Background
Discussion
The case for using synovial biopsy in drug development
Synovial biopsy technique and safety – new approach on board
Obtaining high quality tissue and potential pitfalls
Synovial tissue analysis in trials – which method is the best?
Histological analysis and immunohistochemistry (IHC)
Western blot and mass spectrometry
In situ hybridization
Single/multiple gene analysis and transcriptome profiling
Transcriptome interpretation
What have we learned from histopathological analysis of synovial biopsies in clinical trials?
Drug | Timing of biopsies | Key finding | Reference |
---|---|---|---|
DMARDs/anti-TNF/experimental | 2–16 weeks | Number of CD68+ macrophages in sublining synovial layer is a good biomarker of therapeutic response. | |
Methotrexate | 16 weeks | Decrease in the numbers of inflammatory cells, including CD3+ and CD8+ T cells, CD38+ plasma cells, CD68+ macrophages (lining layer), inflammatory and destructive mediators (Ki67, IL-1β, TNF-α, E-selectin, ICAM-1, VCAM-1, MMP-1). Responders displayed a reduction in the expression of all ICAM-1, VCAM-1, TNF-α and IL-1 β. | |
Methotrexate | 12 weeks | No change in synovial hyperplasia, lymphoplasmocytic infiltrate, CD68+ macrophages, CD3+ T cells and CD138+ plasma cells | [50] |
Leflunomide | 16 weeks | Decrease in the numbers CD68+ macrophages (sublining), inflammatory and destructive mediators (ICAM-1, VCAM-1, MMP-1). Responders displayed a reduction in the expression of ICAM-1, VCAM-1 and TNF-α. | [81] |
Prednisolone | 24 h | Decrease in the expression of TNF-α (lining and sublining), IL-8 (lining), as well as reduced synovial fluid IL-8 levels. Change in TNF-α correlated with clinical response to, and subsequent relapse after therapy | [82] |
Prednisolone | 2 weeks | Reduction in the number of sublining synovial macrophages, a trend toward decreased infiltration by CD4+ T cells, CD38+ plasma cells, and CD55+ fibroblast-like synoviocytes | [76] |
Infliximab (3 mg/kg) | 48 h/4 weeks | Reduced number of CD68+ intimal macrophages after 48 h, a trend to decreased amount of CD38+ plasma cells, CD3+ T cells, sublining CD68+ macrophages after 48 h/4 weeks. Decreased numbers of CD3+, CD38+ and both intinal and sublining CD68+ cells were observed in clinical responders after 4 weeks. | [23] |
Infliximab (10 mg/kg) | 2 weeks | Reduction in the numbers of infiltrating synovial CD3+ T cells, CD22+ B cells, CD68+ macrophages and in the expression of IL-8, MCP-1 and TNF-α. High levels of synovial TNF-α prior to treatment may predict responsiveness to therapy. | |
Rituximab | 4 weeks | Incomplete depletion of CD22+ B cells, no correlation with the change in DAS28. | [62] |
Rituximab | 4 weeks 16 weeks | CD19+ B cells significantly but incompletely decreased at 4 weeks, with further reduction at 16 weeks in some patients. Decrease in CD68+ macrophages at 4 and 16 weeks, CD3+ T cells decreased at 16 weeks. The reduction of CD138+ plasma cells predicted clinical improvement at 24 weeks. | [64] |
Rituximab | 12 weeks | Depletion of CD20+ B cells, trend to decrease in CD68+ macrophages. No correlations between changes in CD20+ or CD68+ and changes in the DAS28. Positivity for circulating IgM ACPA, in combination with a high infiltration of CD79a + B cells is a predictor of clinical outcome after rituximab. | |
Tocilizumab | 12 weeks | Decrease in synovial hyperplasia, lymphoplasmocytic infiltrate, CD68+ macrophages, CD3+ T cells and CD138+ plasma cells | [50] |
Anakinra + pegsunercept | 4 weeks 52 weeks | Decrease in number of CD3+ T cells and TGFβ expression as biomarker therapeutic response at weeks 4 and 52 of combination therapy. Baseline CD3+ and sublining CD68+ infiltration, VEGF and TGFβ expression were predictive of subsequent structural outcome at 6 or 12 months. | [19] |
