Antibodies

Question 1

anti-muscle-specific tyrosine kinase antibodies

Answer 1

Myasthenia gravis 40% #

but 85-90% of patients have antibodies to acetylcholine receptors

Question 2

antibodies to acetylcholine receptors

Answer 2

Myasthenia gravis

85-90% of patients have antibodies to acetylcholine receptors. In the remaining patients, about about 40% are positive for anti-muscle-specific tyrosine kinase antibodies

Question 3

Anti soluble liver antigen antibody positive

Answer 3

Autoimmune hepatitis 3

90% women, 30-50yr
2/3 get remission with corticosteroids….but 80% relapse after steroids stopped

Question 4

Anti smooth muscle antibody,
ANA
Anti actin antibodies

Negative AMA…

indicate….

Answer 4

Autoimmune hepatitis type 1

Aged 10- elderly
Most common
Reasonable remission response with corticosteroids

Can have raised anti-DSDNA

Question 5

What antibodies are usually present in multifocal motor neuropathy

Answer 5

GM1 anti ganglioside antibody in 80%

Question 6

Antibody associated with neuromyelitis optica

Answer 6

NMO-IgG or antibodies against aquaporin 4

Normal MRI brain, spinal cord lesion involving 3 or more levels

Question 7

Anti-centromere antibodies

Answer 7

Limited cutaneous systemic sclerosis

sclerodactyly, calcinosis, perioral puckering and gastro-oesophageal reflux symptoms in a middle-aged female

Question 8

Anti GBM antibodies

Answer 8

Goodpastures

Question 9

Anti-cardiolipin antibodies

Answer 9

Anti phospholipid syndrome

Also present in up to 10% of the general population
and found in around 30-40% of SLE.
In both patients with primary and SLE associated APS positive results correlate with a predisposition for arterial or venous thrombosis, foetal loss, or thrombocytopoenia.

Question 10

Antibodies to acetylcholine receptors

Answer 10

Myasthenia gravis

Question 11

Myasthenia gravis

Answer 11

Antibodies to acetylcholine receptors in 85-90%

Question 12

Lambert Eaton Myasthenia Syndrome antibodies

Answer 12

Antibodies to voltage-gated calcium channels (VGCCs) have been reported in 75-100% of LEMS who have SCLC

50-90% of LEMS patients who don’t have underlying cancer

Question 13

What conditions have ANA

Answer 13

Diffuse cutaneous systemic sclerosis
Limited cutaneous systemic sclerosis
Sjogren's syndrome
SLE
Autuimmune hep 1

Question 14

Anti saccharomyces cerevisiae antibodies

Answer 14

More likely to be positive in Crohn’s

Question 15

pANCA in which inflammatory bowel disease

Answer 15

More likely UC

Question 16

Most likely antibody to be positive in SLE

Answer 16

ANA

anti-dsDNA and anti-Smith very specific but not sensitive

Question 17

which ANCA is more assx w microscopic polyangiitis

Answer 17

pANCA (against MPO) - positive in 50-75%

cANCA (against PR3) - positive in 40%

Question 18

pemphigus vulgaris antibodies

Answer 18

antibodies directed against desmoglein 3, a cadherin-type epithelial cell adhesion molecule

More common in Ashkenazi Jews

Question 19

primary biliary cholangitis antibody

Answer 19

anti-mitochondrial antibodies (AMA) M2 subtype are present in 98% of patients and are highly specific

first-line: ursodeoxycholic acid

Question 20

anti-phospholipase A2 antibodies

Answer 20

idiopathic membranous glomerulonephritis

Question 21

anti-histone antibodies ( 80-90%)

Answer 21

Drug-induced lupus
ANA +ve
DsDNA -ve

Question 22

specific test for lupus

Answer 22

anti-DsDNA

Typically associated with SLE but high levels may be found in autoimmune hepatitis

Question 23

Anti-liver/kidney microsomal type 1 antibodies (LKM1)

Answer 23

autoimmune hepatitis 2

Affects children only

Question 24

anti-ENA-antibodies

Answer 24

group of six tests:
anti-Sm (SLE, highly specifc)
anti-RNP (Mixed connective tissue disease and SLE).
anti-Ro (Sjögren's, 70%)
anti-La (Sjögren's 40%)
anti-Scl70 (Scleroderma)