Maternal Alloantibodies Research Articles

Invasive equine trophoblast expresses conventional class I Major Histocompatibility Complex antigens

Monoclonal antibodies and alloantisera were used in an indirect immunohistochemical assay to determine the expression of class I and class II Major Histocompatibility Complex (MHC) antigens by equine placental cells and the endometrial tissues at the fetal-maternal interface. MHC class I antigens were expressed at high density on the surface of the trophoblast cells of the chorionic girdle at days 32-36, just prior to their invasion of the endometrium. The mature gonadotrophin-secreting cells of the endometrial cups, which are derived from the chorionic girdle cells, had greatly reduced levels of MHC class I antigen expression while no MHC class I antigens were detectable on the non-invasive trophoblast cells of the allantochorion, except in small isolated patches. MHC class I antigens immunoprecipitated from chorionic girdle cells with either monoclonal antibodies or alloantisera had a relative molecular mass of 44,000, which was identical to that of MHC class I antigens precipitated from lymphocytes with the same reagents. MHC class II antigens were not detected on any trophoblast cells, although they were expressed at high levels by the endometrial glandular and lumenal epithelium immediately bordering the endometrial cups. MHC class I antigens were also expressed at high levels by endometrial tissues in the area of the cups. The high level of MHC class I antigen expression by endometrial glands within and bordering the cups was in sharp contrast to the greatly reduced class I antigen expression by the mature endometrial cup cells themselves.(ABSTRACT TRUNCATED AT 250 WORDS)

The Detection of Antibodies in Pregnancy: A Comparison of Two Assay Systems

In this study we have compared the ability of two assay systems, erythrocyte antibody rosette inhibition (EAI) and cellular enzyme-linked immunospecific assay (CELISA) to detect maternal alloantibody activity during pregnancy. Antibody activity to antigens on paternal lymphocytes was present in nine of 23 primigravid sera tested by EAI and in seven of 23 by CELISA. In multiparous sera, antibodies directed to paternal lymphocytes were detected in 11 of 15 individuals by EAI and in six of 15 by CELISA. The techniques correlated significantly when assaying the humoral response in sera from multiparous women. The lack of correlation when assaying primigravid sera suggests that both assays encounter difficulty in detecting the low titres of antibodies present.

Alloimmunthrombozytopenie beim Neugeborenen aufgrund mütterlicher Anti-PlA1-Antikörper

The case of pregnant woman, whose first child was born with neonatal alloimmune thrombocytopenia (NATP) and PlA2/PlA1 constellation, is used as an example to draw up a programme for the care of pregnant women whose children are expected to be born with NATP. In one of 2,000 to one of 3,000 cases, the PlA1-positive foetal platelets cause a sensitization of the PlA1-negative mother. Transplacental passage of maternal IgG alloantibodies leads to accelerated destruction of foetal platelets. The pathophysiologic process is similar to Rh-erythroblastosis foetalis. The infants show symptoms ranging from cutaneous manifestations to intracranial haemorrhages.

Neonatal alloimmune thrombocytopenia

Neonatal alloimmune thrombocytopenia (NAIT) occurs when maternal alloantibodies to antigens present on fetal platelets cause their immune destruction resulting in thrombocytopenia in the newborn infant or fetus. Bleeding may be severe; intracranial haemorrhage and permanent neurological damage are the most serious complications. Despite the severity of the disease, there is often a delay in making the correct diagnosis and instigating appropriate treatment. Recent evidence that NAIT is more common than has previously been recognised, a better understanding of the molecular basis of platelet serology and advances in technology, which have made it possible to take blood samples from fetuses and transfuse them in utero, have all contributed to a growing interest in this condition. In addition, it is exciting to realise that an aggressive approach to the management of established cases and ‘at risk’ pregnancies can prevent serious neurological sequelae and dramatically improve the outcome for affected infants.

