RhD Antigen Research Articles

Detection of fetal RhD gene from maternal blood

Hemolytic disease of the newborn (HDN) is a clinic phenomenon which occurs during pregnancy due to the Rhesus (Rh) D alloimmunization between a Rh (-) pregnant woman, who has become sensitive to RhD antigens, and her Rh (+) fetus. As a result of the attack of maternal RhD antibodies on fetal RhD antigens, fetal anemia, HDN and fetal death may occur. % 40 of Rh (-) pregnant women carry Rh (-) fetus. However, all Rh (-) pregnant women are offered anti-D Immunoglobulin (Anti-D Ig) at 28 weeks' gestation in case of fetomaternal haemorrhage, so the pregnant women carrying Rh (-) fetus are exposed to blood products unnecessarily. Although the RhD of fetus can be detected, methods used for prenatal diagnosis recently are invasive tests and they can result in abortion in a certain percentage. The discovery of circulating cell-free fetal nucleic acids in maternal plasma has opened up new possibilities for non invasive prenatal diagnosis. The aim of this study was to detect prenatal RhD by analysing the presence of the RhD gene of fetal DNA in maternal blood. Total free DNA was isolated from the blood of 19 Rh (-) pregnant women, who had RhD alloimmunization with their husbands, in the 11-14 th week of their pregnancy. The existence of a gene in isolated DNA was investigated with TaqMan prob and "Real-time PCR" method by using primers belonging to exon 7 of RhD gene. Using a quantitative real-time PCR assay, the presence of RhD gene sequences was evaluated in the serum of patients at the onset of pregnancy. We have analyzed 19 Rh (-) pregnant women. Twelve of them were Rh (-) and the rest of them were 7 Rh (+). After birth the baby's blood groups were concordant with our results. The results obtained by RhD primer were analysed. The possibility of detection of fetal RhD gene in maternal blood contributed to noninvasive prenatal diagnosis.

Weak D prevalence among Indian blood donors

Weak D prevalence among Indian blood donors

Associações entre os fenótipos ABO, RhD, mutações da proteína Duffy e a malária vivax em habitantes do estado do Amazonas, Brasil

Abstract In this study we investigated the associations between theABO blood groups, RhD antigen and Duffy protein mutations[125 G>A ( FYA/FYB ), 265 C>T, 298 G>A (Fy x antigen) and theGATA box mutation -33(T>C)] with vivax malaria in inhabitants ofthe state of Amazonas, Brazil, an endemic area for malaria.Identification of Plasmodium vivax and the measurement ofparasitemia were achieved by standard screening tests and clinicalevaluations of 497 patients in which ABO, RhD and Duffyphenotyping was performed, as was Duffy blood group genotypingusing PCR/RFLP reactions. These results were compared withpreviously published data of the same variables in blood donorsfrom the Brazilian Amazon without any history of malaria. Ourdata show that the presence of the A antigen and FYA/FYB-33 and FYB/FYB-33 genotypes in the population may give a selectiveadvantage, thereby reducing the P. vivax infection rate in this region,however without association with the parasite load of vivax malariainfection. We did not find associations between the RhD antigenand

Potential of genotyping to personalize transfusion medicine.

Blood transfusion pioneers Blood transfusion has been part of medical treatments for centuries. Physicians performed ‘bloodletting’ to prevent or cure a whole range of illnesses and diseases until they realized blood’s essential role in preserving life. The first human–human blood transfusion reported dates back to 1818. Before that, transfusion attempts using animal blood from various species failed tragic ally. Despite the use of human blood, transfusions were not tolerated by all recipients and fatal reactions were common [1]. This phenomena remained a mystery for many years until the turn of the 20th century when Karl Landsteiner discovered the ABO blood group system. He was the first to provide a scientific basis for donor–recipient compati­ bility. Many discoveries that followed brought change to the practice of transfusion medicine. Albert Hustin was the first to add citrate to avoid blood coagulation during sampling in 1916. This simple solution stopped the need for arm–arm transfusion, which saved thou­ sands of soldiers during World War I and this advance led to the creation of the first blood­ collecting center by Arnault Tzanck (Paris, France in 1928). For all those years, blood transfusion improved the quality of life with thanks to ABO typing, which greatly reduced serious adverse reactions. However, incompatibility still remained a problem for a small portion of recipients until 1940, when Karl Landsteiner and Alexander Wiener made one more impor­ tant discovery – the RhD antigen, named after the Rhesus monkeys they used for their experi­ ments. From then onwards, blood transfusion became safe for everyone. Since these pioneers’ work, the practice of blood transfusion has evolved. The International Society of Blood Transfusion (Amsterdam, The Netherlands) recognizes 30 blood groups com­ prising over 300 antigens. Blood components are now separated to fulfill specific medical needs, automated apparatus to collect these products are used and all blood donations are tested for transmissible diseases.

