Hematopoietic stem cell transplantation in patients with gain-of-function signal transducer and activator of transcription 1 mutations

Abstract

Background: Gain-of-function (GOF) mutations in signal transducer and activator of transcription 1 (STAT1) cause susceptibility to a range of infections, autoimmunity, immune dysregulation, and combined immunodeficiency. Disease manifestations can be mild or severe and life-threatening. Hematopoietic stem cell transplantation (HSCT) has been used in some patients with more severe symptoms to treat and cure the disorder. However, the outcome of HSCT for this disorder is not well established.

Objective: We sought to aggregate the worldwide experience of HSCT in patients with GOF-STAT1 mutations and to assess outcomes, including donor engraftment, overall survival, graft-versus-host disease, and transplant-related complications.

Methods: Data were collected from an international cohort of 15 patients with GOF-STAT1 mutations who had undergone HSCT using a variety of conditioning regimens and donor sources. Retrospective data collection allowed the outcome of transplantation to be assessed. In vitro functional testing was performed to confirm that each of the identified STAT1 variants was in fact a GOF mutation.

Results: Primary donor engraftment in this cohort of 15 patients with GOF-STAT1 mutations was 74%, and overall survival was only 40%. Secondary graft failure was common (50%), and posttransplantation event-free survival was poor (10% by 100 days). A subset of patients had hemophagocytic lymphohistiocytosis before transplant, contributing to their poor outcomes.

Conclusion: Our data indicate that HSCT for patients with GOF-STAT1 mutations is curative but has significant risk of secondary graft failure and death.

Keywords: Hematopoietic stem cell transplantation; Janus kinase; chronic mucocutaneous candidiasis; gain of function; graft rejection; graft-versus-host disease; hemophagocytic lymphohistiocytosis; signal transducer and activator of transcription.

Conflict of interest statement

Disclosure of potential conflict of interest: S. Okada has received grants from the Japan Agency for Medical Research and development, AMED, and the Japan Society for the Promotion of Science (16H05355 and 25713039). S. L. Guthery has received grants from the National Institute of Diabetes and Digestive and Kidney Diseases and Regeneron Pharmaceuticals. C. Lindemans has consultant arrangements with Chimerix and has a US patent for IL-22 and F-652 as ISC growth factors (US 61/901,151). K. E. Sullivan has consultant arrangements with Immune Deficiency Foundation, ADMA Pharmaceuticals, and UpToDate; has received grants from Baxter; has received payment for lectures from the American Academy of Allergy, Asthma & Immunology; and has received royalties from Elsevier. K. Imai has consultant arrangements with CSL Behring K.K., has received grants from CSL Behring K.K. and Sony, and has received payment for lectures from CSL Behring K.K. H.D. Ochs has consultant arrangements with Grifols Pharma and has received a grant from the Jeffrey Modell Foundation. T.R. Torgerson has consultant arrangements with Baxalta Biosciences, CSL Behring, and ADMA Biosciences; has received grants from Baxalta Biosciences, CSL Behring, and the National Institutes of Health; and has received payment for lectures from Baxalta Biosciences, CSL Behring, Questcor Pharmaceuticals, and the Robert Wood Johnson Foundation. The rest of the authors declare that they have no relevant conflicts of interest.

Copyright © 2017. Published by Elsevier Inc.

Figures

FIG E1.

Indication for HSCT in patients with GOF-STAT1 mutations. All patients in this cohort had severe infections (n = 15). Indications for HSCT were IPEX-like symptoms (n = 3), CID (n = 6), CID with HLH (n = 2), IPEX-like symptoms and CID (n = 2), or only severe infections (n = 2).

FIG E2.

