High-resolution human leukocyte antigen allele and haplotype frequencies of the Polish population based on 20,653 stem cell donors.

We present high-resolution allele and haplotype frequency (HF) estimations of the Polish population based on more than 20,000 registered stem cell donors. Sequencing-based donor human leukocyte antigen (HLA) typing led to unambiguous typing results in most cases (between 94.3% for HLA-DRB1 and 96.9% for HLA-B). HF estimations were carried out with a new, validated implementation of the expectation-maximization algorithm that allowed processing of data with ambiguities. Our results confirm several earlier results, for example, the relative commonness of the haplotype A*25:01 g, B*18:01 g, C*12:03, DRB1*04:01 in the Polish population. Because of the large sample size, we were able to obtain results of unprecedented accuracy. The estimated population-specific HFs were then used to analyze questions of strategic donor registry planning. Simulated matching probabilities by donor file size suggest that there is a need for intense donor recruitment efforts in Poland despite the large German donor registry and the genetic relatedness of both populations. Based on the current German registry size of approximately 4 million donors, the recruitment of 100,000 Polish donors would produce a stronger increase in matching probabilities for Polish patients than the recruitment of 3.3 million additional German donors.

Safety and efficacy of hematopoietic stem cell collection from mobilized peripheral blood in unrelated volunteers: 12 years of single-center experience in 3928 donors.

We present results of peripheral blood stem cell (PBSC) mobilization, collection, and follow-up from 3928 consecutive unrelated stem cell donors. Assessments were performed prospectively at baseline, leukapheresis, 1 month, 6 months, and annually after PBSC donation. During follow-up, side effects were recorded by return post questionnaires. The median CD34+ cell counts on day 5 were 67.5/microL in male and 51/microL in female donors. Bone pain and headache were the most common side effects of recombinant human granulocyte-colony stimulating factor. Central venous access was required for 23 donations (0.6%). Throughout the follow-up, the absolute neutrophil counts were slightly below the initial baseline values but remained within the normal range. The majority of the donors reported good or very good health. Malignancies occurred in 12 donors (0.3%), among whom were 1 case of acute myeloid leukemia, 1 case of chronic lymphatic leukemia, and 2 cases of Hodgkin disease. Only the incidence of Hodgkin lymphoma differed significantly from an age-adjusted population. In conclusion, 7.5 microg/kg per day lenograstim proved to be safe and effective for mobilizing hematopoietic stem cells for allogeneic transplantation. Long-term monitoring of healthy PBSC donors remains important to guarantee the safety standards of PBSC mobilization and collection.

Estimation of high-resolution HLA-A, -B, -C, -DRB1 allele and haplotype frequencies based on 8862 German stem cell donors and implications for strategic donor registry planning.

Human leukocyte antigen (HLA) haplotype frequency distributions in specific populations can be applied to optimize both individual stem cell donor searches and donor registry planning. We present allele and haplotype frequencies derived from a data set of 8862 German stem cell donors who were typed at high resolution for the HLA-A, HLA-B, HLA-C, and HLA-DRB1 genes upon registration. Calculated haplotype frequencies were used to estimate the probability p to find matching donors subject to donor registry size n. The impact of various matching standards on p(n) was analyzed. When high-resolution matching for HLA-A, HLA-B, HLA-C, and HLA-DRB1 is required, p(1,000,000) is 0.678. The corresponding value for n = 7,000,000 is 0.859. In a scenario with low-resolution matching and no consideration of HLA-C, p(1,000,000) is 0.863 and thus larger than p(7,000,000) in the scenario with stricter matching requirements. As recent findings support the importance of high-resolution matching of HLA-A, HLA-B, HLA-C, and HLA-DRB1 for outcomes of hematopoietic stem cell transplantation, our results are highly relevant for strategic planning and resource allocation of donor centers and registries.

Losing the genetic twin: donor grief after unsuccessful unrelated stem cell transplantation.

