Cord Red Blood Cells Research Articles

A new cold autoagglutinin specificity: the third external loop of band 3

Cold autoagglutinins (CAs) are almost always of immunoglobulin (Ig)M class and specific for carbohydrate antigens. We report a case of hemolytic anemia caused by a mixture of IgM and IgG cold agglutinins. Both agglutinins were specific for the third extracellular loop of band 3. The patient, a 46-year-old man with no medical history, was admitted for an acute, life-threatening hemolytic anemia caused by a cold agglutinin. Improvement was obtained after plasmapheresis, red blood cell (RBC) transfusions, and steroid therapy. Recovery was complete and no etiology was found. Conventional serologic procedures and immunochemical methods were used. The patient's autoantibody was directed to an antigen equally expressed by adult and cord RBCs, resistant to papain, neuraminidase, and endo-beta-galactosidase treatments. This pattern of reactivity excluded all known specificities of cold agglutinins. The antibody failed to react with RBCs treated by alpha-chymotrypsin or pronase, suggesting that it may be directed to the third extracellular loop of band 3. Serum fractionation showed that the cold agglutinin was composed of IgM and IgG class antibodies. Antibody specificity was confirmed by blocking tests using murine monoclonal antibodies against band 3 and by immunoprecipitation. This is to our knowledge the first observation of a CA specific for band 3. The coexistence of IgM and IgG molecules, a very unusual feature for a CA, may be related to the peptidic nature of the target antigen.

Mercury and heavy metal profiles of maternal and umbilical cord RBCs in Japanese population

Mercury (Hg) and other heavy metal profiles, namely, lead (Pb), arsenic (As), cadmium (Cd), and selenium (Se) were investigated in maternal and umbilical cord (cord) red blood cells (RBCs) at parturition in Japanese population. Correlation coefficients of Hg, Pb, As, Cd, and Se between maternal and cord RBCs were 0.91, 0.79, 0.89, 0.31, and 0.76, respectively, and the respective means of cord/maternal RBCs ratios were 1.63, 0.52, 0.62, 0.12, and 1.18. These results indicate that fetal exposure to these metals (excluding Cd) strongly reflected each maternal exposure level. Among these metals, the placental transfer of methylmercury (MeHg) seemed to be extremely high but that of Cd to be limited. Hg showed positive correlations with Se in maternal RBCs but not in cord RBCs, and the Se/Hg molar ratio was lower in the latter, suggesting that the protective effects of Se against MeHg are less expected in fetuses than in mothers.

Blocking of fetal K antigens on cord red blood cells by maternal anti‐K

A 26-year-old Caucasian female in her second pregnancy grouped as A, D+ R(1)R(1) K- with anti-K (titre: 256) at booking. Her partner was typed as K1 positive. Baby was born with Hb 23.1 g/dl. Cord samples were referred to our laboratory for investigation and were found to be DAT 5+, IgG and anti-K was eluted from the red cells. Cord samples typed as A, R(1)r K- by DiaMed DiaClon Rh subgroups & K card. We report a case of false negative K1 phenotyping due to blocking with maternal anti-K.

Changes in mercury concentrations of segmental maternal hair during gestation and their correlations with other biomarkers of fetal exposure to methylmercury in the Japanese population

