Anti-M antibodies as a cause of intrauterine fetal death and neonatal hyperbilirubinaemia.

A preterm male infant (35 weeks), appropriate for gestational age with birth weight of 2.20 kg was born to a 28-year G2 P0 mother. The mother's blood group was A positive and the father's was B positive. Her first pregnancy was an intrauterine fetal death due to immune hydrops. The mother's blood was positive for indirect Coomb's test with 1:32 dilution and anti-M antibodies. This pregnancy was induced at 35 weeks of gestation. Investigations from the cord blood revealed A positive blood group, positive direct Coomb's test, haematocrit of 41.4%, cord reticulocyte count of 5.3% and total serum bilirubin (TSB) of 2.7 mg/dL. Phototherapy was started at 27 h of life for visible jaundice. In view of progressive pallor and a sudden rise of bilirubin, the infant was subjected to exchange transfusion on day 5 of life. The transfusion was given with O negative and anti-M antibodies negative donor blood. Total serum bilirubin (TSB) prior to exchange transfusion was 28 mg/dL and packed cell volume (PCV) was 21%. Phototherapy was continued for a total duration of 8 days.

First example of hemolytic disease of the newborn caused by anti-Or and confirmation of the molecular basis of Or.

BACKGROUND AND OBJECTIVES: The rare MNS antigen Or (MNS31) is sensitive to ficin, papain and sialidase, but partially resistant to trypsin (0.05%); the effect of alpha-chymotrypsin is not known. A point mutation, 204C --> T in exon 3 of GYPA, is associated with the Or+ phenotype. We report here the first case of hemolytic disease of the newborn (HDN) caused by anti-Or, and expand the information on the nature of the Or determinant. MATERIALS AND METHODS: A woman, gravida 4, para 0, delivered a baby whose red blood cells (RBCs) were positive (2+) on the direct antiglobulin test (DAT). The mother's serum, an eluate made from the baby's RBCs and the RBCs of the baby's father were investigated. Exon 3 of GYPA, extracted from the father's genomic DNA, was amplified and sequenced. RESULTS: The mother's serum reacted at room temperature, 37 degrees C and on the indirect antiglobulin test with RBCs from the baby's father. The father's RBCs were M+N+S-s+Or+. The antibody in the mother's serum and in the baby's eluate was identified as anti-Or. The serum did not react with the father's RBCs treated with trypsin (180,000 U/ml), but did react with his alpha-chymotrypsin-treated RBCs. Amplification and sequencing of DNA from the father revealed a single point mutation, 204C --> T, in GYPA exon 3. At birth, the baby had clinical symptoms of HDN and was transfused with 36 ml of packed RBCs and received phototherapy for eight days. At week 11, the baby's M+N+S+s+Or+ RBCs were negative on the DAT. CONCLUSION: This is the first case of HDN caused by anti-Or. The observed point mutation, 204C --> T, confirms that of a previous report and predicts a change of Arg (Or-) to Trp (Or+) at amino acid 31.

MN blood group affects response of serum LDL cholesterol level to a low fat diet.

Previous studies found that MZ twin pairs who are blood group NN have greater intrapair variability in plasma lipid levels than those who are MM or MN. This led to the prediction that the response of plasma lipid levels to a low fat diet would depend on MN blood group, the greatest response being in those who are NN. The present study was based upon 254 patients who took part in the Australian Polyp Prevention Project. This was a 2 x 2 x 2 randomised factorial design based upon the presence or absence of the three factors: a dietary fibre supplement, a beta-carotene supplement and reduced intake of dietary fat. The lowering of plasma, low density lipoprotein (LDL) cholesterol, in response to a low fat diet was greatest in those who were NN and least in MN heterozygotes. Overall, a reduction in LDL level was observed in the 47% of the APPP population who were on a low fat diet and who were homozygous MM or NN. The result was consistent with a balanced polymorphism at or near the GLYA locus on chromosome 4 that influences the sensitivity of plasma lipid levels to dietary fluctuations in fat intake.

