[Plasma concentrations and urinary excretion of beta2 microglobulin after renal transplantation (author's transl)].

beta2-Microglobulin (beta2m)levels were measured daily after transplantation in 44 recipients of renal allograft. beta2m was measured by radioimmunoassay. After transplantation, serum beta2m becomes inferior to 4 micrograms/ml within 4 days whereas urinary beta2m decreases down to 0,5 microgram/ml within 6 days. A correlation between serum creatinine and serumbeta2m is presented and a few dissociations between the 2 values are discussed. Picks of urinary beta2m concentrations were observed either before (22/30 cases) or concomitant (16/30 cases) with rejection episodes. However, a few patients presented massive urinary excretion of beta2m without development of a typical rejection. This study allows to define two types of renal alterations after transplantation : one associated with renal insufficiency and elevated serum beta2m, the other with proximal tubular dysfonction resulting in massive (up to 700 mg/24 h) urinary excretion of beta2m.