Immunoglobulin E-Mediated Allergies in Lung-Transplanted Adults

Anti-pig IgE and IgA Antibodies in Naive Primates and Nonhuman Primates With Pig Xenografts

BACKGROUND

Natural preformed anti-pig IgM/IgG antibodies in primates play an important role in xenograft rejection. As it is not clear how IgE and IgA engage in the immune system in xenotransplantation, we investigated natural preformed and elicited anti-pig IgE/IgA in naive primates and after xenotransplantation in nonhuman primates.

METHODS

The binding of IgM/IgG/IgE/IgA antibodies to red blood cells (RBCs) from wild-type (WT), α1,3-galactosyltransferase gene-knockout (GTKO), and GTKO/cytidine monophospho-N-acetylneuraminic acid hydroxylase gene-knockout/β-1,4 N-acetylgalactosaminyltransferase 2 gene-knockout (ie, triple-knockout pigs) pigs were measured by flow cytometry in naive human (n = 50) and baboon (n = 14) sera. Antibody binding to WT and GTKO pig RBCs (pRBCs) was also measured in the sera of baboons (nonsensitized n = 7, sensitized n = 2) and rhesus monkeys (nonsensitized n = 2, sensitized n = 11) following WT or GTKO pig organ/tissue xenotransplantation. Deposition of IgM/IgG/IgE/IgA in the grafts was detected by immunohistochemistry.

RESULTS

The majority of humans had natural preformed IgM/IgG/IgE/IgA to WT and GTKO pRBCs. In contrast, IgM/IgG/IgE/IgA to triple-knockout pRBCs were present at lower levels and frequency (P < 0.01). Baboons also had IgM/IgG/IgE/IgA antibodies against WT pRBCs, but fewer to GTKO and triple-knockout (P < 0.01). After xenotransplantation into nonhuman primates, when IgM/IgG increased, IgE/IgA also increased, but to a lesser extent. In addition to IgM/IgG, IgE or IgA deposition was observed in rejected pig xenografts.

CONCLUSIONS

Primates develop serum anti-pig IgE/IgA antibodies both naturally and during xenograft rejection. The pathophysiological role, if any, of anti-pig IgE/IgA antibodies remains unknown.

Transfer and loss of allergen-specific responses via stem cell transplantation: A prospective observational study

BACKGROUND

Currently, no estimates can be made on the impact of hematopoietic stem cell transplantation on allergy transfer or cure of the disease. By using component-resolved diagnosis, we prospectively investigated 50 donor-recipient pairs undergoing allogeneic stem cell transplantation. This allowed calculating the rate of transfer or maintenance of allergen-specific responses in the context of stem cell transplantation.

METHODS

Allergen-specific IgE and IgG to 156 allergens was measured pretransplantation in 50 donors and recipients and at 6, 12 and 24 months in recipients post-transplantation by allergen microarray. Based on a mixed effects model, we determined risks of transfer of allergen-specific IgE or IgG responses 24 months post-transplantation.

RESULTS

After undergoing stem cell transplantation, 94% of allergen-specific IgE responses were lost. Two years post-transplantation, recipients' allergen-specific IgE was significantly linked to the pretransplantation donor or recipient status. The estimated risk to transfer and maintain individual IgE responses to allergens by stem cell transplantation was 1.7% and 2.3%, respectively. Allergen-specific IgG, which served as a surrogate marker of maintaining protective IgG responses, was highly associated with the donor's (31.6%) or the recipient's (28%) pretransplantation response.

CONCLUSION

Hematopoietic stem cell transplantation profoundly reduces allergen-specific IgE responses but also comes with a considerable risk to transfer allergen-specific immune responses. These findings facilitate clinical decision-making regarding allergic diseases in the context of hematopoietic stem cell transplantation. In addition, it provides prospective data to estimate the risk of transmitting allergen-specific responses via hematopoietic stem cell transplantation.

Decrease of Airway Allergies After Lung Transplantation Is Associated With Reduced Basophils and Eosinophils

BACKGROUND

Allergies are hypersensitive reactions of the immune system on antigen exposure similar to immune reactions after transplantation (Tx). Their activity can change after Tx. The lung as a transplantable organ is challenged two-fold, by antigens from the blood and the air environment. Herein we analyzed if airway allergies change after lung Tx.

