OBJECTIVETo evaluate the sensitivity and specificity of international classification criteria (2002) for primary Sjögren's syndrome (pSS) and the role of lower lip biopsy in diagnosis of pSS in Chinese patients.

METHODSPatients who were diagnosed by the experts/rheumatologists as pSS during 1990-2002 from the Department of Rheumatology, Peking Union Medical College Hospital were retrospectively collected as experimental group. Patients who were diagnosed as non-pSS connective tissue diseases or non-connective tissue diseases served as control group. Those with a history of head-neck radiation, hepatitis C virus infection, AIDS, lymphoma, sarcoidosis, graft versus host disease (GVHD), and anti-acetylcholine drug use were exempted. Both groups were required to complete questionnaires about symptoms such as dry eyes and dry mouth, and complete the objective tests of keratoconjunctivitis and xerostomia including Schirmer test, corneal staining, unstimulated salivary flow, sialography, lower lip biopsy, and antinuclear antibodies (including anti-SSA/SSB antibodies) test.

RESULTSA total of 330 pSS patients were included in experimental group and 185 non-pSS patients in control group. The mean age of both groups matched (47.8 +/- 10.9 years vs. 46.2 +/- 13.6 years, P > 0.05). The sensitivities of the criteria in pSS patients with lower lip biopsy and in pSS patients without lower lip biopsy were 89.2% and 87.2%, respectively; the overall sensitivity was 88.5%. The specificity was 97.3%. A total of 11.3% pSS patients with negative anti-SSA/SSB anti- bodies were diagnosed as pSS by lower lip biopsy.

CONCLUSIONThe international classification criteria (2002) for pSS is feasible in Chinese patients. It has high sensitivity and specificity, and may serve as diagnosis criteria in routine clinical practice.