MATERNAL IMMUNE RESPONSES TO THE FETUS IN EARLY PREGNANCY AND RECURRENT MISCARRIAGE

Direct evidence that maternal immune rejection of the fetus causes some unexplained recurrent spontaneous abortions was sought in 18 women with this condition. Tests of maternal cell-mediated immunity to fetal (paternal) antigens were done before conception, in early pregnancy, and at miscarriage, and were compared with those in 10 controls in their first pregnancies. Maternal cytotoxic alloantibody production and the blocking effect of maternal sera on maternal lymphocyte activation were also evaluated. There was no evidence for maternal cell-mediated reactivity to paternal antigens in normal early pregnancy or in most women who aborted, but circulating cytotoxic cells were found at miscarriage in a third of affected women. There was no correlation between the production of cytotoxic antibodies and serum blocking activity, and the success of the pregnancy. These data provide evidence that cell-mediated immune reactivity may be changed in some women who abort recurrently but show that circulating immunological blocking factors are not relevant to the success of pregnancy. Their induction by maternal immunisation with paternal leucocytes does not explain why this procedure prevents recurrent spontaneous abortions.

The alloantibody response to semiallogeneic pregnancy in the rat. I. Alloantibodies in sera and placental eluates directed to RT1A antigens.

Maternal alloantibodies to paternal cells were monitored by cellular ELISA, the indirect hemagglutination and erythrocyte antibody rosette inhibition assays in sera and placental eluates from primigravid and multigravid inbred rats. In primigravid animals, antibodies in sera were routinely detected only by the indirect hemagglutination assay and were of low titer; weak antibody activity was detectable only by indirect hemagglutination in 1 of the 8 placental eluates assayed from these animals. Alloantibodies in high titer were present in sera and placental eluates from multigravid rats and were found to be directed predominantly to the RT1A (class I MHC) antigens of the paternal strain. These data provide no support for the hypothesis that the difficulty in detecting maternal antibodies during a 1st pregnancy is due to their preferential binding to antigenic determinants expressed on the placenta.

Cyclosporin A prevents sensitization after blood transfusion in multiparous rats.

1. Humoral immune responses to allogeneic blood transfusions and semi-allogeneic pregnancies were monitored by the indirect haemagglutination assay in strains of inbred rats. 2. Similar titres and ranges of cross-reactive alloantibodies were induced by blood transfusions and pregnancy; the maternal alloantibody response to paternal antigens was not increased by an unrelated antigenic stimulus. 3. Immunosuppression with cyclosporin A was effective in preventing the primary humoral immune response produced by blood transfusion but not in abrogating the established immune response to previous pregnancy. 4. These studies have established an animal model of sensitization that both stimulates the clinical situation of many potential renal transplant recipients and permits analyses of the different antigenic stimuli involved.

Maternal alloantibody responses during early pregnancy detected by a cellular enzyme-linked immunospecific assay

Using a cellular enzyme-linked immunospecific assay (CELISA), we have examined sera from nulliparous women and women in the first trimester of a first or subsequent pregnancy for the presence of antibodies directed to surface determinants on peripheral blood lymphocytes from unrelated donors. Maternal antibody activity was found in sera from 1/13 nulliparae, 19/37 primigravidae, and 8/12 multigravidae. Cytotoxic antibody activity was present in 3/12 multigravidae but in no other group. Absorption with packed, pooled platelets did not remove the antibody activity from three of the primigravid sera; unabsorbed sera, however, bound equally well to T and B lymphocytes. These data suggest that the antibody detected by CELISA is not directed to any of the classical HLA antigen series (-A, -B, -C, or -DR) but may be directed to the HLA linked non-class 1 HT antigen system.

Humoral immune responses in murine pregnancy. V. Relationship to the differential immunogenicity of placental and fetal tissues

The nature of the humoral immune response induced in virgin female mice by injections of F1 placental and fetal tissues has been examined and compared to that induced by immunization with F1 adult spleen cells and by multiple allogeneic pregnancy. In a ‘responder’ strain mouse, as defined by the ability of multiple allogeneic pregnancy to elicit an anti-paternal humoral immune response, both F1 placental and fetal tissues induced the formation of alloantibodies primarily of the IgG1 sub-class, similar to those induced by allogeneic pregnancy, but different from those elicited by adult spleen cells. However, only the placental tissues induced alloantibodies possessing all the characteristics of those appearing in multiparous allogeneic pregnancy. In contrast, the alloantibodies induced by the injected fetal tissue possessed complement-dependent cytotoxic activity, indicating that the inability of pregnancy-induced alloantibodies to mediate cytotoxicity may not be related to their restriction to the IgG1 sub-class. In a ‘non-responder’ mouse strain, where multiple allogeneic pregnancy does not lead to a maternal alloantibody response, F1 placental tissues, in contrast to fetal and adult tissues, failed to induce a humoral immune response. Injection of F1 placental tissue therefore elicits responses that mimic both the properties and the strain-dependent distribution of the alloantibodies identified in normal murine pregnancy. This implies that the immunogenic stimulus in pregnancy emanates from the placental rather than the fetal compartment of the allogeneic conceptus.

