The new classification criteria of SS require that a patient have at least two of the following objective features:
- Positive serum anti-SSA and/or anti-SSB or positive rheumatoid factor plus antinuclear antibodies ≥1:320;
- Ocular staining score ≥3; and
- Labial salivary gland biopsy exhibiting focal lymphocytic sialadenitis with a focus score ≥1 foci/4 mm2.
Implications for Clinical Practice
Although the classification criteria for SS are straightforward and objective, using these criteria may be challenging, Dr. Criswell says. One of the challenges will be the need for earlier collaboration and interaction with other specialists, including ophthalmologists and oral medicine specialists, for classification. These specialists are also necessary for the ongoing management of SS patients. “While a rheumatologist might have felt comfortable doing a Schirmer’s test to measure dry eyes, a rheumatologist typically would not be using a slit lamp, which is required for ocular staining and assessment.” The need for this extra assessment “could be seen as a disadvantage, but we feel it is a tremendous service to the patient, given that ocular manifestations can have devastating complications,” she says.
Also, an oral medicine specialist will need to perform the labial salivary gland biopsy. Without that biopsy and assessment, an opportunity will be missed to document and quantify the autoinflammatory component of the disease and to begin treating the patient for the progressive effects of hyposalivation, Dr. Criswell says. A subset of patients with SS is at greater risk for developing lymphoma than patients with other autoimmune diseases. The biopsy can identify early lymphoma or a patient at high risk for the disease.
Some patients with SS do not complain of dry eyes or dry mouth, even though both symptoms have been considered hallmarks of the disease. Ocular staining or a biopsy of the salivary gland tissue can provide clear evidence of SS. “A syndrome of dry eyes and dry mouth can have many causes,” Dr. Criswell says. “We want these new criteria to identify those individuals who have an autoimmune basis for those symptoms. This arms clinicians and researchers with a new tool to identify and target individuals who have dry eye and dry mouth as part of an autoimmune disease.”
These criteria formally say that if you have rheumatoid serology, you are much less likely to have PMR. None of the other criteria out there for polymyalgia, diagnostic or otherwise, have addressed that. That is very important.
—Eric L. Matteson, MD