METHODS

We systematically reviewed patients' airway allergies before and after lung Tx between 1992 and 2014. The course of lymphocytes, thrombocytes, and leukocytes, among them neutrophils, eosinophils, and basophils, was analyzed in patients in whom airway allergies have changed and in whom they did not change.

RESULTS

From 362 lung transplanted patients, 44 patients had suffered from allergies before Tx (12.2%). In 20 of these patients (45.5%), airway allergies disappeared completely within 1 year after lung Tx and were persistently absent thereafter. In these patients, basophils and eosinophils decreased significantly (P < .0012); in contrast, cells did not decrease in patients whose allergies did not disappear. Leukocytes overall, and in particular, neutrophils, decreased significantly in patients whose allergy disappeared (P < .014, P < .012, respectively).

CONCLUSIONS

Airway allergies disappeared in almost half of cases after lung Tx. Along with this reduction, basophils and eosinophils decreased as potentially responsible cells for this phenomenon. These findings may stimulate intensified research on basophils and eosinophils as major drivers of airway allergies.

Novel developments in the mechanisms of immune tolerance to allergens

Allergy is the result of a disbalanced immune response to environmental innocuous antigens. Despite of accumulating data to define the pathomechanisms that take place in case of allergic diseases a detailed understanding of sequence of events that lead to the "normal" scenario of tolerance development are still under debate. Allergen-specific immunotherapy is the only causal treatment of allergic diseases. It modifies the immune response to a particular antigen to achieve tolerance against the symptom-causing allergen. This process is considered to mirror physiological peripheral tolerance induction. A number of immunological changes have been described to occur under allergen immunotherapy, including the generation of allergen-specific regulatory T cells, the induction of allergen-specific IgG4, an increase in the Th1/Th2 cytokine ratio and decreased activation and function of effector cells such as mast cells, basophils and eosinophils.

Non-atopic IgE and eosinophil cationic protein after allogeneic hematopoietic stem cell transplantation in children

Allogeneic hematopoietic stem cell transplantation (HSCT) in childhood is associated with severe pulmonary complications, but the pathophysiologic mechanisms remain unclear. Our aim was to evaluate the association of total and specific IgE, eosinophil cationic protein (ECP) and eosinophilia in HSCT recipients with pulmonary complications. We prospectively measured total and specific serum IgE, eosinophils, and ECP before and 28, 100, and 180 days after HSCT. We included 30 children (age 2-17 years) undergoing HSCT. Nine patients had a history of previous atopy without being associated with pulmonary complications after HSCT until day +360. Specific IgE levels showed a decline after HSCT, associated with the absence of allergy symptoms, suggesting a reduction of atopy. Elevated total serum IgE levels occurred in seven patients on day +28 after HSCT. This elevation did not coincide with allergy symptoms. ECP showed no correlation with total allergy symptoms, eosinophilia, IgE levels, or pulmonary complications. There was a significant correlation (p = 0.0367) between ECP levels on day +28 and concurrent acute graft-versus-host disease (GvHD). Non-atopic serum ECP and IgE levels are elevated on day +28 after HSCT in children, with ECP showing a potential relation to acute GvHD.

Bronchial asthma developing after 15 years of immunosuppressive treatment following renal transplantation

A 42-year-old woman who underwent renal transplantation from her mother at the age of 26 due to IgA nephropathy had since been treated with immunosuppressive agents, including prednisolone (PSL), azathioprine (AZA) and cyclosporine (CsA). The patient had remained clinically stable for 15 years. However, in the middle of May 2010, she developed bronchial asthma for the first time after performing house-cleaning activities and was treated with corticosteroids and antiasthmatic agents. The use of immunosuppressive agents as a treatment for severe bronchial asthma might have been related to the manifestation of bronchial asthma in this case.

Allergic sensitization in kidney-transplanted patients prevails under tacrolimus treatment

BACKGROUND

Type I allergies have repeatedly been reported after solid organ transplantation despite T cell-targeted immunosuppressive therapy. A causal relationship with tacrolimus has been proposed.

OBJECTIVE

The present study directly compared the occurrence of allergic sensitization and disease under tacrolimus- vs. cyclosporin A-based immunosuppressive therapy.