Neonatal alloimmune thrombocytopenic purpura.

We reviewed 58 literature reports of neonatal alloimmune thrombocytopenic purpura (NAITP). The mortality rate was 9%. The total incidence of suspected intracranial hemorrhage was 28%. We reviewed 17 sibship cases for the relation of birth order to treatment and outcome. Among firstborn affected infants (n = 17) the mortality rate and incidence of central nervous system sequelae were 24 and 47%, respectively, compared to rates of 5 and 15%, respectively, in their younger affected siblings (n = 20). The improved outcome in the latter group appeared to be related to more frequent cesarean section delivery and more frequent and earlier use of corticosteroids and maternal platelet transfusions in the neonate. Sensitive assays of maternal platelet alloantibody are now available, but they lack specificity for NAITP affecting the current gestation. There are two reports in which sensitive assays revealed rising titers of maternal platelet alloantibody during advancing gestation. We propose further study to determine if this is specific for the antepartum diagnosis of NAITP.

The expression of major histocompatibility antigens by human chorionic villi

Frozen sections of human placentae taken at selected stages throughout gestation were stained with monoclonal antibodies to HLA-A, B, C and DR antigens, using an indirect immunoperoxidase technique. No staining of villous trophoblastic tissue was detected. Antibody to HLA-A, B, and C antigens clearly stained membranous elements of the villous stroma. Antibody to HLA-DR antigens stained rare, elongated cells of the villous stroma in the term placenta. Monoclonal antibodies to syncytiotrophoblast membrane were used as a control. This antigen distribution was confirmed by absorption of these monoclonal antibodies in an indirect radioimmunoassay. Adult spleen homogenate gave much stronger absorption than a trophoblast membrane preparation with antibodies to HLA-A, B, C or DR antigens. The opposite absorption pattern was observed with the anti-trophoblast monoclonal antibodies. Detergent solubilisation did not affect the absorption capacity of trophoblast membrane for HLA-A, B, C or DR antigens. Maternal antibody could be eluted from trophoblastic areas of term placental sections by washing at physiological pH, but this did not effect the binding of monoclonal antibodies. Thus the HLA antigens were not masked by preformed maternal alloantibody. These observations confirm that chorionic villous trophoblast does not express detectable HLA antigen. This may be the principal reason for the lack of rejection of the fetal allograft.

Ontogeny & kinetics of the placental immunoabsorbent barrier

This study was designed to identify and characterize the allo- and autoantibodies induced following successful paternal lymphocyte immunization to prevent recurrent spontaneous abortion. Firstly the titers of maternal anti-paternal antibodies in women with successful pregnancies as determined by the flow cytometry crossmatch (FCXM) were highly variable; however, in all cases, the initial pre-immunization titers were negative and the post-immunization titers were positive by the FCXM in successfully treated women. Secondly, the specificities of maternal alloantibodies to paternal HLA antigens (immunogen) were evaluated. Not all predicted antibodies to mismatched paternal HLA antigens were found by microlymphocytotoxicity (MCX) assays and the specificities varied. Thirdly, antibodies in post- but not pre-immunization sera reacted with two lymphoid cell lines, SupT1 and SB; in addition, the rise and fall of the titers of these sera with paternal cells seemed to be reflected with the cell lines by the FCXM. Fourthly, autoantibodies to activated lymphocytes were detected and seemed to correlate with successful immunization since women who had another abortion following immunotherapy lacked these autoantibodies.

