| 1. |
- Jordan, Stanley C., et al.
(författare)
-
Imlifidase desensitization in crossmatch-positive, highly-sensitized kidney transplant recipients : Results of an international phase 2 trial (Highdes)
- 2021
-
Ingår i: Transplantation. - 0041-1337 .- 1534-6080. ; 105:8, s. 1808-1817
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Highly-HLA sensitized patients have limited access to life-saving kidney transplantation due to a paucity of immunologically suitable donors. Imlifidase is a cysteine protease that cleaves IgG leading to a rapid decrease in antibody level and inhibition of IgG-mediated injury. This study investigates the efficacy and safety of imlifidase in converting a positive crossmatch test to negative, allowing highly sensitized patients to be transplanted with a living or deceased donor kidney.METHODS: This open-label, single arm, phase 2 trial conducted at five transplant centers, evaluated the ability of imlifidase to create a negative crossmatch test within 24 hours. Secondary endpoints included post-imlifidase DSA levels compared to pre-dose levels, renal function, and pharmacokinetic/pharmacodynamic profiles. Safety endpoints included adverse events and immunogenicity profile.RESULTS: 89.5% of the transplanted patients demonstrated conversion of baseline positive crossmatch to negative within 24 hours after imlifidase treatment. DSA most often rebounded 3-14 days post-imlifidase dose, with substantial interpatient variability. Patient survival was 100% with graft survival of 88.9% at 6 months. 38.9% had early biopsy proven antibody mediated rejection with onset 2-19 days post-transplantation. Serum IgG levels began to normalize after ~3-7 days post-transplantation. Anti-drug antibody levels were consistent with previous studies. Seven adverse events in six patients were classified as possibly or probably related to treatment and were mild-moderate in severity.CONCLUSIONS: Imlifidase was well tolerated, converted positive crossmatches to negative, and enabled patients with a median cPRA of 99.83% to undergo kidney transplantation resulting in good kidney function and graft survival at 6 months.
|
|
| 2. |
- Winstedt, Lena, et al.
(författare)
-
Enterococcus faecalis V583 contains a cytochrome bd-type respiratory oxidase
- 2000
-
Ingår i: Journal of Bacteriology. - 0021-9193. ; 182, s. 2845-2854
-
Tidskriftsartikel (refereegranskat)abstract
- We have cloned an Enterococcus faecalis gene cluster, cydABCD, which when expressed in Bacillus subtilis results in a functional cytochrome bd terminal oxidase. Our results indicate that E. faecalis V583 cells have the capacity of aerobic respiration when grown in the presence of heme.
|
|
| 3. |
- Bengtsson, Jenny, et al.
(författare)
-
CtaG is required for formation of active cytochrome C oxidase in Bacillus subtilis
- 2004
-
Ingår i: Microbiology. - : Microbiology Society. - 1465-2080 .- 1350-0872. ; 150, s. 415-425
-
Tidskriftsartikel (refereegranskat)abstract
- The Gram-positive bacterium Bacillus subtilis contains two respiratory oxidases of the haem-copper superfamily: cytochrome aa(3), which is a quinol oxidase, and cytochrome caa(3), which is a cytochrome c oxidase. Cytochrome c oxidase uniquely contains a di-copper centre, Cu-A. B. subtilis CtaG is a membrane protein encoded by the same gene cluster as that which encodes the subunits of cytochrome c oxidase. The role of B. subtilis CrtaG and orthologous proteins present in many other Gram-positive bacteria has remained unexplored. The sequence of CtaG is unrelated to that of CtaG/Cox11p, of proteobacteria and eukaryotic cells. This study shows that B. subtilis CtaG is essential for the formation of active cytochrome caa(3) but is not required for assembly of the core subunits I and II with haem in the membrane and it has no role in the synthesis of active cytochrome aa(3). B. subtilis YpmQ, a homologue to Sco1p of eukaryotic cells, is also a membrane-bound cytochrome c oxidase-specific assembly factor. Properties of CtaG- and YpmQ-deficient mutants were compared. Cells lacking YpmQ showed a low cytochrome c oxidase activity and this defect was suppressed by the supplementation of the growth medium with copper ions. It has previously been proposed that YpmQ/Sco1p is involved in synthesis of the Cu-A centre. The results of this study are consistent with this proposal but the exact role of YpmQ in assembly of cytochrome c oxidase remains to be elucidated.
|
|
| 4. |
- Bockermann, Robert, et al.
