Objective. To investigate whether single nucleotide polymorphisms (SNPs) within cytotoxic T-lymphocyte antigen-4 (CTLA-4) are associated with ANCA-associated small vessel vasculitis (SVV). Methods. ...The CTLA-4 CT60 (exon 4), +49 (exon 1) and −318 (promoter region) genotypes were determined by PCR and restriction fragment length polymorphism (RFLP) in 222 white Caucasians of UK origin with SVV and 670 ethnically matched controls. Results. The CTLA-4 exon 1 (+49) and 4 (CT60) polymorphisms are associated with SVV (+49: χ2 = 10.965, P = 0.004; CT60: χ2 = 12.017, P = 0.002). Both disease-susceptible and disease-protective haplotypes have been identified in this cohort, and their frequencies are similar in the subtypes of WG and microscopic polyangiitis. Conclusion. This study provides further evidence that CTLA-4, a susceptibility locus for a number of common autoimmune diseases, may also be involved in the development of ANCA-associated SVV.
Intestinal absorption of calcium affects bone mineralization and varies greatly. In human duodenum, expression of the calcium channel TRPV6 was directly related to blood 1,25‐dihydroxyvitamin D in ...men, but effects of age with lower median vitamin D receptor levels were more significant in women.
Introduction: The TRPV6 calcium channel/transporter is implicated in animal studies of intestinal calcium absorption, but in humans, its role and relationship to differences in mineral metabolism is unclear. We aimed to characterize TRPV6 expression in human intestine including defining relationships to the vitamin D endocrine system.
Materials and Methods: TRPV6 transcript expression was determined in endoscopic mucosal biopsies obtained from normal duodenum. Expression was compared with that in ileum and with in situ hybridization in archival tissues and related to sequence variants in genomic DNA. TRPV6 expression was related in 33 subjects to other transcripts involved in calcium absorption including the vitamin D receptor (VDR) and to blood vitamin D metabolites including 1,25‐dihydroxyvitamin D 1,25(OH)2D.
Results: TRPV6 transcripts were readily detected in duodenum but not in ileum. Expression was highest in villous epithelial cells. Sequence variants in the coding and upstream regions of the gene did not affect TRPV6 expression. The relationship between duodenal TRPV6 expression and 1,25(OH)2D differed in men and women. In men, linear regression showed a strong association with 1,25(OH)2D (r = 0.87, p < 0.01), which was unaffected by age. In women, there was no significant overall relationship with 1,25(OH)2D, but there was a significant decrease with age (r = −0.69, p < 0.001). Individual expression of TRPV6 and VDR was significantly correlated. The group of older women (>50) had lower median levels of both TRPV6 and VDR transcripts than younger women (p < 0.001 and 0.02, respectively).
Conclusions: Duodenal TRPV6 expression is vitamin D dependent in men, but not in older women, where expression of TRPV6 and VDR are both reduced. These findings can explain, at least in part, the lower fractional calcium absorption seen in older postmenopausal women.
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Introduction. Valoctocogene roxaparvovec (AAV5-hFVIII-SQ) is an adeno-associated virus gene therapy that transfers a B-domain deleted factor VIII (FVIII) cDNA to hepatocytes. The open-label, ...single-arm, multicenter phase 3 GENEr8-1 trial (NCT03370913) evaluated valoctocogene roxaparvovec in 134 men with severe hemophilia A (HA) and demonstrated an 83.8% reduction in annualized treated bleeding rate (ABR) and superiority to FVIII prophylaxis (P <0.001). The relationship between baseline FVIII activity and ABR was estimated in congenital HA (den Uijl, et al. Haemophilia 2011;171:41-4); it is unknown if a similar relationship exists after gene transfer. We present here post-hoc analyses of transgene-derived FVIII activity and bleeds in GENEr8-1.
Methods. Men ≥18 years of age with severe HA previously on FVIII prophylaxis who were negative for FVIII inhibitors and anti-AAV5 antibodies received one 6x10 13 vg/kg infusion of valoctocogene roxaparvovec. FVIII activity was measured by chromogenic substrate (CSA; lower limit of quantitation LLOQ, 3.0 IU/dL) and one stage assays (OSA; LLOQ, 1.0 IU/dL); median FVIII activity in every 4- or 6-week window was assessed. Self-reported treated bleeds were counted after week 4, when routine prophylaxis was scheduled to end. The relationship between number of treated joint bleeds and matched median FVIII activity levels in each 4- or 6-week window was modeled using negative binomial regression.
Results. As of the data cut date, mean follow-up was 71.6 weeks; 1 participant was lost to follow-up at week 66. At weeks 49-52 (latest time with data for all participants; intent-to-treat population), 9% (12/134) had CSA FVIII activity <3 IU/dL, 3% (4/134) had median FVIII activity ≥3-<5 IU/dL, 17% (23/134) had median FVIII activity ≥5-<15 IU/dL, and 71% (95/134) had median FVIII activity ≥15 IU/dL.
