Keio University · Medicine
Professor Mitsuhiro Akiyama's research lab focuses on the immunological mechanisms underlying autoimmune and fibrotic diseases, with a central emphasis on the role of T follicular helper (Tfh) cell subsets—particularly Tfh2 cells—in the pathogenesis of IgG4-related disease (IgG4-RD). The lab investigates how specific Tfh subsets drive IgG4 class-switching, plasma cell differentiation, and chronic inflammation, while also exploring the impact of immune checkpoint molecules such as OX40 and TIGIT on disease activity. Their work integrates clinical immunology with translational research to identify novel therapeutic targets for autoimmune and vasculitic disorders.
Figures are computed from collected data and may differ slightly.
The Tfh2 cell count was specifically increased in IgG4-related disease and was correlated with elevated serum levels of IgG4 and IL-4 and plasmablast counts. Tfh2 cells were the only component that was not affected by glucocorticoid treatment, suggesting that Tfh2 cells are the cell type implicated in IgG4-related disease.
Tfh2 cells, but not Tfh1 or Tfh17 cells, induce the differentiation of naïve B cells into plasmablasts and enhanced production of IgG4 in patients with active, untreated IgG4-RD. Furthermore, activated Tfh2 cells reflect disease activity, suggesting the involvement of this T cell subset in the pathogenesis of IgG4-RD. Interestingly, the number of activated Tfh1 cells was also increased in IgG4-RD, correlating with disease activity but not with serum IgG4 level, suggesting the involvement of Tfh1
IgG4-related disease (IgG4-RD) is a recently recognized disease entity characterized by high serum IgG4 concentrations and infiltration of IgG4+ plasma cells with hyperplastic ectopic germinal centres at affected sites. Although the underlying immune mechanism of this disease remains unclear, T cells are abundantly present at affected sites and key players in IgG4-RD pathogenesis. The role of T cell subsets has been investigated thoroughly in this disease. Recent advances in this field have clar
Autoimmune diseases can afflict every organ system, including blood vessels that are critically important for host survival. The most frequent autoimmune vasculitis is giant cell arteritis (GCA), which causes aggressive wall inflammation in medium and large arteries and results in vaso-occlusive wall remodeling. GCA shares with other autoimmune diseases that it occurs in genetically predisposed individuals, that females are at higher risk, and that environmental triggers are suspected to beget t
<b>Objective:</b> Granulomatosis with polyangiitis (GPA) is a multi-organ vasculitic syndrome typically associated with neutrophil extracellular trap (NET) formation and aggressive tissue inflammation. Manifestations in head and neck (H&N) GPA include septal perforations, saddle-nose deformities, bony erosions of the orbital and sinus walls, middle ear damage and epiglottitis, indicative of bone, cartilage, and connective tissue destruction. Whether H&N-centric lesions engage disease pathways di
OX40 is associated with high IL-21 production in peripheral TIGIT+ Tfh cells, and the increase in peripheral TIGIT+ Tfh cells reflects disease activity in IgG4-RD.
CC-chemokine ligand 18 is a useful biomarker associated with disease activity in IgG4related disease IgG4-related disease (IgG4-RD) is a systemic disorder characterised by elevated serum IgG4 levels, tissue infiltration by IgG4 + plasma cells and severe fibrosis. 1 2 However, biomarkers for IgG4-RD disease activity are lacking. 3 A recent report demonstrated that CC-chemokine ligand 18 (CCL18) was a substantial biomarker for fibrotic diseases. 4 Here, we investigated the correlation between seru
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