DETECTION OF RED-CELL SENSITIZATION BY ANTIBODY AND COMPLEMENT - CURRENT PRACTICE AND FUTURE PERSPECTIVES

In autoimmune haemolytic anaemia (AHA) antibody(ies) are directed at ' self' red blood cells (RBC) and can effect their destruction. This rem oval of RBC may be enhanced by the additional presence of complement o n the cell membrane. The diagnosis of AHA requires the demonstration o f such antibody(ies), which are able to sensitise autologous erythrocy tes in vivo. AHA has been described in a variety of animal species but the techniques employed in the laboratory diagnosis have, generally, been extrapolated from those used in human serology. The application o f newer and more sensitive techniques to the assessment of RBC sensiti sation with antibody and complement, has improved the diagnosis of AHA . Furthermore, it is now possible to assess the significance of the de gree of RBC sensitisation and to evaluate treatment regimens. Approach es to the assessment of RBC sensitisation are: 1. Agglutination tests a) Broad spectrum antiglobulin reagents b) Monospecific reagents - ant i IgG, anti IgM and anti C3 c) Monoclonal antibodies (with subclass sp ecificity) 2. Enzyme-linked immunosorbent assays (ELISA) a) Whole RBC b) Isolated cell membranes c) Purified antigen 3. Flow cytometry. Accu rate assessment of subpopulations of RBC, with varying degrees of sens itisation. These techniques require refinement but are potentially the most sensitive. Rigorous controls are required to achieve reproducibl e results. With the regular use of such assay systems in clinical path ology and in toxicology screening, it will be necessary to consider a national quality control scheme.