While on FVIII prophylaxis prior to gene transfer, 32% of participants (43/134) had an ABR of 0. Following gene transfer, 75% of participants (101/134) were bleed-free through their last follow-up prior to the data cut. The remaining 33 participants reported 149 treated bleeds total, 62% (93/149) as traumatic and 38% (56/149) as spontaneous. By location, 53% (79/149) occurred in joints, 19% (28/149) in muscle, 14% (21/149) in soft tissue, and 14% (21/149) in other or unspecified locations.
Relative to FVIII level, 54% of treated bleeds (80/149) occurred when CSA FVIII was <3 IU/dL (LLOQ), 12% (18/149) when FVIII was ≥3-<5 IU/dL, 23% (35/149) when FVIII was ≥5-<15 IU/dL, and 11% (16/149) when FVIII was ≥15 IU/dL. Of 16 treated bleeds that occurred when FVIII was ≥15 IU/dL, 13 were traumatic.
Treated joint bleeds followed a similar pattern: 51% (40/79) occurred when FVIII was <3 IU/dL, 15% (12/79) when FVIII was ≥3-<5 IU/dL, 27% (21/79) when FVIII was ≥5-<15 IU/dL, and 8% (6/79) when FVIII was ≥15 IU/dL. A negative binomial regression model based on these data and matched FVIII activity levels predicts <1 treated joint bleed in 2 years for individuals treated with valoctocogene roxaparvovec with FVIII activity ≥15 IU/dL (CSA; Figure).
Clinical value of the CSA at low FVIII levels is limited by its LLOQ of 3 IU/dL. Of 12 participants with median FVIII levels below the CSA LLOQ at weeks 49-52, 9 had improved or the same ABR post-gene therapy relative to prophylaxis. The OSA, with its LLOQ of 1 IU/dL, provided important information here. By OSA, 1 had FVIII <1 IU/dL, 5 had FVIII ≥1-<5 IU/dL, and 3 had FVIII ≥5 IU/dL. The remaining 3 participants who had increased ABR after gene transfer had FVIII levels by OSA of 0, 2.1, and 4.8 IU/dL. For participants with OS FVIII <5 IU/dL at week 52 (n = 11), median (IQR) ABR was 1.2 (0-7.9), similar to the median (IQR) ABR of 1.6 (0.6-3.5) reported for people with moderate HA (Abdi, et al. J Throm Haemost 2020;1812:3203-10).
Conclusions. Gene transfer with valoctocogene roxaparvovec led to sustained endogenous FVIII production and reduced ABR in this phase 3 trial. After gene transfer, the majority of bleeds were traumatic. When FVIII was ≥15 IU/dL, reports of treated bleeds, including joint bleeds, were rare. CSA FVIII activity was predictive of bleeding risk post-gene transfer, as for epidemiologic congenital HA results. At FVIII levels below the CSA LLOQ, the OSA provided clinically relevant information; bleeding with OSA FVIII <5 IU/dL was similar to observations in people with moderate HA, though further exploration with more data is needed.
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Pipe: Biomarin: Consultancy, Other: Clinical trial investigator; Regeneron/ Intellia: Consultancy; uniQure: Consultancy, Other; Spark Therapeutics: Consultancy; Takeda: Consultancy; Sanofi: Consultancy, Other; Sangamo Therapeutics: Consultancy; Roche/Genentech: Consultancy, Other; Pfizer: Consultancy; Novo Nordisk: Consultancy; Freeline: Consultancy, Other: Clinical trial investigator; HEMA Biologics: Consultancy; CSL Behring: Consultancy; Catalyst Biosciences: Consultancy; Genventiv: Consultancy; Grifols: Consultancy; Bayer: Consultancy; ASC Therapeutics: Consultancy; Apcintex: Consultancy; Octapharma: Consultancy; Shire: Consultancy. Ozelo: BioMarin Pharmaceutical Inc.: Consultancy, Other: Clinical trial investigator, Speakers Bureau; Bayer: Consultancy, Speakers Bureau; Novo Nordisk: Consultancy, Other: Clinical trial investigator, Travel support, Speakers Bureau; Pfizer: Consultancy, Other: Clinical trial investigator, Research Funding; Roche: Consultancy, Other: Clinical trial investigator, Travel support, Research Funding, Speakers Bureau; Sanofi: Consultancy, Other: Clinical trial investigator; Takeda: Consultancy, Other: Clinical trial investigator, Travel support, Research Funding, Speakers Bureau; Grifols: Other: Grants review. Kenet: Takeda: Consultancy; Roche: Consultancy; Novo Nordisk: Consultancy; Shire: Research Funding; Pfizer: Consultancy, Research Funding; Opko Biologics: Research Funding; Bayer: Consultancy, Research Funding; Alnylam: Consultancy, Research Funding. Reding: Bayer, CSL Behring, Sanofi Genzyme, Takeda: Speakers Bureau; Bayer, Biomarin (institutional research funding): Research Funding; Bayer, CSL Behring, NovoNordisk, Sanofi Genzyme, Takeda: Honoraria; Bayer, CSL Behring, NovoNordisk, Sanofi Genzyme, Takeda (advisory committees): Membership on an entity's Board of Directors or advisory committees. Mason: BioMarin Pharmaceutical Inc.: Other: Participation as a clinical trial investigator; Roche: Other: Participation as a clinical trial investigator, Travel support, Speakers Bureau. Leavitt: Syntimmune: Research