METHODS

The prevalences of IgE-mediated sensitization and allergy were assessed in a cross-sectional study of kidney-transplanted adults receiving tacrolimus (n = 100) or cyclosporin A (n = 100).

METHODS

included a standardized questionnaire, skin prick test and measurement of total and specific IgE against common nutritive and inhalant allergens. Results The prevalence of sensitization was significantly higher in the tacrolimus- than in the cyclosporin A-treated group (34%, n = 34, vs. 20%, n = 20; P = 0.026). The rate of clinically relevant allergy in patients receiving tacrolimus was twice that in patients receiving cyclosporin A (15%, n = 15, vs. 8%, n = 8; P = 0.12). No other factor (age, serum drug level, concomitant immunosuppressive medication, time since transplantation, underlying disease) was found to have an influence on sensitization or allergy prevalence (logistic regression).

CONCLUSION AND CLINICAL RELEVANCE

Our results suggest that post-transplant immunosuppression with tacrolimus is associated with an increased occurrence of IgE-mediated sensitization and probably manifestation of allergic disease, which has to be treated specifically despite immunosuppressive therapy.

Impact of systemic immuno-suppression after solid organ transplantation on allergen-specific responses

INTRODUCTION

  The immunosuppressive therapy in solid organ transplantation targets mainly the T- and B-cell-mediated immune response. However, there is evidence that it neither suppresses sensitization nor clinical manifestation of allergic diseases in organ-transplanted patients.

OBJECTIVE

  This study addresses the question whether allergen-specific responses are altered by systemic immunosuppression via negative effects on the T-regulatory cell compartment and a more pronounced suppression on Th1-type T-cell responses.

MATERIAL AND METHODS

  Peripheral blood mononuclear cells from 65 solid organ-transplanted (kidney, liver, lung) children, adolescents, and young adults and 18 healthy, matched controls were included, and their clinical and sensitization status assessed. Allergen-specific proliferation, intracellular cytokine production, frequency of forkhead box P3 (FOXP3)+ CD3+ CD4+ CD25(high) cells, mRNA expression of IL-10, transforming growth factor (TGF)-β and FOXP3 (real-time RT-PCR) of peripheral blood mononuclear cells or bronchoalveolar lavage fluid (BAL)-derived cells, and the inhibitory capacity of T-reg cells were investigated.

RESULTS

  Immunosuppression led to a significantly altered regulatory marker profile expressed by enhanced TGF-β mRNA production and a reduced frequency of FOXP3+ CD4+ CD3+ cells in solid organ transplanted individuals. FOXP3 expression in BAL cells of lung-transplanted patients was significantly decreased. Allergen-specific proliferation was not significantly altered despite long-term immunosuppression. However, suppression of allergen-specific responses via the T-regulatory cell fraction was deficient in immunosuppressed individuals.

CONCLUSION

  The results suggest an insufficient control of allergen-specific responses via the Treg-cell compartment under systemic immunosuppression.

Relevance of MICA and other non-HLA antibodies in clinical transplantation

The clinical importance of HLA-specific antibodies for organ allograft outcome is well established. In the past few years, there has been an increasing interest in non-HLA antigens as targets of injury in organ transplant recipients. This increased interest has been spurred by the fact that HLA-identical kidney transplants also undergo immunological rejections. Polymorphisms within non-HLA genes associated with evoking an immune response to alloantigens are currently being studied for their association with transplant outcome. Non-HLA antigens, such as the polymorphic MHC class I-related chain A (MICA), expressed on endothelial cells have been implicated in the pathogenesis of hyperacute, acute and chronic organ allograft rejections. Use of endothelial cells as targets may clarify the specificities of other clinically relevant non-HLA antibodies in graft rejections. This review summarizes past and current knowledge of the clinical importance and specificities of non-HLA antibodies, and mechanisms by which these antibodies may contribute to graft destruction in clinical transplantation. The aims of current research into the role of non-HLA antigens and their genetics in predicting outcome are to develop an improved insight into the basic science of transplantation and to develop a risk or prognostic index for use in the clinical setting. Non-HLA antibody responses are receiving increasing interest in acute and chronic rejection and specificity, affinity, and pathogenicity need to be investigated to estimate their contribution. Undoubtedly, this will continue to be an area of interest in terms of fully understanding the role of non-HLA antigens as targets of immune-mediated injury and the potential for clinical intervention.