Arthritis & Rheumatism, Volume 63,
November 2011 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Chicago, Illinois November 4-9, 2011.


Low Vitamin D Levels Are Common in Primary Antiphospholipid Syndrome: A Role in the Pathogenesis of the Disease?

Andreoli1,  Laura, Piantoni1,  Silvia, Allegri1,  Flavio, Meroni2,  Pier Luigi, Tincani1,  Angela

Rheumatology Unit, University of Brescia, Brescia, Italy
University of Milan, Milan, Italy

Background/Purpose:

Low levels of vitamin D (vit.D) have been described in different systemic autoimmune diseases (SAD). In vitro studies and animal models have shown anti-inflammatory properties of vit.D. Therefore, hypovitaminosis D has been claimed to be involved in the pathogenesis of SAD. Primary Antiphospholipid Syndrome (PAPS) is characterized by thrombotic events and/or obstetric disease, whose pathogenesis is mediated by antiphospholipid antibodies. Differently from other SAD, PAPS patients (pts) do not usually have a full-blown disease that requires corticosteroids (and therefore the association of vit.D supplementation as osteoporosis prophylaxis), nor have particular limitations in sun exposure. These factors are relevant to vit.D levels. Thus, pts with PAPS appear to be a good model for studying hypovitaminosis D in SAD. Purpose:To assess the prevalence of hypovitaminosis D in a large cohort of PAPS (in comparison with normal population from the same geographical area) and investigate the association with clinical manifestations.

Methods:

We enrolled 115 PAPS (19 m, 96 f, median age: 46 years) and 128 normal healthy donors (NHD) (55 m, 73 f, median age: 34). Vit.D levels were tested by the LIAISON® chemiluminescent immunoassay (DiaSorin, Italy), kindly provided by the manufacturer. The samples were grouped upon the season for statistical analysis.

Results:

Vit.D deficiency (<10 ng/ml) was more prevalent in PAPS than NHD (17%vs. 5%). Seasonal variability was present in both groups (higher levels in the summer, lower levels during winter). However, median values were lower in PAPS than NHD at all time points, with the greatest difference during summertime (median: 28 vs. 40.1 ng/ml; p<<0.01), suggesting that PAPS pts may be somehow prevented from vit.D generation upon sun exposure. PAPS pts may receive specific instructions regarding the use of sunscreens in the presence of positive anti-nuclear antibodies (ANA). Comparing pts with positive (n=63) and negative ANA (n=40), we found comparable Vit.D levels during the summer (median: 27.7 vs. 28). PAPS were subdivided upon clinical features (thrombotic vs obstetric). Both groups had lower vit.D levels than NHD. Thrombotic PAPS had significantly lower levels than obstetric PAPS (median value: 20.8 vs. 33.3; p<<0.01).

Conclusion:

Pts with PAPS displayed significantly lower levels of vit.D than NHD. Although these pts have limited inflammatory burden and organ involvement, rarely requiring immunosuppression, these epidemiological data make them similar to pts with SAD such as Systemic Lupus Erythematosus or Rheumatoid Arthritis. Using ANA positivity as a surrogate marker for sun exposure, we suggest that sun avoidance may not be the main reason for low vit.D levels. Hypovitaminosis D may be part of the mosaic of factors that determine autoimmunity, rather than a consequence of chronic disease and its treatment (factors that are poorly represented in PAPS). In particular, this hypothesis may be supported by the observation that pts with thrombotic PAPS, i.e. more aggressive disease, are more deficient than those with exclusive obstetric manifestations. This could fit well with a recent in vitro observation of anti-thrombotic properties of vit.D.

To cite this abstract, please use the following information:
Andreoli, Laura, Piantoni, Silvia, Allegri, Flavio, Meroni, Pier Luigi, Tincani, Angela; Low Vitamin D Levels Are Common in Primary Antiphospholipid Syndrome: A Role in the Pathogenesis of the Disease? [abstract]. Arthritis Rheum 2011;63 Suppl 10 :9
DOI:

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