論文

Epstein-Barr virus-positive mucocutaneous ulcer (EBVMCU) is a B-cell proliferative disorder that has been designated as a provisional entity in the 2017 World Health Organization classification for lymphoid neoplasms. While EBVMCU may contain varying numbers of cells with Hodgkin and Reed-Sternberg cells-like morphology, the clinical course is benign and must be distinguished from lymphomas. Patients who develop EBVMCU are commonly immunocompromised, with methotrexate (MTX) as the leading cause. Most previously reported cases of EBVMCU describe mucosal ulcers with very little documentation on skin lesions and its course. Here, we report a case of MTX-associated EBVMCU of the lower leg that underwent spontaneous regression after MTX withdrawal, during which negative conversion of local Epstein-Barr virus activation was confirmed.

Interleukin-2 (IL-2) regulates immune homeostasis by fine-tuning the balance between effector and regulatory T (Treg) cells. To identify regulators of IL-2 signaling, we performed genome-wide CRISPR-knockout screening in IL-2–dependent cells derived from a patient with adult T cell leukemia (ATL) and found enrichment of single guide RNAs targeting PRDM1, which encodes B lymphocyte–induced maturation protein 1 (BLIMP1). BLIMP1 inhibits IL-2 production by T cells; however, its role in IL-2 signaling remains unknown. Here, we show that overexpressing Prdm1 down-regulated IL-2 signaling, whereas Prdm1-deficiency enhanced IL-2 signaling in mouse CD4+ T cells and Treg cells with augmented IL-2 signaling in T cells from influenza-infected mice and during adoptive T cell transfer–induced colitis. Deleting PRDM1 in human CD4+ T cells and Treg cells also increased IL-2 signaling. Furthermore, CD4+ T cells from patients with ATL expressed less BLIMP1 and had enhanced IL-2 signaling, whereas overexpressing PRDM1 in ATL cells suppressed IL-2 signaling. Thus, BLIMP1 inhibits IL-2 signaling during normal and pathophysiological responses, suggesting that manipulating BLIMP1 could have therapeutic potential.

BackgroundPartial recombinase activating gene deficiency (pRD) leads to combined immunodeficiency with immune dysregulation. It can be cured by allogeneic hematopoietic cell transplantation (HCT), but optimal referral criteria and approaches remain to be defined.ObjectiveOur study evaluated low-toxicity approaches to HCT for pRD.MethodsThirteen children and adults with pRD received radiation-free, predominantly reduced-intensity conditioning (pentostatin/cyclophosphamide/busulfan) HCT with posttransplantation cyclophosphamide–based graft-versus-host disease (GVHD) prophylaxis at median (range) age 20 (4-46) years.ResultsWith median 2.6 years’ follow-up, overall survival for the entire cohort was estimated at 92% and 83% at 1 and 2 years and 100% and 90% for reduced-intensity conditioning recipients (n = 12), with 2 deaths attributed to sepsis. Reversal of clinical manifestations was associated with immune reconstitution, with minimal de novo autoimmunity, 15% 1-year cumulative incidence of grade III-IV acute GVHD, and no chronic GVHD. Vα7.2-positive T-cell proportion increased rapidly after HCT, while mucosa-associated invariant T-cell reconstitution lagged. Dysreactive CD19hiCD21lo and 9G4+ B cells decreased after HCT, along with clinically relevant autoantibodies. However, baseline elevated anti–type I interferon antibodies, potentially predisposing to severe viral infections, decreased slowly, although neutralizing activity was reduced at last follow-up. Outcomes did not differ by donor carrier status or HLA matching. Bronchiectasis exacerbations incurred rehospitalizations in long-term follow-up of patients who entered HCT with irreversible lung disease.ConclusionReduced-intensity conditioning HCT with posttransplantation cyclophosphamide–based GVHD prophylaxis is safe and effectively reverses immune dysfunction in patients with pRD.