Rh Blood Type Research Articles

The affecting factors for the detection of RH blood type

Objective To explore the affecting factors for the detection of RH blood type and to ensure the labs to detect blood type rapidly and accurately by analyzing the methods of detecting RH blood type.Methods RH antigen was detected in the blood samples from 106 852 donators; the samples with negative RH ( D )were screened by normal saline and then re-tested by polybrene and indirect antihuman globulin.Results 316 of 106 852 ( 0.3％ ) donators were RH ( D ) negative,3 of whom had Du subtype.Conclusions Normal saline for screening RH ( D ) negative blood samples,and indirect antihuman globulin and polybrene for confirming RH ( D ) negative can effectively ensure the accuracy of detection of RH blood type and has important significance of blood transfusion safety. Key words: Blood transfusion; Detection of RH blood type; Clinical significance

The relationship between ABO/rhesus blood groups and type 2 diabetes mellitus in Maghnia, western Algeria

AbstractBackground: To determine the relationship between ABO/rhesus (Rh) blood groups and type 2 diabetes mellitus in a western Algerian population.Method: This case-control study was conducted at the Regional Hospital Centre of Maghnia, Tlemcen, from July 2008 to May 2009, involving 280 patients with type 2 diabetes mellitus and 271 healthy controls. Blood samples were collected from the patients after consent had been obtained. The samples were tested for ABO and Rh blood groups, using the Beth-Vincent and Simonin-Michon methods. The allele frequencies were calculated according to the Bernstein formulas.Results: The χ2 test results showed that there was no association between the ABO blood group and type 2 diabetes mellitus. It was also noted that the O blood group was distributed with the highest frequency among diabetic subjects (52.85%). For the Rh system, d allele frequency presence was higher in diabetics than in nondiabetics (0.3778 and 0.3644 respectively). The difference between phenotype frequ...

Frequencies of ABO Gene and Rh Blood Groups in Hamadan, Iran

Background: Determining of gene frequencies of A, Band 0 genes from ABO blood group system and D and d genes from Rhesus system are objectives of the present study. Methods: The study was a cross sectional descriptive study. All the voluntary blood donors, 7361 people, attending to the Hamadan, Iran, Blood Bank during 1996 were studied. Primary information from the sex of blood donors and their results of ABO & Rh blood types were obtained from the official records of Hamadan Blood Bank. Then the frequencies of genes A, B, 0 of ABO system and D and d genes of Rhesus system were calculated. The final results were compared with each other according to their sex. Results: In ABO system, the most frequent blood types were 0, A, Band AB, respectively. Conclusion: The frequent alleles were 0, A, B, respectively. The frequency of AB type in women was about twice than the men. About 92% of subjects were Rh positive.

Evaluation of the effects of two techniques for analysis the formation mechanism in a rhesus D- index case

Objective To evaluate the effects of serological typing and PCR-SSP genotyping which were used for Rh blood typing and genetic basis of the Rh D- index case and her family members. Methods Rh D,C, c, E, e antigens were detected by serological typing. The characteristic sequence fragments of RHD and RHCE were amplified by PCR-SSP with a commercial reagent. Results Rh phenotypes of the proband' s family members were normal. The genotypes of PCR were consistent with their serological phenotypes. The full specific RHD bands of the proband were found. No specific RHCE bands were detected. The full specific bands of RHD and RHCE of her family members were normal. Conclusion Serological typing and PCR-SSP genotyping were complementary to RhD- diagnosis. Combination of the two technologies can help to analyze the genetic background of RhD-. Key words: RhD-; Serological typing; PCR-SSP; Genotyping; Genetic background

