Outcomes of Related and Unrelated Donor Searches Among Patients with Primary Immunodeficiency Diseases Referred for Allogeneic Hematopoietic Cell Transplantation
التفاصيل البيبلوغرافية
العنوان:
Outcomes of Related and Unrelated Donor Searches Among Patients with Primary Immunodeficiency Diseases Referred for Allogeneic Hematopoietic Cell Transplantation
INTRODUCTION: Patients with primary immunodeficiencies (PIDs) are potentially cured by allogeneic hematopoietic cell transplantation (HCT). The spectrum of PIDs has expanded greatly beyond those that present in infancy or are diagnosed on newborn screening and require urgent, preemptive HCT. Many PID diagnoses are now made later in life and the role of HCT is only considered upon severe disease manifestations; in these cases, the kinetics and goals of a donor search may be different than for severe combined immunodeficiency. Across all PIDs, related donor searches have the additional selection factor of the inherited disease, such searches may yield more limited options than searches for patients with hematologic malignancies; thus, unrelated donor options often become more critical in these patients. We retrospectively evaluated the outcomes of donor searches among PID patients referred for HCT at the National Institutes of Health (NIH), where the minimum patient age for evaluation is 3 years old and where donor options included matched sibling or matched related (MSD/MRD), HLA-haploidentical (haplo), or 7–8/8 HLA-matched unrelated (mMUD/MUD) donors. METHODS: Patient (n=161) and donor demographics, MUD search results, HLA typing, pedigrees, mutation testing, and donor selection data were collected. The National Marrow Donor Program HapLogic 8/8 HLA-match algorithm was used to predict the likelihood of a successful MUD search and categorized as very good, good, fair, poor, very poor, or futile per the Memorial Sloan Kettering Cancer Center (MSKCC) Search Prognosis method. RESULTS: There were significant differences by PID mode of inheritance in patient age, disposition (receipt of HCT or not), donor source, and donor relatedness. A related or unrelated donor option could be identified for 94% of patients. Of living 1(st) degree relatives (median 3 (range 0–12) per patient), a median of 1 donor remained for autosomal dominant and X-linked (XL) diseases after HLA typing, mutation testing, and other exclusions, and a median of 2 donors remained for autosomal recessive (AR) diseases. Among patients with a PID of known mode of inheritance (n=142), the best related donor was haplo for 99 (70%) patients, with 56 (39%) haplos age 40 years or older and 5 (4%) 2(nd) degree haplos; 13 (9%) had no family donor options. The best related donor was a heterozygote/asymptomatic carrier of the PID mutation in 36 (49%) patients with AR or XL disease (n=73). Among patients with MUD search performed (n=139), 53 (38%) had very poor/futile 8/8 MUD searches, including 6 (32%) of those with unknown PID mutation and therefore no family donor options. The MSKCC Search Prognosis was less favorable for those of non-European ancestry compared to European ancestry, p=0.002. The majority of patients of Hispanic or African ancestry had very poor/futile MUD searches, 71% and 63%, respectively. No HCT recipients with very poor/futile MUD searches (n=38) received 8/8 MUD grafts. DISCUSSION: Alternative donor options, including haplo and unrelated donors, are critical to enable HCT for patients with PID. MUD search success remains low for those of non-European ancestry, and this is of particular concern for patients with PID due to an unknown genetic defect. Among PID patients, related donor options are reduced and haplos age 40 years+ and/or mutation carriers are often the best family option.