Development of Novel Carbohydrate Blood Group Related Kodecyte Assays
The carbohydrate blood group systems are collectively considered important in human blood transfusion and organ transplantation. Characterised by antibodies with an ability to activate complement, these carbohydrate blood group systems are implicated in the rejection of transplanted organs, and in potentially fatal transfusion reactions. Robust laboratory assays to successfully match patients and donors are imperative to avoid such consequences. Laboratory assays have evolved considerably since the first discovery of a blood group system in 1900; the carbohydrate ABO blood group system described by Landsteiner. However some assays are outdated, and limited by their reliance on having to use human red blood cells as assay reagents. Such reagents suffer from constraints due to natural biological variation and availability, and consequently inter-laboratory variation for these assays is common. This research aimed to apply an alternative set of laboratory reagents, to provide alternative assays to the inaccurate and sometimes imprecise historical tests. Kode™ Technology is an approach to modify surfaces including human red blood cells, allowing the cells to express blood group antigens including those which are biologically foreign to them. This allows production of cell-based reagents which are absolutely standardized both in terms of the antigen they express and the quantity in which they express it. This research used Kode™ Technology to develop two new assays. Firstly, an assay to investigate the stability of complement in stored human serum, and secondly a set of assays to evaluate levels of antibodies to carbohydrate blood group antigens. Results showed that complement in stored human serum is at least twice as stable as previously believed. This is significant for all laboratories who have to store human samples. Antibody levels to four different carbohydrate antigens were established in samples from a healthy New Zealand population, and showed high correlation with antibody titres in the case of ABO antibodies. This work may prove useful to two groups of patients; those preparing for ABO incompatible kidney transplantation, and those having cancer therapy of a type which utilizes their own natural antibodies.