Rhesus Phenotypes Research Articles

A Survey Of The Status Of Common Rhesus Phenotypes In Port Harcourt

AIM:To generate requisite data of the common Rhesus phenotypes that would assist in the provision of safe and efficient blood transfsion service in the Niger Delta. METHOD:Random sampling of adult blood donors and pregnant women presenting to the UPTH using potent commercially prepared Rhesus antisera (Anti-CD,anti-DE,anti-C,anti-anti-c and anti-E). RESULTS:65 samples (35 pregnant women and 30 blood donors) were screened .The commonest Rhesus phenotype was c(100%),followed by D,C,E with 95.38%,21.53% and 16.92%.The prevalence of Rh D negative in this study was also found to be 4.6%. CONCLUSION:The finding that the c phenotype is the most common Rhesus phenotype is at variance with previous studies which indicate that the D phenotype is the most common subtype.This may be attributed to the small size of the sample poulation,increased inter-tribal marriages,rural-to-urban migration and the heterogeneous population of the cosmopolitan city of Port Harcourt. Key words: Survey, Common, Rhesus, Phenotype, Port Harcourt Highland Medical Research Journal Vol.2(1) 2004: 22-27

The Half-life of Infused Factor VIII Is Shorter in Hemophiliac Patients with Blood Group 0 than in those with Blood Group A

A considerable inter-individual variation in half-life of infused factor VIII is observed among patients with hemophilia A. The factors contributing to this wide range in factor VIII half-life are not known in detail. We analysed the pharmacokinetics of infused factor VIII in 32 patients with hemophilia A, comprising 20 brothers from 10 families, 3 and 4 brothers from 2 families, and 5 patients from 5 single families, respectively. Multiple linear regression analysis was used to assess the effect of several variables on factor VIII half-life. We found that the pre-infusion von Willebrand factor antigen levels (vWF:Ag) were positively correlated with factor VIII half-life (r = 0.52, p = 0.002), i.e., each variable was associated with about 27% of the variance of the other. In fraternal pairs, familial clustering was significant for ABO blood group (p < 0.001), but could not be detected for factor VIII half-lives or pre-infusion vWF:Ag levels. vWF:Ag level (p = 0.001) and ABO blood group (p = 0.003) significantly determined factor VIII half-life, whereas age, length, bodyweight, the presence or absence of a factor VIII gene inversion, and Rhesus phenotype did not. Patients with blood group O exhibited a statistically significant shorter factor VIII half-life than patients with blood group A (15.3 versus 19.7 h, respectively) (p = 0.003). Patients with blood group A and O differ in respect to the presence of anti-A antibodies in the latter. It is possible that these anti-A antibodies interact with endogenous vWF, thus affecting the half-life time of the factor VIII/vWF complex.

Flow cytometric analysis of erythrocytic D antigen density profile.

Red blood cells (RBC) were studied with flow cytometry (FCM) after staining with a directly fluoresceinated anti-D antiserum. The immunofluorescence distribution profiles were slightly asymmetrical, due to a significant, yet small skewness. This skewness was not associated specifically with D antigen positivity, making a homogeneous, normal D antigen distribution on the RBC very likely. With the exception of Du, D-positive RBC could always be distinguished from D-negative ones. FCM was successful in bringing the following phenomena to light: difference in mean fluorescence intensity between the different rhesus phenotypes, the D gene dosage effect, the depressing effect of C antigen on D antigenicity, the nonspecific attachment of IgG on (D-negative) RBC and rhesus mosaicism. The absolute number of D antigen sites could be calculated, using an absolute fluorescence standard.

Flow Cytometric Analysis of Erythrocytic D Antigen Density Profile

Red blood cells (RBC) were studied with flow cytometry (FCM) after staining with a directly fluoresceinated anti-D antiserum. The immunofluorescence distribution profiles were slightly asymmetrical, due to a significant, yet small skewness. This skewness was not associated specifically with D antigen positivity, making a homogeneous, normal D antigen distribution on the RBC very likely. With the exception of D^u, D-positive RBC could always be distinguished from D-negative ones. FCM was successful in bringing the following phenomena to light: difference in mean fluorescence intensity between the different rhesus phenotypes, the D gene dosage effect, the depressing effect of C antigen on D antigenicity, the nonspecific attachment of IgG on (D-negative) RBC and rhesus mosaicism. The absolute number of D antigen sites could be calculated, using an absolute fluorescence standard.

