• Terminally differentiated B cells• Function– Antibody secretion
Plasma Cells
• 2 heavy chains:• 2 light chains:
• 2 heavy chains: μ, γ, α, δ, ε• 2 light chains: κ, λ
Describe Plasma cell on HE
Has clock faced nuclei
Below is an image of reactive plasma cells, When would we see them?
• Chronic infections (eg. Hpylori gastritis,osteomyelitis,endometritis)• Autoimmune processes(lupus, hepatitis)
• Multiple myeloma• Monoclonal gammopathy of undeterminedsignificance (MGUS)• Plasmacytoma– Extramedullary plasmacytoma– Solitary plasmacytoma of bone• Lymphoplasmacytic lymphoma• AmyloidosisAll exmaples of:
Neoplastic plasma cell conditions
How do we differentiate between reactive and neoplastic plasma cell conditions?
• Monoclonal antibodies in theserum or urine• Light chain restriction in cellcytoplasm (kappa v lambda) byflow cytometry orimmunohistochemistry• Immunophenotypic aberrancy(i.e. CD56 on plasma cells)
Normally, the production andcoupling of heavy and lightchains is
tightly balanced.
Monoclonal antibodies = M protein– Serum• Plasma cells actively secreting antibodies: what are we looking for in the serum?
intactimmunoglobulins and free light chains when performing clonality assessment
What do we look for in clonality assesment of Uring?
• Antibodies may be filtered when kidney damage• Free light chains (small) may pass through glomerulus– Bence Jones proteins = free light chains
–Bence Jones proteins=
free light chains
– Identification is donewith electrophoresis– _______May be present in plasma cell disorders and B-celllymphomas (monoclonal gammopathy); rarelyreactive states
Clonality assesment of M protein
What isSerum/Urine Electrophoresis(SPEP/UPEP)
Fractionate the serum and apply with electric fieldpeaks show most abundant proteinalbumin is always high, but others should all be present and lowerif one is overexpressed, will peak
What is Immunofixation?
Take pt serum and run itall should stain a little bitoverabundace or over-represented stain most likely pathologic
• Most common plasma cellneoplasm• Malignant• Epidemiology– 15% of all heme malignanciesin US– ♂ > ♀– AAs > Caucasians– 50-70 y/o• Median age 68-70 y/o
Multiple Myeloma
Three key Dx critera for multiple myeloma
Diagnostic criteria1. Clonal plasma cells2. M protein3. End organ damage
Wha tis the Dx critera for MM as far as Clonal plasma cells are concerned?
What are Dx criteria in MM as far as M protein is concerned?
What end organ damage do we see in MM (CRAB)
• HyperCalcemia• Renal insufficiency• Anemia• Bone disease
What is true of the plasma cells in picture below of Multpile Myeloma?
The are clonal
Why is it important to obtain both electrophoresis on theserum and urine for the diagnosis of myeloma?
– 99% of myelomas have an M protein* (IgG>IgA) and/orBence Jones protein– 60-70% have a serum M protein* and Bence Jonesproteins– 20% have only Bence Jones protein
Multiple Myeloma causes this as a result of end organ damage
Lytic bone lesions– Bone pain– Pathologic fractures– Most common sites:– Vertebrae (66%)– Ribs (44%)– Skull (41%)-Pelvis (28%)– Femur (24%)– Osteopenia
MM causes hypercalcemia secondary to:
Secondary to bone resorption– Signs and symptoms:– Weakness, lethargy → Coma– Polyuria, stones, renal failure– Constipation, abd pain– Depression– Arrythmias
Renal insufficiency, 50% of patients with MM, this is due to:
– Bence Jones (light chain) proteinuria• Direct nephrotoxicity• Formation of tubular casts» Obstruction» Secondary inflammation(also from HyperC, amyloidosis and light chain gammapoathy)
MM can lead toAnemia– May be associated with______– Secondary to marrow replacement by plasma cells and/orrenal disease
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