Methylmercury (MeHg) is one of the most hazardous substances that affects the fetus through fish consumption. The objective of this study was to evaluate the changes in the level of exposure to MeHg by assessing the mercury (Hg) concentrations of the segmental hair at parturition and 3 months after parturition, and to study their correlations with the total Hg concentrations of maternal and cord red blood cells (RBCs) and neonatal hair as biomarkers of fetal exposure to MeHg at parturition. In total, 40 paired samples of maternal hair from the scalp, maternal and cord RBCs, and 21 samples of neonatal hair from the scalp were collected at parturition. In addition, 19 samples of maternal hair from the scalp were collected at 3 months after parturition. The maternal hair samples were cut into 1 cm segments from the scalp end toward the tip. The geometric mean of the Hg concentrations in cord RBCs was approximately 1.6 times higher than that in the maternal RBCs, and a strong correlation coefficient ( r=0.91) was found between them. The increase or decrease in the Hg concentrations of the segmental hair during gestation differed largely among individuals. The correlation coefficients between the Hg concentrations of the segmental hair and cord RBCs were the strongest ( r=0.90) in the hair segment 1 cm from the scalp and decreased gradually with the distance from the scalp. The correlation coefficients between the Hg concentrations of the segmental hair collected at 3 months after parturition and maternal RBCs were over 0.9 in the hair segments 5 and 6 cm from the scalp, suggesting that the time required for the incorporation of Hg from the blood into a growing hair was very short. The geometric mean of Hg concentrations in the neonatal hair at parturition was similar to that in the maternal hair 1 cm from the scalp at parturition, and they exhibited a strong correlation ( r=0.95). The findings of this study indicate that maternal hair close to the scalp at parturition and neonatal hair are useful biomarkers of fetal exposure to MeHg at parturition. In addition, the segmental maternal hair throughout gestation is essential to obtain important information on MeHg exposure during the different sensitive windows or bolus MeHg exposure during gestation.

Fetal genotyping for the K (Kell) and Rh C, c, and E blood groups on cell‐free fetal DNA in maternal plasma

When a pregnant woman has an antibody with the potential to cause hemolytic disease of the fetus and newborn, it is beneficial to determine whether her fetus has the corresponding antigen to assess risk. In many countries this is now done routinely for RhD, by testing cell-free fetal DNA in the maternal plasma. Similar tests for K, C, c, and E are reported. Real-time quantitative polymerase chain reaction incorporating an allele-specific primer was developed for detecting the K allele of KEL and the C, c, and E alleles of RHCE. These methods were used to test DNA isolated from plasma of pregnant women with antibodies to K, C, c, or E. Accuracy of the tests was determined by comparing results with serologic tests performed on cord red blood cells (RBCs) after delivery or by molecular genotyping on DNA obtained from fetal cells. The K test incorporated an allele-specific primer with two locked nucleic acids and a mismatch. In 70 tests, including 27 K+ fetuses, only one false-negative and no false-positive results were obtained. The C, c, and E tests, performed on 13, 44, and 46 samples, respectively, gave rise to no false results. Reliable methods have been developed for predicting fetal K, C, c, and E phenotypes, by testing fetal DNA in the plasma samples of pregnant women whose RBCs lack the corresponding antigens. These methods are now being used routinely in a diagnostic service in the United Kingdom.

Potential use of autologous umbilical cord blood red blood cells for early transfusion needs of premature infants

This prospective study investigated whether the odds of receiving a red blood cell (RBC) transfusion in premature infants can be predicted at birth and for whom of these infants harvesting of umbilical cord blood (UCB) for autologous transfusion within 30 days after birth would be worthwhile. Characteristics were evaluated from 288 premature infants with a gestational age between 24 and 36 weeks and who were admitted to our neonatal center. In 144 (63%) of these infants UCB collection was attempted and the early transfusion needs could be compared with the amount of UCB available for transfusion. Sixty-nine of 114 (61%) inborn infants with a gestational age of less than 32 weeks received one or more RBC transfusions of 10 mL per kg within 30 days after birth. Apgar score at 1 minute of less than 6 and gestational age of less than 32 weeks were independently associated with the chance of receiving a transfusion in this group. In 31 of 69 (46%) infants, at least 15 mL of UCB per kg of birth weight was collected and in 28 of 69 (41%) this would have been sufficient to cover their early transfusion needs. The decision to collect UCB for postnatal transfusion can be made just after labor, based on Apgar score and gestational age. The collection of UCB is most effective and efficient for premature infants between 29 and 31 weeks of gestation. For infants less than 29 weeks of gestation, the technical aspects of UCB collection need improvement. This pilot study requires a prospective clinical study to evaluate the proportion of premature infants that can be fully or substantially supported with autologous UCB.