Morphogenetic variability during selection of elite water polo players

In this population-genetic study, we compared morphological and genetic variability of a control group of individuals with that of developing and elite water polo players from Serbia, using a test of determination of homozygously recessive characteristics in humans (HRC-test). Comparisons of the frequencies of ABO and Rh blood types were also made for the groups examined. The degree of genetic homozygosity showed not only statistically significant differences in the mean values obtained for the studied samples (control group 5.1 ± 0.2; emerging water polo players 3.5 ± 0.1; elite water polo players 1.9 ± 0.3 HRCs, out of 20 analysed characteristics), but also differences in the type of distribution, as well as the presence of specific combinations of such traits. During identification of swimming talents, the degree of genetic homozygosity showed a significant decrease, from 4.8 ± 0.3 in the group of pre-competitive young boys, to 2.7 ± 0.3 in selected adult team members, to only 1.9 ± 0.3 in elite water polo players. In the group of pre-competitive young individuals, all characteristics tested also had homo-recessive combinations, while in the group of elite water polo players only 8 of 20 traits were expressed as homozygously recessive. In the group of elite water polo players, who were World and European champions as well as Olympic champions, the frequencies of the A and B blood types were low, AB was absent, and the frequency of the O blood type was high at 72.2% (i.e. almost twice the expected percentage).

Recombinant polymeric IgG anti-Rh: a novel strategy for development of direct agglutinating reagents

Anti-Rh alloantibodies are used in research and clinic laboratories to define the Rh antigenic profile of human blood samples. IgM anti-Rh antibodies directly agglutinate Rh-positive RBCs. Anti-Rh antibodies of the IgG isotype bind to Rh antigens with a higher intrinsic affinity than IgM and sensitize RBCs, but do not induce direct hemagglutination. The aim of this work was to produce IgG anti-Rh possessing direct hemagglutinating properties of IgM. To achieve this goal, recombinant antibody technology was used to construct genes encoding Ig light and heavy chains that will form polymers with anti-Rh specificity. Expression vectors and liposome-mediated DNA transfer were used to generate transfectomas secreting human recombinant IgG3 anti-Rh. ELISA, SDS-PAGE, and hemagglutination were used to identify and characterize the recombinant antibody produced. Thus, a recombinant polymeric IgM-like IgG3 anti-Rh antibody was produced that directly agglutinates RBCs with specificity identical to that of the parent non-agglutinating IgG. The results obtained suggest that the technology used here to generate polymeric IgM-like IgG3 anti-Rh antibodies can be applied to produce Rh blood typing reagents. This approach might also be used to develop reagents for which cell surface antigen binding and agglutination or aggregation is required.

ABO, D blood typing and subtyping using plug-based microfluidics.

A plug-based microfluidic approach was used to perform multiple agglutination assays in parallel without cross-contamination and using only microliter volumes of blood. To perform agglutination assays on-chip, a microfluidic device was designed to combine aqueous streams of antibody, buffer, and red blood cells (RBCs) to form droplets 30-40 nL in volume surrounded by a fluorinated carrier fluid. Using this approach, proof-of-concept ABO and D (Rh) blood typing and group A subtyping were successfully performed by screening against multiple antigens without cross-contamination. On-chip subtyping distinguished common A1 and A2 RBCs by using a lectin-based dilution assay. This flexible platform was extended to differentiate rare, weakly agglutinating RBCs of A subtypes by analyzing agglutination avidity as a function of shear rate. Quantitative analysis of changes in contrast within plugs revealed subtleties in agglutination kinetics and enabled characterization of agglutination of rare blood subtypes. Finally, this platform was used to detect bacteria, demonstrating the potential usefulness of this assay in detecting sepsis and the potential for applications in agglutination-based viral detection. The speed, control, and minimal sample consumption provided by this technology present an advance for point of care applications, blood typing of newborns, and general blood assays in small model organisms.

Anti-D and anti-i activities are inseparable in V4-34-encoded monoclonal anti-D: the same framework 1 residues are required for both reactivities

The heavy-chain V4-34 germline gene segment is mandatory for pathologic cold-reacting autoantibodies with anti-I/i specificity (cold agglutinins) and is also preferentially used by monoclonal immunoglobulin M alloantibodies against D and other Rh antigens. The use of the V4-34 segment by monoclonal anti-D has previously been shown to also confer anti-I/i reactivity (cold agglutinin activity), which has implications for the use of such antibodies for Rh blood typing. V4-34 framework 1 (FR1) sequence is believed to be critical for cold agglutinin activity of cold agglutinins. The aim of this investigation was to use site-directed mutagenesis of a recombinant V4-34-encoded anti-D to determine the contribution of V4-34 FR1 sequence to anti-D activity and whether mutational modifications in the FR1 region could separately alter anti-D and anti-i activities. The results show that amino acid changes in V4-34 FR1 at W7, A23, and Y25 have a profound effect on anti-D activity as well as on anti-i activity. It was not possible to substantially reduce or remove anti-i activity without reducing anti-D activity to a comparable extent. The same nonpolar hydrophobic amino acids in FR1 are critical for maintaining both anti-D and anti-i activity. It is proposed that these residues influence the conformation of the antigen-binding site.

