Histocompatibility testing guidelines for hematopoietic stem cell transplantation using volunteer donors: report from The World Marrow Donor Association. Quality Assurance and Donor Registries Working Groups of the World Marrow Donor Association

Immunohematopoietic stem cell transplantation in Cape Town: a ten-year outcome analysis in adults

BACKGROUND AND OBJECTIVES

Immunohematopoietic stem cell transplantation has curative potential in selected hematologic disorders. Stem cell transplantation was introduced into South Africa in 1970 as a structured experimental and clinical program. In this report, we summarize the demography and outcome by disease category, gender, and type of procedure in patients older than 18 years of age who were seen from April 1995 to December 2002.

PATIENTS AND METHODS

This retrospective analysis included 247 individuals over 18 years of age for whom complete data were available. These patients received grafts mostly from peripheral blood with the appropriate stem cell population recovered by apheresis.

RESULTS

Patient ages ranged from 20 to 65 years with a median age of 42 years. There were 101 females and 146 males. There were no withdrawals and 63% survived to the end of the study. At 96 months of follow-up, a stable plateau was reached for each disease category. Median survival was 3.3 years (n=6, 14.6%) for acute lymphoblastic anemia, 3.1 years (n=44, 18%) for acute myeloid leukemia, 2.8 years (n=47, 19%) for chronic granulocytic leukemia, 2.8 years (n=71, 29%) for lymphoma, 1.5 years (n=23, 9%) for myeloma, 1.43 years (n=10, 4%) for aplasia, and 1.4 years (n=38, 15%) for a miscellaneous group comprising less than 10 examples each. Multivariate analysis showed that only diagnosis and age had a significant impact on survival, but these two variables might be interrelated. There was no significant difference in outcome by source of graft.

CONCLUSION

The results confirm that procedures carried out in a properly constituted and dedicated unit, which meets established criteria and strictly observes treatment protocols, generate results comparable to those in a First World referral center. Low rates of transplant-related mortality, rejection and graft-versus-host disease are confirmed, but the benefits cannot be extrapolated outside of academically oriented and supervised facilities.

Reduced-intensity allogeneic hematopoietic stem cell transplantation for myelodysplastic syndrome and acute myeloid leukemia with multilineage dysplasia using fludarabine, busulphan, and alemtuzumab (FBC) conditioning

Reduced-intensity conditioned (RIC) hematopoietic stem cell transplantation (HSCT) has improved the accessibility of transplantation in patients previously ineligible. We report the results of allografting following conditioning with fludarabine, busulphan, and alemtuzumab in 62 patients with myelodysplastic syndromes (MDSs) (matched sibling donors [24] or volunteer unrelated donors [VUDs, 38]). The median age for sibling recipients was 56 years (range, 41-70 years) and for VUD recipients, 52 years (range, 22-65 years), with a median follow-up (survivors) of 524 days (range, 93-1392 days) and 420 days (range, 53-1495 days), respectively. The nonrelapse mortality (NRM) at days 100, 200, and 360 was 0%, 5%, and 5%, respectively, for siblings and 11%, 17%, and 21%, respectively, for VUD. The overall survival at one year was 73% for siblings and 71% for VUDs, with a disease-free survival (DFS) of 61% and 59%, respectively. The prognostic significance of the International Prognostic Scoring System (IPSS) was preserved. Of recipients, 86% achieved full-donor chimerism. The cumulative incidence at day 100 of grades III to IV graft-versus-host disease (GVHD) for VUD recipients was 9% and for sibling recipients, 0%. There were 26 patients (16 sibling and 10 VUD) who received donor lymphocyte infusion (DLI) at a median of 273 days (range, 126-1323 days). RIC allogeneic HSCT using this protocol appears to be safe and permits durable donor engraftment. Longer follow-up is required to confirm any potential survival advantage. (Blood. 2004;104:1616-1623)

The World Marrow Donor Association (WMDA): its goals and activities

The major goal of the World Marrow Donor Association (WMDA) is to facilitate the transfer of hematopoietic cells for transplantation purposes across international borders. It also has the goal of establishing guidelines on ethical, technical, medical, and financial aspects that concern the donor and donor-cell transfer. It has a Board and five Working Groups, namely the Donor Registry Working Group, the Quality Assurance Group, the Ethic Working Group, the Finance Working Group, and the Clinical Working Group. It has three types of membership, that is, full organizational membership, nonvoting organizational membership, and individual corresponding membership. Current important projects are speeding up the search process, accreditation of registries and collecting information about severe adverse effects in donors.