Unfavorable effect of type 1 and type 2 diabetes on maternal and fetal essential fatty acid status: a potential marker of fetal insulin resistance

Pregestational maternal diabetes increases obesity and diabetes risks in the offspring. Both conditions are characterized by insulin resistance, and diabetes is associated with low membrane arachidonic (AA) and docosahexaenoic (DHA) acids. We investigated whether type 1 and type 2 diabetes in pregnancy compromise maternal and fetal membrane essential fatty acids (FAs). We studied 39 nondiabetic (control subjects), 32 type 1 diabetic, and 17 type 2 diabetic pregnant women and the infants they delivered. Maternal and cord blood samples were obtained at midgestation and at delivery, respectively. Plasma triacylglycerols and choline phosphoglycerides and red blood cell (RBC) choline and ethanolamine phosphoglyceride FAs were assessed. The difference in maternal plasma triacylglycerol FAs between groups was not significant. However, the type 1 diabetes group had lower plasma choline phosphoglyceride DHA (3.7 +/- 0.9%; P < 0.01) than did the control group (5.2 +/- 1.6%). Likewise, RBC DHA was lower in the type 1 [choline: 3.4 +/- 1.5% (P < 0.01); ethanolamine: 5.9 +/- 2.5% (P < 0.05)] and type 2 [choline: 3.5 +/- 1.6% (P < 0.05)] diabetes groups than in the control group (choline: 5.5 +/- 2.2%; ethanolamine: 7.5 +/- 2.5%). Cord AA and DHA were lower in the plasma (type 1: P < 0.01) and RBC (type 2: P < 0.05) choline phosphoglycerides of the diabetics than of the control subjects, and cord RBC ethanolamine phosphoglycerides were lower in DHA (P < 0.05) in both diabetes groups than in the control group. Diabetes (either type) compromises maternal RBC DHA and cord plasma and RBC AA and DHA. The association of these 2 FAs with insulin sensitivity may mean that the current finding explains the higher incidence of insulin resistance and diabetes in the offspring of diabetic women.

Maternal and Cord Blood Long-Chain Polyunsaturated Fatty Acids Are Predictive of Bone Mass at Birth in Healthy Term-Born Infants

Long-chain polyunsaturated fatty acids (LC PUFA) are associated with bone mass in animals and human adults, yet no data exist for human infants. Thus, the objective of this study was to establish that LC PUFA status is associated with bone mass in healthy infants. Thirty mother-infant pairs were studied for LC PUFA status by measuring maternal and cord blood red blood cells (RBC) for arachidonic acid (AA), eicosapentaenoic acid (EPA), and DHA. Infant anthropometry and lumbar spine 1-4, femur and whole-body bone mineral content (BMC) were measured within 15 d of delivery. Maternal and infant LC PUFA were tested for their relationship to BMC using Pearson correlation and backward step-wise regression analyses. At birth, the average gestational age was 39.3+/-1.1 wk and body weight was 3433+/-430 g. Cord RBC AA was positively correlated with whole-body BMC, AA:EPA positively correlated with lumbar spine 1-4 BMC and femur BMC. Maternal RBC AA was positively correlated with whole-body BMC. After accounting for infant weight using regression, whole-body BMC was positively predicted by cord RBC AA but none of the maternal LC PUFA; lumbar spine 1-4 BMC was positively predicted by cord RBCAA:EPA ratio but negatively by maternal DHA; and femur BMC was not predicted by cord LC PUFA but was negatively predicted by maternal DHA. Imbalances among the n-6 and n-3 LC PUFA by term gestation are associated with lower bone mass, suggesting that the maternal diet should be balanced in n-6 and n-3 LC PUFA.