Anti‐D and anti‐i activities are inseparable in V4‐34‐encoded monoclonal anti‐D: the same framework 1 residues are required for both reactivities

BACKGROUND: The heavy‐chain V4‐34 germline gene segment is mandatory for pathologic cold‐reacting autoantibodies with anti‐I/i specificity (cold agglutinins) and is also preferentially used by monoclonal immunoglobulin M alloantibodies against D and other Rh antigens. The use of the V4‐34 segment by monoclonal anti‐D has previously been shown to also confer anti‐I/i reactivity (cold agglutinin activity), which has implications for the use of such antibodies for Rh blood typing. V4‐34 framework 1 (FR1) sequence is believed to be critical for cold agglutinin activity of cold agglutinins.STUDY DESIGN AND METHODS: The aim of this investigation was to use site‐directed mutagenesis of a recombinant V4‐34‐encoded anti‐D to determine the contribution of V4‐34 FR1 sequence to anti‐D activity and whether mutational modifications in the FR1 region could separately alter anti‐D and anti‐i activities.RESULTS: The results show that amino acid changes in V4‐34 FR1 at W7, A23, and Y25 have a profound effect on anti‐D activity as well as on anti‐i activity. It was not possible to substantially reduce or remove anti‐i activity without reducing anti‐D activity to a comparable extent.CONCLUSIONS: The same nonpolar hydrophobic amino acids in FR1 are critical for maintaining both anti‐D and anti‐i activity. It is proposed that these residues influence the conformation of the antigen‐binding site.

Identification and screening the mimic epitopes of human Rh(D)blood type antigens

Objective To screen the mimic epitopes of Rh(D)blood group antigens and identify their immunity from phage display peptide library.Methods A twelve mer phage peptide library was biopanned with anti-Rh(D)monoclonal antibody immobilized on plastic surface.After three round panning,thirty-five clones were randomly selected and positive clones were identified by ELISA and cross-reaction,followed by antibody competition inhibition assay and DNA sequencing to obtain the mimic epitopes of Rh (D)blood type antigens.The target phage clones were characterized and the antigenicity was analyzed by Western blot.Results After the third round screening,phages were enriched,and eleven positive clones were obtained.According to sequencing and competition inhibition analysis,the same-WP-Q-structure existed in seven of the eleven clones,and they had more than 40%inhibition ratio.The other clones had no same characteristics with low inhibition ratio possibly due to non-specific binding.Western blot analysis indicated that these phage clones could be specifically recognized by the anti-Rh(D)serum and they shared the same antigenicity of Rh(D)protein.Conclusions Rh(D)mimotope of-WP-Q-structure is successfully obtained by phage peptide library screening with anti-Rh(D)monoelonal antibody.The results lay the foundation for further exploration of pathogenesis and vaccine development of Rh(D)hemolytic diseases of newborn. Key words: Rh-Hr Blood-group system; Blood group antigens; Epitopes; Peptide library

