Primary systemic vasculitis with severe α1-antitrypsin deficiency revisited

Area of Science:

• Rheumatology
• Genetics
• Epidemiology

Background:

• Primary systemic vasculitis (PSV) encompasses a group of rare autoimmune diseases characterized by inflammation of blood vessels.
• Severe alpha-1 antitrypsin (α1-AT) deficiency is a genetic condition that can lead to lung and liver disease.
• The potential association between PSV and α1-AT deficiency requires further investigation.

Purpose of the Study:

• To investigate the clinical characteristics and epidemiology of PSV in patients with severe α1-AT deficiency.
• To determine if there is an increased risk of PSV among individuals with the PiZZ phenotype.

Main Methods:

• Retrospective study identifying patients with PSV (GPA, MPA, EGPA, PAN) and severe α1-AT deficiency (PiZZ phenotype) between 1996-2008.
• Collected clinical and laboratory data, including disease relapses and permanent organ damage.
• Calculated the incidence and point prevalence of PSV in individuals with severe α1-AT deficiency using a defined population denominator.

Main Results:

• Five patients with PSV and PiZZ phenotype were identified.
• During follow-up, patients experienced relapses and developed significant organ damage (VDI scores increased over time).
• The incidence rate of PSV in PiZZ carriers was 397/million, and the point prevalence was 4689/million, representing a nearly 10-fold increase compared to the general population.

Conclusions:

• Severe α1-AT deficiency is associated with a substantially elevated risk of developing PSV.
• The findings suggest a dose-response relationship and a potential causal link between the PiZ allele and vasculitis.
• This highlights the importance of considering α1-AT deficiency in the workup of vasculitis patients.