BACKGROUND: Stem cell transplantations from related or unrelated donors are used to cure leukaemia and other blood diseases. When a patient dies after an unsuccessful transplantation, interested unrelated donors are informed about the failure by their donor centre. Studies focussing on failed related donations show that donors undergo an intense grieving process. As there are only two investigations about reactions from unrelated donors, knowledge about their reactions is less comprehensive. METHODS: We conducted a prospective study of reactions of unrelated donors to the information of failed transplantations, subject to various communication methods (letter, phone). Questionnaires were sent to 395 unrelated donors who received the news of their recipients' deaths between November 2005 and August 2006. In addition, twelve in-depth interviews with selected donors were carried out. RESULTS: Unrelated donors were emotionally affected by the recipients' deaths, and it is appropriate to speak about a "Donor Grief" phenomenon, as the results of 325 returned questionnaires (return rate 82.3%) and in-depth interviews show. Donors demonstrated a range of feelings such as sadness, disappointment, grief, and helplessness. These feelings were often unexpectedly intense given the fact that the recipient was a stranger. Although the news caused grief, donors underlined that they nevertheless wanted to be informed. They preferred knowledge of the failure to uncertainty. The method of providing the information is only of secondary importance. Most donors favoured the way of communication they had experienced. CONCLUSION: This result indicates that both phone and letter communication can be justified. However, phone communication seems to be superior with respect to aspects of sensitivity. In spite of transplantation failure and the associated negative feelings, most donors were happy to have donated and would be willing to do so again. Our results underline the special responsibility of donor centres for informing and supporting unrelated volunteer donors in case their recipients have died.

Single-dose pegfilgrastim for the mobilization of allogeneic CD34+ peripheral blood progenitor cells in healthy family and unrelated donors.

BACKGROUND AND OBJECTIVES: Short-term treatment with granulocyte colony-stimulating factor (G-CSF) has been established as the standard regimen for mobilizing allogeneic peripheral blood progenitor cells (PBPC) from healthy donors. The pegylated form of filgrastim (pegfilgrastim) has a longer elimination half-life because of decreased serum clearance and might be a convenient alternative for stem cell mobilization. DESIGN AND METHODS: Twenty-five family (n=15) or unrelated (n=10) healthy donors received a single-dose of 12 mg pegfilgrastim for mobilization of allogeneic PBPC. Donors with inadequate mobilization (blood CD34+ cells

Second donation of granulocyte-colony-stimulating factor-mobilized peripheral blood progenitor cells: risk factors associated with a low yield of CD34+ cells.

BACKGROUND: There are still limited data on the efficacy and safety of repeated donations of granulocyte-colony-stimulating factor (G-CSF)-mobilized peripheral blood progenitor cells (PBPCs) for allogeneic transplantation. STUDY DESIGN AND METHODS: Sixty-seven healthy donors undergoing two consecutive mobilizations of PBPCs within a median interval of 5 months (range, 0.1-47 months) were investigated. For both first mobilization (FM) and second mobilization (SM), G-CSF (lenograstim) at 7.5 microg per kg per day was administered. RESULTS: The nonhematologic side effects were comparable between both mobilizations. A significantly lower yield of CD34+ cells x 10(6) per kg of donor weight was obtained on Day 5 of SM in female (n = 31; FM, 5.0; SM, 3.23; p = 0.008) but not in male (n = 36; FM, 5.96; SM, 5.36; p = 0.24) donors. Multivariate analysis identified a lower CD34+ blood concentration on Day 5 of FM (p < 0.001) as well as female sex (p = 0.015) as independent risk factors for a lower yield of progenitor cells, whereas donor age and body mass index, interval between donations, and schedule of G-CSF application showed no significant impact. CONCLUSION: The identified risk factors allow the estimation of the efficacy of a SM in an individual donor before G-CSF administration, thus avoiding distress to both the donor and the recipient.