Biotype Diets System®: Blood types and food allergies

Purpose: The goal of this research was to determine patterns in adverse food reactions among human biotypes, if any.Design: Blood types A1, A2, B, AB, O and Rh‐negative were correlated to four kinds of food allergies and hypersensitivities.Materials and Methods: Three studies were conducted from 1985 to 2004. Blood types were correlated to food scores from: (1) mRAST‐IgE food allergy tests, (2) mRAST‐IgG food hypersensitivity tests, and (3) T‐cell food hypersensitivity tests (ELISA/ACT® LRA). An allergy history was recorded. Data were evaluated by statistical analyses, including: ANOVA, MANOVA, Mann–Whitney U, Kruskal–Wallis, and Chi Square. Clinical categories were established by means and ranges. (4) Blood‐type specific lectins were included from the scientific literature.Results: Results were reported by blood types and food groups as raw scores and classes, and included the following: blood type A1 reacted most strongly to nuts and beans, eggs, dairy, and nightshades; while type A2 reacted to the same but more strongly to dairy, eggs and gluten grains. Type B reacted most to eggs, nuts and beans, dairy, gluten grains, nightshades, and sugars. Type O reacted most to dairy, eggs, gluten grains, and nightshades. Type AB reacted most to nuts and beans, seafood, eggs, and dairy; while A2B also reacted to gluten grains. Type Rh‐negative was most reactive to eggs, dairy, nuts and beans, and gluten grains. The highest IgE scores were among types B and Rh‐negative. The highest IgG scores were among types O, A2 and Rh‐negative. The most lectins reacted with type AB.Conclusions: The research showed patterns in food group allergies and hypersensitivities based on ABO, A1/A2 and Rh blood types. Biotype Diets is the first diet‐typing system supported by original scientific research, and has greater accuracy and specificity than other systems. More information is available at www.biotype.net.

Family history of gastric cancer: a correlation between epidemiologic findings and clinical data

The pathogenetic mechanisms behind gastric cancer are still unclear. Its familial aggregation, on the other hand, has been very well documented by many epidemiologists. Nonetheless, only a limited number of studies have analyzed possible correlations between demographic and clinical data. Between January 1988 and August 2004, 541 patients underwent gastric resection with a curative intent at our department; demographic information, laboratory data, imaging, operative notes, and pathology reports were available for all patients. During 2004 we conducted a series of structured interviews with the surviving patients or their closest relatives regarding oncological family history, limited to first-degree relatives. Family history could be obtained in 383 patients (70.8%). Gastric cancer was by far the most frequently associated tumor: 21.9% of the overall number of tumors reported in the family histories were gastric cancers. Patients were also subdivided into those having at least one other family member with stomach cancer (71 patients; 18.5%) and those with no relatives affected by gastric cancer (312 patients; 81.5%). No statistically significant differences between the groups were observed regarding the primary tumor location, size, pTNM classification, and ABO or Rh blood types. However, the intestinal histotype was significantly (P = 0.015) more frequently represented in individuals with at least one family member affected by gastric cancer compared with those with no relatives with stomach cancer (71.8% vs 55.1%, respectively). Stomach cancer has a relevant degree of familial aggregation and in our series of patients, this was even more pronounced for the intestinal histotype.

Autoantibody Formation in Sickle Cell Disease Patients Receiving Multiple Blood Transfusions.