Umbilical cord and maternal blood red cell fatty acids and early childhood wheezing and eczema

Background Few studies have explored whether fetal exposure to n-6 and n-3 fatty acids influences the inception of atopic disease. Objective To assess prenatal fatty acid exposures as predictors of early childhood wheezing and eczema. Methods In the Avon Longitudinal Study of Parents and Children, late pregnancy maternal blood samples and umbilical cord blood samples were assayed for n-6 and n-3 fatty acids (percentage of total red cell phospholipid), and mothers were asked about wheezing and eczema in their children. We measured associations of 11 n-6 and n-3 fatty acid exposures with wheezing at 30 to 42 months, with wheezing patterns defined by presence (+) or absence (−) of wheezing during 2 periods, 0 to 6 months and 30 to 42 months (transient infant, +/−; later-onset, −/+; persistent, +/+; n = 1191 and n = 2764 for cord and maternal analyses, respectively), and with eczema at 18 to 30 months (n = 1238 and n = 2945 for cord and maternal analyses, respectively). Results In cord blood red cells, the ratio of arachidonic:eicosapentaenoic acid was positively associated with eczema (adjusted odds ratio [OR] per doubling, 1.14; 95% CI, 1.00-1.31; P = .044), the ratio of linoleic acid:α-linolenic acid was positively associated with later-onset wheeze (OR, 1.30; CI, 1.04-1.61; P = .019), and the ratio of α-linolenic acid:n-3 products was negatively associated with later-onset wheeze (OR, 0.86; CI, 0.75-0.99; P = .040). However, these associations were no longer significant after adjusting for multiple comparisons. Conclusions It seems unlikely that fetal exposure to n-6 and n-3 fatty acids is an important determinant of early childhood wheezing and atopic disease.

