title: Lymphotoxin-beta receptor blockade reduces CXCL13 in lacrimal glands and improves corneal integrity in the NOD model of Sjögren's syndrome.
abstract: BACKGROUND
  In Sjögren's syndrome, keratoconjunctivitis sicca (dry eye) is associated with infiltration of lacrimal glands by leukocytes and consequent losses of tear-fluid production and the integrity of the ocular surface. We investigated the effect of blockade of the lymphotoxin-beta receptor (LTBR) pathway on lacrimal-gland pathology in the NOD mouse model of Sjögren's syndrome.
  
  
  METHODS
  Male NOD mice were treated for up to ten weeks with an antagonist, LTBR-Ig, or control mouse antibody MOPC-21. Extra-orbital lacrimal glands were analyzed by immunohistochemistry for high endothelial venules (HEV), by Affymetrix gene-array analysis and real-time PCR for differential gene expression, and by ELISA for CXCL13 protein. Leukocytes from lacrimal glands were analyzed by flow-cytometry. Tear-fluid secretion-rates were measured and the integrity of the ocular surface was scored using slit-lamp microscopy and fluorescein isothiocyanate (FITC) staining. The chemokine CXCL13 was measured by ELISA in sera from Sjögren's syndrome patients (n = 27) and healthy controls (n = 30). Statistical analysis was by the two-tailed, unpaired T-test, or the Mann-Whitney-test for ocular integrity scores.
  
  
  RESULTS
  LTBR blockade for eight weeks reduced B-cell accumulation (approximately 5-fold), eliminated HEV in lacrimal glands, and reduced the entry rate of lymphocytes into lacrimal glands. Affymetrix-chip analysis revealed numerous changes in mRNA expression due to LTBR blockade, including reduction of homeostatic chemokine expression. The reduction of CXCL13, CCL21, CCL19 mRNA and the HEV-associated gene GLYCAM-1 was confirmed by PCR analysis. CXCL13 protein increased with disease progression in lacrimal-gland homogenates, but after LTBR blockade for 8 weeks, CXCL13 was reduced approximately 6-fold to 8.4 pg/mg (+/- 2.7) from 51 pg/mg (+/-5.3) in lacrimal glands of 16 week old control mice. Mice given LTBR blockade exhibited an approximately two-fold greater tear-fluid secretion than control mice (P = 0.001), and had a significantly improved ocular surface integrity score (P = 0.005). The mean CXCL13 concentration in sera from Sjögren's patients (n = 27) was 170 pg/ml, compared to 92.0 pg/ml for sera from (n = 30) healthy controls (P = 0.01).
  
  
  CONCLUSIONS
  Blockade of LTBR pathways may have therapeutic potential for treatment of Sjögren's syndrome.
authors: Immunology Research Department, Department of Veterans Affairs Medical Center, 215 North Main Street, White River Junction, VT 05009, USA. roy.a.fava@dartmouth.edu
authors: Roy A
authors: RA
authors: Fava
authors: Susan M
authors: SM
authors: Kennedy
authors: Sheryl G
authors: SG
authors: Wood
authors: Anne I
authors: AI
authors: Bolstad
authors: Jadwiga
authors: J
authors: Bienkowska
authors: Adrian
authors: A
authors: Papandile
authors: John A
authors: JA
authors: Kelly
authors: Clio P
authors: CP
authors: Mavragani
authors: Margaret
authors: M
authors: Gatumu
authors: Kathrine
authors: K
authors: Skarstein
authors: Jeffrey L
authors: JL
authors: Browning
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000494:pharmacology; D054382:Chemokine CXCL13 / Q000235:genetics / Q000378:metabolism*; D003315:Cornea / Q000187:drug effects / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D020869:Gene Expression Profiling; D006801:Humans; D007150:Immunohistochemistry; D007638:Keratoconjunctivitis Sicca / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism; D007765:Lacrimal Apparatus / Q000187:drug effects / Q000378:metabolism*; D053259:Lymphotoxin beta Receptor / Q000037:antagonists & inhibitors / Q000276:immunology / Q000378:metabolism*; D008297:Male; D051379:Mice; D016688:Mice, Inbred NOD; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D009077:Mucins / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012859:Sjogren's Syndrome / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism*; D013666:Tears / Q000378:metabolism; D014699:Venules / Q000378:metabolism / Q000502:physiology
chemical_list: D000911:Antibodies, Monoclonal; D054382:Chemokine CXCL13; D053259:Lymphotoxin beta Receptor; D009077:Mucins; C075185:sulfated glycoprotein p50