Myeloma and Lymphoma Flashcards
Where does the process of B cell differentiation occur and what are the steps?
First stage in bone marrow (Ag independent stage)
Pro-B > Pre B > Immature B > Naïve B (outside of bone marrow)
Second stage is in the secondary lymphoid organs (antigen dependent) - mature naïve develop into proliferating blast cells
What is significant about B cell differentiation in terms of diagnosing myeloma?
The plasma cells acquire different antigens at different points of differentiation, these antigens can be detected - each antigen CD? acts as a marker for the different intermediate cells in B cell differentiation
How are immunoglobulins classified?
According to amino acid sequence in the constant region of the heavy chains - IgG, IgM, IgA, IgD, IgE
and the light chains - kappa or lambda
What 5 major are normally identified in protein electrophoresis of serum, which is of interest in terms of myeloma?
1) Serum albumin
2) Alpha-1 globulin
3) Alpha-2 globulin
4) Beta globulins
5) Gamma globulins - called the M spike, this is of interest in myeloma, a normal M spike of polyclonal immunoglobulin which is shallow with no obvious peaks
In myeloma, how would the gamma globulin peak appear on protein electrophoresis and why?
Rather than the shallow increase you would have one large peak reflecting the large scale production of monoclonal immunoglobulins - compared to the polyclonal production in a normal M spike
If an M spike is identified on protein electrophoresis, what is the next step?
Immunofixation - enables the detection and identification of type of monoclonal Ig
How is immunofixation carried out?
- Serum or urine is placed on a gel and electric current is applied to separate out the proteins
- Anti immunoglobulin antisera is added to each migration lane
- If the immunoglobulin is present, a complex is precipitated
What is myeloma?
An incurable malignant disorder of clonal plasma cells
What is annual incidence of myeloma?
60-70 per million in the Uk
What is the median age of presentation of myeloma?
70
What ethnicity is at greater risk of developing myeloma?
Afro-carribean higher risk compared with Caucasians
Myeloma is seen to be one of a spectrum of plasma cell dyscrasias - which 2 conditions lie before myeloma and which lies after in terms of severity?
1) MGUS - monoclonal gammopathy of undetermined significance
2) Asymptomatic/smouldering/indolent myeloma
3) Myeloma
4) Plasma cell leukaemia
What is significant about MGUS?
Its is now thought that most cases of myeloma are preceded by MGUS
Name 7 other plasma cell dyscrasias?
1) MGRS - monoclonal gammopathy of real significance
2) High-risk MGUS
3) Amyloidosis
4) Solitary plasmacytoma (with/without bone involvement)
5) Systemic AL amyloidosis
6) POEMS syndrome
7) Myeloma with adverse cellular features
What is solitary plasmacytoma?
Get a discrete mass of abnormal plasma cells which can be deposited in bones such as femur or humerus but on further investigation no myeloma can be found in the marrow
What is the IMWG diagnostic criteria for myeloma? 3
1) Clonal BM plasma cells >10% or biopsy proven bony or extramedullary plasmacytoma AND any one or more of
2) CRAB features
3) MDEs
What are CRAB features?
Symptoms because of myeloma C - hypercalcaemia R - renal insufficiency A - anaemia (plasma cell taking up too much room in the bone marrow) B - bone lesions
What are ‘myeloma defining events’?
Having a myeloma defining event is implication for asymptomatic/ smouldering myeloma cases - so more inclined to treat
Name the 3 ‘myeloma defining events’ as defined by the IMWG diagnostic criteria?
1) >60% of plasma cells on BM biopsy
2) SFLC ratio (serum free light chain measurement) >100g/L provided the absolute levels of the involvement of LC is >100mg/L
3) >1 focal lesion on MRI measuring >5mm
What percentage of myeloma patients have renal insufficiency at diagnosis?
20-25%
What percentage of myeloma patients have renal insufficiency at some point during their disease course?
50%
What percentage of myeloma patients will have persistent renal impairment despite therapy?
50%
What percentage of myeloma patients will require RRT (renal replacement therapy)?
2-12%
What is meant by external factors affecting the kidney in myeloma?
Factors separate to the myeloma which are making the kidneys worse which we can do something about
Name the 9 external factors affecting the kidney in myeloma?
1) Renal venous thrombosis
2) Bisphosphonates (used to treat hypercalcaemia which is usually due to myeloma)
3) ACE inhibitors
4) Type 1 cryoglobulinaemia
5) Dehydration
6) NSAIDs
7) CT contrast
8) Hyper viscosity - extra proteins produced by neoplastic cells make blood very viscous
9) Hypercalcaemia
What is the immediate management for AKI with suspected myeloma, why should it be treated immediately?
It is a medical emergency - ‘time = nephrons’
Immediate treatment = steroids