Aim: To study autoantibody (autoAB) formation in our sickle cell disease (SCD) patients before and after instituting the practice of transfusing C, E, K blood type negative (CEKneg) packed red blood cell (pRBC) units.Material and Methods: We retrospectively reviewed blood bank records of all SCD patients that were transfused pRBCs since 1990 to date. Statistical analysis was performed using the Chi square test and Fischer's exact test.Results: During 1990–2004, a total 500 SCD patients (240 male, 260 female) received 16,617 pRBCs in our medical center. Of these, 387 (178m, 209f) received 7338 sickle negative ‘regular' pRBC units crossmatched only for ABO and Rh blood types. 121 (31.3%, 56m, 65f) patients received 7338 pRBCs and developed alloantibodies (alloABs), and those patients developed 4 cold and 30 warm autoABs. 266 patients (68.7%, m, f; 6925 transfusions) never developed alloABs, but 5 patients developed cold and no warm autoABs.16 patients developed autoABs (15 warm) simultaneously in addition to the multiple alloABs after a single pRBC transfusion. 113 patients (62m, 51f) always received 2354 CEKneg pRBCs (from 1997), 6 patients (4m, 2f; p<0.01) developed one alloAB each and only 1 warm autoAB.Patients receiving CEK matched pRBCS developed autoABs at 6 times↓frequency. It was found that the technologist required 30 more minutes and $153 extra in reagent costs for this extended CEK match. It was found that most Rh negative pRBC units were also CEKneg. 90% of our donors are Caucasian.The patients who received only ABORh matched transfusions and yet did not develop alloABs, also did not develop any warm autoABs compared to 30 warm autoABs encountered in corresponding patients that developed alloABs (p<0.001).Extended antigen matching (by an additional C,E,K antigen match) ↓ alloAB and autoAB formation. In some patients, allosensitization possibly activates the immune system into a hyperactive state leading to further, earlier, multiple and simultaneous alloAB and autoAB formation.Conclusions: This study showed that utilizing CEK negative pRBCs dramatically ↓ autoAB formation in our SCD patients. Patients that did not develop alloABs also did not develop any warm autoABs (p<0.001). AutoAB formation was more common in patients that developed multiple alloABs simultaneously, but did not result in any significant complications. These patients were also more prone to develop allergic reactions (p<0.002), prompting speculation whether allosensitization possibly activates the immune system into a hyperactive state or if certain patients are gentically more predisposed to allosensitization or both. In our population, extended antigen matching made it easier to transfuse blood units due to less formation of alloABs and autoABs. However, it resulted in a significant overuse of Rh negative pRBCs and extra cost and effort to find CEKneg pRBCs for every transfusion.Table:Incidence of autoantibody formation in patient groupsMajor patient groups# of pts# of pRBCsNumber of autoABs (% of patients)[Incidence/1000 Tx ]TotalWarmP value (CEK vs Regular)0.0050.02CEKmatched Tn pts11323541 (0.88%)[0.425]1 (1%)[0.46]Regular (ABORh)3871426339 (10%)[2.73]30 (8%)[2.1]alloAB forming pts121733834 (28%)[4.63 ]30 (25%)[4.1]No alloAB forming pts26669255 (2%)[0.7]0P value(alloAB vs non-alloAB)<0.001<0.001

Induction of Graft Versus Leukemia Effect by Mixed Bone Marrow Transplantation.

Mixed bone marrow transplantation (MBMT) is a special kind of stem cell transplant by combining autologous bone marrow transplantation (ABMT) with HLA mismatched haploidentical (3/6 loci mismatched) sibling bone marrow stem cells for the those patients who failed finding HLA matched sibling donor or HLA matched unrelated donor(MUD). As the main aim of MBMT is to induce graft versus leukemia (GVL) effect, there is no any prophylaxis regimen to be used for preventing graft versus host disease (GVHD) during the MBMT. In this study, we explore the relationship of graft versus leukemia effect induced by MBMT and long disease-free survival (DSF) of patients between two different transplant groups. (1) MBMT group: 8 patients treated by MBMT were 5 male and 3 female aged 8–40 years old suffering from acute myelocytic leukemia (AML) 6 cases (M3 2 cases, M4 2cases, M5 2case) and actue lymphoblast leukemia 2 cases (L1 and L2). After getting complete remission(CR), all of patients had received 3–5 courses of chemotherapy and then were treated by MBMT. At day +2 to +5, after autologous stem cell infusion at day 0, 20–50 ml allogenic born marrow stem cells were collected from HLA mismatched-haploidentical (3/6 loci mismatch) and ABO, Rh blood type identical sibling donor of patients with the mean number of mononuclear cell (MNC) 2.39x108 ( 0.5–5.0 x108 ) and then were infused intravenously immediately to receptor. The mean number of MNC from allogenic bone marrow accounts for 1/20 to 1/50 (1/30) of that from autologous bone marrow. Prophylaxes regimen for preventing GVHD had not been used in all cases with MBMT. (2) ABMT group: 10 cases of ABMT were compared as control including 6 male and 4 female aged from 21 to 44 year old suffering from acute myelocytic leukemia (AML) 5 cases (M3 1 cases, M2 2 cases, M5 2 case) and NHL 5 cases. We find quiet different results in two groups: (1) All cases in MBMT group had developed typical or atypical manifestations of acute GVHD in clinic within day +10 to day +100, which were diagnosed by skin pathologic biopsy. 3 patients were died because of severe aGVHD (IIIo–IVo) in the early stage after transplant. 5 cases with mild aGVHD were treated with prednisone, CSA and MTX and got control quickly, whose marrow finally kept mixed chimeris for half a year conformed by HLA gene detection and sex cheomosome analysis. All of these 5 patients are non-relape up to now and have acquired long disease-free survival for 129, 118, 113, 97 and 92 months respectively. The total relapse rate is 0%. (2) AMBT group: 6 cases of 10 were relapsed and died within 2 years after AMBT. 3 cases have get DFS for 119, 100 and 35 months respectively. The total relapse rate in 2 year is 60% in ABMT group. The results and conclusions we have get from the study indicate that MBMT may be an effective and safe therapy with much lower relapse and longer DFS because of inducing and existing of GVL effects. Patients with long DSF in MBMT group have showed close relationship with their mixed chimeris and GVL effects after MBMT. However, there are still some problems should be solved in MBMT:A more suitable infusion ratio of MNC from HLA mismatched haploidentical sibling donor and autologous marrow,A better strategy for co-infusion or delayed infusion of allogeneic stem cell,Does MBMT need GVHD prophylaxis or not?Immunotherapy for post-MBMT with DLI or DSI.

