Modifying T cell phenotypes using TYK2 inhibitor and its implications for the treatment of systemic lupus erythematosus.

OBJECTIVES: The tuning effects of JAK/TYK2 inhibitors on the imbalance between T follicular helper (Tfh) and T regulatory (Treg) cells, related to systemic lupus erythematosus (SLE) pathogenesis, were investigated using human peripheral blood samples. METHODS: Peripheral blood mononuclear cells from untreated patients with SLE and healthy controls were analysed. Tfh1 cells were identified in nephritis tissue, and the effect of Tfh1 cells on B-cell differentiation was examined by coculturing naïve B cells with Tfh1 cells. RESULTS: Tfh1 cell numbers were increased in the peripheral blood of patients, and activated Treg cell counts were decreased relative to Tfh1 cell counts. This imbalance in the Tfh to Treg ratio was remarkably pronounced in cases of lupus nephritis, especially in types III and IV active nephritis. Immunohistochemistry revealed Tfh1 cell infiltration in lupus nephritis tissues. Co-culture of Tfh1 cells (isolated from healthy individuals) with naïve B cells elicited greater induction of T-bet+ B cells than controls. In JAK/TYK2-dependent STAT phosphorylation assays using memory CD4+ T cells, IL-12-induced STAT1/4 phosphorylation and Tfh1 cell differentiation were inhibited by both JAK and TYK2 inhibitors. However, phosphorylation of STAT5 by IL-2 and induction of Treg cell differentiation by IL-2+TGFß were inhibited by JAK inhibitors but not by TYK2 inhibitors, suggesting that TYK2 does not mediate the IL-2 signalling pathway. CONCLUSIONS: Tfh1 cells can induce T-bet+ B cell production and may contribute to SLE pathogenesis-associated processes. TYK2 inhibitor may fine-tune the immune imbalance by suppressing Tfh1 differentiation and maintaining Treg cell differentiation, thereby preserving IL-2 signalling, unlike other JAK inhibitors.

Biological/targeted synthetic DMARDs do not arrest bone loss in patients with rheumatoid arthritis: a multicenter prospective observational study.

OBJECTIVE: To elucidate the differential effects of biological/target synthesized DMARDs (b/tsDMARDs) on bone metabolism in patients with rheumatoid arthritis (RA) in a real-world cohort. METHODS: This was a multicentre prospective observational study of RA patients enrolled at the time of 1st b/tsDMARDs administration. Bone mineral density (BMD) and bone turnover markers (BTMs) were measured during the 52-week observation. The study was designed to enrol all eligible RA patients. The end-points were differences in changes in BMD according to b/tsDMARD type, and the correlation between BMD and BTMs. RESULTS: A total of 1,164 patients were enrolled in this study. b/tsDMARDs improved RA disease activity from mean CDAI 25.5 at baseline to 4.5 at week 26. Patients not receiving anti-osteoporotic agents (anti-OP) at baseline with no history of fracture experienced a significant decrease in both femoral neck (F: mean 0.666-0.655 g/cm3) and radial (R: 0.518-0.514) BMD at week 26. Despite maintaining low CDAI levels during weeks 26-52 (5.3-4.4), there was a continued decline in BMD (F: 0.653, R: 0.509. Weeks 52). None of b/tsDMARDs type preserved BMD. Conversely, patients receiving anti-OP at baseline maintained stable BMD throughout the study (Weeks 0/26/52. F: 0.551/0.551/0.555, R: 0.415/0.416/0.415). Although BTMs were changed by b/tsDMARDs, the changes were unrelated to those in BMD. CONCLUSION: Our study suggested the progression of osteoporosis in RA patients during b/tsDMARDs treatment without anti-OP. BTMs may not reflect BMD change. Regular monitoring of BMD in RA should be considered for early management of osteoporosis.

TGF-ß3 in differentiation and function of Tph-like cells and its relevance to disease activity in patients with systemic lupus erythematosus.

