Histo-blood group antigens as allo- and autoantigens

Association of histo-blood group antigens and predisposition to gastrointestinal diseases

Infectious gastroenteritis is a common illness afflicting people worldwide. The two most common etiological agents of viral gastroenteritis, rotavirus and norovirus are known to recognize histo-blood group antigens (HBGAs) as attachment receptors. ABO, Lewis, and secretor HBGAs are distributed abundantly on mucosal epithelia, red blood cell membranes, and also secreted in biological fluids, such as saliva, intestinal content, milk, and blood. HBGAs are fucosylated glycans that have been implicated in the attachment of some enteric pathogens such as bacteria, parasites, and viruses. Single nucleotide polymorphisms in the genes encoding ABO (H), fucosyltransferase gene FUT2 (Secretor/Se), FUT3 (Lewis/Le) have been associated with changes in enzyme expression and HBGAs production. The highly polymorphic HBGAs among different populations and races influence genotype-specific susceptibility or resistance to enteric pathogens and its epidemiology, and vaccination seroconversion. Therefore, there is an urgent need to conduct population-based investigations to understand predisposition to enteric infections and gastrointestinal diseases. This review focuses on the relationship between HBGAs and predisposition to common human gastrointestinal illnesses caused by viral, bacterial, and parasitic agents.

Autoantibodies to red blood cell surface Glycophorin A impact the activation poise of circulating leukocytes

BACKGROUND

Both M and N alleles encode antigens on Glycophorin A (GPA), a red blood cell (RBC) surface sialoglycoprotein. Interaction between RBC GPA and leukocyte surface lectins may downregulate their activation. The current study investigates if RBC autoantibodies against GPA, such as auto-anti-M/N, prime an activated phenotype in peripheral blood leukocytes.

METHODS

Leukocyte activation was assessed in whole blood from patients with auto-anti-GPA (anti-M/N) and compared to those with allo-anti-M/N and healthy subjects. Control samples from healthy subjects with no antibodies incubated in vitro with either anti-GPA or anti-Rh were analyzed for neutrophil and monocyte surface activation marker expression, reactive oxygen species (ROS) content, and formation of aggregates with RBCs. Samples incubated with an IgG₁ isotype antibody served as controls.

RESULTS

Ex vivo, neutrophil CD66b and monocyte CD63 surface expression was increased in patients with auto-anti-M/N compared to those with allo anti-M/N (p = .1757; p = .0698) and to healthy subjects (p = .0186; p = .013). In vitro, neutrophil CD66b and monocyte CD63 surface expression was increased following incubation with anti-GPA compared to anti-Rh (p = .0003; p = .0328) and isotype control (p = .000; p = .0062). Intracellular ROS content increased in both neutrophils and monocytes incubated with anti-GPA compared to anti-Rh (p = .0012; p = .0693) and isotype control (p = .001; p = .0021). Percentage of neutrophil-RBC aggregates was decreased when incubated with anti-GPA compared to isotype control (p < .01).

CONCLUSIONS

Neutrophils and monocytes in peripheral blood exposed to an antibody directed against GPA on RBC surfaces, such as M or N antigens, may be primed towards an activated phenotype.

The Potential Contribution of ABO, Lewis and Secretor Histo-Blood Group Carbohydrates in Infection by Toxoplasma gondii

The glycosyltransferases encoded by genes from the human ABO, Lewis, and Secretor histo-blood group systems synthesize part of the carbohydrate antigens in hematopoietic and non-hematopoietic tissues. The combined action of these glycosyltransferases strongly influences cell, tissue, mucosa, and exocrine secretion carbohydrate phenotypes, including those serving as habitat for mutualistic and pathogenic microorganisms. A set of reports investigated associations between Toxoplasma gondii infection and the ABO histo-blood group system, but the results are contradictory. As T. gondii uses the gastrointestinal tract as a route for infection, and in this organ, the expression of ABO, Lewis, and Secretor histo-blood group carbohydrates occurs, it is reasonable to suppose some biological relationship between them. This text reviewed association studies published in recent decades focusing on the potential contribution of the ABO, Lewis, and Secretor histo-blood group carbohydrates and infection by T. gondii.

