Abstract
Purpose :
The pathogenesis of primary Sjögren’s syndrome (pSS) is associated with abnormal B cell activation, resulting in production of excessive autoantibodies and disorder to the cytokine network. IL-14 (also known as Taxilin) is a cytokine that was shown to enhance B cell proliferation, especially of germinal center B cells. Transgenic mice overexpressing human IL-14 alpha can develop many clinical features of pSS in the same relative time frame as seen in patients. Our purpose was to evaluate IL-14 as a biomarker and its correlation to B cell activating factor (BAFF), a well-established cytokine in pSS through upregulating innate immune activation and chronic autoimmune B cell activation, in patient with non-SS dry eye (NSDE), pSS, diseases and healthy controls (HC).
Methods :
Total of 181 serum samples were collected. Among them, 65 were pSS patients (age 53.15 ± 14.08 years) who meet the 2012 ACR Classification Criteria for Sjögren’s Syndrome, 20 were dry eye patients excluding SS (age 44.85 ± 11.39 years, NSDE), 50 were Rheumatoid Arthritis patients (age 54.95 ± 15.35 years, RA) and 46 were healthy controls (age 43.49 ± 14.57 years, HC). Serum level of IL-14 was evaluated by quantitative Western Blots assay and BAFF level was evaluated by ELISA assay (R&D System). The study protocol was approved by Peking University People's Hospital IRB committee. Statistical analysis was done by software Prism 6.0 with unpaired t tests.
Results :
1. After normalized with internal control, the relative intensity ratio for serum IL-14 level in HC group was 2.13 ± 0.81, NSDE group was 2.11 ± 0.98 (p=0.99), pSS group was 2.92 ± 0.93 (p<0.0001) and RA group was 2.47 ± 0.95 (p=0.15). Serum BAFF level (pg/ml) in HC group was 323.56 ± 65.85, DE group was 355.21 ± 87.86 (p=0.22), pSS group was 455.94 ± 155.16 (p<0.0001) and RA group was 448.38 ± 220.07 (p=0.0002)
2. In pSS patients, the serum level of IL-14 decrease as age increase (<40 years, 3.48 ± 0.88, 40-60 years, 2.83 ± 0.98, (p=0.048) and >60 years, 2.76 ± 0.81, (p=.023)). Whereas the serum level of BAFF (pg/ml) increase as age increases (<40 years, 414.22±119.94, 40-60years, 406.22±148.29, (p=0.87), >60 years, 524.57±159.46, (p=0.008)).
Conclusions :
1. Elevation of serum IL-14 level can serve as a key cytokine biomarker for the stratification of SS vs NSDE.
2. IL-14 and BAFF may work in different fashions to maintain the abnormal B cell activation as seen is pSS patients.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.