Overall posttransplantation event-free survival (EFS). A, Overall posttransplantation EFS in patients with GOF-STAT1 mutations. B, EFS analysis comparing patients with IPEX-like presentation versus patients with CID, significant infections, or both. C, EFS analysis comparing patients with T385M amino acid substitution versus patients with other GOF-STAT1 mutations. D, EFS analysis comparing patients younger or older than 12 years. E, EFS analysis comparing patients receiving myeloablative versus nonmyeloablative conditioning regimen. In Fig E2, B and D, numbers in brackets represent the number of patients in each group.

FIG E3.

Secondary graft failure data. A total of 19 HSCTs were performed in 15 patients with GOF-STAT1 mutations, including 3 patients who underwent 2 HSCTs and 1 patient who underwent 3 HSCTs. A total of 6 events of secondary graft failure were reported, 2 of which occurred in the same patient (patient no. 9). A, Survival curve showing the timing of each of the 6 events. B, Incidence of different variants in the graft failure group compared with their incidence in all HSCTs performed does not show any statistical significance. Each of the following variants was analyzed: presence of T385M amino acid substitution, clinical phenotype of IPEX-like disease, age less than or equal to 12 years at transplantation, use of a myeloablative conditioning protocol, and use of any stem cell donor other than an MRD (T385M mutation: 33.3% vs 31.58%, P = .94; IPEX-like: 50% vs 31.58%, P = .43; age < 12 years: 66.67% vs 73.68%, P = .7512; myeloablative conditioning: 16.66% vs 31.58%, P = .49; non-MRD: 100% vs 78.95%, P = .24).

FIG 1.

Evaluation of expression and phosphorylation of GOF-STAT1 mutants by using immunobiotting. GOF-STAT1 mutations led to enhanced phosphorylated STAT1 (pSTAT1) expression after stimulation with IFN-γ. U3C cells were transfected with STAT1 mutants or WT and stimulated with IFN-γ for 20 minutes. Western blotting was performed with anti-phosphorylated STAT1, anti-STAT1, and anti-β-actin antibodies. Mutations affecting Y701 prevent STAT1 phosphorylation.

FIG 2.

Luciferase reporter assay to evaluate transcriptional activation by GOF-STAT1 mutants. STAT1 mutants led to enhanced luciferase GAS-induced activity. Transcriptional responses to increasing concentrations of IFN-γ (white bar, nonstimulated; light gray bar, 10 U/mL; dark gray bar, 100 U/mL; black bar, 1000 U/mL) were added to U3C cells transfected with STAT1 mutants or WT STAT1 and cultured for 16 hours before GAS-induced activity was measured. Experiments were performed in triplicate, and data are expressed in relative luciferase units (RLU). Individual reporter assays were performed 3 times to confirm reproducibility. Y701 mutation eliminated transcriptional activity of STAT1.

FIG 3.

Cytokine-induced STAT1 phosphorylation. A, Pre-HSCT PBMCs from patient 1 (H328R) led to hyperphosphorylation and delayed dephosphorylation after IL-6 and IL-27 stimulation. B, Post-HSCT PBMCs from patient 2 IT385M) show normal phosphorylation kinetics compared with healthy control subjects (HC).

FIG 4.

Outcome of patients with GOF-STAT1 mutations after HSCT. Fifteen patients with GOF-STAT1 mutations underwent HSCT. Primary engraftment occurred in 12. Six had secondary graft loss. Six are alive, and 5 have full immune reconstitution and reversal of disease manifestations.

FIG 5.

Overall posttransplantation survival and survival analysis. A, Overall posttransplantation survival in patients with GOF-STAT1 mutations. B, Survival analysis comparing patients with an IPEX-like presentation versus patients with CID, significant infections, or both. C, Survival analysis comparing patients with T385M amino acid substitution versus patients with other GOF-SLAT1 mutations. D, Survival analysis comparing patients younger or older than 12 years of age. E, Survival analysis comparing myeloablative and nonmyeloablative protocols. In Fig 5, B-E, numbers in brackets represent the number of patients in each group. In patients undergoing more than 1 HSCT, survival is calculated since the last transplantation performed.