CCR1 antagonist | 2 weeks | Reduction in overall cellularity, number of CD4+ and CD8+ T cells, CD68+ macrophages and the number of CCR1+ cells. | [22] |
RecIL-10 | 12 weeks | No significant change in number of inflammatory cells or in the scores for the expression of cytokines. | [85] |
IL-1 receptor antagonist | 24 weeks | Reduction in intimal and sublining CD68+ macrophages and CD3+ lymphocytes. | [86] |
Anti-CCL2 antibody | 6 weeks | No immunohistologic changes. | [66] |
C5aR-antagonis | 4 weeks | No immunohistologic changes. | [67] |
IFN-β (18/36/54 million IU/week) | 4 weeks 12 weeks | Decrease in number of CD3+ T cells at 4 weeks and CD38+ plasma cells at 12 weeks along with changes of several inflammatory and destructive molecules (e.g. MMP-1, IL-6 or IL-1β). | [87] |
IFN-β (6.6/132 μg/week) | 24 weeks | No changes in synovial tissue infiltrates. | [68] |
Synovial transcriptome: a new biomarker?
Drug | Timing of biopsies | Key finding | Reference |
---|---|---|---|
Infliximab | Baseline | Differential baseline gene expression in responders and non-responders. Overexpression of genes involved in T-cell mediated immunity, cell surface receptor mediated signal transduction, major histocompatibility complex II (MHCII)-mediated immunity, cell adhesion, cytokine and chemokine mediated signalling, cell adhesion mediated signalling, signal transduction, and macrophage-mediated immunity identified in responders. | [88] |
Infliximab | 9 weeks | Unique baseline transcriptome in all patients. 279 differentially expressed genes between good responders and non-responders. Significant change in expression of 115 genes in the good responding group involved in immune response, cell communication, signal transduction and chemotaxis. | [56] |
Adalimumab | 12 weeks | Deregulated baseline expression of 439 genes involved in cell cycle and immune responses in good vs. poor responders. Differential expression of 632 genes enrolled in cell division, signal transduction, antigen processing/presentation, T-cell activation, and apoptosis upon adalimumab treatment in a group of good responders. | [73] |
Rituximab | 12 weeks | Deregulated baseline expression of 2458 genes involved in immunoglobulin clusters, antigen processing and presentation via MHCII in non-responders vs. responders. Treatment with rituximab resulted in downregulation of 220 genes enriched in immunoglobulin clusters, chemotaxis, leukocyte activation and immune responses; upregulation of 329 genes involved in cell development and wound healing. | [51] |
Rituximab | 12 weeks 21 months | Baseline differential expression of genes involved in T cell and macrophage function, remodelling and interferon-α biology between non-responders vs. responders at months 3, 9 and 21. Downregulation of CD20 at 3 and 12 months, differential expression of multiple genes involved in B and T cell biology at 21 months (e.g. CD27, CD38, CD8, CD52, CTLA4, CD122, FOXP3, IL-6, IL-12, IL-13, IL-17RA, IL-23a, IL-32, CCL5, MMP3, FASLG) | [89] |
Tocilizumab | 12 weeks | Downregulation of 3413 genes involved in cytokine/chemokine pathways and T cell activation, upregulation of 3270 genes involved in healing process. Downregulation of genes involved in induction of apoptosis and myeloid cell differentiation, and upregulation of genes involved in regulation of Ras protein signal transduction and ubiquitin-dependent protein catabolic processes observed in responders achieving remission at 6 months. | [50] |
Methotrexate | 12 weeks | Downregulation of 586 genes enriched in T cell activation and immune response pathways, upregulation of 610 genes. Downregulation of genes enrolled in cell division in responders achieving remission at 6 months. | [50] |