Human Neutrophil Alloantigen-3a Alloimmunization among Pregnant Korean Women / 대한수혈학회지

BACKGROUND: Alloantibodies against human neutrophil alloantigen (HNA)-3a are associated with severe and fatal transfusion related acute lung injury (TRALI). HNA-3 genotyping and HNA-3a antibody (Ab) identification are essential to diagnosis and prevention of TRALI caused by HNA-3a Ab. However there had been no laboratory for HNA-3a Ab identification in Korea. The aims of this study were to establish the HNA-3a Ab test in Korea and to estimate the incidence of HNA-3a alloimmunization among pregnant Korean women. METHODS: HNA-3a homozygotes and HNA-3b homozygotes were identified by HNA-3 genotyping. Three HNA-3a homozygotes and three HNA-3b homozygotes are included in the granulocytes panel, which consisted of 10 donors for granulocytes. Sera from 650 pregnant Korean women were tested for granulocyte Ab using a mixed passive hemagglutination assay (MPHA). When a HNA-3a Ab was detected, the woman's HNA-3 was typed to support her HNA-3a alloimmunization. RESULTS: MPHA showed positive reactions in the sera from 26 women (4.0%, 26/650). HLA Abs were detected in 18 women (2.8%, 18/650), among whom HNA Abs were identified simultaneously in 7 women. Granulocyte Abs were detected in sera from 15 women (2.3%, 15/650). The incidence of HNA-3a, HNA-1b, HNA-1a, HNA-2a, and unidentified HNA Abs among pregnant Korean women was 0.77% (5/650), 0.77% (5/650), 0.62% (4/650), 0.15 (1/650), and 0.31% (2/650), respectively. CONCLUSION: In this study, we established the HNA-3a Ab test using MPHA for diagnosis and prevention of TRALI caused by HNA-3a Ab. The incidence of HNA-3a Ab in pregnant Korean women was 0.77% (5/650).

Establishment of Platelet Antigen and Antibody Tests by Mixed Passive Hemagglutination with Frozen-stored Platelets / 대한수혈학회지

BACKGROUND: Platelet antigen and antibody tests have been used in platelet immunological disorders, such as neonatal alloimmune thrombocytopenia (NAIT) and post-transfusion purpura (PTP). Mixed passive hemagglutination (MPHA) method has several advantages, including frozen preservation of platelets, ability to differentiate between anti-HLA and platelet-specific antibodies, and quick and easy interpretation without expensive equipment. In this study, we intended to develop the MPHA method using indicator cells of anti-Rh(D) sensitized group O, Rh+ RBCs. METHODS: We made indicator cells sensitized with anti-Rh(D) with various strengths (1:32 to 1:256) and determined the optimal strength. We determined the sensitivity of the MPHA and compared the results using flow cytometry. We observed the changes of the reaction according to the storage time of indicator cells. RESULTS: The optimal sensitization strengths of the indicator cells were 1:192 and 1:256. MPHA showed strong positive results with 1:8,192 diluted positive control, while the detection limit of flow cytometry was 1:128. Until the second week (mean 16 days), the indicator cells showed good results comparable to those of fresh ones. CONCLUSION: We developed the MPHA method using indicator cells of anti-Rh(D) sensitized group O, Rh+ RBCs. We produced the indicator cells in our own laboratory and obtained platelet panels with rare antigen typing using frozen-stored platelets. This technology will be used effectively for detection of platelet antigens and identification of platelet antibodies and also for platelet crossmatching.

Establishment of Mixed Passive Hemagglutination Assay Using In-House Anti-Rh(D) Sensitized Human O RBCs for the Detection of Granulocyte Specific Antibodies / 대한수혈학회지

BACKGROUND: Granulocyte specific antibodies are associated with several clinical conditions including febrile transfusion reaction and transfusion-related acute lung injury as well as immune neutropenias. The identification of granulocyte specific antibodies is important for the diagnosis of these disorders. However, there have been rarely confirmed clinical reports in Korea since the testing techniques are complicated and difficult to maintain. In this study, development of in-house indicator cells and renewedly establishment of the mixed passive hemagglutination assay (MPHA) as a serologic test to detect and identify granulocyte specific antibodies were conducted. METHODS: The in-house indicator cells for MPHA were made by sensitizing human Rh(D) positive O RBCs with human IgG anti-Rh(D) (DiaMed AG, Switzerland) and then combining with AHG anti-IgG (Immucor Inc., USA). To determine the optimal conditions, various combinations of anti-Rh(D) IgG sensitization strengths of indicator cells, microwell coated antigens (intact granulocyte vs. extracted granulocyte) and reaction conditions were compared. RESULTS: The best test conditions for MPHA were as follows: optimal results were obtained with the anti-Rh(D) sensitization dilutions of 1/64-1/192 and the reaction condition of 4 hours incubation at room temperature in humid chamber. Extracted granulocytes coated at the plate showed better results than intact granulocytes. HLA antigens were completely removed from extracted granulocyte antigens after acidified chloroquine treatment. CONCLUSION: Granulocyte MPHA using in-house anti-Rh(D) sensitized indicator cells was developed for the first time in Korea. The newly established MPHA would be effectively used for the diagnosis and treatment of disorders associated with granulocyte specific antigen-antibody reactions in Korea.

Development of Homemade Indicator Cells for Platelet Antibody Test by Mixed Passive Hemagglutination / 대한임상병리학회지

BACKGROUND: Platelet antibody test has been used in the diagnosis and management of immunological platelet disorders and platelet crossmatch. Mixed passive hemagglutination (MPHA) test is a cost-effective, reproducible, easy to perform and convenient method. Anti-IgG coated indicator red cells used for MPHA test have not been made in Korea and those cells have been exclusively donated by Dr. Shibata in Japan. This study was designed to produce domestic indicator cells and to determine its acceptability by comparing to the results obtained with Dr. Shibata's indicator cells. We produced homemade indicator cells by coating human RhD-positive O RBC with human IgG anti-D (check cell) and then coated with rabbit anti-human IgG. METHODS: Sixty three sera from healthy male donors, 58 sera tested positive in platelet suspension immunofluorescence test (PSIFT), and 61 sera tested negative in PSIFT were evaluated by MPHA employing both homemade and Dr. Shibata's indicator cells. RESULTS: The concordance rate between PSIFT and homemade MPHA was 74%. Test results of MPHA with homemade indicator cell showed excellent correlation with Shibata's indicator cell (P=0.002). All of 63 sera from healthy volunteer male blood donors without history of transfusion were tested negative with homemade MPHA method. Test results of MPHA employing homemade indicator cells showed excellent correlation with those of PSIFT (P=2.67x10-8). CONCLUSIONS: Homemade indicator cells we developed in this study were able to replace Dr. Shibata's indicator cells for the MPHA test.