HLA relationships of pregnancy, microchimerism and autoimmune disease

Mother-child histocompatibility and risk of rheumatoid arthritis and systemic lupus erythematosus among mothers

The study objective was to test the hypothesis that having histocompatible children increases the risk of rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE), possibly by contributing to the persistence of fetal cells acquired during pregnancy. We conducted a case control study using data from the UC San Francisco Mother Child Immunogenetic Study and studies at the Inova Translational Medicine Institute. We imputed human leukocyte antigen (HLA) alleles and minor histocompatibility antigens (mHags). We created a variable of exposure to histocompatible children. We estimated an average sequence similarity matching (SSM) score for each mother based on discordant mother-child alleles as a measure of histocompatibility. We used logistic regression models to estimate odds ratios (ORs) and 95% confidence intervals. A total of 138 RA, 117 SLE, and 913 control mothers were analyzed. Increased risk of RA was associated with having any child compatible at HLA-B (OR 1.9; 1.2-3.1), DPB1 (OR 1.8; 1.2-2.6) or DQB1 (OR 1.8; 1.2-2.7). Compatibility at mHag ZAPHIR was associated with reduced risk of SLE among mothers carrying the HLA-restriction allele B*07:02 (n = 262; OR 0.4; 0.2-0.8). Our findings support the hypothesis that mother-child histocompatibility is associated with risk of RA and SLE.

The role of fetal-maternal microchimerism as a natural-born healer in integrity improvement of maternal damaged kidney

PURPOSE

To identify the fetal stem cell (FSC) response to maternal renal injury with emphasis on renal integrity improvement and Y chromosome detection in damaged maternal kidney.

MATERIALS AND METHODS

Eight non-green fluorescent protein (GFP) transgenic Sprague- Dawley rats were mated with GFP-positive transgenic male rats. Renal damage was induced on the right kidney at gestational day 11. The same procedure was performed in eight non-pregnant rats as control group. Three months after delivery, right nephrectomy was performed in order to evaluate the injured kidney. The fresh perfused kidneys were stained with anti-GFP antibody. Polymerase chain reaction (PCR) assay was also performed for the Y chromosome detection. Cell culture was performed to detect the GFP-positive cells. Technetium-99m-DMSA renal scan and single-photon emission computed tomography (SPECT) were performed after renal damage induction and 3 months later to evaluate the improvement of renal integrity.

RESULTS

The presence of FSCs was confirmed by immune histochemical staining as well as immunofluorescent imaging of the damaged part. Gradient PCR of female rat purified DNA demonstrated the presence of Y-chromosome in the damaged maternal kidney. Moreover, the culture of kidney cells showed GPF- positive cells by immunofluorescence microscopy. The acute renal scar was repaired and the integrity of damaged kidney reached to near normal levels in experimental group as shown in DMSA scan. However, no significant improvement was observed in control group.

CONCLUSION

FSC seems to be the main mechanism in repairing of the maternal renal injury during pregnancy as indicated by Y chromosome and GFP-positive cells in the sub-cultured medium.

Sex differences in Sjögren's syndrome: a comprehensive review of immune mechanisms

Autoimmune diseases (ADs) are estimated to affect between 5 and 8 % of the US population, and approximately 80 % of these patients are women. Sjögren’s syndrome (SS) is an AD that occurs predominately in women over men (16:1). The hallmark characteristic of SS is diminished secretory production from the primary exocrine gland and the lacrimal or salivary glands resulting in symptoms of dry eye and mouth. The disease is believed to be mediated by an inflammatory and autoantibody response directed against salivary and lacrimal gland tissues. This review will examine the literature on sex differences in the immune response of patients and animal models of Sjögren’s syndrome in order to gain a better understanding of disease pathogenesis.

Hematopoietic stem cell infusion/transplantation for induction of allograft tolerance

PURPOSE OF REVIEW

The present review updates the current status of basic, preclinical, and clinical research on donor hematopoietic stem cell infusion for allograft tolerance induction.

RECENT FINDINGS

Recent basic studies in mice provide evidence of significant involvement of both central deletional and peripheral regulatory mechanisms in induction and maintenance of allograft tolerance effected through a mixed chimerism approach with donor hematopoietic stem cell infusion. The presence of heterologous memory T cells in primates hampers the induction of persistent chimerism. Durable mixed chimerism, however, now has been recently induced in inbred major histocompatibility complex-mismatched swine, resulting in tolerance of vascularized composite tissue allografts. In clinical transplantation, allograft tolerance has been achieved in human leukocyte antigen-mismatched kidney transplantation after the induction of transient mixed chimerism or persistent full donor chimerism.

