1,000 Transplants Over 19 Years: Rebuilding Immune Barriers for Children Born Without Protection

Background

Children born with primary immunodeficiency disorders (PID) have genetic defects that compromise their immune systems from birth, leaving them vulnerable to repeated and life-threatening infections. One example is a five-year-old boy known as Xiao Yu, who from six months of age suffered recurrent severe respiratory infections caused by a CIITA gene mutation leading to MHC class II deficiency, a rare condition with roughly 100 cases reported globally. Without curative intervention, such patients rely on supportive measures like immunoglobulin replacement, which provides only temporary passive protection.

What was achieved

From its first pediatric allogeneic hematopoietic stem cell transplant in 2007 to the 1,000th case in 2026, the Children's Hospital of Chongqing Medical University completed the milestone over 19 years. By August 2026, its hematology and oncology department had performed 352 PID transplants with an overall survival rate exceeding 90%. The volume of PID cases is reported to far exceed that of many leading international centers, with survival rates comparable to top benchmarks. The hospital is the single center globally with the highest number of Wiskott-Aldrich syndrome (WAS) transplants, at 142 cases.

Notable achievements include the world's first successful curative hematopoietic stem cell transplant for TYK2 gene deficiency using unrelated donors. Published follow-up data showed restored TYK2 protein levels, corrected JAK/STAT signaling defects, significantly reduced severe infections, and effective management of chronic graft-versus-host disease over four years. The 1,000th transplant involved Xiao Yu, who received stem cells from a 10/10 HLA-matched unrelated donor identified through the China Marrow Donor Program. Post-transplant chimerism testing showed 100% donor cells on two occasions, and he was discharged successfully. The center operates 32 transplant units, performs over 100 transplants annually in recent years, and maintains long-term survival rates above 90%, described as reaching international advanced levels.

How it works

Treatment for these conditions begins with precise diagnosis. The hospital maintains an advanced molecular diagnostics platform, developed with the Chongqing Key Laboratory for Child Infection and Immunity, capable of functional verification of over 500 primary immunodeficiency diseases through combined genetic, protein, and signaling pathway analysis. A joint outpatient clinic between the rheumatology/immunology and hematology/oncology departments streamlines the path from diagnosis to transplant planning.

Hematopoietic stem cell transplantation replaces the patient's defective blood-forming and immune stem cells with healthy ones from a donor. After HLA matching, often with unrelated donors via national registries, the patient receives a conditioning regimen, typically chemotherapy, to clear defective marrow and prevent rejection. Donor stem cells, commonly collected from peripheral blood, are infused intravenously. The cells engraft in the bone marrow and begin producing functional blood and immune cells. Recovery occurs in specialized laminar flow units with close monitoring of donor cell chimerism (percentage of donor-origin cells), infection prevention, graft-versus-host disease management, and gradual immune reconstitution. Long-term follow-up tracks sustained function and complications. The program emphasizes a full-chain approach: pre-transplant assessment, intra-transplant management, and post-transplant monitoring.

What it means for international patients

The hospital has been designated among the first batch of facilities in Chongqing authorized to provide international medical services. It has developed a dedicated international care area, offers multilingual assistance and professional interpretation, conducts multidisciplinary team consultations, and supports direct billing arrangements with international insurance providers. A bilingual (Chinese/English) consultation hotline is available for inquiries.

These capabilities may be relevant for families of children with complex PID or similar rare immune disorders seeking high-volume transplant experience. International patients must confirm eligibility, current program availability, specific disease suitability, and all logistical details directly with the hospital, as individual medical assessments and criteria determine access.

About the hospital

The Children's Hospital of Chongqing Medical University, located in Chongqing, is a tertiary grade-A comprehensive pediatric hospital affiliated with Chongqing Medical University. Founded in 1956 through the relocation of the pediatrics department from Shanghai Medical College, it serves as a National Children's Regional Medical Center and a National Clinical Medicine Research Center. According to the 2024 Chinese Hospital Science and Technology Value (STEM) report, its comprehensive ranking stands second among children's hospitals in China.

The hospital maintains strengths in pediatrics as a national key discipline and operates multiple national-level platforms, including for rare disease research and international science and technology cooperation. It leads the Western Pediatric Development Alliance, encompassing 267 member units across 15 provincial-level regions. Its hematology and oncology department has built expertise in hematopoietic stem cell transplantation for both malignant and non-malignant conditions, including a range of rare diseases.