Funding; Sangamo Therapeutics: Research Funding; Pfizer: Research Funding; Merck: Consultancy; CSL DOVA: Consultancy; Catalys: Consultancy; BioMarin: Consultancy, Research Funding; BPL: Consultancy; Behring: Consultancy; HEMA Biologics: Consultancy; Rigel: Consultancy. Laffan: Shire: Membership on an entity's Board of Directors or advisory committees; Leo-Pharma: Speakers Bureau; Alexion: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Speakers Bureau; AstraZeneca: Consultancy; Sobi: Membership on an entity's Board of Directors or advisory committees, Other: Travel support; Bayer: Other: Travel support, Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BioMarin Pharmaceutical Inc.: Research Funding. Quon: Orthopaedic Institute for Children: Current Employment. von Drygalski: Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Hematherix, Inc: Membership on an entity's Board of Directors or advisory committees, Patents & Royalties: Super FVa; Novo Nordisk: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: Research Funding; CSL Behring: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Biomarin: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; uniQure: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Genentech: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Chou: Bayer: Other: Clinical trial investigator, Speakers Bureau; Novo Nordisk: Consultancy, Other: Clinical trial investigator, Speakers Bureau; BioMarin: Other: Clinical trial investigator; Sanofi: Consultancy, Other: Clinical trial investigator, Speakers Bureau; Chugai: Consultancy, Other: Clinical trial investigator, Speakers Bureau; Pfizer: Other: Clinical trial investigator, Speakers Bureau; CSL: Consultancy, Other: Clinical trial investigator, Speakers Bureau. Shapiro: Sobi: Consultancy; Shire: Consultancy; Pfizer: Consultancy, Speakers Bureau; Bayer: Other: Travel support, Speakers Bureau; Takeda: Speakers Bureau; Roche: Speakers Bureau; CSL Behring: Other: travel support. Dunn: Genentech/Roche: Consultancy, Speakers Bureau; ATHN: Research Funding; Biomarin: Consultancy, Research Funding; Freeline: Research Funding; Takeda: Research Funding; World Federation of Hemophilia USA: Membership on an entity's Board of Directors or advisory committees; CSL Behring: Consultancy; Uniqure: Consultancy; Sanofi: Research Funding; Kedrion: Consultancy. Wang: Bioverativ: Consultancy, Other: Clinical trial investigator; CSL Behring: Consultancy, Other: Clinical trial investigator; Novo Nordisk: Consultancy, Other: Clinical trial investigator; Genentech: Consultancy, Other: Clinical trial investigator; Takeda: Consultancy, Other: Clinical trial investigator; Hema Biologics: Consultancy, Other: Clinical trial
Objective
T lymphocytes have been implicated in the pathogenesis of antineutrophil cytoplasmic antibody–associated vasculitis (AAV). Patients with myeloperoxidase (MPO) antineutrophil cytoplasmic ...antibody (ANCA) experience relapses less frequently than those with proteinase 3 ANCA, suggesting greater immune regulation. This study was undertaken to investigate MPO‐specific T cell reactivity during disease remission and the factors regulating their responsiveness.
Methods
MPO‐specific T cells were quantified by enzyme‐linked immunospot assay with additional Treg cell depletion or exogenous interleukin‐2. Serum tryptophan and its metabolites were measured. In vivo blockade of indoleamine 2,3‐dioxygenase (IDO) was performed, and its effect on MPO reactivity was assessed.
Results
During disease remission, MPO‐specific interferon‐γ–producing T cell frequencies were comparable with those found in healthy controls and significantly lower than those found in patients with acute disease. CD4+CD25+ regulatory cells did not play a role in maintaining these low MPO‐specific T cell frequencies, since depletion of Treg cells did not augment MPO‐specific responses, and FoxP3 levels were diminished in patients compared with controls. Treg cell function, however, was comparable in patients and controls, suggesting numerical rather than functional deficiency. We found diminished serum tryptophan levels and elevated levels of its metabolite kynurenine in patients with MPO AAV as compared with controls. To confirm the effect of tryptophan degradation on MPO responses in vivo, we inhibited degradation in MPO‐immunized WKY rats and found greater immune responsiveness to MPO and a tendency to more severe glomerulonephritis.
Conclusion
Our findings indicate that MPO‐specific T cell frequencies are regulated during disease remission in association with tryptophan degradation. The tryptophan regulatory pathway is induced during active disease and persists during disease remission.
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