𝛂1-antitrypsin antibody (AATD)

Question 1

Epi of AATD

Answer 1

most common hereditary disorder in adults –> increased risk of emphysema and liver disease

• risk of emphysema increases with smoking (but those with severe deficinecy may have emphysema despite beong non-smokers)
• genotype variants:
  a) severe deficiency: ZZ, Znull, Nullnull and most SZ
  PiZZ homozygous - most severe deficiency state –> extrapulmonary (cirrhosis, HCC, vasculitis and panniculitis)
  increased risk of developing pulmonary emphysema and liver disease

b) intermediate levels for M heterozygotes (MZ, MS and Mnull)

c) Normal levels (MM)

Question 2

Ix for AATD

Answer 2

1) Quantitative AAT level with CRP (coz AAT is an acute phase reactant too - thus it could be high due to acute inflammation if CRP is also high)

2) Qualitative test: protein phenotyping to identify variant. Also to offer family testing

3) PFT & 6MWT

4) CT densitometry: most sensitive/ specific to measure emphysema progression

Question 3

Mx of AATD

Answer 3

1) Identify patient with severe AAT deficiency.
2) Ensure smoking is stopped 3) Identify and modify any other potential risk factor(s). 4) Optimise current COPD therapy.
5) Assess patient in an expert reference centre.
6) Instigate augmentation therapy if indicated (weekly infusions of AAT at 60 mg·kg−1 for 2 years) in FEV1 35-70%
7) Continue monitoring.
8) Surgical volume reduction and EBV placement may be considered in selected patients with AATD