ImmunoChemistry

Question 1

Different immunological serum proteins

Answer 1

Immunoglobulins
Immunoglobulin G subclasses
Functional antibodies
Complement proteins
Rheumatoid factor
Cyroglobulins
Cerebrospinal fluid oligoclonal bands

Question 2

What immunoglobulins are measured?

Answer 2

IgG, IgA, IgM

Question 3

What goes IgG indicate?

Answer 3

Specific immune response
3 week half life
Main antibody in blood

Question 4

What does IgA indicate?

Answer 4

Mucosal immunity
Often dimerised

Question 5

What does IgM indicate?

Answer 5

Early immune response (first antibody produced)
Often pentameric structure.

Question 6

What are immunoglobulins G subclasses used for?

Answer 6

To investigate subclass deficiencies
Eg recurrent chest infection

Question 7

What are functional antibodies used for?

Answer 7

Check if immune system responds correctly to vaccines

Question 8

Examples of functional antibodies

Answer 8

Tetanus toxoid antibodies
Meningococcal C antibodies

Question 9

What complement proteins are measured?

Answer 9

C3 and C4

Question 10

Purpose of measuring complement proteins

Answer 10

Indicators of acute phase reaction
Indicators of chronic inflammation
Low levels assocaited with SLE or angioedema

Question 11

Examples of functonal complement testing

Answer 11

CH100/ AH100 - haemolytic complement activity

Question 12

What is rheumatoid factor?

Answer 12

Autoantibody usually IgM against the Fc of IgG

Question 13

Clinical RF what does it indicate?

Answer 13

Rheumatoid arthritis
Systematic lupus erythematosus
Infection

Question 14

What are cryoglobulins?

Answer 14

Proteins that precipitate at low temps

Question 15

What are cryofglobilins an indicator of?

Answer 15

Raynauds
Arthritis
Nephritis

Question 16

What does cerebrospinal fluid oligoclonal binds detect?

Answer 16

Intrathecal IgG production
In Multiple sclerosis

Question 17

Principle of nephelometry

Answer 17

Patient serum diluted
Specific antibody added
Immune complexes form
Analyser measures light scattered by these complexes

Question 18

Amount of scattered light in nephelometry =

Answer 18

Amount of analyte

Question 19

What is nephelometry used for?

Answer 19

IgG, IgA, IgM
C3, C4
rheumatoid factor
IgG subclasses

Question 20

Strengths of nephelometry

Answer 20

Very sensitive
Automated
Includes antigen excess testing to avoid falsely low results

Question 21

Principle of turbidimetry

Answer 21

Measures light passing through the sample
More immune complexes = less light passes through

Question 22

What is turbidimetry used for?

Answer 22

Similar analyses as nephelometry eg immunoglobulins, C3 + C4
Some IgG subclasses

Question 23

Differences of turbidimetry from nephelometry

Answer 23

Nephelometry measures scattered light
Turbimetry measures light blocked

Question 24

Principle of radical immunodiffusion RID

Answer 24

Patient sample diffuses through
Agar that contains antibody
Precipitin ring forms at zone of equivalence

Question 25

Diameter of ring in radical immunodiffusion =

Answer 25

Concentration of analyte

Question 26

What is radical immunodiffusion used for?

Answer 26

Haemolytic complement function - CH100, AH100 Classical pathway uses sheep red blood cells coated with haemolysin Alternative pathway uses chicken red blood cells

Question 27

Interpretation of radical immunodiffusion

Answer 27

Large clear zone = high complement activity Small/no zone = complement deficiency or poor sample handling

Question 28

Types of electrophoresis

Answer 28

Serum protein electrophoresis Immunofixation electrophoresis Isoelectric focusing

Question 29

What does serum protein electrophoresis separate serum proteins into?

Answer 29

Albumin Alpha - 1 Alpha -2 Beta Gamma regions

Question 30

What is serum protein electrophoresis used to detect

Answer 30

Paraproteins - monoclonal immunoglobulins Polyclonal increases - inflammation

Question 31

What is immunofixation electrophoresis used to identify?

Answer 31

Type of monoclonal protein eg IgM kappa

Question 32

What is Isoelectric focussing used for?

Answer 32

Cerebrospinal fluid oligoclonal bands Detects intrathecal IgG production

Question 33

Low IgG, A, M

Answer 33

Protein losing states Poor nutrition Immune deficiency Selective IgA deficiency

Question 34

High IgG, A,M levels indicate

Answer 34

Autoimmune disease MM Early infection - high IgM

Question 35

Low C3, C4 indicates

Answer 35

Systemic lupus erythematosus Angioedema Chronic inflammation.

Question 36

Normal levels of C3, C4 but low function indicates…

Answer 36

Non functional complement proteins

Question 37

Elevated rheumatoid factor indicates…

Answer 37

Rheumatoid arthertis Systemic lupus erythematosus Infection Autoimmune liver disease

Question 38

Presence of Cryoglobulins indicates

Answer 38

Raynauds Arthritis Nephritis

Question 39

What is oligoclonal bands in cerebrospinal fluid but not serum an indication of

Answer 39

Multiple sclerosis