Blood group serology

Blood group serology

Immunologic basis and immunoprophylaxis of RhD induced hemolytic disease of the newborn (HDN).

RhD antigen is the most immunogenic and clinically significant antigen of red blood cells after ABO system. It has historically been associated with hemolytic disease of the newborn (HDN) which is now routinely prevented by the administration of polyclonal anti-D immunoglobulin. This management of HDN has proven to be one of the most successful cases of prophylactic treatment based on antibody mediated immune suppression (AMIS). Despite the increasing efficiency of treatment, the mechanism of action of anti-D is not completely defined. There is a widespread interest in obtaining a reliable therapeutic monoclonal anti-D, due to difficulty of maintaining a pool of high titer volunteer donors for plasma collection and also increasing demand for antenatal prophylaxis and safety issues with plasma derived products. Candidate monoclonal anti-D preparations should demonstrate appropriate functionality in both in vitro and in vivo assays comparable to polyclonal anti-D immunoglobulin. These criteria are reviewed in addition to the factors regulating development of D specific immune response in D negative individuals and its suppression in HDN prophylaxis.

Fetal anemia due to non-Rhesus-D red-cell alloimmunization

Although anti-RhD was once the major etiology of hemolytic disease of the fetus/newborn (HDFN), the widespread adoption of antenatal and postpartum Rhesus immune globulin has resulted in a marked decrease in the prevalence of alloimmunization to the RhD antigen in pregnancy. Maternal alloimmunization to other red cell antigens continues to play a role as the cause of fetal disease since no prophylactic immune globulins are available to prevent the formation of these antibodies. An increasing incidence of the Kell (anti-K1) antibody has been noted in the United States. Guidelines for intervention in cases of irregular red cell antibodies are limited by the bias of anecdotal reports in the literature in favor of severe cases of HFDN. Although most diagnostic protocols used in the management of the RhD-alloimmunized pregnancy can be applied in cases of non-RhD sensitization, Kell (K1 and K2) alloimmunization should be managed more conservatively.

The Mechanisms of Action of Intravenous Immunoglobulin and Polyclonal Anti-D Immunoglobulin in the Amelioration of Immune Thrombocytopenic Purpura: What Do We Really Know?

Intravenous immunoglobulin (IVIg) has been used for more than 25 years to treat an ever-increasing number of autoimmune diseases including immune thrombocytopenic purpura. Although the exact mechanism of action of IVIg has remained elusive, many theories have been postulated, including mononuclear phagocytic system blockade/inhibition, autoantibody neutralization by anti-idiotype antibodies, pathogenic autoantibody clearance due to competitive inhibition of the neonatal immunoglobulin Fc receptor, cytokine modulation, complement neutralization, and immune complex formation leading to dendritic cell priming. Polyclonal anti-D immunoglobulin is a polyclonal IVIg product enriched for antibodies directed to the RhD antigen on red blood cells and that has also been successfully used to treat immune thrombocytopenia in RhD(+) patients. The primary theory to explain polyclonal anti-D immunoglobulin function has classically been mononuclear phagocytic system blockade, although modulation of Fcgamma receptor expression and/or immunomodulation may also play a role. Work using a murine model of immune thrombocytopenic purpura to further our understanding of the mechanism of action of these 2 therapeutic agents is a focus of this article.

Differences in Regulatory T Cell Function in Alloimmunized Versus Non-Alloimmunized Mice Following Multiple Red Cell Transfusions.