Association between ABO and Duffy blood types and circulating chemokines and cytokines

Blood group antigens are inherited traits that may play a role in immune and inflammatory processes. We investigated associations between blood groups and circulating inflammation-related molecules in 3537 non-Hispanic white participants selected from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Whole-genome scans were used to infer blood types for 12 common antigen systems based on well-characterized single-nucleotide polymorphisms. Serum levels of 96 biomarkers were measured on multiplex fluorescent bead-based panels. We estimated marker associations with blood type using weighted linear or logistic regression models adjusted for age, sex, smoking status, and principal components of population substructure. Bonferroni correction was used to control for multiple comparisons, with two-sided p values < 0.05 considered statistically significant. Among the 1152 associations tested, 10 were statistically significant. Duffy blood type was associated with levels of CXCL6/GCP2, CXCL5/ENA78, CCL11/EOTAXIN, CXCL1/GRO, CCL2/MCP1, CCL13/MCP4, and CCL17/TARC, whereas ABO blood type was associated with levels of sVEGFR2, sVEGFR3, and sGP130. Post hoc pairwise t-tests showed that individuals with type Fy(a+b−) had the lowest mean levels of all Duffy-associated markers, while individuals with type A blood had the lowest mean levels of all ABO-associated markers. Additional work is warranted to explore potential clinical implications of these differences.

ABO-Incompatible Living Donor Liver Transplantation with Reduced Rituximab Dose: A Retrospective Analysis of 65 Patients - Can We Fast-Track Liver Transplant Surgery and Improve Long-Term Survival?

BACKGROUND ABO-incompatible (ABO-i) living donor liver transplantation (LDLT) is a feasible alternative for donor liver allograft in emergency situations, especially in Asia, where deceased-donor organs remain scarce. The reported outcomes of ABO-i LDLT after optimal desensitization are comparable to those of ABO-compatible LDLT. In this retrospective study, we found improved outcomes after ABO-i LDLT with a low-dose rituximab in combination with double-filtration plasmapheresis (DFPP) and prophylactic antibiotic therapy. MATERIAL AND METHODS Between January 2006 and December 2018, a total of 65 recipients underwent ABO-i LDLT surgeries at our center. The study cohort consisted of 50 recipients (Era III) who underwent ABO-i LDLT using the recently updated desensitization protocol, which included rituximab 200 mg intravenous injection once a week prior to LDLT, 4 sessions of DFPP in all patients, and prophylactic antibiotics for 3 months. RESULTS The 3-year overall survival rate achieved in ABO-i LDLT patients was 72.7% (66.6% for Era I and 33.3% for Era II patients). In the study population, 11 patients developed complications due to infection. Five of these patients (10%) died due to overwhelming sepsis. Four patients (8%) were diagnosed with multiple strictures and diffusely scattered dilatation of intrahepatic bile ducts on computed tomography, without vascular complications. Three of them had evidence of antibody-mediated rejection (AMR). CONCLUSIONS Our experience shows that the ABO-i LDLT protocol of lowered rituximab combined with pre-transplant sessions of plasmapheresis and a quadruple immunosuppressive regimen can be effective in chronic liver failure patients with clinical urgency in the absence of an ABO-compatible donor. Fast-tracking the use of ABO-i LDLT is feasible in patients with an acute liver failure (ALF) and can safely increase the donor liver pool, with an acceptable outcome.

B Cell Responses: Cell Interaction Dynamics and Decisions

B cells and the antibodies they produce have a deeply penetrating influence on human physiology. Here, we review current understanding of how B cell responses are initiated; the different paths to generate short- and long-lived plasma cells, germinal center cells, and memory cells; and how each path impacts antibody diversity, selectivity, and affinity. We discuss how basic research is informing efforts to generate vaccines that induce broadly neutralizing antibodies against viral pathogens, revealing the special features associated with allergen-reactive IgE responses and uncovering the antibody-independent mechanisms by which B cells contribute to health and disease.

ABO-Incompatible Living Donor Liver Transplantation in Focus of Antibody Rebound

BACKGROUND

Living donor liver transplantation (LDLT) is an option to expand the donor organ pool for patients with life-threatening diseases who cannot be supplied with a cadaver organ. Next to the donor risks, complications after ABO-incompatible LDLT (ABOi LDLT) in the recipient are subject to controversial discussion. Improvement in ABOi graft survival rates have been achieved with plasma treatment procedures (PTP) and immunosuppression but antibody-mediated rejection (AMR) and graft loss still occur.

