Urinary aluminium excretion following renal transplantation and the effect of pulse steroid therapy.

Urinary aluminium was measured in 48 patients with primary graft function for 14 days following renal transplantation. The plasma aluminium prior to transplantation was greater in those prescribed aluminium-containing phosphate binders (1.7 +/- 0.2 vs 0.6 +/- 0.2 mumol/L, P less than 0.05) and correlated with the duration of dialysis therapy (r = 0.42, P less than 0.008). After an initial reduction the plasma aluminium returned to pre-transplant values by the fifth day. The 24 h urinary aluminium excretion, aluminium clearance and fractional aluminium excretion all increased during the first week to a maximum around the sixth postoperative day, thereafter returning to values obtained during the first postoperative days, suggesting an early 'wash-out' of a readily accessible aluminium pool followed by a lower steady state determined by the rate of release of aluminium from tissue stores. For the whole group, aluminium excretion, at this steady state, was five times that of urinary aluminium excretion in normal subjects. Acute allograft rejection was diagnosed in 25 patients, who were treated with pulsed methyl prednisolone. Apart from improving graft function, no additional effect was observed on aluminium excretion, suggesting that the readily accessible aluminium pool does not come from lysosomal release, but probably from aluminium bound to small molecular weight protein.