泌尿器科領域悪性腫瘍の化学療法中にみられる腎障害の研究 - 腎障害の早期発見のための血中ならびに尿中β2-Microglobulin測定の有用性 -

Serum and urinaryβ2microglobulin levels were measured, by radioimmunoassay, in 29 patients with urogenital malignancies who were treated by different modes of anticancer chemotherapy. While the level of serum β2microglobulin paralleled that of serum creatinine or creatinine clearance in the healthy control, no good correlation was seen between the level of β2microglobulin and that of serum creatinine or creatinine clearance in the patients. Although abnormally high levels of serum β2microglobulin were seen in 4 patients with normal creatinine clearance, the elevation of serum β2 micro globulin paralleled the decrease in renal function in most patients. When serumβ2microglobulin or creatinine clearance on the logalithmic scale is plotted against the urinary excretion ofβ2microglobulin (24 hours excretion of β2 micro globulin, β2microglobulin clearance orβ2microglobulin clearance/creatinine clearance) on the logalithmic scale, 4 patterns of renel impairment are delineated on the graph; normal levels of serumβ2microglobulin or creatinine clearance with normal levels of β2microglobulin excretions indicate normal renal function ("Normal"), normal levels of serum β2microglobulin or creatinine clearance with the elevation of β2microglobulin excretions indicate the pattern of tubular impairment ("Tubular"), abnormal levels of increased serum β2microglobulin or decreased creatinine clearance with normal levels of β2microglobulin excretions indicate the pattern of glomerular impairment ("Glomerular") and abnormal levels of β2microglobulin or creatinine clearance with the elevation of β2microglobulin excretions indicate the pattern of both glomerular and tubular impairments ("Glomerular+Tubular"). Most of patients revealed the pattern of "Glomerular + Tubular" or that of "Glomerular". This was attributed to the loss of functioning nephrons due to primary renal diseases (e.g. solitary kidney, hydronephrosis, pyelonephritis, hypertensive nephropathies). In spite of an appearance of the pattern of "Tubular" with the course of the chemotherapy, the renal function returned to the normal ranges during the interval of cessation of the administration. However, in some patients, the pattern of "Tubular" still existed in the association with the pattern of "Glomerular". Although a transient decrease in creatinine clearance and increase in β2microglobulin excretions associated with recovery was observed repeatedly in each course of the therapy, a trend of a decrease in renal function was evident through the entire course of chemotherapy. In conclusion, determination of serum and urinary β2microglobulin is a useful adjunct for assessing changes in renal function and detecting tubular damage with anticancer chemotherapy. A correlation study between serum β2microglobulin or creatinine clearance and urinary excretions of β2microglobulin enables to classify the pattern of renal impairment.