The alpha-1 antitrypsin (AAT) haplotype Pi*S, when inherited along with the Pi*Z haplotype to form a Pi*SZ genotype, can be associated with pulmonary emphysema in regular smokers, and less frequently with liver disease, panniculitis, and systemic vasculitis in a small percentage of people, but this connection is less well established.
These associations include ERAP1, CCR1-CCR3, STAT4, KLRC4, GIMAP4, and TNFAIP3 in Behçet's disease; BLK and CD40 in Kawasaki disease; SERPINA1 and SEMA6A in antineutrophil cytoplasmic antibody associated vasculitides; IL12B and FCGR2A/ FCGR2A in Takayasu arteritis; and CECR1 in a newly defined vascular inflammatory syndrome associated with adenosine deaminase (ADA2) deficiency.
GWASs also revealed that polymorphic variants of genes encoding proteinase 3 (PR3), the predominant antigenic target of ANCA in GPA, and its main inhibitor, alpha-1 antitrypsin, are highly associated with GPA and, even more significantly, with PR3-ANCA positivity (regardless of the clinical diagnosis); this emphasizes the central pathogenic role of PR3 and humoral autoimmunity in PR3-ANCA positive vasculitis.
Individuals who are deficient in AAT (those with levels < 11 micromol/L) are at risk for developing such clinical manifestations as emphysema, cirrhosis, panniculitis, and anticytoplasmic neutrophilic antibody (C-ANCA)-positive vasculitis (Wegener's granulomatosis).
C-antineutrophil cytoplasmic antibody positivity in vasculitis patients is associated with the Z allele of alpha-1-antitrypsin, and P-antineutrophil cytoplasmic antibody positivity with the S allele.
To ascertain whether a relationship exists between the PiZ alpha 1-antitrypsin (alpha 1AT) variant and antineutrophil cytoplasm antibodies (ANCA)-positive vasculitis in a large group of Swedish patients, and whether analysis for the presence of the PiZ variant might be useful for diagnostic or prognostic purposes.
This is the third reported case of systemic necrotizing vasculitis in association with alpha-1 antitrypsin deficiency of the PI ZZ type, and the first to show significant response to cyclophosphamide and steroids.
The coding exons of ADA2 were sequenced in 60 children and adolescents with a diagnosis of PAN, cutaneous PAN, or unclassifiable vasculitis (UCV), any chronic vasculitis with onset at age 5 years or younger, or history of stroke.
Human adenosine deaminase type 2 deficiency (DADA2), due to biallelic deleterious mutations in the ADA2 gene, is the first described monogenic type of small- and medium-size vessel vasculitis.
All vasculitis relapses in the belimumab group (n = 6) occurred in patients who had PR3-ANCA-associated vasculitis with cyclophosphamide-induced disease remission.
Reduction of adenosine deaminase 2 (ADA2) activity due to autosomal-recessive loss-of-function mutations in the <i>ADA2</i> gene (previously known as <i>CECR1</i>) results in a systemic vasculitis known as deficiency of ADA2 (DADA2).
Of 85 patients with ANCA and vasculitis included in this study, 67 (78.8%) had MPO-ANCA, 10 (11.8%) had PR3-ANCA, and 8 (9.4%) had both MPO- and PR3-ANCA.
<i>Conclusion</i>: In contrast to typical C-ANCA and P-ANCA, atypical P-ANCA seropositivity was not associated with severe vasculitis or poor prognosis in patients with the OID.