It is well known that non-specific autoantibodies interfere with the results of cross-match tests and irregular antibody examination.

We retrospectively analyzed the results of laboratory tests and the effects of RBC transfusion in 13 patients with autoantibodies.

9 patients were diagnosed with autoimmune hemolytic anemia and 4 patients with non-autoimmune hemolytic anemia. 12 patients had warm-type autoantibodies and one patient had the cold-type. One patient had autoantibodies that were specific to the patient's RBC (autoimmune anti-c) and another patient had both autoantibodies and alloantibodies (Anti-c, E, Di^a, and M).

6 of 13 patients exhibited 50% or higher increase in hemoglobin after transfusion, but no patients showed severe levels of hemolytic markers (LD, AST, T-Bil, and I-Bil).

We conclude that it is important to detect the presence of alloantibodies in patients with autoantibodies, and to selectad equate RBC preparation methods that match patients' main blood type to prevent alloantibody production.

Much effort has been made to reduce the incidence of vasovagal reaction (VVR) on blood donation, with some successful intervention procedures being reported recently. However, the mechanism of VVR has not been clearly elucidated and the effect of these procedures needs to be investigated. Psychological factors introduced by anxiety or pain and physiological factors due to blood volume reduction were hypothesized to be the most likely causes of VVR.

In this study, psychological factors were examined by analyzing VVR occurrence before volume reduction on blood donation. Characteristics of donors who suffered VVR were compared in two groups. One group had volume reduction and the other did not. In the group without volume reduction, physically short, thin male teenagers were dominant. For female cases, one third were under 50 kg in body weight. Among these, psychological factor-dependent VVR cases were often severe, suggesting the donation standard for females should be changed such that the lower limit in body weight is over 50 kg.

DNA blood typing is useful to compensate for serology. However, because of the racial genetic polymorphisms in blood group systems, we developed DNA typing using the liquid bead array system (Luminex) for the Japanese population.

Blood samples from 5,036 randomly selected Japanese blood donors were used. The blood group systems of Rh (RhCcEe), MNS, Duffy, Kidd, Diego, and Dombrock were subjected to DNA typing using the known single nucleotide polymorphisms (SNPs) that correspond to the respective blood group antigens. The genotype determined by Luminex was compared with the phenotype determined by serology. To explore the cause of discrepancies between the DNA and serological results, nucleotide sequencing was performed.

From the 5,036 Japanese individuals tested, Duffy and Diego blood groups showed 100% identity in serology and Luminex inspection, and Rh, MNS, and Kidd showed more than 99.8% concordance rate. Nucleotide sequencing revealed that the majority of discrepancies between serological and Luminex results were caused by variant and null alleles. Our Luminex genotyping method is useful in cases where serology is difficult, such as when reagent antibodies for blood typing are not available, and in patients after blood transfusion and those with a positive direct antiglobulin test.

The total nucleated cell (TNC) count of bone marrow grafts used for transplantation is crucial for successful engraftment of the bone marrow graft. However, transplant center physicians sometimes encounter cases where the TNC count of the delivered bone marrow graft reported by the collection center is significantly different from the TNC count measured at the transplant center. This motivated us to investigate the difference in TNC counts of each bone marrow graft for unrelated bone marrow transplants (BMTs) via the Japan Marrow Donor Program. We generated questionnaires about graft TNC counting methods, and collected 797 datasets for unrelated BM grafts from 10 transplant or collection centers. The data revealed a lack of uniform testing procedures among the participating centers to estimate the bone marrow graft TNC counts. The TNC counts from both the collection and transplant centers were comparable for 512 of the data pairs. However, for some data pairs, the discrepancy in TNC count by the collection and transplant centers was as much as three-fold. We speculate that these differences in TNC count among centers are due to the lack of standardized methods for estimating bone marrow TNC counts.

To reduce the unacceptably high variation associated with enumeration of CD34⁺ cells, international guidelines have been formulated and periodic external quality assessment (EQA) programs have been implemented in Europe and the USA. In Japan, a variety of flow cytometric methods are used for CD34⁺ cell enumeration due to a lack of standardization. Since no data are available regarding the degree of measurement variability in Japan, we performed an EQA of CD34⁺ cell enumeration for the first time. 115 laboratories across Japan that routinely enumerate CD34⁺ cells participated in this program. Two commercially available, stabilized, whole blood CD34⁺ samples were used. Coefficients of variation of the measurements were 18.7 and 24.7%, and some outliers were found. We used the standard deviation index to evaluate each laboratory. Each laboratory was also requested to provide related methodology details by completing a questionnaire. The number of single/dual platform methodology users was 93/22, and the number of ISHAGE/non-ISHAGE gating strategy users was 100/15. Many participants used the international standard methods, and their results showed less variation. Repeated external quality assessment has been reported to reduce the inter-laboratory variation and promote standardization of CD34⁺ cell enumeration. Therefore, it is extremely important to continue this survey.