The role of preimplantation genetic diagnosis in the management of severe rhesus alloimmunization: first unaffected pregnancy: Case report

Rhesus (Rh) D alloimmunization may cause haemolytic disease of the fetus and newborn if the fetal Rh blood type is positive. Although the incidence of severe RhD alloimmunization has decreased with prophylactic anti-D immunoglobulin administration during and after pregnancy, sensitization still occurs in a small group of women. In such women, Rh disease will continue to be significant problem and for their babies who may be affected. Preimplantation genetic diagnosis (PGD) may be utilized to avoid materno-fetal blood group incompatibility in an RhD-sensitized woman. Biopsy of a single cell from early cleavage-stage embryos screening for RhD-negative embryos allows the transfer of only RhD-negative embryo(s) into the uterus. This avoids any complications related to haemolytic disease of the fetus and newborn. This article describes the first reported case of an unaffected pregnancy using PGD for Rh disease. IVF and embryo transfer resulted in a clinical pregnancy and the birth of a healthy girl confirmed to be blood type RhD negative. PGD in couples with a heterozygous RhD-positive male partner provides an option for avoiding haemolytic disease of the newborn in RhD alloimmunized mothers.

Relationship between ABO blood groups and skin cancers

Studies of associations between various cancers and the ABO blood groups have shown elevated relative risks for some categories of disease. To date, no report has evaluated the relationship between the ABO blood groups and the skin cancers. To investigate this association, we conducted a retrospective study of premalignant and malignant tumors diagnosed in Turkey. All tumors were histologically confirmed. Blood information was obtained for 98 individuals with premalignant and malignant skin tumors, and the distribution of ABO and Rh blood type for cases was compared with that of 419 healthy blood donors from the same geographic area. Although patients with blood group A were higher, group 0 lower than in controls, the differences were not significant. The distribution of Rh factor, blood group B and AB among cases and controls also did not differ significantly. We found a significant relationship between age and skin cancer (p=0.0001). Old patients had 1.238 times higher risk for skin cancer. Further studies in larger series on blood group antigens are needed to elucidate the relationship between these antigens and skin cancer.

自動輸血検査装置ＩＤ‐ＧｅｌＳｔａｔｉｏｎの使用経験‐試験管法及びＡｕｔｏＶｕｅとの比較検討‐

We compared the ID-GelStation (GS) with Auto Vue system (AV) equipment and standard tube test (TT) with regard to ABO and Rh blood typing and red cell antibody screening in 190 samples, 59 antibody-positive sera and 71 antibodies. GS showed an equal reaction to TT and AV in ABO cell typing and Rh typing. In ABO reverse typing, GS tended to show s stronger reaction than AV but a weaker reaction than TT, with which 9 of 109 samples needed to retested.In red cell antibody screening for 71 antibodies, the papain two-stage technique of GS apparently showed stronger reaction than the bromeline one-stage technique, especially for anti-Rh antibody. Further, GS detected antibodies such as anti-Fy, anti-Jk and anti-Jr which were detectable in antiglobulin testing. GS was more sensitive for anti-Rh antibody than AV in antiglobulin testing, the most important in the present blood transfusion tests. However, GS was less sensitive than the polyethylene glycol antiglobulin test (PEG-IgG) of TT. Only 4 of 10 anti-Fy and anti-Jk could be detected, suggesting that GS and AV, in which a low ionic strength solution (LISS) is used, have lower ability to detect low titer antibodies than PEG-IgG. Use of the more sensitive PEG-IgG may be for the detection of some low titer antibodies.

