This study is for patients with Severe Combined Immune Deficiency (SCID) who need a blood stem cell transplant. It's testing a new treatment called **JSP191**, which is an antibody. Antibodies are proteins that help fight infections. JSP191 targets a specific part of blood-forming cells called **CD117**. CD117 is important for these cells to survive and grow. By blocking CD117, the study aims to prepare the body for a successful transplant.

• The study lasts for several months and involves follow-up visits.
• Participants must be 12 years or younger and have a suitable stem cell donor.
• Participants cannot have other active infections or be on conflicting treatments.

This study might offer a new way to help children with SCID, but there are risks, like any medical study. It's important to talk with doctors to understand if joining this study is the right choice.