Reduced-intensity, risk factor-stratified immunosuppression for acquired hemophilia A: single-center observational study.

Immunosuppressive therapy (IST) is administered to patients with acquired hemophilia A (AHA) to eradicate autoantibodies against coagulation factor VIII (FVIII). Data from registries previously demonstrated that IST is often complicated by adverse events, in particular infections. This pilot study was set out to assess the feasibility of reduced-intensity, risk factor-stratified IST. We followed a single-center consecutive cohort of twenty-five patients with AHA receiving IST according to a new institutional treatment standard. Based on results from a previous study, GTH-AH 01/2020, patients were stratified into "poor risk" (FVIII < 1 IU/dl or inhibitor ≥ 20 Bethesda units (BU)/ml) or "good risk" (FVIII ≥ 1 IU/dl and inhibitor < 20 BU/ml). Outcomes were compared between the current cohort and the GTH registry as a historic control (n = 102). Baseline characteristics of the cohort were not different from the historic control. Partial remission, defined as FVIII recovered to > 50 IU/dl, was achieved by 68% of patients after a median time of 112 days, which was lower and significantly later than in the historic control (hazard ratio: 1.8, 95% confidence interval 1.2-2.8). Complete remission, overall survival, and frequency of fatal infections were not different. Grade 3 and 4 infections were more frequent. The impact of risk factors that was observed in the historic cohort was no longer apparent, as partial and complete remission and overall survival were similar in "good risk" and "poor risk" patients. In conclusion, reduced-intensity, risk factor-stratified IST is feasible in AHA but did not decrease the risk of infections and mortality in this cohort.

Differential Effects of Gut-Homing Molecules CC Chemokine Receptor 9 and Integrin-ß7 during Acute Graft-versus-Host Disease of the Liver.

Homing of allogeneic donor T cells to recipient tissue is imperative for the development of acute graft-versus-host disease (GVHD) after bone marrow transplantation (BMT). In this study we show that alteration of T cell homing due to integrin-ß7 deficiency on T cells or its ligand MAdCAM-1 in BMT recipients contributes to the pathophysiology of experimental GVHD. In contrast, lack of CC chemokine receptor 9 on donor T cells alters tissue homing but does not impact GVHD survival. We further demonstrate that MAdCAM-1 is aberrantly expressed in hepatic murine GVHD as well as in patients with active liver GVHD. However, infiltration of donor T cells in gut but not liver was dependent of MAdCAM-1 expression, indicating, that homing and/or retention of donor T cells rests on divergent molecular pathways depending on the GVHD target tissue.

IL-17-induced CXCL12 recruits B cells and induces follicle formation in BALT in the absence of differentiated FDCs.

Ectopic lymphoid tissue, such as bronchus-associated lymphoid tissue (BALT) in the lung, develops spontaneously at sites of chronic inflammation or during infection. The molecular mechanisms underlying the neogenesis of such tertiary lymphoid tissue are still poorly understood. We show that the type of inflammation-inducing pathogen determines which key factors are required for the formation and maturation of BALT. Thus, a single intranasal administration of the poxvirus modified vaccinia virus Ankara (MVA) is sufficient to induce highly organized BALT with densely packed B cell follicles containing a network of CXCL13-expressing follicular DCs (FDCs), as well as CXCL12-producing follicular stromal cells. In contrast, mice treated with P. aeruginosa (P.a.) develop BALT but B cell follicles lack FDCs while still harboring CXCL12-positive follicular stromal cells. Furthermore, in IL-17-deficient mice, P.a.-induced BALT largely lacks B cells as well as CXCL12-expressing stromal cells, and only loose infiltrates of T cells are present. We show that Toll-like receptor pathways are required for BALT induction by P.a., but not MVA, and provide evidence that IL-17 drives the differentiation of lung stroma toward podoplanin-positive CXCL12-expressing cells that allow follicle formation even in the absence of FDCs. Taken together, our results identify distinct pathogen-dependent induction and maturation pathways for BALT formation.

Multifaceted activities of CCR7 regulate T-cell homeostasis in health and disease.

CCR7 is a homeostatically expressed chemokine receptor that is known to regulate the homing of various types of immune cells to primary, secondary, and tertiary lymphoid organs. Recent evidence suggests that, in addition to controlling cell migration, CCR7-mediated signals affect T-cell homeostasis in lymph nodes at various levels and also influence T-cell activation and polarization. In this review, we highlight these findings and discuss recently proposed functions of the CCR7 pathway in the induction and maintenance of chronic inflammation.