Diagnostic Potential of Tear Proteomic Patterns in Sjo¨gren’s Syndrome Naohisa Tomosugi,*,† Kazuko Kitagawa,‡ Nobuo Takahashi,‡ Susumu Sugai,§ and Isao Ishikawa† Division of Nephrology, Department of Internal Medicine, Department of Ophthalmology, Division of Hematology and Immunology, Department of Internal Medicine, Knanazawa Medical University, 920-0265 Ishikawa, Japan Received December 20, 2004
Histological and functional changes of the lacrimal gland might be reflected in proteomic patterns in tear fluids. In this study, we carried out a determination of the disease biomarkers in tear fluid for Sjo¨ gren’s syndrome (SS) and a performance of noninvasive diagnostic test based on the proteomic patterns. Thirty-one SS patients and 57 control subjects were enrolled to this study. Their details were 23 cases with primary SS, 8 with secondary SS, 14 with dry eyes, 22 with miscellaneous ocular diseases, and 21 of healthy volunteers. Protein profiling in tear fluids was identified by surface enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS). Multiple protein changes were reproducibly detected in the primary SS group, including 10 potential novel biomarkers. Seven of the biomarkers (2094, 2743, 14191, 14702, 16429, 17453, 17792 m/z) were down-regulated and 3 biomarkers (3483, 4972, 10860 m/z) were up-regulated in primary SS group, comparing to the protein profiles of control subjects. When cutoff value of SS down-score was set less than 0.5, this result yielded 87% sensitivity and 100% specificity. The positive predictive value for this sample set was 100%. There was a significant inverse correlation between SS down-scores and epithelial damages of the ocular surface in primary SS patients. These findings support the potential of proteomic pattern technology in tear fluids as the noninvasive diagnostic test for primary SS. Keywords: Sjo¨ gren’s syndrome • SELDI-TOF-MS • biomarker • noninvasive diagnostic test
Introduction Sjo¨gren’s syndrome(SS) is a chronic autoimmune-mediated inflammatory disease characterized by progressive lymphocytic and plasmacytic infiltration in exocrine glands, especially the lacrimal, parotid, and salivary glands, resulting in glandular destruction and a consequent decline in glandular function.1-3 These immune responses can also affect exocrine organs, including the kidney, lung, liver, gastrointestinal tract, nervous system, and small vessels.4 Diagnostic criteria for primary SS (p-SS) include dry eye and/ or dry mouth, focal lymphocyte infiltration in exocrine glands, the presence of autoantibodies against the nuclear factors SSA/Ro(anti-SSA antibody) and SS-B/La(anti-SSB antibody) and destruction of the lining epithelial cells of the ocular surface estimated by rose bengal score.5-8 By these criteria, p-SS is often diagnosed in its late stages when focal lymphocytic infiltration * To whom correspondence should be addressed. Tel: (076) 286-2211. Fax: (076) 286-2786. E-mail:
[email protected]. † Division of Nephrology, Department of Internal Medicine, Knanazawa Medical University. ‡ Department of Ophthalmology, Knanazawa Medical University. § Division of Hematology and Immunology, Department of Internal Medicine, Knanazawa Medical University.
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Journal of Proteome Research 2005, 4, 820-825
Published on Web 04/02/2005
and glandular destruction has already occurred.9,10 Especially in lacrimal gland, it is not easy to obtain the tissue samples exhibiting an ongoing disease process by biopsy. For these reasons, the initial and early event in the pathogenesis of p-SS and the precise mechanism responsible for the decreased secretion of tear fluids in p-SS remain unknown.11 The development of an accurate and noninvasive diagnostic test that also provides insights into the mechanisms of p-SS would be of considerable value. The tear film alterations responsible for the development of p-SS have been induced by not only tear quantity but also tear quality. A reduced production of aqueous tear was clarified when examined by the Schirmer test. Reduction of tear film stability as shown by the tear film break-up time test seems to be responsible for a disturbance of the quality of the mucus layer composition. However, there was no screening test for the changes in quality of tear components, which should accurately reflect the physiologic state of lacrimal gland and the level of its function. Here we used a new technology; surface enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDITOF-MS), to detect distinctive tear proteomic patterns for p-SS. SELDI-based ProteinChip Array technology has been 10.1021/pr0497576 CCC: $30.25
2005 American Chemical Society
research articles
Tear Proteomic Patterns in Sjo1 gren’s Syndrome Table 1. Clinical Characteristics of the Study Populationa,b,c characteristic
age, y women, %d Schirmer test, mm Rose Bengal, score anti-SSA, IU/mL anti-SSB, IU/mL
p-SS (n ) 23)
58.2 (11.9) 23 (100) 6.7 (3.5) 5.4 (2.2) 101.2 (54.4) 46.2 (74.8)
s-SS (n ) 8)
(9.6)f
60.6 8 (100)f 9.6 (4.9)f 6.0 (3.0)f 73.2 (60.9)f 76.8 (80.2)f
dry eye (n ) 14)
(14.8)f
52.4 12 (85.7)f 14.5 (10.0)e 1.5 (2.1)e negative negative
miscellaneous (n ) 22)
(17.2)f
52.1 19 (86.4)f 14.0 (9.4)e nd nd nd
volunteer (n ) 21)
53.3 (12.1)f 18 (85.7)f 16.5 (6.5)e nd nd nd
a Abreviations: p-SS, primary Sjo¨gren’s syndrome; s-SS, secondary Sjo¨gren’s syndrome; nd, not done; ns, not significant. b Data are median(sd) unless otherwise indicated. c P-SS was compared with other groups by nonparametric Steel’s method unless otherwise indicated. d Data were analyzed by Fisher’s exact test. e