Attachment of influenza C virus to human erythrocytes.

Binding experiments with radioactively labelled influenza C virions were carried out to investigate the interaction of the virus with human erythrocytes. The erythrocytes from any of 35 different individuals were found to contain influenza C virus-binding sites though their number was variable among the individuals and was much less than that on mouse, rat and chicken erythrocytes. Attachment of influenza C virus to human erythrocytes was inhibited completely by prior treatment of the virus with anti-HE monoclonal antibody having a strong haemagglutination inhibition activity. Pretreatment of erythrocytes with neuraminidase or the neuraminate-O-acetylesterase of influenza C virus resulted in a marked reduction in the level of virus binding. Thus it appears that human erythrocytes have a low level of O-acetylated sialic acid-containing glycoconjugates that can interact specifically with the HE glycoprotein of influenza C virus. Proteolytic digestion of erythrocytes with ficin, bromelain or V-8 protease inhibited virus binding almost completely, suggesting that the erythrocyte receptor for influenza C virus is a glycoprotein. In contrast to these enzymes, trypsin treatment of erythrocytes reduced virus binding by only about 50%, and alpha-chymotrypsin treatment did not inhibit at all. It was also found that treatment of erythrocytes with monoclonal antibody to the M or N blood group antigen greatly inhibited virus binding to the cells. These results, taken together, suggest that most influenza C virus receptors on human erythrocytes, if not all, reside on glycophorin A which is known to possess the M or N blood group activity.

Subunit structure of Vicia graminea anti-(blood-group N) lectin.

The subunit of the Vicia graminea lectin with blood-group-N specificity was examined by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and gel filtration in 6M-guanidinium chloride, and its molecular weights was found to be 25 000. The unique N-terminal sequence fof the first nine residues of the lectin confirmed that Vicia lectin consists of four identical chains non-covalently linked. Finally the microheterogeneity of the lectin shown by analytical isoelectric focusing is discussed.

Effect of periodate oxidation on specific activities and carbohydrate components of human blood group N- and M-specific glycoproteins and glycopeptides.

Mild as well as strong periodate oxidation of isolated erythrocyte N and M glycoproteins and glycopeptides gave extensive to complete destruction of N-specificities as measured with Vicia graminea extracts and of N- as well as M- activities determined with all but 1 of 8 animal anti-N and 13 anti-M sera. Results with human antisera differed somewhat, while the specificity of mildly oxidized N-glycoprotein was completely destroyed as determined with all 8 human anti-N sera used, that of strongly oxidized N-active substance was completely inactivated towards one of the human antisera; the remainder showed 63--94% destruction, and 2 sera indicated no effect of oxidation. Similarly, while 10 of 14 human anti-M indicated complete inactivation of M-specific glycoproteins and glycopeptides after mild or strong oxidation, 2 showed partial inactivation and 2 human anti-M sera showed no inactivating effect of oxidation. The most relevant findings of quantitative carbohydrate analysis of periodate oxidized N- and M-specific substance were extensive transformation of N-acetylneuraminic acid (NAN) to its C8 and C1 analogues on mild oxidation and pronounced destruction of NAN and its analogues on strong oxidation; however, some intact NAN always remained. In all instances galactose (Gal) was destroyed to a much larger extent in N-derived than in M-derived glycoproteins and glycopeptides.

[Qualitative demands on a anti-N blood group test reagent from Vicia graminea (anti N vg)]. / Qualitative Anforderungen an ein Blutgruppentestreagens Anti-N aus Vicia graminea (Anti Nvg)

Qualitative demands made on anti-NVg are enunciated. Apart from a short description of the production and directions for the use indications for testing the specific effect, the purity and the titre are given. Furthermore, serological peculiarities of the anti-NVg for special questions are reported. Anti-NVg shall enlarge the series of the out superseding the usual anti-N-serum of the blood-group-serological diagnostic remedies with-rabbit.