Identification of the platelet alloantigen (PlA1) in circulating immune complexes of normal human sera.

An analysis of cell membrane material present in circulating immune complexes isolated from normal human sera by precipitation with polyethylene glycol (PEG) has been performed with the platelet alloantigen PlA1 and rhesus antigen used as markers. PEG precipitates obtained from the sera of subjects of known PlA1 and rhesus phenotype were resuspended in buffer and analyzed as representative of circulating immune complexes (CIC). The consumption of anti-PlA1 serum by CIC was determined by immunofluorescence and by inhibition of sodium 51chromate release from PlA1-positive target platelets. With these two techniques, PlA1 alloantigen activity was detected in CIC. This finding suggests that at least some of the cell membrane material present in CIC is derived from platelets.

A study of different rhesus phenotypes and their binding characteristics.

A method has been developed using the Auto Analyzer to study the binding characteristics of anti-D with cells of various rhesus phenotypes. A positive association has been demonstrated between site density and association constant. A hypothesis is proposed for the presence of two types of antigenic sites on the cell surface recognised only by affinity difference. The high affinity site binds both arms of an IgG anti-D molecule, whereas the low affinity site binds only one.

A Study of Different Rhesus Phenotypes and their Binding Characteristics

A Study of Different Rhesus Phenotypes and their Binding Characteristics

Demonstration of the Rhesus haplotype CdE (r-y) in the genotype of 48 subjects from 8 families. Genotype CdE/CdE (r-yr-y) in 2 members of the same family.

Forty-eight individuals heterozygous for CdE (R-Y) haplotype were identified in the pedigrees of 8 kindreds containing 128 members. Two homozygotes CdE/CdE (r-yr-y) were found in a large inbred kindred. Our study among French blood donors of the Seine-Maritime region demonstrated that about one of two individuals possessing the Rhesus phenotype CcdEd (rh'rh') carried the CdE (r-y) haplotype.

Evidence of the existence of the rhesus complex Cde (r') in a Chinese.

Abstract. A study of the Rhesus phenotypes of a Chinese‐Indian family in Singapore has provided evidence for the existence of the Rhesus complex Cde (r') in a Chinese. This finding appears noteworthy in view of the low frequency of ‘Rhesus negative’ complexes hitherto reported in Chinese.

Evidence for the Existence of the Rhesus complex Cde (r’) in a Chinese

A study of the Rhesus phenotypes of a Chinese-Indian family in Singapore has provided evidence for the existence of the Rhesus complex Cde(r') in a Chinese. This finding appears noteworthy in view of the low frequency of ‘Rhesus negative’ complexes hitherto reported in Chinese.

Rhesus phenotypes and Rh (D) haemolytic disease of the newborn.

Rhesus phenotypes and Rh (D) haemolytic disease of the newborn.

Rhesus Phenotypes and Rh(D) Haemolytic Disease of the Newborn

Rhesus Phenotypes and Rh(D) Haemolytic Disease of the Newborn

The ABO and Rhesus blood groups in Perthes' disease

Determinations were carried out of the ABO blood groups and Rhesus phenotypes of a series of 142 children with Perthes' disease. Where possible their parents and sibs were also grouped. Sera from the mothers of affected children were examined for the presence of Rhesus antibodies. No apparent association was demonstrated between Perthes' disease and any ABO phenotype. The disease is also apparently independent of ABO incompatibility between mother and child. There is the suggestion in these families of an increased incidence of the Rhesus cc phenotype among the affected children. The level of significance is estimated at 0.02, even after taking into account the numerous significance tests possible on the data. Parental and sibship studies show that any association between Perthes' disease and the Rhesus Cc phenotypes, if one does exist, is unlikely to be the product of genetical stratification within the population. Maternal Rhesus antibody, acting through the agency of haemolytic disease of the newborn, plays no detectable part in the aetiology of a subsequently developing Perthes' disease in the child.