METHODS

Since 2008, we have prepared 10 patients for ABOi LDLT. Seven of the 10 patients for transplantation had hepatocellular carcinoma (HCC).

RESULTS

All patients underwent PTP before and after ABOi LDLT as well as immunosuppression according to the treatment schedule. We did not use anti-CD20 monoclonal antibodies in the transplant setting. We transplanted 6 of 10 preconditioned patients. After 3 years, 5 of the 6 transplanted patients were still alive.

CONCLUSION

Even if B-cell depletion with anti-CD 20 treatment in the setting of ABOi LDLT is commonly accepted, our center successfully administered only quadruple drug immunosuppression combined with PTP. Especially patients with HCC had a high titer increment also pre-transplantation and were at high risk for arterial thrombosis and graft loss.

Structural diversity and biological importance of ABO, H, Lewis and secretor histo-blood group carbohydrates

ABO, H, secretor and Lewis histo-blood system genes control the expression of part of the carbohydrate repertoire present in areas of the body occupied by microorganisms. These carbohydrates, besides having great structural diversity, act as potential receptors for pathogenic and non-pathogenic microorganisms influencing susceptibility and resistance to infection and illness. Despite the knowledge of some structural variability of these carbohydrate antigens and their polymorphic levels of expression in tissue and exocrine secretions, little is known about their biological importance and potential applications in medicine. This review highlights the structural diversity, the biological importance and potential applications of ABO, H, Lewis and secretor histo-blood carbohydrates.

Histo-blood group glycans in the context of personalized medicine

BACKGROUND

A subset of histo-blood group antigens including ABO and Lewis are oligosaccharide structures which may be conjugated to lipids or proteins. They are known to be important recognition motifs not only in the context of blood transfusions, but also in infection and cancer development.

SCOPE OF REVIEW

Current knowledge on the molecular background and the implication of histo-blood group glycans in the prevention and therapy of infectious and non-communicable diseases, such as cancer and cardiovascular disease, is presented.

MAJOR CONCLUSIONS

Glycan-based histo-blood groups are associated with intestinal microbiota composition, the risk of various diseases as well as therapeutic success of, e.g., vaccination. Their potential as prebiotic or anti-microbial agents, as disease biomarkers and vaccine targets should be further investigated in future studies. For this, recent and future technological advancements will be of particular importance, especially with regard to the unambiguous structural characterization of the glycan portion in combination with information on the protein and lipid carriers of histo-blood group-active glycans in large cohorts.

GENERAL SIGNIFICANCE

Histo-blood group glycans have a unique linking position in the complex network of genes, oncodevelopmental biological processes, and disease mechanisms. Thus, they are highly promising targets for novel approaches in the field of personalized medicine. This article is part of a Special Issue entitled "Glycans in personalised medicine" Guest Editor: Professor Gordan Lauc.

Pathogenesis and mechanisms of antibody-mediated hemolysis

BACKGROUND

The clinical consequences of antibodies to red blood cells (RBCs) have been studied for a century. Most clinically relevant antibodies can be detected by sensitive in vitro assays. Several mechanisms of antibody-mediated hemolysis are well understood. Such hemolysis after transfusion is reliably avoided in a donor-recipient pair, if one individual is negative for the cognate antigen to which the other has the antibody.

STUDY DESIGN AND RESULTS

Mechanisms of antibody-mediated hemolysis were reviewed based on a presentation at the Strategies to Address Hemolytic Complications of Immune Globulin Infusions Workshop addressing intravenous immunoglobulin (IVIG) and ABO antibodies. The presented topics included the rates of intravascular and extravascular hemolysis; immunoglobulin (Ig)M and IgG isoagglutinins; auto- and alloantibodies; antibody specificity; A, B, A,B, and A1 antigens; A1 versus A2 phenotypes; monocytes-macrophages, other immune cells, and complement; monocyte monolayer assay; antibody-dependent cell-mediated cytotoxicity; and transfusion reactions due to ABO and other antibodies.

CONCLUSION

Several clinically relevant questions remained unresolved, and diagnostic tools were lacking to routinely and reliably predict the clinical consequences of RBC antibodies. Most hemolytic transfusion reactions associated with IVIG were due to ABO antibodies. Reducing the titers of such antibodies in IVIG may lower the frequency of this kind of adverse event. The only way to stop these events is to have no anti-A or anti-B in the IVIG products.

