Table 2 HSCT in patients with pathogenic PAX1 variants.

ATG, anti-thymocyte globulin; PBSC, peripheral blood stem cells; URD, unrelated donor.

PatientP1P2P3P4
Age at transplantation12 months4.5 months3.5 months4 months
Transplant characteristics
  Donor type, HLA-matchingURD, 9/10Mother, 4/8Mother, 4/8URD, 4/6
  Source of stem cellsBone marrowT cell–depleted bone
marrow
PBSCCord blood
  Conditioning regimenAlemtuzumab 1 mg/kg
Fludarabine 150 mg/m2
Melphalan 140 mg/m2
Busulfan 8 mg/kg
Cyclophosphamide 200 mg/kg
First HSCT:
  Treosulfan 30 g/m2
  Fludarabine 120 mg/m2
  ATG 4 mg/kg
Second HSCT (7 months):
  Thiotepa 10 mg/kg
  Cyclophosphamide 150 mg/kg
  ATG 25 mg/kg
Busulfan 16 mg/kg
Fludarabine 160 mg/m2
ATG 20 mg/kg
Engraftment and immune reconstitution
  Time post-transplant9 months2 months11.5 months after 2nd HSCT4 years
  Chimerism (source)100% Donor, whole bloodAutologous78% recipient; 22% donor100% donor
  ANC (×10−3/μl)1.964.53.272.99
  ALC (×10−3/μl)0.710.452.70.44
  CD3+ cells/μl24795424
  CD4+ cells/μl7641321
  CD8+ cells/μl1281304
  CD19+ cells/μl1893622650*
  CD16/56+ cells/μl91n.d.32386
Outcome, age,
and cause of death
Alive, 6 years and 4 months,
waiting for thymic
transplantation
Deceased, 9.5 months,
respiratory distress
Deceased, 4 years and 7 months,
septic shock
Alive, 4 years and 4 months

*Post-rituximab for severe autoimmune hemolytic anemia.