W. J. Judd

Antibodies that Define NANA‐Independent MN‐System Antigens

The hemagglutinating properties of a large proportion of anti‐M and anti‐N reagents, and sera containing antibodies to MN‐related antigens, have been shown to be unaffected by treatment of red blood cells with neuraminidase. These antibodies, which define NANA‐independent MN‐ system structures, provide further evidence that MN blood group specificity may also be determined by moieties other than N‐ acetylneuraminic acid.

Electronic verification of donor-recipient compatibility : the computer crossmatch

Background: This article describes standard operating procedures (SOPs) for a computer crossmatch to replace the immediate‐spin crossmatch for ABO incompatibility between patient blood samples submitted for pretransfusion testing and the blood component selected for transfusion. These SOPs were developed following recent changes to the Standards for Blood Banks and Transfusion Services of the American Association of Blood Banks (AABB).

The evaluation of a positive direct antiglobulin test (autocontrol) in pretransfusion testing revisited.

Direct antiglobulin tests (DATs) using anti‐IgG were performed on 65,049 blood samples from prospective transfusion recipients; 3570 tests (5.49%) were positive. Using criteria published previously (primarily excluding patients not transfused within the preceding 14 days), 778 samples from other than neonatal patients were selected for further evaluation. Eluates that did not react were obtained on 518 (66.6%) of these samples. Warm‐reactive autoantibodies were apparent in 192 eluates, while 16 contained drug‐related antibodies, anti‐A or anti‐B from prior transfusion with ABO mismatched blood components, or anti‐D passively acquired from immune serum globulin. Fifty‐two eluates contained alloantibodies; however, in only six of these cases did the corresponding serum lack unexpected alloantibodies, as determined by routine pretransfusion studies. Three additional weakly reactive clinically significant alloantibodies were detected solely through additional serum tests performed on DAT‐positive samples.

An Anti‐B Reagent Prepared from the α‐D‐Galactopyranosyl‐Binding Isolectins from Bandeiraea Simplicifolia Seeds

A method for the large scale preparation of the α‐D‐galactosyl binding isolectins from Bandeiraea simplicifolia seeds using an absorbent prepared by linking D‐galactosamine to CH‐Sepharose is described. The addition of N‐acetyl‐D‐galactosamine (GalNAc) to these isolectins produced an anti‐B reagent (BS I + GalNAc anti‐B). Although BS I + GalNAc anti‐B readily agglutinated red blood cells from the majority of group B and AB donor and patient blood samples tested, it reacted weakly with group B and AB cord red blood cells and failed to agglutinate five of 100 group AB donor blood samples when tested by an automated technique. The reagent did not agglutinate the red blood cells from seven acquired‐B red blood cell samples and was strongly reactive with Tn‐poly‐agglutinable red blood cells. These findings indicate that this lectin anti‐B preparation may be of more value in investigative immunohematology, rather than as an alternative to human group A serum as a source of anti‐B for blood‐typing purposes. The results of tests on Tn‐polyagglutinable red blood cells with BS I + GalNAc anti‐B and the purified isolectins BS I(A4) and BS I(B4) are also presented, and discussed in relation to current concepts on the structure of the Tn receptor.

Discrepancies in reverse ABO typing due to prozone. How safe is the immediate-spin crossmatch?

Three group O sera manifesting prozone in reverse ABO tests are reported. All were implicated in erroneous blood typing results. One sample failed to react with A1 red cells (RBCs) in immediate‐spin (IS) tests, had anti‐A and ‐B titers of 8192 and 2048, respectively, by indirect antiglobulin technique (IAT), and was from a diabetic patient; the parenteral administration of A substance present in porcine insulin is a possible cause of hyperimmunity in this case. The second sample was from the recipient of a single unit of group B fresh‐frozen plasma; the serum anti‐A and ‐B titers were 10,240 by IAT, but only weak reactions with A1 and B RBCs were noted in routine IS reverse typing tests; the hyperimmunity in the patient concerned was likely due to crossreacting anti‐A, B stimulated by B‐active glycoproteins and/or glycolipids in the transfused plasma. The third serum also had anti‐A and anti‐B IAT titers of 10,240 but did not react with A1 and B RBCs by IS; the hyperimmunity in this case may be related to sepsis from intestinal flora carrying A‐ and/or B‐like antigens. These antibodies lysed A1 and/or B RBCs in tests incubated at room temperature (RT) and strongly agglutinated those RBCs by IS when diluted 10‐fold with saline. The absence of the prozone phenomenon in tests with RBCs suspended in diluents containing EDTA is consistent with the previously published mechanism for anti‐A prozone: namely, the steric hindrance of agglutination by the C1 component of human complement. In addition, weak (≤ 1+) anti‐A/‐B agglutination without lysis was also seen with 5 of 231 other sera in 2‐minute RT tests, but all five reached ≥3+ by IS and lysed A1 and/or B RBCs in 5‐minute RT tests. These findings raise concerns regarding the ability of the IS crossmatch to detect ABO errors, particularly if tests are not centrifuged immediately. While prozones in true IS tests are rare, failure to detect anti‐A/‐B due to C1 blocking occurs more frequently in tests left briefly at RT. Accordingly, use of EDTA is indicated when IS crossmatches are performed to demonstrate ABO incompatibility.

