Table 1 Final set of items for both clinical practice and translational research
| Clinical practice | Translational research |
|---|---|
|
1. Biopsy sampling - A minimum of four synovial biopsies needs to be retrieved in small joints. - Biopsies shall be retrieved in different areas of the joint, if possible. - If it is clinically relevant, bacteriological, fungal and mycobacteriological assessment should be performed. - Polymerase chain reaction analysis for RNA 16S should be performed if clinically relevant, especially if empiric antibiotic course has been started. - If it is clinically relevant, polymerase chain reaction analysis for Lyme and Whipple diseases should be performed. 2. Biopsy processing - The biopsies should spend 24 h in formalin 4%. - At least two biopsies should be formalin-fixed and paraffin-embedded. 3. Histological criteria - Synovial biopsy surface should be more than 2.5 mm2. - A lining layer should be seen. - Morphology of the synovial tissue should be preserved. 4. Staining and immunohistochemistry (IHC) - H&E staining should always be performed. - CD68 staining should be performed. - In particular clinically relevant cases, additional staining should be performed (CD3, CD20, CD138, CD31 or FVIII). - If performed, IHC results can be given using a semi-quantitative score. 5. Biopsies interpretation and pathologist’s report - A synovitis score should be performed, analysing: lining layer hyperplasia, inflammatory infiltrate and resident cell activation (Krenn, other). - Synovial pathotype should be described. - Presence or absence of lymphoid follicles within the membrane should be described. - Analysis can be semi-quantitative or quantitative depending on the question. - If a semi-quantitative or quantitative analysis is performed for multiple biopsies, an average score should be calculated and given for the analysis of inflammation and vascularisation. - The pathologist should mention the presence of granulomas |
1. Biopsy sampling - A minimum of six synovial biopsies needs to be retrieved in large joints. - A minimum of four synovial biopsies needs to be retrieved in small joints - Biopsies shall be retrieved in different areas of the joint, if possible. 2. Biopsy processing - The biopsies should spend 24 h in formalin 4%*. 3. Histological criteria - Synovial biopsy surface should be more than 2.5 mm2. - A lining layer should be seen. - Morphology of the synovial tissue should be preserved. 4. Staining and IHC - H&E staining should always be performed. - CD68 staining should be performed. - CD3, CD19 or CD20 staining should be performed. - Additional CD 31 or FVIII, CD4, CD8, CD138 staining might be performed depending on the question. 5. Biopsies interpretation and Pathologist’s report - A synovitis score should be performed, analysing: lining layer hyperplasia, inflammatory infiltrate and resident cell activation (Krenn, other). - Lining layer hyperplasia should be scored. - Synovial pathotype should be described. - Presence or absence of lymphoid follicles within the membrane should be described. - Analysis can be semi-quantitative or quantitative depending on the question. - If a semi-quantitative or quantitative analysis is performed for a single biopsy: at least three areas of the biopsy should be assessed. 6. RNA analysis - Biopsies of one patient can be pooled for RNA extraction if needed. |