Scientific Brief

Ex Vivo GeneCorrection in X-CGD Patient Stem Cells

Abstract: Paving the Way for Accelerated Clinical Development of Adoptive Cell Immunotherapies

Precision genome engineering requires technologies that allow efficient and reproducible delivery of DNA, mRNA and RNP-based reagents into a range of primary and stem cells. In addition, clinical gene editing requires a transfection platform that is GMP-compliant and scalable to accommodate billions of cells in a single transfection. Here, we share data on gene correction in patient-derived cells following transfection of CRISPR-Cas9 with repair template using the clinically validated MaxCyte® Flow Electroporation® technology. We demonstrate efficient modification of CD34+ hematopoietic stem cells and subsequent engraftment in both mouse peripheral blood and bone marrow. Finally, we show restored enzyme activity with clinical potency.


X-linked chronic granulomatous disease (X-CGD) is caused by a single nucleotide mutation in the CYBB gene which encodes a critical component (gp91-phox) of NADPH oxidase, an enzyme that is key for the anti-microbial activity of phagocytes. Correction of mutation within the faulty CYBB gene offers a new curative treatment for X-CGD patients. The patients’ own cells are harvested, the mutated gene corrected using CRISPR-mediated gene editing, and the cells with the corrected gene returned to the patient. The engrafted cells multiply to create a new population of cells displaying “normal” function and eliminating disease.

Case Study

ex-vivo gene correction-05
ex-vivo gene correction-A
ex-vivo gene correction-04
ex-vivo gene correction-01
ex-vivo gene correction-03


  • Gene editing using MaxCyte non-viral engineering enables rapid development of next-generation adoptive cell therapies for treatment of a wide variety of diseases.
  • The high viability of cells following electroporation allows for high rates of long-term engraftment that are required for patient treatment.
  • MaxCyte Flow Electroporation Technology efficiently co-delivers a diversity of payloads including mRNA, sgRNA, and RNPs to difficult-to-engineer primary cells commonly used for adoptive cell therapies including hematopoietic stem cells and T cells.
    • The high efficiency and low toxicity of MaxCyte Flow Electroporation provides for high levels of gene editing including: Gene knockout/disruption
    • Gene knock-in
    • Single nucleotide gene mutation correction
  • MaxCyte clinical scalability and regulatory compliance provide for streamlined clinical translation of new therapies.