Congenital Dyserythropoetic Anemia with Sideroblasts and Ringed Forms

Letters to the EditorCongenital Dyserythropoetic Anemia with Sideroblasts and Ringed Forms Khaled Kamaleddin Mohamed and MD Abdulatif AlfaraidyFachartz Khaled Kamaleddin Mohamed Consultant Pediatrician, Department of Pediatrics, King Faisal University/King Fahd Hospital of the University, P.O. Box 40163, Al Khobar 31952, Saudi Arabia Search for more papers by this author and Abdulatif Alfaraidy Professor and Chairman, Department of Pediatrics, King Faisal University/King Fahd Hospital of the University, P.O. Box 40163, Al Khobar 31952, Saudi Arabia Search for more papers by this author Published Online:1 Sep 2002https://doi.org/10.5144/0256-4947.2002.408SectionsPDF ToolsAdd to favoritesDownload citationTrack citations ShareShare onFacebookTwitterLinked InRedditEmail AboutIntroductionTo the Editor. Congenital dyserythropoietic anemias (CDA) are a group of hereditary refractory anemias characterized by ineffective erythropoiesis, typical morphological abnormalities of erythroblasts, low or no reticulocyte response, hyperbilirubinemia and splenomegaly.1 We report a case of CDA with ringed sideroblasts presenting neonatally. This is a rare finding in CDA.2CASE REPORTA full-term male Saudi infant presented after delivery with pallor, splenomegaly (6 cm below left costal margin) and a systolic murmur over the left precordium. CBC showed hemoglobin at 11.8 g%, hematocrit 36.8%, mean corpuscular volume (MCV) 100 fl, and reticulocytes at 12.5%. Peripheral blood smear suggested erythroblastosis fetalis. Hb electrophoresis showed Hb A1 at 21.3%, Hb F 70.9%, and Hb Bart's at 7.2%. G6PD screen was normal. Echocardiography showed a small ventricular septal defect and patent ductus arteriosus. The diagnosis of a-thalassemia, probably Hb H disease, was initially considered.On the fourth day of life, the Hb dropped to 9.7 g% and the patient was transfused. Two months later, the Hb dropped to 4.2 g% and a second packed RBC transfusion was given. At age of 4½ months, Hb was 5.8 g%, MCV 77 fl, and reticulocytes 2.5%. Repeat Hb electrophoresis showed Hb A1 at 99%, and Hb A2 at 1%. Hb H preparation as well as acidified serum (Ham) test was negative. Serum ferritin was high. Bone marrow aspiration showed brisk erythropoiesis with dyserythropoietic features such as moderate megaloblastic morphology, binuclearity, cytoplasmic bridges, many mitotic granules and occasional ring sideroblasts.DISCUSSIONCDAs are a group of hereditary refractory anemias characterized by ineffective erythropoiesis, typical morphological abnormalities of erythroblasts, low or no reticulocyte response, hyperbilirubinemia and splenomegaly.3 CDA can be diagnosed in early childhood, however, diagnosis is complicated due to poor knowledge of the morphological criteria and the large number of differential diagnoses that have to be excluded.4Our patient had an early onset of anemia and splenomegaly (at birth) He had sideroblasts in the bone marrow with occasional ring forms, which is a rare finding in CDA.2 Absence of microcytosis and hypochromia makes sideroblastic anemia unlikely.5The first Hb electrophoresis revealed a picture of α-thalassemia trait. The level of Hb Bart's (7.2%) should have been considered relatively low for Hb H disease.6 The correct diagnosis of CDA was made at the age of 4½ months after presentation. However, the mean age for establishing the correct diagnosis seems to be much later in other reports.7ARTICLE REFERENCES:1. Delaunay J, Iolascon A. "The cogenital dyserythropoietic anemias" . Baillieres Best Pract Res Clin Hematol. 1999; 12:691–705. Google Scholar2. Soysal T, Akun E, Ozaras R, et al.. "Congenital dyserythropoietic anemia type 1 with ringed sideroblasts" . Hematologia (Budapest). 2000; 30:45–9. Google Scholar3. Tekinalp G, Sarici SU, Erdinc AS, et al.. "Lethal hydrops fetalis due to congenital dyserythropoietic anemia in a newborn: association of a new skeletal abnormality" . Pediatr Hematol Oncol. 2001; 18:537–42. Google Scholar4. Rossler J, Havers W. "Diagnosis and genetics of congenital dyserythropoietic anemia (CDA)" . Klin Pediatr. 2000; 212:153–9. Google Scholar5. Elias S. Sideroblasts anemias. In: Behrman , Kliegman , Jenson editors. Nelson Textbook of Pediatrics. Philadelphia: Saunders, 2000: 1471. Google Scholar6. Quadri MI, Islam SI, Zaki Nasserullah. "The effect of α-thalassemia on cord blood red cell indices and interaction with sickle cell gene" . Ann Saudi Med. 2000; 20:367–70. Google Scholar7. Iolascon A, Delaunay J, Wickramasinghe SN, et al.. "Natural history of congenital dyserythropoietic anemia type 2" . Blood. 2001; 15;1258–60. Google Scholar Previous article Next article FiguresReferencesRelatedDetails Volume 22, Issue 5-6September-November 2002 Metrics History Published online1 September 2002 InformationCopyright © 2002, Annals of Saudi MedicinePDF download

Relationship between total homocysteine and folate levels in pregnant women and their newborn babies according to maternal serum levels of vitamin B12.

To determine total homocysteine and folate levels in pregnant women according to vitamin B12 (B12) levels, and to analyse the impact of maternal B12 levels on the nutritional status of their newborn babies. Cross sectional observational study. Two public hospitals in Jundiai City, São Paulo, Brazil. Sixty-nine pregnant women and their respective newborn babies at the time of delivery. Maternal blood was collected up to 8 hours before delivery. Umbilical cord blood was collected after the expulsion of the placenta. Total homocysteine was measured by high perfomance liquid chromatography, folate by ion capture methodology and B12 by enzyme immunoassay. Relationship between low maternal vitamin B12 levels and total homocysteine and folate levels in pregnant women and newborn babies. There was a significant correlation between maternal and neonatal B12 levels, but not between maternal B12 and neonatal red blood cell (RBC) folate. There was a weak correlation between maternal B12 levels and neonatal serum folate. However, there were significant correlations between maternal and neonatal total homocysteine levels and between neonatal B12 and neonatal total homocysteine levels. Mean (+/- SD) umbilical cord blood B12, RBC folate, serum folate and total homocysteine levels were 1.7 +/- 0.8, 1.8 +/- 0.8, 2.2 +/- 0.8 and 0.9 +/- 0.3 times higher than maternal B12, RBC folate, serum folate and total homocysteine values, respectively. These data suggest that pregnant women with low B12 levels are unable to provide the necessary amount of B12 to their fetuses. The clinical consequences could be the presence of neurological abnormalities as well as the lack of utilisation of homocysteine for methionine transformation.