(författare)
-
Imlifidase-generated Single-cleaved IgG : Implications for Transplantation
- 2022
-
Ingår i: Transplantation. - : Ovid Technologies (Wolters Kluwer Health). - 0041-1337 .- 1534-6080. ; 106:7, s. 1485-1496
-
Tidskriftsartikel (refereegranskat)abstract
- Background. Imlifidase is an immunoglobulin G (IgG)-specific protease conditionally approved in the EU for desensitization in highly sensitized crossmatch positive kidney transplant patients. Imlifidase efficiently cleaves both heavy chains of IgG in a 2-step process. However, low levels of the intermediate cleavage product, single-cleaved IgG (scIgG), may persist in the circulation. The study objective was to investigate Fc-mediated effector functions of scIgG and its potential impact on common clinical immunologic assays used to assess transplant eligibility.Methods. Imlifidase-generated scIgG, obtained by in vitro cleavage of HLA-sensitized patient serum or selected antibodies, was investigated in different complement- and Fc gamma R-dependent assays and models, including clinical tests used to evaluate HLA-specific antibodies.Results. ScIgG had significantly reduced Fc-mediated effector function compared with intact IgG, although some degree of activity in complement- and Fc gamma R-dependent models was still detectable. A preparation of concentrated scIgG generated from a highly HLA-sensitized individual gave rise to a positive signal in the anti-HLA IgG LABScreen, which uses anti-Fc detection, but was entirely negative in the C1qScreen. The same high-concentration HLA-binding scIgG preparation also generated positive complement-dependent cytotoxicity responses against 80%-100% of donor T and B cells, although follow-up titrations demonstrated a much lower intrinsic activity than for intact anti-HLA IgG.Conclusions. ScIgG has a significantly reduced capacity to mediate Fc-dependent effector functions. However, remaining HLA-reactive scIgG in plasma after imlifidase treatment can cause positive assay results equivalent to intact IgG in clinical assays. Therefore, complete IgG cleavage after imlifidase treatment is essential to allow correct decision-making in relation to transplant eligibility.
|
|
| 5. |
|
|
| 6. |
- Jordan, Stanley C, et al.
(författare)
-
IgG Endopeptidase in Highly Sensitized Patients Undergoing Transplantation.
- 2017
-
Ingår i: New England Journal of Medicine. - : Massachusetts Medical Society. - 0028-4793 .- 1533-4406. ; 377:5, s. 442-453
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Donor-specific antibodies create an immunologic barrier to transplantation. Current therapies to modify donor-specific antibodies are limited and ineffective in the most highly HLA-sensitized patients. The IgG-degrading enzyme derived from Streptococcus pyogenes (IdeS), an endopeptidase, cleaves human IgG into F(ab')2 and Fc fragments inhibiting complement-dependent cytotoxicity and antibody-dependent cellular cytotoxicity, which suggests that IdeS might be useful for desensitization. We report on the combined experience of two independently performed open-label, phase 1-2 trials (conducted in Sweden and the United States) that assessed the efficacy of IdeS with regard to desensitization and transplantation of a kidney from an HLA-incompatible donor.METHODS: We administered IdeS to 25 highly HLA-sensitized patients (11 patients in Uppsala or Stockholm, Sweden, and 14 in Los Angeles) before the transplantation of a kidney from an HLA-incompatible donor. Frequent monitoring for adverse events, outcomes, donor-specific antibodies, and renal function was performed, as were renal biopsies. Immunosuppression after transplantation consisted of tacrolimus, mycophenolate mofetil, and glucocorticoids. Patients in the U.S. study also received intravenous immune globulin and rituximab after transplantation to prevent antibody rebound.RESULTS: Recipients in the U.S. study had a significantly longer cold ischemia time (the time elapsed between procurement of the organ and transplantation), a significantly higher rate of delayed graft function, and significantly higher levels of class I donor-specific antibodies than those in the Swedish study. A total of 38 serious adverse events occurred in 15 patients (5 events were adjudicated as being possibly related to IdeS). At transplantation, total IgG and HLA antibodies were eliminated. A total of 24 of 25 patients had perfusion of allografts after transplantation. Antibody-mediated rejection occurred in 10 patients (7 patients in the U.S. study and 3 in the Swedish study) at 2 weeks to 5 months after transplantation; all these patients had a response to treatment. One graft loss, mediated by non-HLA IgM and IgA antibodies, occurred.CONCLUSIONS: IdeS reduced or eliminated donor-specific antibodies and permitted HLA-incompatible transplantation in 24 of 25 patients. (Funded by Hansa Medical; ClinicalTrials.gov numbers, NCT02224820 , NCT02426684 , and NCT02475551 .).
|
|
| 7. |
- Karlsson, Christofer A.Q., et al.
