Immunological evaluation of renal transplant patients: changes in levels of beta-2-microglobulin, immunoglobulins and complement components during graft rejection.

Levels of IgG and IgM and complement components C4 and C3 were measured using rate nephelometry and serum levels of beta-2-microglobulin (beta 2m) by rocket immunoelectrophoresis (RIEP) and these assays have been applied serially following cadaveric renal transplantation on 28 patients 14 of whom were treated with cyclosporin A. There were 31 rejection episodes of which 7 were irreversible. Elevated pre-transplant serum beta 2m levels fell rapidly in the first 24-48 hr post-transplant in all patients with primary functioning grafts and the mean base-line control value was 4.5 +/- 1.27 micrograms/ml in patients with stable graft function in the period 5-10 days post-transplant. At the onset of all 31 rejection episodes however the level of beta 2m increased compared to control values and significantly exceeded the 95% confidence limits of +/- 2.0 micrograms/ml. Control values for serum IgG and IgM were significantly lower than paired pre-transplant levels and, whereas IgM increased during rejection episodes with significant differences between paired rejection and control values, no significant changes in IgG levels were detected. In contrast mean control values for C4 and C3 were not significantly different to mean pre-transplant values; however, mean levels of C4 and C3 decreased significantly during rejection episodes compared to both pre-transplant and control values.