SUMMARY

Tolerance induction in clinical kidney transplantation has been achieved by donor hematopoietic stem cell infusion. Improving the consistency and safety of tolerance induction and extending successful protocols to other organs, and to organs from deceased donors, are critical next steps to bringing tolerance to a wider range of clinical applications.

Review: The feto-placental unit, pregnancy pathology and impact on long term maternal health

Pregnancy induces a number of alterations to maternal physiology to accommodate the increased demands made by the developing fetus and placenta. These alterations appear at least in part to be driven by products derived from the feto-placental unit, including microchimeric cells, as well as placental exosomes and microparticles, inducing changes to maternal physiology both during pregnancy and beyond. Further, increasing evidence suggests that some of these alterations are dependent on the sex of the fetus. Pre-eclampsia and asthma represent two common pregnancy complications that have provided valuable insight into how the feto-placental unit influences maternal physiology in a sex-specific manner. Pregnancy-induced alterations in maternal physiology may expose pre-existing subclinical pathologies and provide insight into future maternal health and disease. While most pregnancy-induced alterations to the maternal system are reversed following delivery, some can persist after parturition leading to cardiovascular, metabolic and autoimmune disease and increased risk of early mortality.

Fetal microchimerism: benevolence or malevolence for the mother?

For a long time, the conventional view was that the fetus and maternal vascular system are kept separate. In fact there is a two way traffic of cells through the placenta and the transplacental passage of cells is in fact the norm. The fetal cells can persist in a wide range of woman's tissues following a pregnancy or an abortion and she becomes a chimera. Fetal cells have been found in the maternal circulation and they were shown to persist for the entire life in humans, thus demonstrating long-term engraftment and survival capabilities. Microchimerism is a subject of much interest for a number of reasons. Studies of fetal microchimerism during pregnancy may offer explanations for complications of pregnancy, such as preeclampsia, as well as insights into the pathogenesis of autoimmune diseases which usually ameliorate during pregnancy. The impact of the persistence of allogenic cells of fetal origin and of the maternal immunological response to them on the mother's health is still not clear. On the beneficial side, it has been proposed that genetically disparate fetal microchimerism provides protection against some cancers, that fetal microchimerism can afford the mother new mechanisms of protection to some diseases, that fetal microchimerism can enlarge the immunological repertoire of the mother improving her defense against aggressor. Fetal cells are often present at sites of maternal injury and may have an active role in the repair of maternal tissues.

Microchimerism: sharing genes in illness and in health

Microchimerism is defined as the presence of two genetically distinct cell populations in the same individual. It can arise from several causes including the bidirectional transfer of cells between mother and fetus during pregnancy, twin-to-twin transfer in utero, from organ transplantation, and blood transfusion. Recently, scientists have found male fetal cells from decades earlier imbedded in tissues and organs of some women with autoimmune diseases. The significance of these findings as they relate to real or potential health implications in autoimmune diseases, graft-versus-host reactions, and transfusion complications is discussed here.

Separate influences of birth order and gravidity/parity on the development of systemic sclerosis

OBJECTIVE

Birth order has been valuable in revealing the role of environmental influences on the risk of developing certain diseases such as allergy and atopy. In addition, pregnancy has profound effects on the immune system such as short-term effects that permit fetal survival as well as longer-term effects that could influence late-onset diseases. In order to better evaluate these influences, we studied the association of birth order and gravidity/parity as risk factors for systemic sclerosis (SSc; scleroderma).

METHODS

Data regarding SSc cases and their unaffected sibling controls were obtained from the Scleroderma Family Registry and DNA Repository. The case-sibling design was used to minimize confounding due to differences in age, race, ethnicity, or calendar time. The gravidity/parity analysis was based on sibships with at least one SSc-affected and one unaffected sister.

RESULTS

Birth order was examined in 974 sibships, comparing SSc cases (n = 987) with their unaffected siblings (n = 3,088). The risk of scleroderma increased with increasing birth order (odds ratio [OR] 1.25, 95% confidence interval [95% CI] 1.06-1.50 for birth order 2-5; OR 2.22, 95% CI 1.57-3.15 for birth order 6-9; and OR 3.53, 95% CI 1.68-7.45 for birth order 10-15). Gravidity/parity was analyzed in 168 sibships (256 unaffected sisters, 172 SSc cases). We found an association between a history of one or more pregnancies and SSc (OR 2.8).

CONCLUSION

Birth order and pregnancy were independently associated with a higher risk of developing SSc. These findings suggest that immune development in early childhood and/or pregnancy-associated events, including but not limited to microchimerism, plays a role in SSc susceptibility.

