EJVES Extra
Volume 12, Issue 2 , Pages 13-14, August 2006

Autoantibodies in Cases with Abdominal Aortic Aneurysms are Seldom and without Association with Progression Rate

  • S. Urbonavicius

      Affiliations

    • Department of Vascular Surgery, Viborg Hospital, Denmark
    • ,
  • N.H. Heegaard

      Affiliations

    • Department of Autoimmune Diseases, Statens Serum Institut, Denmark
    • ,
  • B. Honore

      Affiliations

    • Institute of Biochemistry, University of Aarhus, Denmark
    • ,
  • H. Vorum

      Affiliations

    • Institute of Biochemistry, University of Aarhus, Denmark
    • ,
  • J.S. Lindholt

      Affiliations

    • Department of Vascular Surgery, Viborg Hospital, Denmark
    • Corresponding Author InformationCorresponding author. Dr. J.S. Lindholt, PhD, Vascular Reserach Unit, Viborg Hospital, Postbox 130, 8800 Viborg, Denmark.

Accepted 1 May 2006.

Article Outline

Introduction

Antibodies against Chlamydia pneumoniae are associated with the progression of abdominal aortic aneurysms (AAA), but cross-react with immunoglobulins in AAA walls indicating an autoimmune reaction.

Report

Of 82 men with a small AAA followed for 1–5 years, 17% (10–27%) had antibodies against immunoglobulin, 3.7% had antinuclear antibodies (ANA), 19.5% (11–30%) had antinuclear core antibodies (ANCA), 2.4% had anti-beta-2-gpI IgG and 3,7% antibodies against cardiolipin.

The presence of antibodies against immunoglobulin and ANCA were not correlated with expansion rate; 2.61 and 2.76mm/year, respectively, compared to 2.40 and 2.39mm/year annually among those without such antibodies.

Discussion

Known autoantibodies are seldomly present in AAA and seem not to influence the progression of AAA.

Keywords: Aotic aneurysm, Pathophysiology, Expansion, Autoimmune

 

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Introduction 

Recently, we published results showing that antibodies against Chlamydia pneumoniae outer membrane protein (OMP) purified from patients with abdominal aortic aneurysms (AAA) react with OMP, but we could not detect any sign of OMP in the wall of AAAs, but other proteins – possibly immunoglobulins – were cross-reacting with the anti-OMP antibody.1

The correlation between antibodies against Cp and the progression of small AAA2 strongly suggests a pathogenetic role of the protein that caused the antibodies to be produced. From the study, we cannot conclude that this protein was OMP, or that another protein with similar epitopes as OMP. The missing presence of OMP suggests another protein to be involved. The demonstrated potential cross-reaction with immunoglobulins could indicate an autoimmune reaction.

Consequently, we have analyzed serum samples from our cohort of screen detected AAA for antibodies against immunoglobulin and other known autoantibodies in order to study the frequency of autoantibodies in AAA and their correlation with the expansion rate of AAA.3

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Report 

Serum from 82 men with a small AAA2 were controlled annually for up till 5 years for expansion, and their baseline serum samples were tested for various known autoantibodies at the only laboratory in Denmark performing the tests routinely.

The median max. initial AAA-diameter: 32mm. Median follow up time was 4.11 years, and median expansion rate was 2.44mm/year. The interobserver variation of the diameter measurements was 1.4mm.4

The results are summarised in Table 1; the frequencies of autoantibodies were limited; 17% (95% C.I.: 10–27%) had IgM and/or IgG antibodies against immunoglobulin, 3.7% (0.8–10.3%) had antinuclear antibodies (ANA), 19.5% (11–30%) had antinuclear core antibodies (ANCA), 2.4% (0.3–8.5%) had anti-beta-2-gpI IgG and 3,7% (0.8–10.3%) had IgM and/or IgG antibodies against cardiolipin.

Table 1. Presence of autoantibodies in a cohort of patients with small abdominal aortic aneurysms, and their association with mean annual expansion rate
AutoantibodiesPresentN=82Frequency95% C.I.Expansion rate (mm/year)P-value*
Ig against Immunoglogulin+1315.9%8.7–25.6%2.670.68
−2.40
Antinuclear antibodies+33.7%0.8–10.3%3.860.18
−2.44
Anti nuclear core antibodies+1619.5%0.3–28.5%3.010.49
−2.45
Anti-beta-2-gpI Immunoglobulin+22. 4%0.3–8.5%4.510.39
−2.47
Ig against cardiolipin+33.7%0.8–10.3%2.480.88
−2.58

*P-values by Wlicoxon's rang sum test.

The presence of antibodies against immunoglobulin and ANCA were not correlated with aneurysmal progression rate; 2.67 and 3.01mm/year, respectively, compared to 2.40 (P=0.68) and 2.45 (P=0.49) mm/year annually among those without such antibodies.

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Discussion 

Known autoantibodies, including antibodies against immunoglobulin, are seldomly present in AAA and seem not to influence the progression of AAA.

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References 

  1. Lindholt JS, Stovring J, Ostergaard L, Urbonavicius S, Henneberg EW, Honore B, et al. Serum antibodies against Chlamydia pneumoniae outer membrane protein cross-react with the heavy chain of immunoglobulin in the wall of abdominal aortic aneurysms. Circulation. 2004;109:2097–2102
  2. Lindholt JS, Juul S, Vammen S, Lind I, Fasting H, Henneberg EW. Immunoglobulin A antibodies against Chlamydia pneumoniae are associated with expansion of abdominal aortic aneurysm. Br J Surg. 1999;86:634–638
  3. Lindholt JS, Jorgensen B, Shi GP, Henneberg EW. Relationships between activators and inhibitors of plasminogen, and the progression of small abdominal aortic aneurysms. Eur J Vasc Endovasc Surg. 2003;25:546–551
  4. Lindholt JS, Vammen S, Juul S, Fasting H, Henneberg EW. The validity of ultrasonographic scanning as screening method for AAA. Eur J Vasc Endovasc Surg. 1999;17:472–475

PII: S1533-3167(06)00058-6

doi:10.1016/j.ejvsextra.2006.05.001

EJVES Extra
Volume 12, Issue 2 , Pages 13-14, August 2006

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