(February 27, 2008 - Insidermedicine) Two new potential susceptibility genes for systemic lupus erythematosus (SLE) have been identified in research published in the New England Journal of Medicine.

Here are some recommendations for diagnosing SLE from the Finnish Medical Society:

•    Be aware that there is no single symptom or finding that is sufficient in itself for making the diagnosis of SLE.

•    When suspecting SLE, basic laboratory investigations should include: blood count, platelets, erythrocyte sedimentation rate, anti-nuclear antibodies, dipstick test of the urine, and urinalysis.

•    Base a diagnosis of SLE on clinical symptoms, laboratory findings, and on the American Rheumatism Association (ARA) classification criteria (1982).

Researchers from Genentech in San Francisco genotyped over 500 000 single nucleotide polymorphisms in the DNA samples of over 1,300 individuals with SLE and nearly 1,800 controls to look for an association between the presence of specific polymorphisms and the presence of SLE. The authors also included in their analysis genotypes from over 1,500 additional controls obtained from public data repositories and confirmed their findings in a Swedish sample of nearly 800 individuals with SLE and over 850 controls.

The investigators found an association between the presence of SLE and polymorphisms in a region upstream of genes encoding for B lymphoid tyrosine kinase (BLK) and chromosome 8p23.1 (C8orf13) as well as on chromosome 16p11.22, near the genes encoding integrin alpha M (ITGAM or CD11b) and integrin alpha X (ITGAX).

Today's research demonstrates how the genes BLK and ITGAM, and possibly other nearby genes, may be involved in the development of SLE and, potentially, other autoimmune disorders. These provide novel targets for research into autoimmune disease.

For Insidermedicine in Depth, I'm Dr. Susan Sharma.