番茄社区

SAN DIEGO -- A broader range of autoantibodies may play a role in Sjogren's syndrome than has previously been appreciated, researchers found.

Among 137 patients with primary Sjogren's syndrome, as defined clinically by dry eye disease and positive lip biopsy, 74% had the typical anti-SSA and/or anti-SSB antibodies, while 6% had anti-centromere antibodies and 5% had anti-cyclic citrullinated peptide (CCP) antibodies, , of Johns Hopkins University reported in a poster session here at the annual meeting of the American College of Rheumatology.

Over the past 20 years, Sjogren's syndrome has increasingly been recognized as an autoimmune disease, with the presence of autoantibodies and focal lymphocytic sialadenitis as evidence of an underling autoimmune process.

Currently, the require at least two of these three criteria:

• Positive serum anti-SSA and/or anti-SSB, or rheumatoid factor and an antinuclear antibody titer of 1:320 or higher
• Labial salivary gland biopsy exhibiting focal lymphocytic sialadenitis with a focus score of 1 focus/4 mm²
• Keratoconjunctivitis sicca (dry eyes) with ocular staining score of 3 or higher

These criteria demonstrate how important anti-SSA and anti-SSB -- so named because of their classic association with Sjogren's syndrome -- have been in diagnosis of the disease.

However, these antibodies alone do not account for all cases of Sjogren's syndrome, and the presence of anti-CCP and anti-centromere autoantibodies may account for some cases of primary Sjogren's syndrome in patients seronegative for anti-SSA and anti-SSB.

The presence of additional antibodies such as anti-CCP and anti-centromere may also define a group of Sjogren's patients with overlap features of additional autoimmune conditions who do not meet the full criteria for these other diseases.

Anti-CCP has been recognized for its association with rheumatoid arthritis, and anti-centromere autoantibodies have traditionally been seen in patients with limited scleroderma, which is characterized by calcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly, and telangiectasia.

"Patients who have anti-centromere antibodies in the context of Sjogren's have a limited scleroderma phenotype," Baer told 番茄社区 at his poster presentation.

"They often have Raynaud's phenomenon, they may have nailfold capillary telangiectasia, and they may have profound dryness. And patients with anti-CCP antibodies, not surprisingly, often have joint pain and swelling, but may not develop an erosive arthritis," he explained.

Of the the eight patients who were seronegative for anti-SSA/SSB but positive for anti-centromere antibodies, three had clinical evidence of systemic scleroderma, indicating the importance of antibodies other than anti-SSA and anti-SSB in this subpopulation of patients with both sicca and scleroderma symptoms.

Exploring alternative autoantibodies associated with Sjogren's syndrome and refining the standards by which lip biopsies are interpreted will improve the ability of physicians to identify and define this condition, Baer observed.

"I think when we start to be more exacting in how lip biopsies are read and defining other markers for the underlying autoimmune disease, the phenotype of Sjogren's syndrome may not prove to be as heterogeneous as it is at present," he said.