Fetal microchimerism and maternal health during and after pregnancy

Trafficking of fetal cells into the maternal circulation begins very early in pregnancy and the effects of this cell traffic are longlasting. All types of fetal cells, including stem cells, cross the placenta during normal pregnancy to enter maternal blood, from where they may be recovered in pregnancy for the purpose of genetic prenatal diagnosis. Fetal cells can also be located in maternal tissues during and after pregnancy, and persist as microchimeric cells for decades in marrow and other organs. Although persistent fetal cells were first implicated in autoimmune disease, subsequent reports routinely found microchimeric cells in healthy tissues and in non-autoimmune disease. Parallel studies in animal and human pregnancy now suggest instead that microchimeric fetal cells play a role in the response to tissue injury. However, it is still not clear whether microchimeric fetal cells persisting in the mother are an incidental finding, are naturally pathogenic or act as reparative stem cells, and the environmental or biological stimuli that determine microchimeric cell fate are as yet undetermined. Future studies must also focus on investigating whether fetal cells create functional improvement in response to maternal injury and whether this response can be manipulated. The pregnancy-acquired low-grade chimeric state of women could have far-reaching implications, influencing recovery after injury or surgery, ageing, graft survival after transplantation, survival after cancer as well as deciding the protective effect of pregnancy against diseases later in life. Lifelong persistence of fetal cells in maternal tissues may even explain why women live longer than men.

High frequency of fetal cells within a primitive stem cell population in maternal blood

BACKGROUND

During pregnancy, fetal cells enter the maternal bloodstream resulting in fetal cell microchimerism. The fetal cells persist in the mother for decades and colonize a variety of maternal organs. They are associated with maternal autoimmune diseases and may also participate in tissue repair. The identity of the microchimeric cells is not certain but they must be able to persist long-term and have potential for multitissue differentiation.

METHODS AND RESULTS

Here we tested the hypothesis that the fetal microchimeric cells are primitive stem cells, represented by CD34+ adherent cells, which have a wide potential for differentiation. We isolated these stem cells from the blood of pregnant females (n = 25) and detected fetal cells of the correct gender, using fluorescence in situ hybridization, in a high proportion (71% male fetuses and 90% female fetuses; false positive rate 11%, false negative rate 29%) of cases. By RT-PCR, we demonstrated that the cells express Oct-4, Nanog and Rex-1. No fetal cells were detected in the mononuclear or total CD34+ cell populations but high frequencies (mean 11.8%) of fetal cells were detected in the adherent CD34+ cell population.

CONCLUSIONS

These results identify adherent CD34+ stem cells as candidate fetal microchimeric cells, which are capable of sustaining the fetal cell population in the long term and have the ability to colonize multiple tissues and organs.

O papel do complexo principal de histocompatibilidade na fisiologia da gravidez e na patogênese de complicações obstétricas

Este trabalho tem por objetivo discutir a estrutura e função dos Antígenos Leucocitários Humanos (HLA), seus métodos de detecção, nomenclatura e os mecanismos imunopatológicos que o associam com a fisiologia da gestação e morbidades obstétricas. Sabe-se que o equilíbrio imunológico entre mãe e concepto é imprescindível na manutenção da gravidez. Moléculas do HLA - notadamente o HLA-G expresso na interface materno-fetal - exercem função importante na tolerância imunológica materna, evitando rejeição fetal e algumas complicações obstétricas. Além disso, o HLA permeia diversas etapas do desenvolvimento conceptual como clivagem, formação do trofoblasto e implantação. Para revisão, foram pesquisados os bancos de dados MEDLINE e LILACS, utilizando os descritores: "HLA antigens"; "pregnancy"; "embryonic development"; "pregnancy complication"; "abortion, habitual"; "pre-eclampsia". O conhecimento sobre a influência do HLA na gravidez é necessário para melhor manejo da gestação e patologias obstétricas auto-imunes, favorecendo intervenções precoces e terapêutica específica, reduzindo a morbimortalidade materna e perinatal.

