Hideo Yagita and hybridoma to PD L1 from Dr. Miyuki Azuma. Figure 1 PD 1 is crucial for tolerance small molecule library induced by apoptotic cells. TNP apoptotic cells have been injected intravenously into PD 1 hetero or homo deficient mice. The mice have been immunized with TNP or preconditioned with apoptotic cells prior to immunization with TNP.

Page 35 of 54 P35 Lowered plating efficiency, proliferation and osteogenic differentiation of synovial fluid mesenchymal progenitors as being a marker of severity of juvenile idiopathic arthritis Elvira Lazic Mosler1, Marija Jelusic Drazic2, Danka Grcevic1,3, Ana Marusic4, Natasa Kovacic1,5 1Laboratory for Molecular Immunology, University of Zagreb School of Medicine, Zagreb HR 10000, Croatia, wnt signaling pathway 2Department of Pediatrics, Division of Pediatric Rheumatology and Immunology, University Hospital Centre Zagreb, Zagreb HR 10000, Croatia, 3Department of Physiology and Immunology, University of Zagreb School of Medication, Zagreb HR 10000, Croatia, 4Department of Research in Biomedicine and Wellness, University of Split School of Medicine, Split HR 21000, Croatia, 5Department of Anatomy, University of Zagreb College of Medication, Zagreb HR 10000, Croatia Arthritis Analysis & Therapy 2012, 14 35 Background: Juvenile idiopathic arthritis is a rheumatic pediatric disease characterized by synovial inflammation in one or more joints. Inflammation results in hyperplastic changes of the synovium, destruction of articular cartilage and subchondral osteoresorption. Murine models of arthritis revealed impaired osteogenic/chondrogenic differentiation of synovial mesenchymal progenitors via inflammation induced activation of NF B.

We aimed to explore frequency, plating effectiveness and osteoblastogenic potential of synovial mesenchymal progenitors and correlate them with intensity of local and systemic inflammation in patients with JIA. Materials and methods: Synovial fluid cells were collected from 19 patients Eumycetoma with oligoarticular JIA and 8 patients with poliarticular JIA, plated in density 1. 5 ? 106/mL in 24 well plates, and cultured in aMEM 10% FCS. Osteoblastogenesis was stimulated by the addition of 50 ug/ml ascorbic acid and 5 mmol b glycerophosphate. To exclude inflammatory and hematopoietic cells, adherent cells had been passaged three times, and osteoblastogenesis again induced in fourth passage. Osteoblastogenesis was assessed by intensity of alkaline phospatase histochemical staining.

In addition, osteoblast Topoisomerase 2 and cytokine/chemokine gene expression had been assessed in P4 osteoblastogenic cultures. Results: Plating performance of synovial mesenchymal progenitors was reduced in patients with pJIA in comparison to patients with oJIA. Passage was successful only in 3 pJIA patients, and 18 oJIA patients. Plated at equal density, P4 synovial adherent cells from pJIA patients formed less fibroblastic colonies. Osteoblastogenesis was higher in children with oJIA than in children with pJIA, both from primary synovial cells, and P4 cells. Osteoblastogenesis from primary synoviocytes negatively correlated with erythrocyte sedimentation rate, and synovial concentration of IL 17. Expression of osteoprotegerin and CCL2 was decreased in P4 osteoblastogenic cultures from pJIA in comparison with oJIA patients.