On the dark side of therapies with immunoglobulin concentrates: the adverse events

Therapy by human immunoglobulin G (IgG) concentrates is a success story ongoing for decades with an ever increasing demand for this plasma product. The success of IgG concentrates on a clinical level is documented by the slowly increasing number of registered indication and the more rapid increase of the off-label uses, a topic dealt with in another contribution to this special issue of Frontiers in Immunology. A part of the success is the adverse event (AE) profile of IgG concentrates which is, even at life-long need for therapy, excellent. Transmission of pathogens in the last decade could be entirely controlled through the antecedent introduction by authorities of a regulatory network and installing quality standards by the plasma fractionation industry. The cornerstone of the regulatory network is current good manufacturing practice. Non-infectious AEs occur rarely and mainly are mild to moderate. However, in recent times, the increase in frequency of hemolytic and thrombotic AEs raised worrying questions on the possible background for these AEs. Below, we review elements of non-infectious AEs, and particularly focus on hemolysis and thrombosis. We discuss how the introduction of plasma fractionation by ion-exchange chromatography and polishing by immunoaffinity chromatographic steps might alter repertoire of specificities and influence AE profiles and efficacy of IgG concentrates.

Transfusion-induced bone marrow transplant rejection due to minor histocompatibility antigens

Traditionally, alloimmunization to transfused blood products has focused exclusively on recipient antibodies recognizing donor alloantigens present on the cell surface. Accordingly, the immunologic sequelae of alloimmunization have been antibody mediated effects (ie, hemolytic transfusion reactions, platelet refractoriness, anti-HLA and anti-HNA effects, etc). However, in addition to the above sequelae, there is also a correlation between the number of antecedent transfusions in humans and the rate of bone marrow transplant (BMT) rejection-under reduced intensity conditioning with HLA-matched or HLA-identical marrow. Bone marrow transplant of this nature is the only existing cure for a series of nonmalignant hematologic diseases (eg, sickle cell disease, thalassemias, etc); however, rejection remains a clinical problem. It has been hypothesized that transfusion induces subsequent BMT rejection through immunization. Studies in animal models have observed the same effect and have demonstrated that transfusion-induced BMT rejection can occur in response to alloimmunization. However, unlike traditional antibody responses, sensitization in this case results in cellular immune effects, involving populations such as T cell or natural killer cells. In this case, rejection occurs in the absence of alloantibodies and would not be detected by existing immune-hematologic methods. We review human and animal studies in light of the hypothesis that, for distinct clinical populations, enhanced rejection of BMT may be an unappreciated adverse consequence of transfusion, which current blood bank methodologies are unable to detect.

Serum antibodies to blood group A predict survival on PROSTVAC-VF

PURPOSE

There is evidence that therapeutic cancer vaccines can lengthen survival for some patients with cancer, but responses vary widely from one person to another. Methods to predict clinical outcomes will advance the field and provide new insights into critical determinants of in vivo efficacy.

EXPERIMENTAL DESIGN

This retrospective study included 141 subjects from phase II trials of PROSTVAC-VF, a poxvirus-based cancer vaccine currently in phase III clinical trials for advanced prostate cancer. A glycan microarray was used to profile prevaccination antiglycan antibody populations in sera as potential biomarkers for PROSTVAC-VF. The screen for predictive biomarkers identified antiglycan antibodies that consistently stratified subjects into groups with different Kaplan-Meier survival estimates. Because of the potential for overfitting, a permutation test was used to estimate the false discovery rate.

RESULTS

Prevaccination antibody levels to blood group A trisaccharide (BG-Atri) were found to have a statistically significant correlation with survival. Long-term survival was approximately doubled in subjects with abundant anti-BG-Atri immunoglobulin M (IgM) relative to subjects with little or no preexisting IgM for BG-Atri. This survival correlation was specific to vaccine treatment, as no correlation was observed in control patients immunized with wild-type poxviruses lacking the key tumor antigen, prostate-specific antigen (PSA). Moreover, anti-BG-Atri IgM levels were not correlated with general measures of disease severity, such as PSA levels, Gleason score, or Halabi predicted survival.

CONCLUSION

In addition to reporting a new potentially predictive biomarker for PROSTVAC-VF, this study highlights the use of glycan microarray technology for improving our understanding of vaccine immunology. Clin Cancer Res; 19(5); 1290-9. ©2012 AACR.

