Myeloma and other plasma cell dyscrasia Flashcards
What is the shape of IgM?
pentamer
What is the structure of IgA?
dimer
How is the Ig variable element generated?
VDJ region recombination
Where do B cells travel to in the periphery?
follicle germinal centre of the lymph node
What are the features of plasma cells on H&E?
eccentric clock face nucleus; open chromatin; plentiful blue cytoplasm; pale perinuclear area
Why do plasma cells ahve open chromatin?
synthesising mRNA
Why do plasma cells have a big blue cytoplasm?
laden with protein
Why do plasma cells have a pale perinucelar area?
golgi apparatus
What are monoclonal immunoglobulins also known as?
paraproteins
How are immunoglobulins detected?
serum electrophoresis
Once detected, how can the abnormal protein band be classified?
serum immunofixation
What is the difference between kappa and lamda light chains?
kappa- monomer whilst lambda are dimers
How much free light chain is produced daily by normal plasma cells?
0.5g
What are the direct umour ell effects in myeloma?
bone lesions; increased calcium; bone pain; marrow failure
what are the paraprotein mediated effects in myleoma?
renal failure; immune suppression; hypervscosity; amyloid
what is typically seen on skull xray with myeloma?
pepperpot appaearnce due to lytic lesions
What are the causes of renal impairment in myeloma?
tubular cell damage by light chains; light chain deposition causing cast nephropathy; sepsis; hypercalcaemia and dehydration; drugs- NSAIDs; amyloid;
What protein do light chains in the tubules bind with to produce insoluble casts?
Tamm-Horsfall protein
What is the most common cause of renal failure in mutliple myeloma?
cast nephropathy
What is average age at diagnosis of myeloma?
65
What is the definition of MGUS?
paraprotein <30g/L; bone marrow plasma cells <10% and no evidence of end organ damage
What is the risk of progression to myeloma with MGUS?
1% per year
What is AL amyloidosis?
small plasma cell clone which has a mutation in the light chain leading to an altered structure which precipitate in tissues as an insoluble beta pleated sheet
What does AL amyloid typically cause in the kidney?
nephrotic syndrome
what does AL amyloid cause in the heart?
cardiomyopathy
What stain is used t o detect amyloid?
congo red stain
What is seen with staining of amyloid?
apple green birefringence under polarised ligth
What is waldenstroms macroglobulinaemia?
lymphoplasmacytoid neoplasm
What is a lymphoplasmacytoid neoplasm?
clonal disorder of cells intermediate between a lymphocyte and a plasma cell
What type of paraprotein is seen in waldenstroms?
IgM
What are the features of hyperviscosity syndrome seen with WM?
fatigue; visual disturbance; sonfusionl coma; bleeding; cardiac failure
