A QUANTITATIVE ELISA FOR MEASURING RED CELL-BOUND IMMUNOGLOBULINS

An ELISA was developed for quantitating red-cell-bound IgG and IgA and its feasibility assessed on 50 blood donations and 32 clinical specim ens with raised cell-bound IgG. Test and quality control samples and i mmunoglobulin standards (in red-cell lysate buffer) were assayed toget her. Calibration curves were derived from the standards, test values b eing read off and related to cell count, The working range was around 5-70 ng/ml, the upper limit being indefinitely extendable by dilution with lysate buffer. Ranges of results (and medians) in molecules per r ed cell were <26-240 (40) for IgG and <29-94 (<29) for IgA in the dona tions with 240-62,700 (1,200) for IgG and <29-4,500 (73) for IgA in th e clinical specimens. The method which can be adapted for any cell-bou nd immunoprotein should be particularly valuable in investigating auto immune haemolysis.