Trends in transplantation of hematopoietic stem cells from unrelated donors

Transplants of hematopoietic stem cells from unrelated donors have become feasible for patients with a growing variety of hematologic disorders. The probability of finding a suitable donor has increased because of the expansion of the network of registries containing more than seven million HLA-typed donors worldwide. The selection of compatible donors has become more effective, thanks to the discovery of new HLA alleles and the development of precise and efficient HLA typing methods using DNA technology. Improved methods for transplantation may provide the opportunity to further decrease treatment-related toxicity and improve survival.

Bone marrow transplantation with unrelated donors: what is the probability of identifying an HLA-A/B/Cw/DRB1/B3/B5/DQB1-matched donor?

Patients transplanted with marrow from an HLA-ABDR serologically matched unrelated donor suffer from more post-transplant complications than those who are transplanted with marrow from an HLA-identical sibling. This is most likely due to either HLA-ABDR incompatibilities not resolved by standard techniques and/or HLA polymorphisms not tested for by routine tissue typing (HLA-Cw,-DQ). By resolving these incompatibilities by molecular techniques combined with the in vitro cytotoxic T lymphocyte precursor frequency (CTLpf) test, we have shown that a high degree of HLA compatibility is associated with increased patient survival. However, higher requirements for HLA matching decrease the number of available donors. We have estimated the probability of finding an HLA-A/B/Cw/DRB1/DRB3/DRB5/DQB1 compatible donor based on 104 consecutive unrelated bone marrow donor searches initiated between January 1995 and December 1997, with December 1998 as the endpoint. For 96 patients (92.3%), one or more ABDR-identical donors were listed in the Bone Marrow Donor Worldwide Registry (BMDW). After contacting the registries, we obtained at least one (mean, 5.36; range, 1-20; total, 461) blood sample for 86 patients. A highly compatible donor was identified for 33/86 patients (38.4%), after testing an average number of 4.5 donors/patients (range, 1-13). However, by accepting an HLA-DRB3 or -DQB1 or -Cw incompatibility, this number would be as high as 68.6%. Approximately half of the patients (n = 40) for whom a search had been initiated have been transplanted: 22 patients with a perfectly matched donor, 15 patients with an HLA-DRB3 or -DQB1 or -Cw mismatch and three with other mismatches. The average time needed to identify the most compatible donor was 4 months. Extremely long searches seemed to be less useful, because after testing the first seven, a more compatible donor was seldom found. These results show that even when requirements for compatibility are high, the chances of finding a donor remain considerably low.

Improving availability and safety of unrelated donor transplants

Transplants of hematopoietic stem cells from unrelated donors have become feasible for a growing population of patients with hematologic malignancy. More than 2,000 patients with acute and chronic leukemia, lymphoma, myeloma, and myelodysplasia are transplanted each year worldwide using marrow or blood stem cells from unrelated volunteers. Many patients have achieved complete immunologic tolerance and have become long-term survivors. The probability of finding a suitable donor has increased, because of the expansion of the network of registries containing more than 5 million HLA-typed donors worldwide. The selection of compatible donors has become more effective, thanks to the discovery of new HLA alleles and the development of precise and efficient HLA typing methods using DNA technology. Prophylaxis of viral and fungal infections has decreased morbidity and improved survival. The availability of more selective immunosuppressive agents provides the opportunity to decrease treatment-related toxicity and graft-versus-host disease.