Anti-Mta associated with three cases of hemolytic disease of the newborn

Abstract The Mta antigen is a low-frequency red blood cell (RBC) surface antigen and is an established antigen of the MNSs blood group system. There has been one report of anti-Mta–induced hemolytic disease of the newborn (HDN) in the literature to date. We describe a family in which three children were affected by neonatal anemia. The clinical and hematologic findings were consistent with HDN, despite repeatedly negative direct antiglobulin tests (DAT) on cord RBCs. Serologic investigations showed that the mother’s serum contained anti-Mta. The father and all three children phenotyped as Mta+, while the mother was Mta–. Adsorption and elution experiments gave results which suggested that anti-Mta may be implicated in recurrent HDN in this family. Immunohematology 2002;18:37–39.

Preeclampsia and Na,K-ATPase Activity of Red Blood Cell Ghosts from Neonatal and Maternal Blood

We determined Na,K-ATPase activity and cholesterol/phospholipid ratio of maternal and cord red blood cell ghosts from either normotensive or preeclamptic pregnant women. The Na,K-ATPase activity of the red cell ghosts from neonatal blood is significantly lower (25–32%) as compared with the ATPase activity of the maternal red cell ghosts, regardless of the presence or not of preeclampsia. This diminution in Na,K-ATPase activity of the neonatal red blood cell ghosts could be due to an increase in the cholesterol/phospholipid molar ratio of the membrane. The Na,K-ATPase activity of the red blood cell ghosts from pregnant women was unaffected by preeclampsia; however, fetal red blood cell ghosts from infants of preeclamptic mothers showed a significantly lower ATPase activity (20%) than fetal red blood cell ghosts from infants of normotensive mothers. A low Na,K-ATPase activity in the neonatal red blood cells from mothers with preeclampsia could be an indication of an important modification of the physiological role of this enzyme.

The Effect of α-Thalassemia on Cord Blood Red Cell Indices and Interaction with Sickle Cell Gene

AA+/--thalassemia is known to be prevalent in the Eastern region of Saudi Arabia. There are no large scale reports regarding the effect of alpha-thalassemia on red cell indices of cord blood from Saudi Arabia. Similarly, there are no reports regarding the interaction of AA+/--thalassemia and the sickle cell gene in relation to red cell indices in cord blood. To address these issues, we undertook a study on neonatal cord blood samples. In a prospective study, cord blood samples from 504 neonates from the Qatif area of the Eastern Province of Saudi Arabia were analyzed for complete blood counts (CBC) and cellulose acetate Hb electrophoresis. Hb S was confirmed by citrate agar Hb electrophoresis. There were 243 case samples with normal Hb electrophoresis (Hb A 27.2+/-7% and Hb F 72.6+/-7.7%). Their mean Hb (g/dL), RBC (x10(12) /L), Hct (%), MCV (fl), MCH (pg), MCHC (g/dL), RDW-SD (fl) and RDWCV (%) were 15.05+/-1.6, 4.5+/-0.5, 47.4+/-5.3, 106+/-8, 33.6+/-2.3, 31.8+/-1.7, 69.2+/-9.5 and 17.9+/-1.7, respectively. There were 136 cases with alpha-thalassemia trait (alphaTT), 57 cases with sickle cell trait (SCT) and 50 cases of sickle cell trait with alpha-thalassemia trait (SCT/alphaTT). There were 10 cases of Hb H disease (6 definite), including one with sickle cell disease (SCD) and two with SCT, Hb Bart's 23.9%-43.6%; four probable with Hb Bart's 10.9%-16.1%, and one with SCT. The effect on red cell parameters in Hb H disease were most pronounced. In addition, there were seven cases of SCD, four of whom had coexistent AA+/--thalassemia trait (SCD/alphaTT). The prevalence of alpha-thalassemia in this cohort of Saudi population was 39.99%. Hb H disease appeared as common as SCD. Sickle cell gene was seen in 23.4% of neonatal samples. alpha-Thalassemia gene significantly reduces MCH, MCV, RDW-SD, Hct, Hb, and increases RBC count in both normal or sickle cell trait neonates. Generally, the variation of red cell parameters is directly proportional to the amount of Hb Bart's in the cord blood. Sickle cell gene in itself produces low MCV, RDW-SD and MCH in cord blood. Further, normal reference values for red cell parameters of cord blood are established.