Red blood cell (RBC) alloimmunization remains a major complication for transfusion-dependent patients such as those with sickle cell disease. Alloimmunization rates in transfusion recipients lacking the antigen can be as high as 70% for the RhD antigen or much lower for minor antigens. Several factors including the host's immune status have been shown to influence the recipient's ability to react to RBC alloantigens. However, it is not clear whether inherent differences in immune response can be identified between those who have or have not developed RBC alloantibodies following multiple transfusions. Increasing evidence indicates that CD4+ regulatory T cells (Tregs) characterized by co-expression of CD25 and the forkhead/winged helix transcription factor (Foxp3) are key regulators of a wide spectrum of immune responses. We have recently found that manipulation of Treg numbers affects the rate and the frequency of RBC alloimmunization in mouse models. We hypothesized that Treg number or function may be reduced in multi-transfused recipients who develop alloantibodies compared to those who do not. To test this, we established a transfusion regimen in which B6 mice were first injected with RBCs from mice transgenic for human glycophorin A (huGPA) antigen plus CpG dinucleotides as an inflammatory signal and thereafter on a weekly basis for three weeks with GPA RBCs alone. Using this protocol, about 50% of mice (n=23, three separate experiments) developed anti-huGPA alloantibodies (IgM and IgG) which were pathogenic based on red cell survival studies. No significant differences in the frequency of Foxp3+CD25+ splenic Treg population between mice that produced alloantibodies (n=12) versus those that did not (n=11) (9.6% ± 0.7% vs. 9.5% ± 0.7%, p=0.9) as measured by intracellular staining of CD4+ T cells was observed. In addition, sorted splenic CD4+CD25+ Tregs isolated from mice that had made allo-anti-huGPA and those that did not were equally anergic following stimulation (p≥0.2), a characteristic of normal Tregs whereas effector CD4+CD25− cells from both groups of mice were highly proliferative. In contrast, when co-cultured at different suppressor/effector ratios (1:4, 1:8 and 1:16), Tregs from transfused immunized mice had an overall twofold less ability in suppressing autologous CD4+CD25− than Tregs from transfused non-immunized mice (p<0.05, n=3 separate experiments). To distinguish whether the reduced Treg suppressive activity of mice that had made alloantibodies was due to impaired suppressor function of the Tregs or a result of increased resistance to suppression by the CD4+CD25− T cells, we compared the suppressive effects of Tregs of these two groups of mice on proliferation of autologous and allogeneic CD4+CD25− cells (n=3). We found that CD4+CD25+ Tregs from transfused non-immunized mice inhibited the proliferation of alloimmunized and non-alloimmunized CD4+CD25− effector cells to the same degree (suppression=27% at suppressor/effector ratio 1:8). In contrast, CD4+CD25+ Tregs from transfused alloimmunized mice were less effective suppressors of CD4+CD25− cells from either immunized or non-immunized mice (suppression=55% at suppressor/effector ratio 1:8). Altogether our data suggest differences in functional capacities of Tregs in multi-transfused mice which have developed alloantibodies versus those who have not. This may underlie the differences in immune response in transfused recipients which consequently dictate the outcome of the induction of red cell alloantibodies.

Major ABO Blood Group Mismatch Increases the Risk for Graft Failure after Unrelated Donor Hematopoietic Stem Cell Transplantation

Two hundred twenty-four patients with leukemia transplanted with an unrelated donor between 1991 and 2003 at the Karolinska University Hospital were analyzed according to association between graft failure and ABO, RhD, MNSs, and Kidd blood group antigen compatibility. Median age was 29 years (range: 0-55). Conditioning consisted of total-body irridiation or busulfan-based myeloablative conditioning. A bone marrow graft was given to 152 patients, and 72 patients received peripheral blood stem cells. Most patients received graft-versus-host disease prophylaxis with cyclosporine and MTX. Graft failure (GF) was seen in 6 (2.7%) patients. In the multivariate analysis major ABO mismatch (odds ratio [OR] 14.9, 95% confidence interval [CI] 2.01-110, P = .008) and HLA-allele mismatch (6.42, 1.19-34.8, P = .03) was significantly associated to GF. In patients with and without major ABO mismatch the incidence of GF was 7.5% and 0.6% ( P = .02), respectively. Using an ABO major mismatched graft increases the risk for GF after unrelated donor hematopoietic stem cell transplantation.

