Anti-HLA antibody testing in hematology patients

Genetic diversity, growth and heart function of Auckland Island pigs, a potential source for organ xenotransplantation

One of the prerequisites for successful organ xenotransplantation is a reasonable size match between the porcine organ and the recipient's organ to be replaced. Therefore, the selection of a suitable genetic background of source pigs is important. In this study, we investigated body and organ growth, cardiac function, and genetic diversity of a colony of Auckland Island pigs established at the Center for Innovative Medical Models (CiMM), LMU Munich. Male and female Auckland Island pig kidney cells (selected to be free of porcine endogenous retrovirus C) were imported from New Zealand, and founder animals were established by somatic cell nuclear transfer (SCNT). Morphologically, Auckland Island pigs have smaller body stature compared to many domestic pig breeds, rendering their organ dimensions well-suited for human transplantation. Furthermore, echocardiography assessments of Auckland Island pig hearts indicated normal structure and functioning across various age groups throughout the study. Single nucleotide polymorphism (SNP) analysis revealed higher runs of homozygosity (ROH) in Auckland Island pigs compared to other domestic pig breeds and demonstrated that the entire locus coding the swine leukocyte antigens (SLAs) was homozygous. Based on these findings, Auckland Island pigs represent a promising genetic background for organ xenotransplantation.

How to improve issuing, transfusion and follow-up of blood components in Southern and Eastern Mediterranean countries? A benchmark assessment

To determine the existence of guidelines regarding the appropriate clinical use of blood and blood components, transfusion requests, and blood issuing/reception documents and procedures. The different bedside transfusion organizations/processes and hemovigilance are also analyzed. The ultimate objective is to identify safe potential options in order to improve blood safety at the lowest cost. Data emanating from eight Arabic eastern/southern Mediterranean countries who responded to five surveys were collected and tabulated. National recommendations for the clinical use of blood components especially for hemoglobinopathies are lacking in some countries. In matter of good practices in the prescription, issuing and reception of BCs, efforts were made either on national or local basis. Procedures regarding patient information and ethical issues are still lacking. Almost all Mediterranean countries apply two blood testing procedures on each patient sample. Only Morocco, Tunisia and Algeria perform bed side blood group testing; Egypt and Lebanon perform antibody screen and antiglobulin cross matching universally. Automation for blood testing is insufficiently implemented in almost all countries and electronic release is almost absent. National hemovigilance policy is implemented in Tunisia, Morocco, and Lebanon but the reporting system remains inoperative. Insufficient resources severely hinders the implementation of expensive procedures and programs; however, the present work identifies safe procedures that might save resources to improve other parts in the transfusion process (e.g. electronic release to improve safety in issuing). Moreover, setting up regulations regarding ethics in transfusing recipients along with local transfusion committees are crucially needed to implement hemovigilance in transfusion practice.

Correlation analysis between virtual and Complement-Dependent-Cytotoxicity crossmatch in a monocenter retrospective series of 118 allografted patients

PURPOSE OF THE STUDY

The detection of patients' anti-HLA antibodies before allogeneic hematopoietic stem cell transplantation (HSCT) may affect post-transplant outcome, due to a potential detrimental impact on engraftment or toxicity-related issues. Crossmatch (XM) techniques provide support to physicians during the pre-transplant phase but the role of Complement-Dependent Cytotoxicity XM (CDC-XM) is not well-defined when performed routinely and in parallel with the virtual XM.

PATIENTS AND METHODS

We report here our experience with both virtual and CDC-XM tests on n = 118 patients undergoing search for a donor other than HLA-identical sibling from July 2013 to June 2018 at our Institution. When anti-HLA antibodies (Abs) were present, they were classified as donor-specific Abs (DSA) or non-DSA.

RESULTS

On the n = 118 patients, n = 35 (29.7 %) had a positive virtual XM test (of which one of more DSA were found in n = 8; 6.8 %) and n = 5 had a positive CDC-XM test. These latter, positive for HLA class II only, were interpreted as false-positive results due to prior administration of anti-CD20 to the patients, all affected by lymphoma; none of them had a positive virtual XM for anti-HLA Abs of class II. Importantly, all these patients successfully engrafted, further supporting the lack of significant impact of CDC-XM positive results in this series.

CONCLUSIONS

According to our data on more than a hundred patients, routinely performed CDC-XM does not seem to add significant information with respect to virtual XM. We cannot exclude the usefulness of CDC-XM in specific situations, although a positive CDC-XM result was an unfrequent event.

The European Society for Blood and Marrow Transplantation (EBMT) Consensus Guidelines for the Detection and Treatment of Donor-specific Anti-HLA Antibodies (DSA) in Haploidentical Hematopoietic Cell Transplantation

Haploidentical donors are now increasingly considered for transplantation in the absence of HLA-matched donors or when an urgent transplant is needed. Donor-specific anti-HLA antibodies (DSA) have been recently recognized as an important barrier against successful engraftment of donor cells, which can affect transplant survival. DSA appear more prevalent in this type of transplant due to higher likelihood of alloimmunization of multiparous females against offspring's HLA antigens, and the degree of mismatch. Here we summarize the evidence for the role of DSA in the development of primary graft failure in haploidentical transplantation and provide consensus recommendations from the European Society for Blood and Marrow Transplant Group on testing, monitoring, and treatment of patients with DSA receiving haploidentical hematopoietic progenitor cell transplantation.