Résultats de l'utilisation du Groupamatic dans la surveillance des allo-immunisations fœto-maternelles

The A.V.I.S. Blood Transfusion Center of Turin performs the screening of foetomaternal allo-immunizations for the S. Anna Hospital of Turin. This hospital includes 3 hospital departments and 3 obstetrical and gynaecological university departments. The number of births in one year is roughly 13.000, i.e. 50 mother-baby couples, are tested every day. The identification system and the sampling process are described. The program used on the Groupamatic system includes: 1.) First run: Blood typing of mother blood with screening of alloantibodies. Second run: Blood typing control, screening of immune anti-A and anti-B antibodies, syphilis screening. 2.) Washing of cord blood red blood cells: First run: Washed red blood cells ABO and Rhesus typing, direct Coombs test. Second run: Blood typing control. Automatic screening of maternal irregular alloantibodies and automatic indirect Coombs test on washed cordblood red cells are simultaneously controlled with standard manual techniques. Sampling and testing are processed within 24 hours after birth. The set of results concerning mother-baby couples are grouped on one card and sent to the hospital department for a quick MHNN prophylaxy. Results of tests performed on 6.351 pregnancies studied until birth are presented. The automated direct Coombs test was positive with: 1--95% of new borns from mother who have a high immune allo antibody anti-A/B titer (IgG after treatment with two Mercapto etanol greater than I/64). 2--100% of new borns from mother who have irregular allo antibodies in Rh, Kell, Duffy or Kidd systems.

The Immunologic Significance of the Mammary Gland

The immunologic role of the mammary gland is to transfer ready-made antibodies, the immunologic endowment, from the maternal serum to the gastrointestinal tract and eventually the bloodstream of the immunologically naive infant. In certain species, the mammary gland deputizes for the fetal membranes which are incapable of transmitting antibodies, and in other it continues a process initiated in utero. Antibody secretion by the mammary gland is highly selective. Certain antibodies are preferentially taken up from the serum and concentrated. Absorption from the host's gastrointestinal tract is equally selective and of short duration. In man, gastrointestinal antibody absorption does not occur. Despite this, secretory IgA antibodies fulfill an immunoprotective role within the lumen of the gut, acting against a variety of enteric microorganisms. These antibodies are synthesized by plasma cells associated with active mammary tissue. Apart from their beneficial roles, mammary glands may exert an inimical role by virtue of the nature of their exosecretions. In some species they transmit maternal isoantibodies that can cause hemolytic disease of the newborn. They secrete certain proteins, such as casein, which are a potent source of allergic reactions, possibly including the sudden infant death syndrome. Finally, variable leukocytes are a largely neglected but constant ingredient of colostrum and milk. These can reach the circulation of the recipient and can interact with mononuclear cells of the host; as a result, transplantation immunity, tolerance, and graft-versus-host disease may develop in some species.

Altered quantitative expression of immunoglobulin allotypes in rabbits.

In 1962, Dray showed that the quantitative expression of allelic allotypes in heterozygous rabbits was affected by exposure of the neonatal rabbits to maternal isoantibodies directed against the antigenic type inherited from the father (Dray, 1962). This phenomenon has become known as allotype suppression. During the decade since the discovery of the phenomenon, a considerable body of information has accumulated about the genetics, structure and localization of the genetically controlled antigenic variants of rabbit immunoglobulins (immunoglobulin allotypes) (reviewed by Mage et al., 1973a). This review will summarize our knowledge of allotype suppression in the light of current concepts of immunoglobulin structure and cellular immunology.KeywordsLight ChainRabbit ImmunoglobulinImmunoglobulin AllotypeAllotypic DeterminantAllotypic SpecificityThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Effect of maternal isoantibodies on the quantitative expression of two allelic genes controlling gamma-globulin allotypic specificities.

Effect of Maternal Isoantibodies on the Quantitative Expression of two Allelic Genes Controlling γ-Globulin Allotypic Specificities

Immunoreactions involving platelet. VI. Reactions of maternal isoantibodies responsible for neonatal purpura. Differentiation of a second platelet antigen system.

Although there is some evidence that neonatal thrombocytopenic purpura, which occurs in otherwise normal children born of healthy mothers, is caused by maternal antibodies formed against fetal platelets (1-3), lack of reliable serologic techniques generally has prevented convincing demonstration of the responsible antibodies and has precluded thorough investigation of the properties and inheritance of specific platelet antigens presumed to be involved. Because experience in this laboratory has shown that complement fixation is the most sensitive technique for detecting several different types of antiplatelet antibodies (4-6), this technique was applied in a search for antibodies in the sera of normal mothers who had given birth to thrombocytopenic infants. In the present report the isoantibodies which were found are characterized, and the sensitivity of the complement fixation technique is compared with that of other techniques employed in attempts to detect antiplatelet antibodies.