Combined HLA-DR and -DQ disparity is associated with a stable course of ulcerative colitis after liver transplantation for primary sclerosing cholangitis

Combined disparity of human leukocyte antigen (HLA)-DR and -DQ between mother and fetus is associated with less severe ulcerative colitis (UC) during pregnancy. We evaluated whether donor-recipient HLA disparity after liver transplantation (LT) affects UC in patients with primary sclerosing cholangitis (PSC). Sixty-nine consecutive patients with PSC underwent LT; all underwent colonoscopy before LT; 48 had UC before and 3 had de novo UC after LT. Clinical and laboratory data, activity and treatment of UC, post-LT cytomegalovirus infection, and disparity of HLA-A, -B, -DR, and -DQ for each donor-recipient pair were evaluated. Pre-LT quiescent UC was present in 26 patients. Post-LT UC activity was evaluated in 36 of 51 patients with UC who had not undergone pre-LT colectomy and who had >12 months' post-LT survival. Of these, 16 were stable, 17 had worsened, and 3 had de novo UC. Seven required colectomy (4 for dysplasia or cancer) after LT. Post-LT cytomegalovirus viremia was neither associated with worse UC activity (P = 0.58) nor de novo UC. Disparity with respect to HLA-A, -B, -DR, and -DQ was found in 58%, 27%, 44%, and 39% donor-recipient pairs, respectively. Post-LT UC course was similar with respect to single HLA disparity. However, disparity in none or only one HLA-DR or -DQ was significantly associated with worse activity compared with patients with disparity at both (65% vs. 0%, P = 0.009). Logistic regression found that the disparity for both -DR and -DQ was the only factor statistically significantly associated with post-LT UC activity. We conclude that disparity in both HLA-DR and -DQ between donor and recipient is associated with stable UC activity after LT.

Fetal arthrogryposis and maternal serum antibodies

Arthrogryposis multiplex congenital (AMC) describes multiple joint contractures resulting from lack of movement in utero. Antibodies directed at the fetal isoform of the muscle acetylcholine receptor (AChR) have been reported in a small number of asymptomatic mothers of AMC babies. We examined sera from 179 mothers of AMC babies and 20 parous and non-parous controls to look for antibodies to AChR or undefined muscle or neuronal proteins. We found positive AChR antibodies in only three sera (1.5%) from asymptomatic AMC mothers. However, there was reactivity with muscle or with neuronal antigens in 33% of the sera, and reactivity to undefined neuronal antigens was more common in sera from mothers of AMC babies with CNS involvement (p=0.001) than those without. The offspring of mothers with AChR antibodies may benefit from treatment during pregnancy. Other maternal antibodies require further study, but these observations add to the emerging literature on maternal antibodies associated with developmental intrauterine disorders.

Adverse effects of intradermal allogeneic lymphocyte immunotherapy: acute reactions and role of autoimmunity

BACKGROUND

Immunotherapy with allogeneic lymphocytes was introduced as a therapeutic option for selected infertile couples in different centres worldwide 20 years ago. It has been suggested for other indications as well, e.g. for pregnant women at risk of a child with Rhesus-D haemolytic disease, or as a vaccine which might reduce the receptiveness for HIV-1 infection. Here we report on our experience on adverse side-effects of intradermal lymphocyte immunotherapy (LIT) for infertile couples using partner's lymphocytes.

METHODS

Prospective 4 week follow-up of all couples from 2000 to 2003 for acute reactions (feedback 2687/3246 [corrected] 83%). All couples treated between 1996 and 2002 received questionnaires after 2-3 years (feedback 1914/3041, 63%).

RESULTS

Local reactions predominantly consisted of redness and itching for approximately 2 weeks. Systemic reactions could be attributed to LIT in 6-8%. Blisters at the injection sites were characteristic of LIT but not dependent on the HLA class I mismatch status between cell donor and host. The incidence of autoimmune disease was 0.1%. Four patients developed thromboembolism in pregnancy which was not ascribed to antiphospholipid syndrome.

CONCLUSIONS

Acute side-effects are comparable to those reported after intradermal vaccination for infectious diseases. Specific risks for anaphylaxis, autoimmune or graft versus host disease were not detected.

Identification of male cardiomyocytes of extracardiac origin in the hearts of women with male progeny: male fetal cell microchimerism of the heart

BACKGROUND

Fetal progenitor cells may cross the placenta during pregnancy, persist for decades in the maternal bloodstream, and find a microenvironment conducive to colonization in a variety of maternal solid organs. Whether extracardiac fetal progenitors are present in the heart of women with male issue is unknown.

METHODS

The hearts from 2 non-pregnant women who had given birth to 2 and 3 male children, respectively, were studied. Myocardial specimens from 2 men and 2 women (without history of pregnancies) were used as controls. Real time polymerase chain reaction was performed to amplify the SRY gene located at the Y chromosome. Fluorescence in situ hybridization (FISH) with probes specific for X and Y chromosomes was combined with alpha-actin immunohistochemistry to identify cardiac muscle cells. Histocompatibility studies were conducted in both patients and their male relatives.

RESULTS

The SRY gene was amplified in the myocardium of both patients. FISH analysis showed clear evidence of male cells with the typical cardiomyocyte phenotype within the myocardium. X- and Y-chromosome bodies in the nuclei were found in 0.25% and 0.20% of cells, respectively. Increased human leukocyte antigen compatibility was observed between patients and their sons.

