Gene Therapy As A Treatment Modality For Severe Combined Immunodeficiency : A Narrative Review

Introduction: Severe combined immunodeficiency (SCID) is a life-threatening genetic disorder marked by severe T-cell defects and often B-cell and NK-cell dysfunction, leading to an increased risk of infections. Treated via gene therapy which is the introduction of modified therapeutic genes either ex vivo or in vivo as a DNA segments. Methods: A Narrative review was conducted followed. Literature was searched on MidLine, pubmed central (PMC), Web of science, Elcevier, Scopus using the following keywords: Severe combined immunodeficiency(SCID), gene therapy and genetic disorders between 2015 and 2024. The included papers were case reports and series, cohort studies, case control and randomized controlled trials. Results: The reviewed literature illustrate that gene therapy has reached significant progress in treating (SCID), particularly X-linked SCID (SCID-X1) and ADA-SCID. Viral vectors especially retroviral, lentiviral, and adeno-associated viral (AAV) vectors have been successfully used to recover T-cell immunity and correct genetic defects, with ADA-SCID patients showing stable immune function and reduced adoption on enzyme replacement therapy. The Protection of lentivirus and foamy virus vectors have been improved, reducing dangers like insertional mutagenesis. Despite their biosafety enhancement, non-viral delivery methods are still limited by their lower transfection efficiency. Conclusion: gene therapy has the ability to treat numerous different primary immunodeficiency (PIDs). There are some limits. Important elements to consider are vector and envelope type, transduction technique, cell dose, delivery modality, conditioning regimen, and illness features. Further research is needed.