265: Major ABO blood group mismatch increases the risk for graft failure after unrelated donor hematopoietic stem cell transplantation

Two hundred and twenty-four patients with leukemia transplanted with an unrelated donor between 1991 and 2003 at Karolinska University Hospital were analyzed according to association between graft failure and ABO, RhD, MNSs and Kidd blood group antigen compatibility. Median age was 29 years (range 0-55).). Two hundred patients and donor pairs were HLA-A, -B, and –DR identical, and 24 patients had an allele-level mismatched donor Conditioning consisted of TBI or busulfan-based myeloablative conditioning. All patients received ATG. A bone marrow graft was given to 152 patients and 72 patients received peripheral blood stem cells. Most patients received GVHD prophylaxis with CsA and MTX.Results: 135 (60%) patients received an ABO mismatched graft and 89 received an ABO matched graft. Of the mismatched grafts, 67 (30%) were major mismatched and 68 (30%) minor mismatched. A bidirectional mismatch was found in 16 (7%) cases. Graft failure (GF) was seen in 6 (2.7%) patients. In the multivariate analysis major ABO mismatch (OR 14.9, 95% CI 2.01-110, p=0.008) and HLA-allele mismatch (6.42, 1.19-34.8, p=0.03) was significantly associated to GF. In patients with and without major ABO mismatch the incidence of GF was 7.5% (5/67) and 0.6% (1/157)(p=0.02), respectively. In patients with and without HLA allele-level mismatch, the incidence of GF was 8.3% (2/24) and 2.0% (4/200)(p=0.09).Conclusion: Using an ABO major mismatched graft increases the risk for graft failure after unrelated donor HSCT. Two hundred and twenty-four patients with leukemia transplanted with an unrelated donor between 1991 and 2003 at Karolinska University Hospital were analyzed according to association between graft failure and ABO, RhD, MNSs and Kidd blood group antigen compatibility. Median age was 29 years (range 0-55).). Two hundred patients and donor pairs were HLA-A, -B, and –DR identical, and 24 patients had an allele-level mismatched donor Conditioning consisted of TBI or busulfan-based myeloablative conditioning. All patients received ATG. A bone marrow graft was given to 152 patients and 72 patients received peripheral blood stem cells. Most patients received GVHD prophylaxis with CsA and MTX. Results: 135 (60%) patients received an ABO mismatched graft and 89 received an ABO matched graft. Of the mismatched grafts, 67 (30%) were major mismatched and 68 (30%) minor mismatched. A bidirectional mismatch was found in 16 (7%) cases. Graft failure (GF) was seen in 6 (2.7%) patients. In the multivariate analysis major ABO mismatch (OR 14.9, 95% CI 2.01-110, p=0.008) and HLA-allele mismatch (6.42, 1.19-34.8, p=0.03) was significantly associated to GF. In patients with and without major ABO mismatch the incidence of GF was 7.5% (5/67) and 0.6% (1/157)(p=0.02), respectively. In patients with and without HLA allele-level mismatch, the incidence of GF was 8.3% (2/24) and 2.0% (4/200)(p=0.09). Conclusion: Using an ABO major mismatched graft increases the risk for graft failure after unrelated donor HSCT.

SI05 Peptide Therapy Suppresses the Adverse Immune Response to Red Cells

RhD is a clinically important blood group and a major target in haemolytic disease of the newborn (HDN). Current anti‐D antibody therapy to prevent antibody production in RhD negative mothers is ineffective if there has already been sensitization. Peptide immunotherapy offers an alternative approach. Helper T cell epitopes of the RhD antigen were previously identified in alloimmunized donors and we have shown that instillation of these immunodominant RhD‐specific peptides to the nasal mucosa of DR transgenic mice prevents antibody responses to RhD protein. We now wished to test whether such tolerance can be effective in switching off antibody responses in mice that have already been immunized and also the mechanism by which tolerance is achieved. DR15 transgenic mice were immunized and boosted with purified RhD protein, and the immunodominant RhD peptides given nasally, either singly or in a mixture, 4 weeks later. This treatment was found to abrogate helper T cell responses of splenocytes stimulated with RhD protein in culture. This loss in splenocyte activity was often accompanied by an increase in IL‐10 production suggesting the presence of regulatory T cells. In addition, we have demonstrated that antibody levels in the serum declined more quickly in mice that had received the peptides. Thus, nasal instillation of immunodominant peptides provides a method by which to reverse established immune responses to red cells, and this approach may be effective in reducing anti‐D titres in alloimmunized women who are at risk of HDN.

