Immunology

Question 1

What is measured in serum to diagnose allergic sensitivity

Answer 1

IgE

Question 2

Which immunologic markers indicate a “true” peanut allergy and high risk of severe reactions

Answer 2

Ara h1, ara h 2, ara h 3 specific IgE

Question 3

Name 10 red flags for primary immunodeficiency

Answer 3

•≥8 new ear infections within 1 year
• ≥2 serious sinus infections within 1 year
• ≥2 months on antibiotics with little effect
• ≥2 pneumonias within 1 year
•≥2 deep seated infections
• failure to thrive infant
• recurrent, deep skin/organ abscesses
• persistent thrush in mouth/elsewhere on skin after age 1
• need iv antibiotics to clear infections
• family history

Question 4

Name the 3 most common primary immunodeficiency syndromes

Answer 4

•Antibody (50%)
• combined (20%)
• phagocytic (18%)

Question 5

Which screening procedures should be done for primary immunodeficiency syndromes (4)

Answer 5

• FBC and differential
• total serum immunoglobulins nb ( G, A, M, E. IgG subclasses if necessary)
• total haemolytic complement: c3 and c4
• flowcytometry of T cells/subsets (Cd3,4,8), circulating B cells (cd19), nk cells (cd56)

Question 6

Which follow up procedures should be ordered for primary immunodeficiencies if the screening is positive (4)

Answer 6

•Neutrophil functions (antimicrrobial activity, adhesion molecule expression)
• monocyte/macrophage functions (cytokine production eg IL2, IFN gamma receptor)
• t lymphocyte functions (proliferation, cytokines)
• molecular/genetic analysis private

Question 7

Which immunoglobulins are detectable in acute infections

Answer 7

• IgM (within days, peak day 7-10)
• igG (7 -14 days after onset, stay in circulation for months)

Increased titres must be shown in follow up samples to confirm active infection in 4-6 weeks

Question 8

Which immunoglobulins are detectable in chronic infections

Answer 8

IgG
4 fold increase in titer
(Chlamydia: IgG, A ,M )

Question 9

Name 3 nuclear antigens that are diagnostic for SLE

Answer 9

• ds dna (>85%)
• SMDP (30%)
• ribosomal P for neuropsychiatric SLE
( Help diagnosis: SSA ( ro 52/ro60 ) 30-40%, SSB (La) 10-30%, u1-snrnp 45%, rnp70 45% , pcna highly sensitive if highly elevated )

Question 10

Name 1 nuclear antigens that are diagnostic for mctd (mixed)

Answer 10

U1 - snrnp (overlap sle/scl/pm)

Question 11

Name 2 nuclear antigens that are diagnostic for polymyositis pm

Answer 11

• Jo-1 (30 %)
• speckled Ana pattern!
Mi-2 helps, pm - scl for polymyositis/scleroderma overlap syndrome

Question 12

Name nuclear antigens that are diagnostic for progressive systemic sclerosis

Answer 12

Scl-70 (topoisomerase 1) (70%)

Fibrillarin exclusively identifies systemic sclerosis

Question 13

What does a CtD screen consist of

Answer 13

Cocktail of 18 associated extractible nuclear antigens
(Negative if <0,7 ratio)

Question 14

Name 2 nuclear antigens that are diagnostic for crest syndrome

Answer 14

Centromere p (90%)
Cenp

Question 15

Name nuclear antigens that are diagnostic for neuropsychiatric SLE

Answer 15

Ribosomal p

Question 16

Name 2 nuclear antigens that are diagnostic for scleroderma

Answer 16

• cenp (>90%) ‘
• Ana pattern: centromere antibodies!
Fibrillarin helps, pm -scl for polymyositis/scleroderma overlap syndrome

Question 17

Serodiagnosis of rheumatoid arthritis? (2)

Answer 17

• Rheumatoid factor (75-82%): higher = more severe
• anti CCP antibodies (anti cyclic citrullinated peptide, 80-92 %): present years before clinical onset

Question 18

Name 3 symptoms anti-phospholipid syndrome

Answer 18

• A/v thrombosis
• recurrent fetal loss/ iugr
• thrombocytopenia

Question 19

Name 5 risk factors anti-phospholipid syndrome

Answer 19

• Female
• pre-existing inflammatory disorders
• cigarette
• hyperlipidaemia
• ht

Question 20

Which autoantibodies are found in anti phospholipid syndrome (2)

Answer 20

• Anti-cardiolipin antibodies (acla): igG, IgA (esp Africans), IGM
• antibodies to beta 2 glycoprotein 1 (associated with thrombosis and foetal loss)

Inhibit thrombin activation protein c, inhibit degradation of factor V byprotein S, bind to vascular endothelium causing complement activation and thromboxane generation, bind to decidual tissue causing complement activation and generation of TNF (this causes the pregnancy loss)

Question 21

Interpret results syphilis serology:
RPR 1:4, tpha negative, igG negative, IgM negative

Answer 21

Negative disease

Question 22

Interpret results syphilis serology:
RPR 1: 64, tpha positive, igG very high, IgM negative or positive

Answer 22

Positive syphilis

Question 23

Interpret results syphilis serology:
RPR neg/nr, tpha positive, igG high, IgM high

Answer 23

Positive for syphilis

Question 24

Interpret results syphilis serology:
RPR neg/nr, tpha negative, igG negative, IgM negative

Answer 24

Negative

Question 25

Interpret results chlamydia serology:
igG 1:128 high, IgM 1:20 high , IgA 1:16 normal

Answer 25

Acute infection

IgA = chronic marker

Question 26

Interpret results chlamydia serology:
igG 1: 512 very high, IgM negative , IgA 1: 64 high

Answer 26

Severe untreated acute infection

Question 27

Interpret results chlamydia serology:
igG 1: 64 borderline high, IgM negative , IgA negative

Answer 27

Borderline, treat based on clinical picture

Question 28

Interpret results rickettsia serology:
igG 1:128 high, IgM 1: 64 borderline high

Answer 28

Active acute tick bite fever

Question 29

Interpret results rickettsia serology:
igG 1: 152 very high, IgM negative

Answer 29

Chronic tick bite fever

Question 30

Interpret results rickettsia serology:
igG negative, IgM negative

Answer 30

Negative for tick bite fever

Question 31

Interpret results rickettsia serology:
Phase 2 igG 1: 512 very high, Phase 1 igG negative, phase 2 IgM 1: 256 very high, phase 1 IgM 1: 64 borderline high

Answer 31

Phase 2> phase 1 therefore acute tick bite fever

Question 32

Interpret results rickettsia serology:
Phase 2 igG 1: 128 high, Phase 1 igG 1: 128 high, phase 2 IgM negative, phase 1 IgM 1: 512 very high

Answer 32

Phase 1 > phase 2 therefore chronic tick bite fever

Question 33

Diagnosis rheumatoid arthritis? (2)

Answer 33

• Rheumatoid factor (>400 = severe)
• anti - ccp antibodies (present before onset)