Case report
Figure 5 Tfh cell phenotype in the peripheral blood and synovial fluid. Gating strategy followed for the identification of CD4 T cells (A). Expression of T cell memory marker CD45RO and PD-1 as well as distribution of the chemokine receptors CCR6 and CXCR3 in peripheral blood and synovial fluid CD4 T cells (B). Identification of peripheral blood and synovial fluid Tfh cells based on expression of CXCR5 and subsequent characterisation of ICOS, PD-1, CCR6 and CXCR3 expression pretofacitinib (C). Tfh cell, T follicular helper cell.
(0.1%) compared with periphery (3.5%), with predominance of potentially pathogenic PD-1 expressing memory B cells (34.5% vs 0.35%) in the synovial fluid (figure 6A,B). The frequency of key proinflammatory cytokine-producing synovial tissue CD4+ T cells decreased following tofacitinib treatment (figure 3A). Thus, immune cell analysis of pretofacitinib synovial tissue and fluid suggests that pembrolizumab induces inflammatory phenotypes that are known to significantly contribute to synovial pathogenesis. SPICE analysis of pretofacitinib synovial tissue showed marked CD4+ T cell polyfunctionality with 34.2% of cells expressing three or more proinflammatory cytokines simultaneously (figure 3B). Post-tofacitinib synovial biopsy analysis demon- strated a marked decrease in the frequency of polyfunctional CD4+ T cells (34.2% vs 19.7%, figure 3C), with specific reduc- tions in Th1 and Th17 associated proinflammatory cytokines transcription factor FOXP3, CD25 was also used to verify gating of Treg cells. In the synovial tissue due to loss of CD25 during the enzymatic digestion of synovial biopsies Treg cells were defined as CD4+CD127 CD39±FOXP3+ (B). Treg cells can be divided into naive and memory Treg subpopulations, note the absence of naive Treg in the SFMC and synovial tissue compared with peripheral blood (C). Data shown from paired PBMC,SFMC and synovial biopsies collected pretofacitinib. PBMC, peripheral blood mononuclear cell; SFMC, synovial fluid mononuclear cell; Treg cells, T regulatory cells. Figure 4 Gating strategy to identify cytokine expressing CD4 T cells and regulatory T cells. Gating strategy followed for the identification of CD4 T cells for the subsequent analysis of proinflammatory cytokine profile (A). Example for the identification of regulatory T cells. in PBMC and SFMC, in addition to expression of the Treg-specific
Figure 6 Phenotype of peripheral blood and synovial fluid B cells at first arthroscopy. Frequency of B cells in PBMC, SFMCs and single synovial biopsy tissue cells (A). while the percentage of synovial fluid B cells is a fraction of the peripheral blood B cell population, the vast majority of synovial fluid B cells belong to the switched memory B cell compartment (CD27+IgD–). Interestingly, synovial fluid B cells had marked expression of PD-1 and the chemokine receptor CXCR3 compared with peripheral blood B cells. data shown are from paired PBMC and SFMC pretofacitinib (B). SFMC, synovial fluid mononuclear cells; PBMCs, peripheral blood mononuclear cells.
interferon- γ (IFN- γ , 40.2% vs 33.8%), IL-17A (3% vs 1.4%) and IL-22 (14% vs 1.4%, figure 3D).
TREATMENT Maintenance treatment now includes Tofacitinib 5 mg twice daily, Methotrexate 10 mg and Folic acid 5 mg weekly. All other medication, including ICI and steroids, has been stopped. OUTCOME AND FOLLOW-UP The patient remains in complete, sustained arthritis remission after 24 months, and complete remission of lung adenocarci- noma 28 months since diagnosis. The patient had complete tumour response before and after tofacitinib. The patient remains in full remission from arthritis and cancer, 75 weeks after commencing tofacitinib.
Murray K, et al . BMJ Case Rep 2021; 14 :e238851. doi:10.1136/bcr-2020-238851
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