Which types of lymphomas can be caused by chronic bacterial infection or auto-immune diseases causing chronic antigenic stimulation?
Mechanism
Give examples
Treatment
chronic antigenic stimulation –> over production of lymphocytes –> emergence of autonomous subclones that give rise to particular types of lymphomas
–> B cell NHL Marginal zone subtype (Marginal zone lymphoma)
Arises mainly at extranodal sites
o H. pylori – gastric MALT = MZL of the stomach
o Sjogren’s syndrome = MZL of salivary glands
o Hashimoto’s thyroiditis (lymphocytic destruction) = MZL of thyroid
–> Enteropathy associated T cell NHL
o Coeliac disease – small intestine EATL
• Can treat low grade disease with non-chemotherapeutic modalities
o i.e. remove antigen e.g. helicobacter eradication by abx treatment
Which virus can give rise to a lymphoma? What type of lymphoma?
HTLV1 virus - retrovirus
Infects T cells by vertical transmission
Stimulates lymphomagenesis
ATLL = Adult T cell leukaemia lymphoma
Sub-type of NHL
How can EBV drive a lymphoma?
• EBV infects B-cells EBV driven proliferation of B cells B-cells express EBV-associated antigens on cell surface proliferating B cells targeted and killed by EBV specific CTL response
- EBV switches on at later life + drives proliferation
- Low CTL due to (1) HIV or (2) immunosuppression –> EBV can drive a lymphoma (loss of CTL function = failure to eliminate EBV driven proliferation of B cells)
Rare NHL subtypes have specific risk factors:
Three main groups/mechanisms.
- Constant antigenic stimulation
Bacteria infection (chronic)
Auto immune disorders
e.g. B cell NHL marginal zone subtype or enteropathy associated T cell NHL - Viral Infection (direct viral integration of lymphocytes) e.. HTLV1 causing ATLL
- Loss of T cell function and EBV infection (EBV driven B cell lymphomas) due to
Loss of T cells (HIV)
Iatrogenic immunosuppression
What type of lymphoma is Marginal zone lymphoma?
B cell NHL
Describe the 3 tissues in the lymphoreticular system
o Generative LR tissue – generation/maturation of lymphoid cells
BM and thymus
o Reactive LR tissue – development of immune reaction
Lymph nodes and spleen
o Acquired LR tissue – development of local immune reaction
Extra-nodal lymphoid tissue (e.g. skin, stomach, lung)
Within the lymph node
where are naive B cells B cells + APC Mature B cells CD4/CD8 T cells + APC
located?
Naive B cells - mantle zone of B cell follicles located in the outer part/cortex of the lymph node
B cells + APC - germinal centres of B cell follicles
• B cell follicles = darker outer mantle zone and a paler central germinal centre
Mature B cells = medulla of lymph node
CD4/CD8 T cells + APC cells - paracortical areas of the lymph node around follicles (after they mature + leave the thymus)
Markers
Mature T helper cell Mature T killer cell T cells B lineage activated B cell Plasma cell T regulatory cells NK cells
Mature t helper cell markers --> CD3 CD4 Mature T killer cell --> CD3 CD8 T cells --> CD3, CD5 B lineage --> CD19*, CD20 activated B cell --> CD19 CD25, CD30 plasma cell --> CD138 T regulatory cells --> CD25, Foxp3 NK cells --> CD3 neg, CD56+ CD16+
All B cells express CD19 except plasma cells
https://www.abcam.com/primary-antibodies/b-cells-basic-immunophenotyping
Commonest type of lymphoma
B cell NHL (80-85%)
How does HL - hodgkin’s lymphoma spread?
tends to only affect 1 or 2 lymph node – spreads in a contiguous fashion involving contiguous lymph node groups
Follicular lymphoma characteristics
epidemiology symptom architecture cells translocation markers management prognosis
middle aged, elderly
Lymphadenopathy
Architecture - follicular
+ nodular pattern
cells - small cleaved
FISH - t14;18
over-expression of bcl-2 (an anti-apoptotic protein)
14 Ig locus
18 BCL2 locus (an anti-apoptotic protein
CD10, BCL-6+
detection of bcl-2 expression by neoplastic B cells in follicles (normal germinal centre in follicle is negative for bcl-2)
FLIPI score (follicular lymphoma international prognostic index - Similar to IPI used in diffuse large B cell NHL)
o Treatment At presentation • Watch and wait • Only treat if clinically indicated o Compression due to nodes (e.g. bowel, bile duct, ureter, vena cava) o Massive painful nodes o Recurrent infections o Treatment
Combination immuno-chemotherapy R-COP or R-CHOP (Rituximab, Cyclophosphamide, Adriamycin (H), Vincristine (O), Prednisolone)
Conventional treatment is not curative, may require 2nd or 3rd line
Prognosis
Incurable
12-15 years median survival
Mantle cell lymphoma characteristics
cyclin D1 overexpression
CD5 +ve
t11;14
Translocation 2;5 is found in which type of lymphoma?
Anaplastic large cell lymphoma