Letter to the Editor Vox Sang 1994;66:297-298 Anti-D Immunization after Transfusion of 4 Units of Fresh Frozen Plasma 1603948 J. de la Rubia R. Garcia F. Arriaga M. Guinot E Lopez M. L. Marty Blood Bank and Hematology Service, Hospital La Fe, Valencia, Spain Although the safety of blood transfusion has become a major concern for physicians, transfusions may still result in either serious or troublesome complications. In fact, about 20% of all transfusions lead to some type of adverse effect [1]. One of the less frequently described side effects of blood transfusion is the development of primary or secondary al loimmunization against red blood cell (RBC) antigens after the administration of fresh fro zen plasma (FFP). A 53-year-old (para 3, gravida 4, abort 1) group A, Rh-D-negative (dcE/dce) woman was admitted to our hospital for cardiac valve replacement. In August 1975, she received two cross-match compatible A, Rh-D-nega tive RBC concentrates during a mitral com missurotomy. In October 1992, the patient underwent a mitral plus tricuspid valve re placement with implantation of mechanical prosthetic heart valves. An antibody screen ing test (AST) was then performed which showed an anti-Lea antibody in the room temperature incubationstep. During surgery and within the following 6 days, she was transfused with 3 units of cross-match com patible A, Rh-D-negative (dce/dce) RBC concentrate and 4 units of group O, Rh-D- positive FFR An AST performed 10 days lat er detected the previous anti-Lea antibody and showed the presence of an anti-D anti body to a dilution of 1:32. No other clinical or hematological abnormalities were observed and she was discharged 17 days later with an acceptable left ventricular ejection fraction. Pretransfusion red cell compatibility testing was performed by means of AST with Bio cells® (Organon Teknika Corporation, Dur ham, N.C., USA) including three steps: room temperature, a 37 °C incubation and an indirect antiglobulin test using a polyspecific antiglobulin reagent. All the results were macroscopically examined. If the screen is positive, a cross-match with the antiglobulin test is done, and compatibility is confirmed using appropriate reagent antisera. Detec tion and identification of antibodies against RBC antigens is carried out using commer cial reagents (Ortho Diagnostic Systems Inc, Raritan, N.J., USA, and Gamma Biologi- cals, Inc, Houston, Tex., USA) according to the manufacturer's instructions [2]. Dithio- threitol inhibition and FFP preparation were performed according to standard methods [3]. The patient had an A, Rh-D-negative (dcE/dce) RBC phenotype. Her husband’s blood type was A, Rh-D-positive (DCe/dce). She had 3 sons of 28,22 and 21 years, respec tively. Two of them were A, Rh-D-negative and the youngest was A, Rh-D-positive (Dce/dce). She had a spontaneous abortion in 1965. No anti-D immune globulin was ad ministered after the abortion. A preopera tive AST only identified an anti-Lea active in saline at 22°C. At 37°C and by indirect anti globulin test the screening was negative. The serum-to-cell ratio usedforthe AST was 2 voi of serum with 1 voi of a 5% saline suspension of RBCs and no enzyme tests were used to screen the serum. However, immunohemat- ological studies after RBC and FFP trans fusions showed anti-Lea and anti-D antibod ies. The titer of the anti-D was 1:32 and a strong reaction (3+) in the AST was seen when serum was mixed and spun with a panel of Rh-D-positive RBC. This anti-D antibody was IgG since it was not destroyed by dith- iothreitol. The detection of anti-D antibody prompted us to check the phenotype of the RBC transfused. Retyping of the RBC con centrates administered, including an indirect antiglobulin test with anti-D, confirmed that they were Rh-D-negative (dce/dce). The AST with the serum of the donors was nega tive . Absorption and elution techniques with DCe/DCe and dCe/dCe RBC confirmed an ti-D to be the only clinically significant anti body present in the patient’s serum. One month later the titer of the anti-D was 1:16. Transfusion of FFP has occasionally been shown to be capable of causing both primary and secondary immunization to red cell al- loantigens [4-9]. Among the antierythrocyte antibodies involved, anti-D has been the most commonly observed [4-8]. Appearance of an anti-D antibody after FFP administra tion could be explained by the presence of residual RBC contaminating FFP units pre pared by standard methods of by minimum levels of RBC stroma [9-12]. In this case the patient had probably become primarily al- loimmunized against the D antigen during her third pregnancy 21 years before. On this admission, no anti-D was detected. How ever, the high titer of the anti-D observed only 10 days after her last FFP transfusion and the fact that it was IgG confirmed a sec ondary alloimmunization. Since there were no transfusional errors and because no an ti-D was passively administered, the only possible source of antigen causing the anam nestic response had to be the presence of residual RBC or traces of RBC stroma in the plasma administered. Plasma has been con sidered to induce primary or secondary im munization against RBC antigens very in frequently [4-8]. In all but 1 of the cases re- Dr Javier de la Rubia Blood Bank and Hematology Service Hospital La Fe Avda Campanar, 21 E—16009 Valencia (Spain) <& 1994 S Karger AG, Basel 0042-9007/94/0664-0297 $5 00/0 Downloaded by: University of Exeter 144.173.6.94 - 6/6/2020 10:15:41 PM