The relevance of HPA-15 antigen expression for anti-HPA-15 antibody detection.

INTRODUCTION: The HPA-15 antigen system is characterized by a low antigen expression on platelets. The antibodies against this antigen are implied in fetal/neonatal alloimmune thrombocytopenia (F/NAIT), post-transfusion purpura, and refractoriness to platelet transfusions. Detection of these antibodies appears to be related to the level of HPA-15 expression on the platelets used in the monoclonal antibody-specific immobilization of platelet antigen (MAIPA) assay. METHODS: We performed genotyping of 300 healthy blood donors for HPA-15 by TaqMan real-time PCR technology, and the HPA-15 antigen expression was investigated in 13 HPA-15aa and 19 HPA-15bb individuals. We also investigated the relevance of HPA-15 antigen expression on donor platelets used in MAIPA for antibody detection in 223 multitransfused hematological patients and 271 women with suspected F/NAIT. RESULTS: In Polish donors, the HPA-15a allele frequencies were lower than the HPA-15b (0.480 vs. 0.515). We identified three HPA-15 expression groups: high (36.7 ± 8.36 MFI - eight cases), medium (19.5 ± 6.2 MFI - 21 cases), and low (6.5 ± 5.9 MFI - three cases). The HPA-15 expression was stable over time. The HPA-15aa and HPA-15bb platelets with high antigen expression were used for anti-HPA-15 antibody detection; anti-HPA-15 antibodies were detected in 4/223 (1.8%) patients receiving multiple transfusions but in none of the 271 women with suspected F/NAIT. Further examination of the four sera by MAIPA with various platelets revealed the optical density in the assay to be closely related to the level of HPA-15 antigen expression. CONCLUSION: Anti-HPA-15 antibody detection should be based on carefully selected platelets with high HPA-15 expression level.

Reticulated platelets as a marker of platelet recovery after allogeneic stem cell transplantation.

Reticulated platelets (RP) are the youngest forms of platelets in blood and reflect the rate of bone marrow platelet production. In the present study, we used flow cytometric analysis to determine the percentage of RPs in patients undergoing allogeneic stem cell transplantation. We investigated 10 patients after transplantation from HLA identical siblings: five with acute myeloid leukemia (AML), four with chronic myeloid leukemia (CML), and one patient with myelodysplastic syndrome (MDS). Of the patients examined, four patients underwent allogeneic bone marrow transplantation and six patients underwent peripheral blood stem cell transplantation. It was observed that the initially reduced percentage of RPs (2.9 +/- 1.7%; mean +/- SD) was significantly higher (P = 0.0109) in all patients (13.6 +/- 6.4%) in the following 10-26 days. The RP percentage peak preceded the recovery of peripheral platelet count up to 45.6 x 10(9)/l on average by 3 days. We found no difference in RP% between the AML and CML patients but we did observe that in CML patients the RP percentage increased on average 7 days earlier than in AML patients. The elevated RP percentage reflects increased bone marrow regeneration and can be considered an additional marker of thrombopoietic recovery in the patients undergoing allogeneic stem cell transplantation.

Transfusion-related acute lung injury and leucocyte-reacting antibodies.

BACKGROUND AND OBJECTIVES: Transfusion-related acute lung injury (TRALI) is underdiagnosed and underreported. This is why we present cases suspected for TRALI, in which leucocyte antibodies were examined. MATERIAL AND METHODS: We analysed 44 patients with respiratory insufficiency, related to transfusion, who met criteria of acute lung injury (ALI). Lymphocyte and granulocyte antibodies were examined in donors and patients by six methods. RESULTS: Based on recent trends, we divided patients into two groups: TRALI (without risk factors for ALI) and possible TRALI (with probable risk factors). The incidence of antibodies was 68.2%, the majority were human leucocyte antigen (HLA) class I and/or II, the minority were non-specific granulocyte antibodies; half of all detected antibodies, however, reacted with granulocytes. Antibodies were found in 17 donors (more often in TRALI than in possible TRALI) and in 19 patients (in four - suspected to be of the donor origin, which would diminish the number of antibodies to 15). In seven available cases, we observed cognate antigen and/or positive cross-match. In the majority of patients, TRALI occurred after transfusion of red cells, in 56.2%- stored above 14 days; all the units were non-leucoreduced. Lookback in two donors showed that transfusions in 20 patients did not result in reported TRALI, even in the patient with cognate antigen. CONCLUSIONS: Our clinical observations suggest that to distinguish between TRALI and possible TRALI is difficult and the results are equivocal - it is worth considering whether it can be omitted. We have confirmed that antibodies are involved in TRALI, although their role is very complex. The role of stored red blood cells in the development of TRALI requires further observations in comparison with a control group of patients without TRALI.

Leucocyte antibodies in blood donors and a look back on recipients of their blood components.

BACKGROUND AND AIM: The role of leucocyte antibodies in donors is poorly understood in pathogenesis of transfusion-related acute lung injury (TRALI). We examined antibodies in donors and traced recipients transfused with their blood components. MATERIAL AND METHODS: Antibodies were examined in 1043 donors by five methods, look back performed in 26 recipients. RESULTS: Anti-human leucocyte antigen detected by enzyme-linked immunosorbent assay in 9.8% women but none in men. Specificities identified using FlowPRA, antibodies detected after several months. TRALI reported in one recipient from immunized donor. In 11 of 26 recipients without TRALI, cognate antigens were identified. CONCLUSION: Detection of antibodies in donors cannot predict TRALI, even in recipients with cognate antigen(s).

Sensitivity of mouse lymphoid and nonlymphoid organs to Silesian air pollutants.

The toxic effect of Silesian air pollutants to mouse organs was examined. Histological changes were found in the examined lymphoid organs (thymus, spleen) as well nonlymphoid organs (liver, kidneys). The alterations in weight indexes of lymphoid organs were also observed. Considerable changes in cellularity, weight index, and histology of the thymus in the mice exposed to air pollutants suggest the atrophy of this organ, which may lead to extrathymic T-cell differentiation and even acceleration of thymocytes maturation, which may lead to certain allergic or auto-immune pollutants of all investigated mouse organs in the following order: thymus, liver, kidneys, and spleen.