The levels of interleukin-6 and platelet-derived microparticles (PMPs) were measured in the blood of 137 patients with side effects from platelet concentrate (PC) transfusion with leukocyte removal filtration, P-selectin-expressing platelet and PMPs in stored PC before and after the filtration, and filtered leukocytes positive for P-selectin glycoprotein ligand-1. The side effects, which were observed in 203 transfusions for 84 patients with hematologic disease and 53 patients with nonhematologic disease with no significant difference between the two groups, included urticaria (75.9%), erythema (18.7%), and fever (17.2%), but no anaphylactic reactions. The levels of interleukin-6 and PMP correlated in both groups, and were significantly higher in the hematologic disease group than in the nonhematologic disease group. The level of PMP, but not interleukin-6, was significantly higher for patients testing positive for allergic reaction than for those testing negative. In the stored PC prior to filtration, the level of interleukin-6 was normal. The level of P-selectin-expressing platelets and PMPs was elevated before filtration, but was significantly lower after filtration. Taken together, the results suggest that PMP is involved in the generation of transfusion reactions, and indicate that both platelets and PMP displaying P-selectin bind to P-selectin glycoprotein ligand-1 of leukocytes retained by the leukocyte filter.

SummaryWe examined the genetic status of human leucocyte antigens (HLA), human platelet alloantigens (HPA) and neutrophil-specific antigens (NA) in patients with type 2 diabetes mellitus and diabetic arteriosclerosis obliterans (ASO). To our knowledge, the present study is the first report showing the relationship among three genetic factors in type 2 diabetes mellitus and ASO patients. HLA typing was performed by the polymerase chain reaction (PCR)-restriction fragment length polymorphism method. HPA-typing and NA-typing were by a PCR-sequence-specific primer method. The incidence of HLA-DRB1*1501 was found to be significant in type 2 diabetes and non-diabetic, particularly ASO-positive patients, compared to control subjects. There were no differences in NA1/NA2 between the control and diabetic or non-diabetic ASO groups. However, the frequency of NA2/NA2 in ASO-positive diabetes and non-diabetic ASO patients was significantly higher than controls. The a/b genotype of HPA-5a/5b was significantly lower in type 2 diabetes and non-diabetic ASO-positive patients than in controls. These findings suggest that genetic studies of HLA, NA and HPA could be useful to understand the pathogenesis of type 2 diabetes and ASO.

Background and objectivesIt is sometimes difficult to obtain antigen‐negative red blood cells (RBCs) for patients with antibodies against RBCs. However, the frequency and severity of the adverse reactions have not been well elucidated. Here, we conducted a multi‐institutional collaborative study to clarify the background, frequency and clinical significance of antigen‐positive RBC transfusions to patients with the respective antibodies.Materials and methodsThe survey included the background of patients, antigens on RBCs transfused, total amount of antigen‐positive RBCs transfused, results from antibody screen and direct antiglobulin tests, specificity of antibodies, adverse reactions and efficacies. All antibodies were surveyed regardless of their clinical significance.ResultsIn all, 826 cases containing 878 antibodies were registered from 45 institutions. The main reasons for antigen‐positive RBC transfusions included ‘negative by indirect antiglobulin test’ (39%) and ‘detection of warm autoantibodies’ (25%). In 23 cases (3% of total), some adverse reactions were observed after antigen‐positive RBC transfusion, and 25 antibodies (9 of 119 clinically significant and 16 of 646 insignificant antibodies) were detected. Non‐specific warm autoantibodies were detected in 9 cases, anti‐E in 5 cases, 2 cases each of anti‐Lea, anti‐Jra or cold alloantibodies, and 1 case each of anti‐Dib, anti‐Leb or anti‐P1. Other antibodies were detected in 2 further cases. Five (22%) of these 23 cases, who had anti‐E (3 cases) or anti‐Jra (2 cases), experienced clinically apparent haemolysis.ConclusionsAdverse reactions, especially haemolysis, were more frequently observed in cases with clinically significant antibodies than those with clinically insignificant antibodies (P < 0·001).

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Background: Anti-M is frequently observed as a naturally occurring antibody of little clinical significance. Naturally occurring anti-M is often found in children although the specific triggers of production, persistence, and evanescence of anti-M have yet to be elucidated.Abbreviation: RBC, red blood cell. Yoshiko Tamai and Hitoshi Ohto equally contributed to this study.