P36 A Novel RhD Variant

Introduction Variants of the RhD antigen are often categorised into weak D and partial D phenotypes, although the distinction between the two groups is unclear. One frequently used definition is the ability to make alloanti‐D in partial D, but not in weak D phenotypes, however some phenotypes characterised as weak D are now known to be associated with alloanti‐D production. On a molecular level, weak D phenotypes usually possess RHD mutations encoding amino acid subsitutions within the cytoplasmic or membrane spanning regions of RhD, whilst partial D phenotypes result from changes in the extracellular loops. Thus, weak D red cells could be regarded as having all epitopes of D, but expressed weakly, whilst partial D cells lack some D epitopes. We investigated the red cells of a black pregnant woman because of aberrant reactions obtained in routine D typing, in order to decide if prophylactic anti‐D should be given.Methods Routine anti‐D sera and a reagent anti‐D panel were tested serologically by their recommended techniques. Genomic DNA was extracted from whole blood and subjected to sequencing of exons 1 to 9 of the RHD gene.Results and treatment The Rh phenotype of the patient was C‐ c+, E‐, e+, V+, VS+. Anti‐D reagents gave variable reactions and a novel pattern of reactions was seen with an anti‐D panel. Sequencing analysis revealed a single G&gt;A mutation at position 490, within exon 4 of the RHD gene, resulting in an Aspartate to Asparagine change at position 164 of the RhD protein (D164N). This appears to be a novel RHD mutation. The patient received prophylactic anti‐D antenatally and at delivery. The maternal antibody screen and Kliehauer screen were negative and she delivered a full term D+ DAT negative infant.Conclusions A novel D variant has been identified with an D164N mutation, predicted to lie within the third extracellular loop of the RhD protein. We propose to call this D variant DDN. The molecular basis of this novel phenotype suggests that this could be categorised as a partial D , as the mutation results in a loss of D epitopes. This would be expected to result in the ability to produce alloanti‐D although alloanti‐D production was not reported in this case.

Non-Invasive Detection of Fetal Rhesus D Status: A Comparison between Polymerase Chain Reaction and Flow Cytometry

Objective: A non-invasive prenatal determination of the fetal RhD status might be useful for the management of pregnancies in RhD-negative women whose partners are RhD positive. Methods: Maternal peripheral blood of 32 RhD-negative women (17–24 weeks of gestation) was collected, and circulating fetal cells were enriched by CD71 mini-magnetic activated cell sorting. The RhD status of the fetuses was assessed using multiparametric flow cytometry, and results were compared to those of reverse transcriptase (RT)-polymerase chain reaction (PCR), or PCR, which acted as control. Flow-cytometric study of fetal cells employed monoclonal antibodies directed against CD71, glycophorin A (GPA) and RhD antigens. Results: The median percentage of CD71- and RhD-positive cells was 0.83% (range 0.14–6.44%), and that of CD71 and GPA-positive cells was 10.07% (range 0.52–45.84%). Flow-cytometric analysis correlated with RT-PCR results of RNA obtained from whole maternal blood. In 1 case, an incorrect result was due to the failure of the amplification of the specific RhD band on RNA extracted from the CD71-positive fraction. In two instances, we observed false-positive results for RhD in PCR of DNA obtained from maternal plasma. Conclusion: Based on our results, flow-cytometric analysis might be proposed as a clinical tool for the non-invasive prenatal determination of the fetal RhD status independently of fetal gender.

Diagnosing Hemolytic Disease of the Fetus — Time to Put the Needles Away?

The RhD (Rh0[D]) antigen is considered the most immunogenic of the antigens found on the surface of the human red cell. In 1941, Levine, Katzin, and Burham1 showed that antibodies to the RhD antigen in pregnant women caused hemolysis and anemia in their offspring. Originally called erythroblastosis fetalis secondary to the finding of a large number of immature red cells in the neonatal circulation, today this condition is known as hemolytic disease of the fetus and newborn.When RhD-positive fetal cells enter the maternal circulation as a result of pregnancy-related events such as miscarriage or delivery, anti-D antibody . . .

In vitro functional test of two subclasses of an anti‐RhD antibody produced by transient expression in COS cells

For over 35 years hemolytic disease of the fetus and newborn (HDFN) due to RhD has been effectively prevented by anti-RhD antibodies obtained from alloimmunized women or deliberately immunized men. However, due to the reduced number of immunized women and for ethical reasons it is foreseen that other sources of anti-RhD will be needed. One such source is recombinant human antibodies. Here we describe the construction of plasmids encoding two subclasses (IgG1 and IgG3) of an anti-RhD antibody, their transient expression in COS cells, and subsequent functional characterization of the antibodies with regard to specificity and ability to mediate a respiratory burst. The recombinant anti-RhD antibodies were specific for the RhD antigen and were able to mediate a respiratory burst. Thus these antibodies might be of use as future rhesus prophylaxis.

