Rh Subgroups Research Articles

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.

Highly Accurate Rhesus and Kell Blood Group Phenotyping of Autologous Red Cells after Allogeneic Blood Transfusion Using a Simplified Method of Microhematocrit Centrifugation and Automation with the DiaMed Classic ID-Gel Station and Diaclon 'Rh Subgroups+K' Gel Cards.

The presence of residual donor red cells in transfused patients impairs the ability to obtain a reliable phenotype for subsequent allogeneic blood transfusions. Post transfusion phenotyping is particularly important in transfused patients developing multiple or weak blood group antibodies. However, separation of autologous and transfused red cells from recently transfused patients is necessary for the proper identification of any suspected red cell alloantibody or autoantibody. The standard technique for the separation of autologous from transfused red cells involves microhematocrit centrifugation with phytate ester solution, a laborious and time consuming method. We have examined the effectiveness of a simplified microhematocrit technique, omitting the use of esters, to separate autologous and transfused cells by performing Rhesus (Rh) and Kell (K) blood group phenotyping, both manually and by automation, pre and post transfusion. The Rh phenotype and K type were recorded on pre- and post-transfusion peripheral blood samples from 100 newly transfused operating theatre patients, both manually and by automation using the DiaMed Classic ID-Gel Station and Diaclon 'Rh subgroups+K' gel cards. On post transfusion blood samples, separation of autologous from transfused cells was performed using the Haematospin 1300, based on the difference in the specific gravity between reticulocytes and mature red cells where the autologous cells concentrate in the top layer of the microcapillary tube. This separation was performed on blood samples taken three days post transfusion, based upon the normal reticulocyte maturation time of three days. On all samples tested, there was 100% correlation between manual and automated ID-GEL Station results. On Rh phenotyping of post transfusion blood samples prior to cell separation, 46 of the 100 patients had a mixed field (Mf) reaction. Repeat Rh phenotyping of day three post transfusion samples, following separation of autologous cells using the microhematocrit centrifugation technique, showed complete correlation with pre transfusion Rh phenotyping results in all but two cases, where a Mf reaction persisted. These two cases had had massive blood transfusions (40 and 36 units of red cells respectively) compared to the amount of red cells (mean 3.3 units, range 1–15) transfused to the other 98 patients. One week after initial Rh phenotyping, allowing sufficient time for autologous reticulocyte recovery in these two patients, repeat Rh phenotyping of separated autologous cells correlated with that of the pre transfusion results. 6 of the 100 patients were K positive on pre transfusion testing. Repeat testing of post transfusion blood samples prior to cell separation showed a Mf reaction for the K antigen in two of these 6 cases, suggesting transfusion of K antigen negative red cell units. Once cell separation was complete, both patients were confirmed as K positive. In conclusion, the simplified microhematocrit centrifugation technique and automated ID-Gel station are reliable, sensitive and less hazardous in providing an accurate Rh phenotype and K type on patient blood samples taken three days post transfusion and could be easily performed in the standard blood transfusion laboratory. The only limitation to this technique is an inability to separate autologous and transfused cells from patients who have undergone massive transfusions within a short space of time.

Specificity C and e: tests using Rh variant cells.

Monoclonal antibodies, specificity C, e, and Rh subgroup? ein the Section 1-Rh were tested with selected blood samples of various Rh variant types in KwaZulu-Natal, South Africa. The standard red cell serological techniques supplied were used.

Neuropsychological correlates of localized cerebral lesions in non-aphasic brain-damaged patients.

A neuropsychological test battery made up of verbal, visual-spatial, and intelligence tests was administered to 82 right and 67 on-aphasic left brain-damaged patients with localized cerebral lesions, in order to draw impairment profiles of the various subgroups. Separate analyses were undertaken on patients with unilobar and multilobar lesions. As for hemisphere effects, LH patients performed worse than RH subjects on verbal tests, while the reverse was true for visual-spatial tasks. As for lobe effects, patients with frontal lobe damage fared worse than other subgroups on word fluency, independent of the side of the lesion. RH patients with multilobar posterior lesions were significantly more impaired than other RH subgroups on the test of Copying Drawings with Landmarks, probably owing to the detrimental effect of unilateral spatial neglect on tasks requiring an accurate visual-spatial analysis.

Erythroblastosis fetalis due to factor c(hr'); a practical method for investigating sensitization to Rh subgroup factors.

Erythroblastosis fetalis (hemolytic disease of the newborn) is a disease wherein the clinical laboratory attains special achievement, inasmuch as the diagnosis, prognosis, and prescription for therapy may be provided by means of laboratory procedures. As a matter of fact, a great deal may be accomplished prior to the birth of the patient. Thus, it seems worthwhile to re-emphasize 2 points that are pertinent to this problem in the average clinical laboratory: 1. The staff of the laboratory should be prepared for a practical solution to the problem when the disease is the result of factors other than D(Rh0). Allen 1 estimated that AB, K, c, E, and C factors account for approximately 20 per cent of all instances of erythroblastosis fetalis. Recent papers u indicate that ABOincompatibility may be the cause of erythroblastosis fetalis more frequently than previously recognized, but most of these patients have only a slight degree of disease that might be overlooked. Even the obvious clinical cases pose a vexing diagnostic problem that will not be discussed in this paper. 2. The cross-matching procedure should include technics that enable detection of incompatibilities of minor groups. This is highly important, owing to the fact that the routine procedures for typing usually include the identification of only 3 of at least 16 blood factors that are clinically significant, and cross-matching is relied upon for the detection of incompatibility from the other factors. This paper deals with a case of erythroblastosis fetalis that resulted from sensitization to c(hr') factor; a delay in accurate diagnosis and adequate therapy was attributable to the use of an unreliable cross-matching technic that is used rather commonly. Further studies with methods that may be used in the average clinical laboratory revealed that sensitization to c(hr') factor was the underlying cause of the erythroblastosis.

Erythroblastosis fetalis associated with Rh-positive mothers

F OLLOWING close upon Landsteiner and Wiener ' s I discovery of the Rh factor, Levine and his associates 2 developed the idea of maternal isoimmunization i n the pathogenesis of erythrob]astosis fetalis, demonstrating the relationship between Rh incompatibili ty and erythroblastosis fetalis. In over 90 per cent of the cases the fa ther and child were Rh positive and the mother, Rh negative. Clinically, erythroblastosis fetalis is considered as a single disease with three chief recognized forms, called fetal hydrops, icterus gravis, and congenital anemia. Erythroblastosis fetalis is generally considered as being synonymous with Rh incompatibili ty and associated with Rh-negative mothers in over 90 per cent of the eases. However, not ~11 cases of erythroblastosis fetalis are caused by the Rh antigen-antibody reaction. On a theoretical basis, incompatibilities can occur f rom any blood antigen which is present in the father, t ransmit ted to the offspring, and absent in the mother. The Rh subgroups, the H r factor, and ABO group incompatibilities are possible etiological agents. The M, N, and P factors are apparent ly not antigenic. Tovey a gives four reasons why the fetus enjoys protection from the mother 's agglutinins in heterospeeific pregnancies :