Immunotyping

Question 1

What is normal sample?

Answer 1

• normal fraction values
• no extra peaks or distortions
• bell-shaped aspect of the gamma fraction
• Beta2 < Beta1

Question 2

When to perform?

Answer 2

• monocloal peak in gamma
• distortions in gamma
• additional peak in Beta2
• Beta2 > Beta1
• additional peak in Beta1
• an isolated increase of Beta1 (no supporting data for another interpretation)
• unusual shape in alpha2
• isolated increase of alpha2

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Question 3

Four steps for IT inerpretations

Answer 3

• locate the abnormality and zoom to the region of interest
• Identify with which antiserum the anomaly was subtracted (kappa or lambda, and heavy chains)
• distinguish between monoclonal and polyclonal subtraction
• characterize the monoclonal abnormality by paring the light chain and the heavy chain

Question 4

How to choose the correct IT dilution

Answer 4

• too high dilution of antisera -> antigen excess, prozone. leads to incomplete subtraction
• too low dilution of antisera -> antibody excess, lack of visibility for a weak M-protein

Question 5

Antigen excess on IFE

Answer 5

• strong monoclonal Ig on gel not diluted enough (donut or hole in band on IFE)
• possible confusion with 2 bands
• in CE, you have incomplete subtraction
• also in CE, you can have incorrect overlaying in the alpha-beta region, instead of anodal to albumin
• possibly change dilution of sample
• want to achieve antibody-antigen equilibrium

Question 6

Dilutions

Answer 6

• Hypogamma (<0.8 g/dl in gamma region, but you also must look in other zones and add these if there)
• Standard (0.8 - 2.0 g/dl)
• Hypergamma (> 2.0 g/dl)
  -Optimized

Question 7

IgG - Normal Kappa and Lambda ratios

Answer 7

• 2/3 Kappa
• 1/3 Lambda

Question 8

Polyclonal subtraction

Answer 8

2/3 kappa reduction, 1/3 lamda reduction
Mostly IgG reduction, followed by some for IgA and IgM in normal ratios

Question 9

Polyclonal IgA

Answer 9

• Beta2 > Beta1
• similar reduction of kappa and lambda
• equal ratios
• wide reduction in IgA
• no reductions in IgM
• beta2 returns to normal on IgA after subtraction

Question 10

Monoclonal IgA

Answer 10

• Beta2 > Beta1
• no bridging
• complete subtraction of the M-protein in Kappa or Lambda
• B2 goes back to normal shape after subtraction
• no reaction with the other light chain
• reduction of IgA to normal after IT
• IgA removal looks similar to removal in one of the light chains
• beta2 leftover is C3 complement (normal)

Question 11

Polyclonal IgM

Answer 11

• small distortion in gamma
• IT removal of 2/3 kappa AND 1/3 lambda
• large subtraction of IgM

Question 12

Monoclonal IgM

Answer 12

• small peak in gamme
• peak in single light chain completely removed, other light chain little removal