Taiwan experience suggests that RhD typing for blood transfusion is unnecessary in southeast Asian populations

The high frequency of RhD (D) antigen among Taiwanese persons (99.67%) often imposes unnecessary risks of under-transfusion on D- patients awaiting D- blood. Also because of the rare occurrence of anti-D among Taiwanese persons, routine pretransfusion D typing has been discontinued in the Mackay Memorial Hospital since 1988. This report is the retrospective evaluation of the outcome of abolishing RhD typing for Taiwanese. More than 10 years of alloantibody data at Mackay Memorial Hospital Blood Bank were reviewed. The cases with anti-D were further used to analyze the potency of D antigen and to observe whether there were differences in the incidence of anti-D before and after discontinuation of routine D typing among Taiwanese individuals. The incidence of anti-D before and after discontinuation of routine pretransfusion D typing has remained unchanged. The immunogenicity of D and "Mi(a)" in Taiwanese persons is found to be similar. In terms of opportunity for immunization, however, the "Mi(a)" antigen (phenotype frequency 7.3% in Taiwanese persons) has become the most important blood group antigen in Taiwan. The results strongly support the exclusion of D typing from routine compatibility testing for individuals of Taiwanese origin. Because the low incidence of D- and relatively high incidence of "Mi(a)"+ phenotypes are common findings throughout southeast Asia, and because a population genetic study revealed that the Taiwanese people are genetically related to southern Asian populations, it is suggested that RhD typing for blood transfusion is unnecessary among southeast Asian populations.

Secondary anti‐D immunization by Del red blood cells

Recent molecular studies of the RHD gene have revealed that D(el) individuals retain a grossly intact RHD gene or have a portion of RHD in their genomes. No D(el) phenotype has yet been shown to induce a primary or secondary alloanti-D immunization, however. A 67-year-old D- Japanese woman with a history of allosensitization from transfusion of D+ red blood cells (RBCs) was negative for anti-D at admission. After she received RBCs from 19 apparently D- donors, she developed anti-D with an 8-fold titer. The titer of anti-D increased further to 128-fold after transfusions of cross-match-compatible D- negative RBCs from 40 donors over the next 2 years. Two of 59 donors were found to be RHD gene-positive and antigen D- with a D(el) phenotype, that is, RHD(K409K). This is the first case in which RBCs having the D(el) phenotype induced a secondary alloanti-D immunization. A D- donor with the RHD(K409K) allele was associated with the development of anti-D. Adverse episodes or evidence of hemolysis was not observed after the transfusion of RHD(K409K) RBCs. Further clinical evidence is needed to reveal whether the D(el) phenotype has a clinically relevant potential for anti-D immunization.

Disaster Impact (11-M) in a Blood Bank.

