Richard E. Broadberry

Heterogeneity of the Human H Blood Group α (1,2) Fucosyltransferase Gene among Para-Bombay Individuals

Background and objectives: The para‐Bombay phenotype has a relatively high frequency of about 1 in 8,000 Taiwanese. Studies were carried out on eight healthy and unrelated Taiwanese with the para‐Bombay phenotype to cast light on its immunogenetic basis. Materials and methods: Blood and saliva samples were tested with standard hemagglutination techniques. Salivary ABH substances were determined by hemagglutination inhibition. PCR techniques were used to amplify the coding region of the H genes. Results: Five different h alleles, designated as h1, h2, h3, h4 and h5, were identified in the Taiwanese with the para‐Bombay phenotype. The h1 allele loses one of the three AG repeats located at the nucleotides 547–552 of the H gene, whereas two of the three T repeats located at the nucleotides 880–882 are deleted in the h2 allele. The h3 allele contains a C658 to T missense mutation, whereas two missense mutations, C35 to T and A980 to C were identified in the h4 allele. A T460 to C missense is present in the h5allele. The h5 allele was identified in an individual whose red blood cells contain blood group A antigen but not H antigen, and thus may be considered a weak variant of the H gene. Conclusions: So far no biologic relevance of the H antigen has been discovered, and its deficiency does not seem to produce any deleterious effects. There may be better understanding of the evolutionary basis for the polymorphisms at these loci after systematic study of different ethnic populations.

Immunohematology in Taiwan

There are major differences in the distribution of blood group antigens and antibodies between the different population groups of Taiwan and whites. As a result, standard Western pretransfusion testing procedures have been modified for use in Taiwan, resulting in great reductions in cost and labor. These differences, in addition to their influence on the clinical practise of transfusion medicine in Taiwan, are also important anthropologically, and it is hoped that more population groups in Asia can be investigated in the near future. Further DNA studies on the B3 phenotype, the MiIII phenotype, and the Lewis phenotypes among our different population groups are in progress and further interesting findings are awaited.

Modification of Standard Western Pretransfusion Testing Procedures for Taiwan

Due to significant differences in blood group antigen and antibody frequencies between Taiwanese and Caucasians, standard Western pretransfusion testing procedures have been modified for use in Taiwan. Pretransfusion testing consists simply of ABO grouping and antibody screening/major cross‐matching using the manual Polybrene method without any antiglobulin phase. The manual Po‐lybrene method is performed using reagents prepared in house and is rapid (about 3 min), inexpensive and easy to perform. Rh(D) typing of patients is unnecessary as the frequency of D in Taiwanese is 99.67% and the occurrence of anti‐D in patients (or in haemolytic disease of the newborn) is uncommon. Great reductions in both cost and labour have resulted from these modifications, and it is suggested that other countries may consider similar modifications.

A newly identified nonsecretor allele of the human histo-blood group α(1,2)fucosyltransferase gene (FUT2)

Background and Objectives: The human Secretor α(1,2)fucosyltransferase gene determines the ABH secretor status and influences the Lewis phenotype of an individual. Studies were carried out on the Lewis (a+b–) nonsecretors of different groups indigenous to Taiwan to demonstrate their se genotypes. Methods: The Lewis phenotype of the blood samples was determined by a microplate method. The se genotypes of the individuals with the Lewis (a+b–) phenotype were analyzed by a polymerase chain reaction restriction fragment length polymorphism (PCR–RFLP) method designed for the se alleles reported previously. PCR and cloning techniques were used to determine the coding sequence of the novel se gene. Results: A new se allele, se685, with a three–nucleotide deletion of GTGGT to GT in the coding region of nucleotides 685 through 689 was identified in a Le (a+b–) nonsecretor from the Ami tribe indigenous to Taiwan. The deletion predicts the loss of the amino acid Val230 in the corresponding secretor enzymes C–terminal segment. The distribution of the se685 allele in the Ami tribe was further verified by PCR–RFLP analysis. Conclusion: The Se gene exhibits heterogeneity with some Se alleles being common but others displaying a unique distribution in different ethnic populations. The newly identified se685 allele seems to exist only in the Ami tribe indigenous to Taiwan.