CONCLUSIONS

This study identified male cardiomyocytes of extracardiac origin, presumably fetal, in the hearts of 2 women with male progeny. Fetal progenitor cells may colonize the heart and under appropriate microenvironmental stimuli, differentiate into cardiomyocytes.

Gender issues in pulmonary vascular disease

Gender differences in pulmonary vascular diseases, as exemplified by primary pulmonary hypertension and scleroderma-related pulmonary hypertension, are not well-explained; however, in general terms, they seem to be related to a combination of genetic predispositions and gender-specific environmental triggers. More information is needed in both areas with respect to mechanisms of disease. More information also is needed about possible gender differences in disease presentation,course, and response to treatments.

Myocyte growth in the failing heart

Adult ventricular myocytes can undergo mitotic division, resulting in an increase in the aggregate number of cells in the heart. The improvement in the methodological approach to the analysis of tissue sections by immunostaining and confocal microscopy has defeated the dogma that myocyte regeneration cannot occur in the adult heart. Most importantly, primitive and progenitor cells have been identified in the human heart. These cells express telomerase and have the capability of undergoing lineage commitment and rapid cell division, expanding significantly the contracting ventricular myocardium. These cell populations possess all the molecular components regulating the entry and progression through the cell cycle, karyokinesis, and cytokinesis. The recognition that myocyte hypertrophy and regeneration, as well as myocyte necrosis and apoptosis, occur in cardiac diseases has contributed to enhancing our understanding of the plasticity of the human heart.

Correlations of Y chromosome microchimerism with disease activity in patients with SLE: analysis of preliminary data

BACKGROUND

Recently it has been suggested that microchimerism may have a significant role in the aetiopathogenesis of some autoimmune diseases.

OBJECTIVES

To evaluate the incidence of microchimerism in systemic lupus erythematosus (SLE), to quantify the phenomenon, to evaluate changes of microchimerism during follow up, and to correlate these data with clinical and laboratory variables.

METHODS

Patients were selected for the study on the basis of the following criteria: (a) pregnancy with at least one male offspring; (b) no history of abortion and blood transfusion. Microchimerism was detected using a competitive nested polymerase chain reaction for a specific Y chromosome sequence and an internal competitor designed ad hoc. Disease activity and organ involvement were also evaluated.

RESULTS

Sixty samples from 22 patients with SLE and 24 healthy controls were examined. Microchimerism was seen in 11 (50%) patients and 12 (50%) controls. The mean number of male equivalent cells was 2.4 cells/100 000 (range 0.1-17) in patients with SLE and 2.5 (range 0.2-1.8) in healthy controls. No differences in the incidence of microchimerism or in the number of microchimeric cells were found between patients and healthy controls. Patients with a history of lupus nephritis had a higher mean number of fetal cells than patients with no such history. Disease activity did not appear to correlate with microchimerism.

CONCLUSIONS

The preliminary data suggest that microchimerism does not interfere with the disease course of SLE, although further analysis on larger groups will be necessary to confirm these observations.

Antibodies to acetylcholine receptor in parous women with myasthenia: evidence for immunization by fetal antigen

The weakness in myasthenia gravis (MG) is mediated by autoantibodies against adult muscle acetylcholine receptors (AChR) at the neuromuscular junction; most of these antibodies also bind to fetal AChR, which is present in the thymus. In rare cases, babies of mothers with MG, or even of asymptomatic mothers, develop a severe developmental condition, arthrogryposis multiplex congenita, caused by antibodies that inhibit the ion channel function of the fetal AChR while not affecting the adult AChR. Here we show that these fetal AChR inhibitory antibodies are significantly more common in females sampled after pregnancy than in those who present before pregnancy, suggesting that they may be induced by the fetus. Moreover, we were able to clone high-affinity combinatorial Fab antibodies from thymic cells of two mothers with MG who had babies with arthrogryposis multiplex congenita. These Fabs were highly specific for fetal AChR and did not bind the main immunogenic region that is common to fetal and adult AChR. The Fabs show strong biases to VH3 heavy chains and to a single Vkappa1 light chain in one mother. Nevertheless, they each show extensive intraclonal diversification from a highly mutated consensus sequence, consistent with antigen-driven selection in successive steps. Collectively, our results suggest that, in some cases of MG, initial immunization against fetal AChR is followed by diversification and expansion of B cells in the thymus; maternal autoimmunity will result if the immune response spreads to the main immunogenic region and other epitopes common to fetal and adult AChR.