Objective: To describe the main problems posed to a hospital's blood bank (BB) by a major disaster situation (the11-M terrorist attack in Madrid, Spain).Report of the events: In the terrorist attack of Madrid in March 11, 2004, there were a total of 192 casualties and 1432 individuals who suffered various, usually complex, injuries. At the Gregorio Marañon Hospital 232 victims of the attack were admitted and 32 of them required surgical procedures. On this day there were 122 requests for blood products for 23 patient.Transfusion issues: Patient identification: initially most of transfusion requests arrived without patient's demographic data nor blood sample; a numeric code was assigned to each case. Blood group testing: only ABO-type and Rh-D antigen were determined. Transfusion policy: patients were transfused with same specific ABO group whenever possible, otherwise with ABO compatible uncrossmatched red blood cells (RBC); for this purpose, retyped group A and O RBC were stored separately. Rh-D negative units were reserved for young D-negative females.Blood donation issues: There was a massive arrival of volunteers to donate blood in a very short period of time, which completely collapsed the BB facilities. It was necessary to improvise for additional space as well as technical staff and paramedical personal to attend to the massive flux of overanxious volunteers. Regular blood donors were rejected in order to guarantee blood supply after the catastrophe. Many volunteers could not donate at the time and a telephone number and address were obtained for recall at a later time if needed. Table I shows the results of HbsAg and HVC testing of blood donated on the day of the catastrophe (group B) compared with donors before the 11-M (group A).Conclusions: At a major public disaster such as the 11-M terrorist attack, donation greatly exceeds the actual needs generated by the catastrophe. Furthermore, this donation is of no use for the immediate needs. Ideally, civil authorities should not encourage blood donation indiscriminately but alert the general population to do so only after an evaluation of available resources and estimated needs. A center's contingency plan should include: coordination with local authorities and regional blood center; hospital heads and directors should cancel all programmed activities, in particular surgical procedures and divert human effort resources to emergency care of the injured; the BB should reorganize its activities, initially focusing in patient identification and testing, redistribution and retyping of available blood products in order to deliver quickly type specific RBC; after above goals have been met, staff resources should be redistributed for blood collection and processing.Table I: Blood testing results an donation data.Total donorsFirst-time donorsRepeat donorsNumberHBsAg+ / VHC+NumberHBsAg+ / VHC+NumberHBsAg+ / VHC+A6622 / 23231 / 23391 / 0B6331 / 55431 / 5900 / 0Between March 11 and March 14, 633 donations were made, 398 on March 11; this represent a 1,658% increment from the usual mean. There was a higher % of HCV positivity in group B compared to regular donors and no difference in HBV and HIV testing between both groups.Table II:Transfusion data.Available RCCHospitalizedDeceasedSurgeryPrevious stockReceived the 11-MTransfused 1st 4hTotal transfused the 11-M23243614926590 (62%)143During the first 4 hours 82% of the transfused patients (19) were registered at the blood bank and 63% of the RBC used that day (90 units) were transfused. 71,72% of RBC were specific ABO-group.

The complexities of the Rh system.

In 1939, Levine & Stetson first described the case of a mother, after giving birth to a stillborn child, having a haemolytic transfusion reaction following transfusion her husband’s blood. Her serum agglutinated her husband’s red cells and those of 80% of ABO-compatible donors. In 1940, Landsteiner & Wiener injected Rhesus-monkey red blood cells into rabbits. The rabbit serum agglutinated Rhesus-monkey red cells, and also 85% of human red cells. They called this antibody anti-Rh, and in 1941 Levine & Stetson’s human antibody was shown to have the same pattern of reactivity as the rabbit anti-Rh antibody. However, by 1942, Fisk & Foord had demonstrated a difference between rabbit and human anti-Rh: red cells from all newborn babies, whether Rh positive or negative as defined by human anti-Rh were positive with the rabbit anti-Rh. In 1963, Levine et al . finally proved that human and rabbit anti-Rh did not react with the same antigen. However, owing to common usage of the term, ‘Rh’ was kept as the title for the human antibodies. The rabbit ‘anti-Rh’ was then called anti-LW in honour of Landsteiner & Wiener. Even today people often make the mistake of referring to the ‘Rhesus’ blood group system; this is incorrect, as the blood-group antigen has nothing to do with Rhesus monkeys, and should be referred to as the ‘Rh’ blood group system. In 1943, Wiener demonstrated the presence of six alleles in the Rh system with three different antisera, and since then the system has been shown to have many further variants and complexities. In 1953, it was discovered that some RhD-positive individuals can make anti-D, and this led to the hypothesis that the RhD antigen is a complex antigen comprised of a series of epitopes. A lack of part of the antigen means that an individual can make antibody to this part. In 1942, Levine confirmed that Rh incompatibility between mother and fetus was the major cause of haemolytic disease of the newborn (HDN). Various studies showed that, depending on the population, 3–25% lack the Rh antigen D, and that RhD-negative individuals readily make anti-D. RhD is thus of critical importance in blood transfusion, and all transfusions are routinely matched for RhD compatibility. In emergency situations RhD-negative blood is given, particularly if the recipient is a female of child-bearing age, to avoid immunization. RhD-negative women can be treated with prophylactic anti-D to prevent HDN. Although the mechanism of action for this process is not fully understood, it is apparent that rapid clearance of fetal red cells from the maternal circulation by passively administered anti-D prevents the mother making immune anti-D. A very successful programme of routine postdelivery administration of anti-D to RhD-negative mothers bearing RhD-positive babies has greatly reduced the incidence of HDN. However, some fetal cells can also enter the maternal bloodstream during pregnancy, and cause immunization. To prevent this cause of HDN, routine antenatal administration of anti-D is now being adopted in many countries.