OBJECTIVES: T peripheral helper (Tph) cells have major roles in pathological processes in SLE. We sought to clarify the mechanisms of Tph cell differentiation and their relevance to clinical features in patients with SLE. METHOD: Phenotypes and functions of Tph cell-related markers in human CD4+ T cells purified from volunteers or patients were analysed using flow cytometry and quantitative PCR. Renal biopsy specimens from patients with LN were probed by multicolour immunofluorescence staining. RESULTS: Among multiple cytokines, transforming growth factor (TGF)-ß3 characteristically induced programmed cell death protein 1 (PD-1)hi musculoaponeurotic fibrosarcoma (MAF)+, IL-21+IL-10+ Tph-like cells with a marked upregulation of related genes including PDCD-1, MAF, SOX4 and CXCL13. The induction of Tph-like cells by TGF-ß3 was suppressed by the neutralization of TGF-ß type II receptor (TGF-ßR2). TGF-ß3-induced Tph-like cells efficiently promoted the differentiation of class-switch memory B cells into plasmocytes, resulting in enhanced antibody production. The proportion of Tph cells in the peripheral blood was significantly increased in patients with SLE than in healthy volunteers in concordance with disease activity and severity of organ manifestations such as LN. TGF-ß3 was strongly expressed on macrophages, which was associated with the accumulation of CD4+ C-X-C chemokine receptor (CXCR5)-PD-1+ Tph cells, in the renal tissue of patients with active LN. CONCLUSION: The induction of Tph-like cells by TGF-ß3 mainly produced from tissue macrophages plays a pivotal role in the pathological processes of active LN by enhancing B-cell differentiation in patients with SLE.

Nailfold microvascular abnormalities are associated with a higher prevalence of pulmonary arterial hypertension in patients with MCTD.

OBJECTIVE: MCTD manifests with microvasculopathy and overlapping clinical features of SLE, SSc and idiopathic inflammatory myopathies (IIM). The aim of this study was to investigate the clinical significance of microvasculopathy in patients with MCTD using nailfold videocapillaroscopy (NVC). METHODS: Fifty patients with newly diagnosed and untreated MCTD were enrolled in this multicentre, prospective and observational study. Clinical features and NVC findings were assessed at baseline and after 1 year post-intervention, along with disease controls [SLE (n = 40), SSc (n = 70) and IIM (n = 50)]. RESULTS: All MCTD patients presented Raynaud's phenomenon and were positive for anti-U1 RNP antibodies, and 22.0% (11/50) had pulmonary arterial hypertension (PAH). The prevalence of NVC scleroderma patterns in MCTD was 38.0%, which was lower than SSc (88.6%) but higher than SLE (10.0%). In addition, when we divided MCTD patients into two groups by presence or absence of NVC scleroderma patterns, we found a higher prevalence of PAH in patients with NVC scleroderma patterns. Namely, NVC scleroderma patterns were observed in all MCTD patients with PAH, and in 21.0% of those without PAH. After intensive immunosuppressive therapy, NVC scleroderma patterns disappeared in half of the MCTD patients but were not changed in SSc patients. CONCLUSIONS: MCTD differed from SLE, SSc and IIM in terms of the prevalence and responsiveness of NVC scleroderma patterns to immunosuppressive therapy. Detection of nailfold microvascular abnormalities in MCTD could contribute to predicting PAH and help us to understand further aspects of the pathogenesis of MCTD.

Enhanced Fatty Acid Synthesis Leads to Subset Imbalance and IFN-γ Overproduction in T Helper 1 Cells.

Recent reports have shown the importance of IFN-γ and T-bet+ B cells in the pathology of SLE, suggesting the involvement of IFN-γ-producing T-bet+ CD4+ cells, i.e., Th1 cells. This study determined the changes in Th1 subsets with metabolic shift and their potential as therapeutic targets in SLE. Compared with healthy donors, patients with SLE had higher numbers of T-bethiCXCR3lo effector cells and T-bet+Foxp3lo non-suppressive cells, which excessively produce IFN-γ, and lower number of non-IFN-γ-producing T-bet+Foxp3hi activated-Treg cells. These changes were considered to be involved in treatment resistance. The differentiation mechanism of Th1 subsets was investigated in vitro using memory CD4+ cells obtained from healthy donors and patients with SLE. In memory CD4+ cells of healthy donors, both rapamycin and 2-deoxy-D-glucose (2DG) suppressed T-bet+Foxp3- cells, and induced T-bet+Foxp3+(lo/hi) cells. Rapamycin induced IFN-γ-producing T-bet+Foxp3lo cells accompanied with enhanced lipid metabolism, whereas 2DG induced IFN-γ-non-producing T-bet+Foxp3hi cells. In memory CD4+ cells of SLE patients, inhibition of fatty acid synthesis, but not ß-oxidation, suppressed IFN-γ production, and up-regulated of Foxp3 expression in T-bet+Foxp3+ cells. Metabolic regulators such as fatty acid synthesis inhibitors may improve the pathological status by correcting Th1 subset imbalance and overproduction of IFN-γ in SLE.