Washed/replaced platelet concentrates (W/R-PCs) are effectively used for the prevention of nonhemolytic transfusion reactions caused by platelet concentrates (PCs) transfusion. In our Blood Center, replaced platelet concentrates (R-PCs) are prepared by replacing the plasma with M-sol, a wash/replacement solution, according to the guidelines of the Japan Society of Transfusion Medicine and Cell Therapy. In future, however, repeatedly washed PCs will be necessary for patients in whom a transfusion reaction cannot be prevented using R-PC or for patients such as antibody-positive IgA-deficient or haptoglobin-deficient patients. In such patients, such transfusion reactions may not be prevented by R-PCs because of their residual amounts of plasma. We prepared repeatedly washed PCs with M-sol and tested their platelet function, indexes, and levels of various components, including IgA and haptoglobin, to evaluate the effect of repeated wash-replacement procedure.
With regard to platelet function (collagen-ADP induced aggregation) and indexes (pH, MPV and %HSR), no difference was noted among twice-washed (W2-PCs), three times-washed (W3-PCs) and R-PCs at 48 hours after preparation. IgA levels were 14.1±3.1mg in R-PCs, 0.7±0.3mg in W2-PCs and 0.07±0.01mg in W3-PCs. Haptoglobin levels were 12.6±9.5mg in R-PCs, 0.54±0.62mg in W2-PCs and 0.07±0.01mg in W3-PCs.
Multiple-time washing of PCs results in a considerable reduction in plasma proteins without a reduction in platelet qualities and is thus considered useful for transfusion in patients who require a maximal reduction in plasma protein, such as antibody-positive IgA-deficient or haptoglobin-deficient patients.

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We report two cases of irregular antibodies detected after platelet concentrate transfusion.
Pre-transfusion antibody testing was negative in both cases. However, we detected anti-Jk^b in case 1, and anti-E in case 2 after platelet concentrate transfusion. The platelet donor was Jk (b+) in case 1, and E (+) in case 2. Therefore, in both cases, a very small amount of red blood cell contamination in platelet concentrate might have caused a primary or secondary immune response.
Usually, we do not choose compatible blood in platelet concentrate transfusion to irregular antibody-positive patients, but sufficient attention should be given to platelet concentrate transfusion in future.
In addition, irregular antibodies with titers which are easy to decrease may be overlooked by pre-transfusion antibody testing.
We look forward to the spread of blood transfusion cards which allow the selection of compatible blood even if irregular antibodies are present at below defectable levels or pre-transfusion antibody testing or when a patient is transfused at another hospital.

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Initial education and training for medical students and residents are important to the establishment of appropriate and safe blood transfusion. Nevertheless, recent diversification in blood transfusion has enlarged routine work in transfusion units, especially in medical university hospitals. At the same time, many medical universities have limitations on the number of medical instructor positions and available class time. Therefore, many institutions cannot provide enough education time. In this study, we investigated education for blood transfusion medicine in a university hospital and the role of the clinical laboratory technologist in clinical training.
The surveys were done as part of collaboration studies for the 2009 Transfusion Conference of University Hospitals. The investigation items included training methods, content, person in charge, time, and degree of achievement. Among the 89 hospitals surveyed, responses were obtained from 70. In addition to lecture style education, small group training of medical students and residents was adopted in 63 (90%) and 37 (53%) institutions, respectively. Medical technologists played considerable roles in small group training of students and residents in 37 (59%) and 29 (78%) institutions, respectively. The small group training of students and residents included blood typing (97% and 95%, respectively), cross-matching (81% and 70%, respectively) and analysis of irregular erythrocyte antibodies (21% and 16%, respectively). The institutions adopting cross-matching for residents had significantly more technologists.
It was clear that clinical laboratory technologists in blood transfusion sections played a major role in blood transfusion studies and education. With limited time and human resources, transfusion physicians and clinical laboratory technologists have cooperated with each other and are actively working in blood transfusion medical education. The end goal is to supply safe, reasonable blood transfusion therapy to patients; however, deteriorating conditions in medical university hospitals makes achieving this ever more difficult.

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Anti-KANNO, encountered in 1991 at Fukushima Medical University Hospital, reacted unlike any other known antibody. The antibody and its high-frequency antigen are named after the first patient. We investigated the reactivity and clinical significance of anti-KANNO in the original two patients, and 12 subsequent cases identified by Red Cross blood centers in Japan's Yamagata and Miyagi Prefectures. Among the 14 patients, 13 were females with a history of pregnancy. Anti-KANNO has the characteristics of a high-titer, low-avidity (HTLA) antibody. It reacts with red cells treated with 2-aminoethylisothiouronium bromide (AET), so it can be distinguished from anti-JMH. As yet, there are no reports of hemolytic transfusion reaction (HTR) or hemolytic disease of the fetus and the newborn (HDFN) attributed to anti-KANNO. It appears that anti-KANNO is more likely stimulated by pregnancy than by transfusion, and is of low clinical significance, except to the extent that it complicates pre-transfusion testing. Further surveillance, investigation, and reporting of anti-KANNO are warranted.

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We are working on reducing the amount of discarded blood components by introducing T&S and MSBOS, promoting proper blood transfusion, and reexamining inventories in our hospital. To reveal the reasons for discard in detail, we analyzed discard rates and reasons from 2004 to 2009. Comparison between the discard rates in 2004 and 2009 revealed that the discard rate of red blood cell (RBC) products decreased from 1.1% to 0.2% and that of platelet concentrates (PC) from 0.3% to 0.1%. The discard rate of fresh frozen plasma (FFP) increased from 0.4% to 0.8%.
The main reason for the marked reduction in the discard rate of RBC products was a reduction in the amounts of expired products at the Department of Blood Transfusion (75 packs in 2004, 6 packs in 2009). In contrast, reasons for the discard of FFP and PC were found mainly in clinical departments (97% in FFP and 92% in PC). Although most cases were unavoidable, some were due to improper handling.
The reasons for discard differed by the type of blood product. However, our analysis revealed that there were still many human errors such as improper handling, besides expiration of products and patients' condition change. Education about the characteristics of each blood product and handling method is necessary to execute safe and effective transfusion therapy.

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[in Japanese]

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