Donath‐Landsteiner hemolytic anemia due to an anti‐Pr‐like biphasic hemolysin

Anemia, hyperbilirubinemia, and reticulocytosis subsequent to viral infection were present in a 32‐year‐old woman. The direct antiglobulin test was negative, and no unexpected antibodies were detected in pretransfusion tests. Rosettes of red cells (RBCs) around neutrophils were observed in peripheral blood smears, and a Donath‐Landsteiner (D‐L) test was positive. However, the patient did not show the classic features of paroxysmal cold hemoglobinuria (PCH). There was no hemoglobinuria, and in vivo hemolysis was not precipitated by cold. The D‐L antibody was IgG, but classic anti‐P specificity was not apparent. Rather, protease‐ or neuraminidase‐treated RBCs, as well as certain sialic acid deficient RBCs of uncommon MN phenotypes, were not hemolyzed in D‐L tests. Further, D‐L antibody activity could be inhibited by MN sialoglycoprotein. These data support a diagnosis of chronic D‐L hemolytic anemia, caused by an anti‐Pr‐like biphasic hemolysin.

The evaluation of a positive direct antiglobulin test in pretransfusion testing.

The results of serologic studies on 879 blood samples with a positive direct antiglobulin test (DAT) are presented. All blood samples were from patients who were either anemic, for reasons other than blood loss, recently transfused, or had serum antibodies detected during routine pretransfusion tests. Blood samples from only 81 of the patients included in this study had serologically reactive eluates (64 autoantibodies, three antibodies to penicillin and cephalothin treated red blood cells, three passively acquired anti‐A antibodies, and 11 transfusion‐induced alloantibodies). The eluted antibodies were also detected in the serum by routine pretransfusion tests in 13 of the patients whose red blood cells eluted autoantibodies, and in five of the patients whose red blood cells eluted transfusion‐induced alloantibodies. All but one of the 11 transfusion‐induced alloantibodies were detected within 14 days posttransfusion. Based on these findings, a cost‐effective and safe approach to the management of blood samples with a positive DAT would be to restrict the preparation and testing of eluates to those samples from recently transfused patients. It is the contention of the authors that the incorporation of the DAT in pretransfusion testing should primarily serve to detect alloantibody formation before such antibodies are evident in the serum, and should not be used to screen patients for unsuspected autoimmune hemolytic anemia. Furthermore, the authors question the necessity for blood banks to routinely perform an autocontrol on all blood samples from prospective transfusion recipients.

Clinical and Laboratory Findings on Two Patients with Naturally Occurring Anti‐Kell Agglutinins

Two patients with naturally occurring anti‐K agglutinins are reported. Both patients manifested clinical symptoms associated with septicemia. Transfusion of one patient with K‐positive blood did not result in hemolytic complications, further stimulation of the anti‐K agglutinin or any change in its immunoglobulin nature.

The use of purified lectins in immunhematology.

A simple method for preparing purified lectins for use in immunohematology, employing bovine albumin as a diluent, is described. The results of tests using purified lectins on normal, polyagglutinable and selected MN‐system variant red blood cells, confirm and extend previously reported results obtained with impure lectin preparations.

Studies on the blood of an Miv/Mk proposita and her family

An individual (J‐1) was shown to be heterozygous for the Mivand Mk genes. Her red cells typed as M+(weak), N‐, S‐, s+(strong), U+, Hil+, Wr(a‐b‐), En(a+weak). Poly‐acrylamide gel electrophoresis analysis of her red cell membranes revealed absence of PAS‐staining bands corresponding to normal MN and Ss sialoglycoprotein (SGP), and presence of a hybrid MNSs SGP [(α ‐ δ)Miv] similar but not identical to that reported for an Miv homozygote. However, J‐1 cannot be homozygous for Miv since the red cells of two of her children are Hil‐ and s‐, carry only a single dose of M antigen, and have a sialic acid content that is consistent with the presumption that they are Mk heterozygotes. J‐Is hybrid MNSs SGP is considered to be gene‐fusion product resulting from unequal crossover between a normal αMand δ gene, and her red cells lack that portion of the Ena antigen that is resistant to ficin. Her hybrid MNSs SGP differs, therefore, from that reported for the Miv homozygote, which probably arose from unequal crossover between αv and δ genes. Further, the red cells of the Miv homozygote carry the ficin‐resistant Ena determinant