(författare)
-
Streptococcus pyogenes Infection and the Human Proteome with a Special Focus on the Immunoglobulin G-cleaving Enzyme IdeS
- 2018
-
Ingår i: Molecular and Cellular Proteomics. - 1535-9476. ; 17:6, s. 1097-1111
-
Tidskriftsartikel (refereegranskat)abstract
- Infectious diseases are characterized by a complex interplay between host and pathogen, but how these interactions impact the host proteome is unclear. Here we applied a combined mass spectrometry-based proteomics strategy to investigate how the human proteome is transiently modified by the pathogen Streptococcus pyogenes, with a particular focus on bacterial cleavage of IgG in vivo. In invasive diseases, S. pyogenes evokes a massive host response in blood, whereas superficial diseases are characterized by a local leakage of several blood plasma proteins at the site of infection including IgG. S. pyogenes produces IdeS, a protease cleaving IgG in the lower hinge region and we find highly effective IdeS-cleavage of IgG in samples from local IgG poor microenvironments. The results show that IdeS contributes to the adaptation of S. pyogenes to its normal ecological niches. Additionally, the work identifies novel clinical opportunities for in vivo pathogen detection.
|
|
| 8. |
|
|
| 9. |
- Lorant, Tomas, 1975-, et al.
(författare)
-
Safety, immunogenicity, pharmacokinetics, and efficacy of degradation of anti-HLA antibodies by IdeS (imlifidase) in chronic kidney disease patients
- 2018
-
Ingår i: American Journal of Transplantation. - : Elsevier BV. - 1600-6135 .- 1600-6143. ; 18:11, s. 2752-2762
-
Tidskriftsartikel (refereegranskat)abstract
- Safety, immunogenicity, pharmacokinetics, and efficacy of the IgG-degrading enzyme of Streptococcus pyogenes (IdeS [imlifidase]) were assessed in a single-center, open-label ascending-dose study in highly sensitized patients with chronic kidney disease. Eight patients with cytotoxic PRAs (median cytotoxic PRAs of 64%) at enrollment received 1 or 2 intravenous infusions of IdeS on consecutive days (0.12 mg/kg body weight ×2 [n = 3]; 0.25 mg/kg ×1 [n = 3], or 0.25 mg/kg ×2 [n = 2]). IgG degradation was observed in all subjects after IdeS treatment, with <1% plasma IgG remaining within 48 hours and remaining low up to 7 days. Mean fluorescence intensity values of HLA class I and II reactivity were substantially reduced in all patients, and C1q binding to anti-HLA was abolished. IdeS also cleaved the IgG-type B cell receptor on CD19+ memory B cells. Anti-IdeS antibodies developed 1 week after treatment, peaking at 2 weeks. A few hours after the second IdeS infusion, 1 patient received a deceased donor kidney offer. At enrollment, the patient had a positive serum crossmatch (HLA-B7), detected by complement-dependent cytotoxicity, flow cytometry, and multiplex bead assays. After IdeS infusion (0.12 mg/kg ×2) and when the HLA-incompatible donor (HLA-B7+) kidney was offered, the HLA antibody profile was negative. The kidney was transplanted successfully.
|
|
| 10. |
- Winstedt, Lena
(författare)
-
Bacterial Terminal Oxidases. Studies in Bacillus subtilis
- 2002
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The final step in aerobic respiratory pathways is catalyzed by terminal oxidases. Bacteria generally have two or more terminal oxidases. Aerobically grown Bacillus subtilis synthesize three terminal oxidases: one cytochrome c oxidase, cytochrome caa3 and two quinol oxidases, cytochrome aa3 and cytochrome bd. In addition, a fourth cytochrome of bd-type has been predicted from the genome sequence. Cytochrome caa3 and cytochrome aa3 both belong to the well characterized family of heme-copper oxidases. Cytochrome bd is unrelated to the heme-copper oxidases and has been less studied. To characterize cytochrome bd in gram-positive bacteria, we cloned four genes, cydABCD, required for the expression of a functional enzyme. The cyd genes were expressed maximally in late exponential growth phase under conditions of low oxygen tension. The roles of different terminal oxidases in B. subtilis were investigated. We found that no single terminal oxidase is essential but one of the quinol oxidases cytochrome aa3 or cytochrome bd is required for aerobic growth. A cydABCD gene cluster, similar to that in B. subtilis, was identified in the closely related bacterium Enterococcus faecalis. The genes encode a cytochrome bd which can function as a terminal oxidase. Although the heme-copper oxidases have been intensely studied, there is not much known about the assembly of this type of enzymes. We have studied two genes, ctaG and ypmQ, required for the synthesis of a functional cytochrome caa3. Our results indicate that the genes are involved in assembly of the di-copper (CuA) center.
|
|
