Transfusion reaction in a case with the rare Bombay blood group
A 62-year-old woman was referred to our hospital because of chest pain. She was admitted to the coronary care unit (CCU) ward with diagnosis of unstable angina. Angiography showed severe three-vessel coronary artery disease. After performing percutaneous coronary intervention, her hemoglobin level was checked and it was 90 g/L. The physician ordered one unit of packed red blood cells for her. Her blood sample was taken and sent to the hospital blood bank for performing pretransfusion tests. Her blood group was determined as the O blood group, and one unit of group O red blood cells was prepared for her. During transfusion of O red blood cells, she developed nausea, restlessness, back pain, hypotension, fever, and chills. Transfusion was immediately stopped and with a presumption of transfusion reaction, her before-transfusion blood sample was rechecked for blood grouping and cross-matching. During cell typing (forward typing), it did not show any reaction to anti-A and anti-B antibodies just like a normal O blood group. When cross-matching with the blood bag of group O was done, it showed incompatibility. A direct antiglobulin test on the after-transfusion blood sample was positive. Her blood sample was sent to the local blood transfusion center for detecting the cause of mismatching. Standard cell typing, reverse typing with O group control cells, and antibody screening and identification were performed. There was a discrepancy between cell typing and reverse typing. In reverse typing, her serum showed strong agglutination with O group control cells. The results of antibody identification showed the presence of a strong antibody which reacted with all panel cells through a wide thermal range with a negative autocontrol. Her red blood cells tested with anti-H antibody, but there was not any reaction to anti-H. The probability that the patient was carrying the rare Bombay blood group raised and further confirmation of the Bombay blood group was done by a reference serology laboratory of Iranian blood transfusion organization. Since the hemoglobin level of the patient decreased to 68 g/L after reaction, two units of the Bombay blood group were sent to Yazd from the blood bank of rare blood groups which was established by Iranian Blood Transfusion Organization for such patients. These two units were cross-matched using the patient's serum and found to be compatible. After transfusing two units of Bombay blood, the patient's hemoglobin improved to 100 g/L and she was referred to a specialized cardiac surgery center for CAD management.