Multiple myeloma

Question 1

What is the gold standard investigation for diagnosing multiple myeloma?

Answer 1

Urine electrophoresis (24 hour urine collection) - looking for monoclonal proteins (Bence Jones proteins) -- spike in the gamma region (as opposed to polyclonal pattern) 
Serum electrophoresis as well - but can miss light chain immunoglobulins (false negative)

Question 2

What is the diagnostic criteria for multiple myeloma?

Answer 2

1. Bone marrow aspirate >10% monoclonal plasmocytosis
2. Evidence of end-organ failure / damage: ‘CRAB’ (one of the following)
   - hypercalcemia
   - renal insufficiency
   - anemia
   - bony lytic lesions
3. M protein in urine or serum

Question 3

Explain the significance of Rouleaux cells on the peripheral blood smear

Answer 3

“stacking” of red blood cells; the absence of negative charge normally dispelling RBCs - zeta charge

Question 4

Name 2 markers that are specific to multiple myeloma (prognosis)

Answer 4

Beta-2 microglobulin - tumour load, prognostic value

LDH - higher levels = shorter survival rates

Question 5

What cell type is implicated in MM?

Answer 5

Plasma cells

Question 6

Briefly describe the structure of an immunoglobulin

Answer 6

Y shaped; light chains - lambda and kappa ; heavy chains - Ig-G,A,M,E,D;
Normal ratio of lambda:kappa = 2:1

Question 7

Explain serum immunofixation

Answer 7

Immunofixation permits the detection and typing of monoclonal antibodies or immunoglobulins in serum or urine5 additional lanes undergo electrophoresis in parallel to SPEP. Each lane is overlaid with different monospecific antibody – usually three for heavy chain components and two for light chain components

Question 8

Explain serum electrophoresis

Answer 8

Detection of M proteins - secreted by abnormally expanded clone of plasma cells by gel electrophoresis on serum protein

Question 9

What is multiple myeloma?

Answer 9

Multiple myeloma is a haematological malignancy of white blood cells / bone marrow –> lymphoid in origin, characterised by neoplastic proliferation of plasma cells producing a monoclonal immunoglobulin