The i phenotype and congenital cataracts among Chinese in Taiwan

To the Editor: In their article describing a transfusion reaction after the administration of incompletely deglycerolized autologous red cells. Cregan et al.’ failed to take note of our 1982 report.* We pointed out that unacceptable concentrations of glycerol present in thawed units of previously frozen red cells can be detected easily by suspending the washed cells in either the intended recipient’s serum (compatibility test) or normal saline. When the glycerol concentration remains high after washing, readily apparent hemolysis occurs in this test. Subsequent to our report, we understand that a large number of facilities discontinued osmolarity determinations in favor of the more easily performed and more clinically related procedure that we described. Two significant events were noted in the paper by Cregan et al.’ but they were essentially ignored. 1) “A crossmatch between the patient’s serum and the transfused unit was not possible, because of the complete hemolysis of transfused red cells upon dilution with saline.” 2) “The technologist. . .recalled problems with hemolysis at the initial typing of the unit in a slide test.” Both events are to be expected when red cells are not adequately deglycerolized. These occurrences confirm the conclusion in our earlier paper that it is not necessary to pcrform a relatively cumbersome osmolarity determination to detect residual glycerol concentrations that can induce intravascular hemolysis. Further, the statement by the authors, “This case of a hemolytic reaction adds to the known risks of autologous transfusion,” impugns autologous transfusion rather than, as it should, a technical oversight. HERBERT SILVER, MD Transmion Service Harrford Hospital Harrfod CT 06115-0729 JOEL UMLAS, MD Mount Auburn Hospital Cambridge, M-4 02138 JANICE ANDERSON Harrford Hospital Harrford, CT 06115

Incidence of ABO subgroups in Chinese in Taiwan

tested for compatibility when the blood was 30 days old. Room temperature, 37OC albumin, and macroscopic IAT portions of the compatibility test were negative. Microscopic examination in the antiglobulin test with a 40 X lens (400 X magnification) showed no agglutination; however, it was noticed that most of the cells were cigarshaped (Fig. I ) . On a subsequent Wright’s stained smear of blood from the segment, more than 90 percent of the red cells were elliptocytes. Occasional red cell fragments and spherocytes were also seen. Many of the cells had regular spicule-like projections consistent with echinocytes (Fig. 2). The unit of blood was not transfused. A fresh sample obtained from the donor confirmed the presence of elliptocytes. The second donor was a 23-year-old white man who had no previous medical problems. He had donated blood at the regional blood center twice. The third donation was drawn with Adsol; the packed red cells were 31 days old when a segment was used for compatibility testing. All tests were negative, but elliptocytes were noted during microscopic examination of the IAT. When a Wright’s stained smear of the segment was examined, approximately 75 percent of the cells were ovalocytes and elliptocytes; some of the cells were echinocytic. The unit was dis-

The para-Bombay phenotype in Chinese persons

The para‐Bombay phenotype occurs more frequently in Oriental than in white populations. This report describes the immunohematologic findings in 20 cases of the para‐Bombay phenotype detected over a period of about 15 months in the Chinese population of Taiwan.

The Lea Antigen and Neonatal Hyperbilirubinemia in Taiwan

Neonatal jaundice is known to be more severe in Taiwanese infants than in Caucasian infants. Although ABO fetomaternal incompatibility and glucose‐6‐phosphate dehydrogenase deficiency have been shown to play a role in the etiology of neonatal jaundice in some Taiwanese infants, the etiology in the majority of cases is unknown. In this study we found that in Taiwanese newborn infants, the red cell Lea antigen appeared later in infants who were jaundiced (peak serum bilirubin levels of >12 mg/dl during the first week of life) than in infants who were not. However, the Leb antigen, and hence the transferases encoded by the Se and Sew genes, did not appear to be similarly involved in the etiology of physiological jaundice. Thus it would appear that the Le gene‐specified transferase is less active or has a delayed function, in jaundiced infants. The relationship between the Le gene‐specified transferase and bilirubin has yet to be established.