Glycan array analysis of the antigen repertoire targeted by tumor-binding antibodies

Immunization with whole cells has been used extensively to generate monoclonal antibodies, produce protective immune responses, and discover new disease antigens. While glycans are abundant on cell surfaces, anti-glycan immune responses have not been well-characterized. We used glycan microarrays to profile 49 tumor-binding monoclonal antibodies generated by immunizing mice with whole cancer cells. A substantial proportion (41%) of the tumor binding antibodies bound carbohydrate antigens. The antibodies primarily recognize a group of 5 glycan antigens: Sialyl Lewis A (SLeA), Lewis A (LeA), Lewis X (LeX), blood group A (BG-A), and blood group H on a type 2 chain (BG-H2). The results have important implications for monoclonal antibody production and cancer vaccine development.

Histoblood groups other than HLA in organ transplantation

Immunological matching of a living related donor and recipient of an allograft is precise, but for cadaver organs matching is controversial, including at least detection of specific sensitization in the recipient against the donor, especially for HLA-DR. With the publication of some cases of ABO histoblood group incompatible transplantations with favorable outcomes, transplantation immunologists now focus on many of the 29 International Society of Blood Transfusion-approved histoblood group systems. So far, research lags behind knowledge about which system occurs in which organ, but modern molecular biology tests, like basic local alignment search tools (BLAST) and the recent inclusion of some systems into the CD classification, make possible the tracking of some histoblood group epitopes to specific tissue components. We have conducted such a search. With respect to tissue distribution, mRNA transcripts, and expressed sequence tags (EST), we observed a huge variety of distribution patterns. The total number of EST in the embryo pool was 752,991 and in the adult pool 1,227,835. Representative results were described for umbilical cord, bone marrow, peripheral stem cells, the nervous system, and the embryo. The ABO histoblood group systems maintain high priority for matching, because of the occurrence of naturally occurring anti-A/B antibodies. Substantial progress has been made in monitoring their levels and immunoglobulin isotypes in recipients, which, beyond hemagglutination, can now be quantitated using ELISA or cytofluorometry. A picture of ever-improving compatibility matching in solid organ and stem cell transplantation beyond mere HLA typing is the consequence.

Duffy and Kidd blood group antigens: minor histocompatibility antigens involved in renal allograft rejection?

BACKGROUND

Minor histocompatibility antigens have been poorly defined. Whether Duffy (FY) and Kidd (JK), polymorphic and immunogenic blood group antigens, widely distributed in human organs, expressed and functional in the kidney, could function as minor histocompatibility antigens and be implicated in renal allograft rejection was questioned.

STUDY DESIGN AND METHODS

A retrospective, homogeneous, single-center cohort of 370 renal transplants was analyzed. In all donor/recipient pairs, FY and JK polymorphisms were identified by real-time polymerase chain reaction. In all donor/recipient pairs the matching (m) or mismatching (mm) status was defined for both systems. All biopsies were reviewed, and historical screening results for FY and JK alloantibodies and graft survival were retrospectively analyzed.

RESULTS

Although graft survival was not different between the groups, it was observed that FY mm grafts had significantly more chronic lesions compared to FY m grafts. HLA-DR11 was more frequent in both recipients (p = 0.0081) and donors (p = 0.0104) of FY mm couples without chronic allograft nephropathy, suggesting a protective effect for this molecule. JK mm grafts had more interstitial inflammation than JK m grafts (p = 0.0369).

CONCLUSION

This renal model unmasks for the first time the role of FY and-to a lesser extent-JK antigens as minor histocompatibility antigens and suggests their potential role for other clinical transplant settings.

Tissue distribution of blood group membrane proteins beyond red cells: Evidence from cDNA libraries

The proteins of blood group systems are expressed on red blood cells (RBC) by definition. We searched nucleotide databases of human expressed sequence tags (EST) to collate the distribution of 22 distinct membrane proteins in cells and tissues other than RBC. The documented blood group genes are: MNS, Rh, Lutheran, Kell, Duffy, Kidd, Diego, Yt, Xg, Scianna, Dombrock, Colton, Landsteiner-Wiener, Kx, Gerbich, Cromer, Knops, Indian, Ok, Raph, John-Milton-Hagen and Gill. The genes were grouped according to their overall and their relative expression in embryo and adults. We describe the distribution of EST in cells, tissues and cell lines with a focus on non-RBC tissues.