Meeting the transfusion needs of a patient with anti-Ena requires an international effort

This extraordinary case showcases the identification of a rare anti-Ena specificity that was assisted by DNA-based red blood cell antigen typing and collaboration between the hospital blood bank in the United States, the home blood center in Qatar, the blood center Immunohematology Reference Laboratory, as well as the American Rare Donor Program (ARDP) and the International Society for Blood Transfusion (ISBT) International Rare Donor Panel. Ena is a high-prevalence antigen, and blood samples from over 200 individuals of the extended family in Qatar were crossmatched against the patient's plasma with one compatible En(a-) individual identified. The ISBT International Rare Donor Panel identified an additional donor in Canada, resulting in a total of two En(a-) individuals available to donate blood for the patient.

Transfusion of incompatible blood to a patient with alloanti-Sc1

Sc1 is a high-prevalence blood group antigen that is part of the Scianna blood group system. The clinical significance of Scianna antibodies is not well understood because of their rarity; there are only a handful of cases in the literature. This scarcity of information can make it difficult to decide on the best course of action when transfusing a patient with alloantibodies to Scianna blood group antigens. We describe a case of an 85-year-old woman presenting with melena and a hemoglobin of 66 g/L. Upon request for crossmatched blood, a panreactive antibody was found, later elucidated to be alloanti-Sc1. Because of the urgent nature of the transfusion, the patient was transfused with 2 incompatible, presumed Sc1+, red blood cell units with no evidence of an acute or delayed transfusion reaction. This case has been shared with the International Society of Blood Transfusion Rare Donor Working Party, via their Outcome of Incompatible Transfusion form, and adds to the body of evidence on clinical significance of antibodies to the antigens of the Scianna blood group system.

Incompatible red blood cell transfusion for hemolytic disease of the fetus and newborn secondary to anti-U: A case report

BACKGROUND

Hemolytic disease of the fetus and newborn (HDFN) is a challenging condition that may necessitate the need for intrauterine or neonatal transfusion. The ability to provide compatible blood depends on antibody identification and antigen prevalence. We describe the case of a newborn that was affected by HDFN secondary to a high-prevalence antigen of unknown specificity.

STUDY DESIGN AND METHODS

A 29-year-old mother underwent emergency cesarean section for fetal distress. The newborn had severe anemia and hyperbilirubinemia. Antibody screening and identification on maternal plasma revealed pan reactivity with negative autocontrol. The cord sample had the same pattern with positive Direct Antiglobulin Test. Incompatible group O red blood cells were transfused to the newborn with no complications.

RESULTS

Testing the maternal sample at a reference laboratory revealed the presence of anti-U at a high titer.

DISCUSSION

In life-threatening conditions, it may be necessary to transfuse incompatible units. In patients who require transfusion in the presence of an identified antibody against a high-prevalence antigen, sources for rare blood should be explored. These include autologous donations for adults, collecting blood from relatives (including mothers), and fresh or frozen units from rare donors through rare donor registries.

Yes, MAM: how the cancer-related EMP3 protein became a regulator of erythropoiesis and the key protein underlying a new blood group system

The MAM blood group system (International Society of Blood Transfusion [ISBT] 041) consists of one high-prevalence antigen to date, first detected in a 31-year-old woman during her third pregnancy. Epithelial membrane protein 3 (EMP3) was recently identified as the gene coding the MAM antigen. Six unique genetic variants have been described in EMP3 in 11 MAM- individuals. EMP3 is an 18-kDa glycoprotein with a large extracellular domain containing at least one N-glycosylation site. The normal function of EMP3 is still unclear, but ex vivo culture of erythropoietic progenitor cells from MAM- individuals shows an increased yield of reticulocytes, suggesting that EMP3 acts as a brake during normal erythropoiesis. EMP3 is abundant on different cell types, including many epithelial tissues and blood cells. Interestingly, EMP3 expression has been suggested as a prognostic marker for a number of cancer types, both for good and poor prognoses. EMP3 may act as a tumor suppressor or an oncogene in different cancer contexts. The protein appears to interact with other cell surface receptors and affects the downstream signaling and function of these proteins. MAM- red blood cells express low levels of CD44 and, consequently, the antigens of the Indian blood group system are only weakly expressed. Clinically, the MAM blood group antigen is important with regard to blood transfusion and pregnancy. Anti-MAM can cause severe hemolytic disease of the fetus and newborn in some pregnancies but have little to no effect in other pregnancies. Cases are typically not detected until problems occur during pregnancy, making the availability of compatible blood a challenge.