Sodium potassium adenosine triphosphatase activity in preterm and term infants and its possible role in sodium homeostasis during maturation

AIMTo investigate sodium (NA+) potassium (K+) adenosine triphosphatase (ATPase) activity in newborn infants at different gestational ages, to elucidate the mechanism underlying poor renal sodium conservation in preterm infants.METHODSFifty three...

The murine monoclonal antibody NaM26-4C6 identifies a common structure on band 3 and glycophorin C.

The murine monoclonal antibody NaM26-4C6 (IgM class), obtained from the splenocytes of a BALB/c mouse immunized with human umbilical cord red blood cells, was characterized by agglutination test and immunoblotting analysis. The structure of the NaM26-4C6 epitope was further elucidated by using a series of peptides synthesized on pins. The antibody agglutinated untreated and chymotrypsin-treated but not trypsin- or neuraminidase-treated human erythrocytes. Agglutination-inhibition test demonstrated that the antibody recognizes an epitope located on the N-terminal trypsin-sensitive portion of glycophorin C. The antibody bound on immunoblots to glycophorin C, and also to the band 3 protein and its 69-kDa N-terminal fragment but did not bind to desialylated and de-O-glycosylated glycophorin C. Peptide mapping allowed localization of the binding site on the 23-kDa N-terminal intracellular peptide of band 3. The antibody binds to the amino-acid sequences 22EDPDIP27 of band 3 protein and 15SLEPDPGM22 of glycophorin C, and residues D and P were found to be essential. The new epitope identified by NaM26-4C6 corresponds to a linear amino acid sequence located on the N-terminal intracellular portion of band 3 and to a more complex structure involving oligosaccharide chains on the N-terminal extracellular domain of GPC.

Rabbit IgG Antibodies against Cord Red Blood Cell Membranes Bind to Complement Receptor 1 (CD35)

We have previously shown that a subpopulation of cord/fetal red blood cells (RBC) binds rabbit IgG antibodies raised against cord RBC and absorbed on adult RBC (F-IgG), while control IgG, raised against and absorbed on adult RBC (A-IgG), fails to do so. In the present study, F-IgG maintained its binding to cord RBC surface antigens following absorption on spectrin but not after absorption on skeleton-stripped RBC membranes. Spectrin-absorbed F-IgG- but not A-IgG-affinity-purified material from cord RBC contained polypeptides with apparent MW of complement receptor 1 (CR1) allotypes. Moreover, on immunoblotting these polypeptides reacted with ¹²⁵I-F-IgG as well as with ¹²⁵I-anti-CR1 mAb, and binding of ¹²⁵I-anti-CR1 mAb was inhibited by unlabelled F-IgG. In addition, cord RBC incubated with F-IgG prior to reaction with anti-CR1 showed decreased fluorescence intensity on flow cytometry. Taken together the results suggest that F-IgG binds to CR1 which shows increased expression/accessibility on a subpopulation of cord/fetal RBC.