Pathogenesis of ABO hemolytic disease

1.1. Observations on 51 families in which ABO hemolytic disease occurred are reviewed. In all but one of the families, the mothers were found to be Group O in conformity with previous reports. This is attributed to the ability of Group O mothers to form antibodies of specificity anti-C as well as anti-A and anti-B.2.2. Affected babies were all either Group A or Group B. Of the Group A babies all but one appeared to be of subgroup A1. The low incidence of subgroup A2 babies is explained by the poor avidity of such red cells for isoagglutinins so that babies of this subgroup are less severely affected by maternal alpha isoantibodies.3.3. Once severe ABO hemolytic disease occurs in a family, then, with rare exceptions, all future babies will be affected unless they belong to Group O.4.4. The incidence of secretors and nonsecretors among the Group O mothers in this series of families was the same as in the general population.5.5. The incidence of nonsecretors among the affected babies, their siblings, and their fathers was lower than in the general population.6.6. When the affected baby is Group A, the titer of the maternal serum for A cells tends to be higher than for B cells and, when the baby is Group B, the reverse is often true. This suggests that in many cases the baby's red cells or body fluids provide the antigenic stimulus accounting for the high titer of the maternal serums. In the remainder of the cases, the alpha and beta antibodies were of equal titers, suggesting predominance of antibody of specificity anti-C and presumably of heteroimmune origin.7.7. It is pointed out that the attempt to distinguish between so-called natural and immune isoantibodies is based on a misconception. All alpha and beta antibodies appear to be of immune origin but, depending on the nature of the antigenic stimulus, the antibodies may be heteroimmune or isoimmune.8.8. Two main patterns of ABO hemolytic disease appear to exist. In one, the maternal isoantibodies are chiefly of heteroimmune origin (so-called “natural” antibodies) and the first-born incompatible baby is generally affected though the manifestations tend to be mild (icterus praecox). In the second form, one or more normal babies of an incompatible blood group may first be born; these babies are secretors and sensitize the mother so that subsequently born babies of incompatible blood group develop typical erythroblastosis. In many of these cases, however, in contrast to Rh hemolytic disease, the first-born incompatible secretor baby may be severely affected.9.9. In general, in cases of ABO hemolytic disease the titer of the maternal alpha and beta isoantibodies is markedly elevated. There appears to be a correlation between antibody titer and severity of the disease, though, as in Rh hemolytic disease, the correlation is not absolute.10.10. The importance of recognizing ABO hemolytic disease is for the intelligent treatment of affected babies and for prognosticating the outcome of future pregnancies.

A Study of Normal and Pathologic Variants<subtitle>I. Patterns of Maternal A and B Isoantibodies in Unselected Pregnancies</subtitle>

INCOMPATIBILITY of mother and child with respect to the blood groups AB and O is a common occurrence. Depending on the incidence of the genes for A, B, and O in a given population, approximately 20 to 25% of all pregnancies are heterospecific in the sense that the fetal red corpuscles possess an agglutinogen, A or B, not present in the mother, while the maternal serum contains the corresponding agglutinin, which is antagonistic to the fetal blood group. It is clear that the fetus ordinarily must be protected against the potentially harmful effects of the maternal isoantibodies. The mechanisms responsible for this protection are not well understood. By the same token, the nature of the process through which the fetus and the newborn infant may suffer damage in some instances of heterospecific pregnancy is not clear. There is unanimous agreement, however, that incompatibility of mother and fetus can produce a

A Study of Normal and Pathologic Variants<subtitle>II. Patterns of A and B Isoantibodies in the Cord Blood of Normal Infants</subtitle>

IN THE PRECEDING paper, 1 the anti-A and B isoantibody patterns of unselected women in homospecific and heterospecific pregnancies were described. The present paper deals with the infants born to those mothers and is concerned with the isoantibodies of the cord bloods and their relationship to the maternal isoantibodies. The methods used were the same as those described in the first paper. OBSERVATIONS Homospecific Pregnancies .–Cord bloods for isoantibody studies were available from 69 of the 92 Group O infants of O mothers. In 23 cases the cord serum could not be obtained either because the child had been delivered at home or in another hospital or because of accidental losses in collecting the samples. The results of the anti-A and anti-B titrations of the 69 cord sera are given in Table 1, together with the corresponding maternal titers drawn within 24 hours after delivery. It will be seen that