ABO and Rh(D) blood typing on the PK 7200 with ready-to-use kits

Abstract The performance of ready-to-use kits was evaluated on the PK 7200 blood grouping system. The Olymp Group (kit 1) and Olymp Group II (kit 2) containing anti-A, -B, -AB, and -D reagents were tested for first and second determinations of A, B, and D antigens. More than 500 RBC samples, including several variant ABO and D phenotypes, were evaluated for specificity, repeatability, reproducibility, and sensitivity. Specificity was tested with well-characterized reagent RBCs. Repeatability was established by at least 12 assays per run with three reagent RBCs, and reproducibility was established on one run per day for 5 days. No discrepancy was observed in ABO and D determinations with either kit. In repeatability, three discrepancies were found with group A and B RBCs with kit 1. In reproducibility, no discrepancies were observed. The kit 1 anti-A reagent detected A3 but not Ax RBCs and anti-AB detected both. A B3 RBC was detected by both kits. Among eight weak D phenotypes, six were positive with kit 1. With kit 2, only one of five weak D phenotypes was detected. Immunohematology 2003;19:54–56.

Is antibody screening in Rh (D)-positive pregnant women necessary?

Objective: Hemolytic disease of the fetus and of the newborn can be caused by incompatibility of maternal and fetal erythrocytes for Rh (D) or other blood type antigens. Routine antibody screening is advocated in all pregnant women, irrespective of whether they are Rh (D)-positive or Rh (D)-negative, to look for clinically significant alloantibodies other than Rh (D) that might cause hemolytic disease of the newborn. The purpose of this study was to assess the incidence of blood type antibodies other than Rh (D) in pregnant women attending for prenatal care in a typical urban population.Methods: A retrospective analysis was undertaken of the charts of all pregnant women followed throughout their entire pregnancy at our Women's Health Center from 1 January 1999 to 30 April 2002.Results: There were 1265 pregnant women included in the study: 465 had blood type A (36.7%), 269 type B (21.3%), 424 type O (33.5%) and 107 type AB (8.5%). A total of 1156 were Rh(D)-positive (91.4%) and 109 were Rh(D)-negative (8.6%). Of the Rh(D)-positive women, 522 (41.3%) underwent routine antibody screening in the first trimester. Only one woman (0.2%) had a positive antibody screen. Of the 109 Rh (D)-negative women, one (0.9%) had a positive third trimester screen witha negative first trimester screen.Conclusion: Routine antibody screening of Rh (D)-positive women is probably not warranted from a clinical cost-benefit perspective.

Fetal cells in maternal blood.

Fetal lymphocytes, trophoblasts, and nucleated red blood cells have each been separated from maternal blood by methods such as flow cytometry, magnetic cell sorting, and charge flow separation. The frequency of fetal cells among circulating maternal mononuclear cells remains to be ascertained. Current estimates range from about 10-5 to 10-7, but the numbers may be increased in women carrying aneuploid fetuses. Fetal cells separated from maternal blood have been studied by methods such as polymerase chain reaction and fluorescence in situ hybridization. Among fetal conditions so far identified are sex; human leukocyte antigen and Rh blood types; trisomy 13, 18 and 21; triploidy; and sickle cell anemia and thalassemia. Thus, fetal cell separation might one day be used for screening of the common aneuploidies and, ultimately, for prenatal diagnosis. Individual fetal erythroid precursors have been cultured after separation in some laboratories. Culturing and karyotyping of separated fetal cells might enable diagnosis of a spectrum of chromosomal and genetic disorders. Further development will be required, however, before regular clinical application of these methodologies.