Gene/smoking link to arthritis

Thursday June 4th, 2009

New research has highlighted a possible new genetic link to rheumatoid arthritis.

Dr Emeli Lundstrom and colleagues at the Karolinska Institutet in Stockholm, Sweden, say that people with some genetic factors are at increased risk, especially when they also smoke - an established environmental risk factor for rheumatoid arthritis.

The team explains that a clear "gene-environment interaction" has been found between smoking and specific versions of the HLA-DRB1 gene among Caucasian patients.

They investigated this link in relation to the risk of developing rheumatoid arthritis with and without anti-citrullinated protein antibodies (ACPAs). ACPAs are autoantibodies found in about 60 per cent of rheumatoid arthritis patients, and are commonly used in diagnosis.

Information was gathered from 1,319 patients and 943 comparable healthy people.

Dr Lundstrom and his colleagues say their results suggest a link with the HLA-DRB1 gene.

In the journal Arthritis & Rheumatism, the authors confirm that the link is statistically significant.

One reason may be that long-term exposure to cigarette smoke may alter the types of amino acids in the lungs, triggering an immune response. Alternatively, toxic substances in smoke may directly affect the immune system, contributing to the development of arthritis.

Lundstrom, E. et al. Gene-Environment Interaction Between the DRB1 Shared Epitope and Smoking Regarding the Risk of Anti-Citrullinated Protein Antibody-Positive Rheumatoid Arthritis. Arthritis & Rheumatism, published online May 28, 2009.

Tags: Europe | General Health | Genetics | Rheumatology

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