Effect of vitamin K1 on glucose-6-phosphate dehydrogenase deficient neonatal erythrocytes in vitro

AIMTo determine whether vitamin K1, which is routinely administered to neonates, could act as an exogenous oxidising agent and be partly responsible for haemolysis in glucose-6-phosphat-dehydrogenase (G-6-PD).METHODSG-6-PD deficient (n=7) and...

Identification of Free Deaminated Sialic Acid (2-Keto-3-deoxy-d-glycero-d-galacto-nononic Acid) in Human Red Blood Cells and Its Elevated Expression in Fetal Cord Red Blood Cells and Ovarian Cancer Cells

Chemical studies have shown the occurrence of the deaminated sialic acid 2-keto-3-deoxy-D-glycero-D-galacto-nononic acid (KDN) in paired samples of blood obtained from mothers and newborns of healthy human individuals. Most of the KDN was found in red blood cells, although low levels were detected in mononuclear cells. No N-glycolylneuraminic acid was detected. Unexpectedly, nearly all of the KDN in fetal cord and matched maternal red blood cells was present as the free sugar and comparatively little occurred conjugated or as cytidine 5'-KDN phosphate. The amount of free KDN in fetal newborn red blood cells was 2.4-fold higher than in red blood cells from the mothers or from healthy nonpregnant women. Free KDN was also identified in normal human ovaries, in ovarian tumors, and in ascites cells obtained from ovarian cancer patients. Importantly, as in fetal cord red blood cells, a distinguishing feature of KDN expression in ovarian tumor cells was an elevated level of free KDN compared with normal controls. A positive correlation was found between an increase in the ratio of free KDN/N-acetylneuraminic acid in ovarian adenocarcinomas and the stage of malignancy. This was particularly evident in tumor cells isolated from the ascites fluid. The central importance of these new findings is 2-fold. First, they show that free KDN is a minor but ubiquitous sialic acid in human red blood cells and that its elevated expression in red blood cells from fetal cord blood compared with maternal red blood cells may be developmentally related to blood cell formation during embryogenesis. Second, the enhanced expression of KDN in ovarian cancer cells suggests that this sialic acid, like the alpha2,8-linked polysialic acid glycotope, may be an oncofetal antigen in these tumors and thus could be an "early warning" signal for onset of disease and/or a marker for detection of recurrence of disease. These new findings highlight the importance of elucidating the role that KDN and KDN-containing glycoconjugates may play in normal development and malignancy.

New method for quantitative determination of fetal hemoglobin-containing red blood cells by flow cytometry: Application to Sickle-Cell Disease

A new method to quantify red blood cells (RBCs) containing fetal hemoglobin (HbF), or F cells, by flow cytometry was developed. The use of formaldehyde as fixative agent and sodium dodecyl sulfate (SDS) to permeabilize fixed RBCs resulted in a low staining background, a negligible Hb leakage, and minimal cell clumping. HbF was detected by immunofluorescence with a murine monoclonal antibody directed to the gamma chain of human Hb. The accuracy of the F-cell count was evaluated on mixed-field populations of adult and cord RBCs. The results of flow cytometry were highly correlated with HbF dosage in the hemolysate by high-pressure liquid chromatography (HPLC) (R > 0.99). The sensitivity of the method allowed the study of HbF distribution at the single-cell level in normal controls and patients with sickle-cell disease (SCD). All patients exhibited a heterocellular distribution of HbF, with highly variable percentages of F cells and non-F cells. As an additional and valuable biological parameter in SCD, the mean HbF content per F cell could be deduced from the measurement of HbF level by HPLC and F-cell count by flow cytometry. Results were unchanged after storing the cells for several weeks in an optimized resuspending solution. Since it does not need uncommon reagents or devices and allows the simultaneous detection of membrane antigens by two-color flow cytometry, this method is convenient for routine laboratories as well as for research purposes.