Renal graft rejection or urinary tract infection? The value of myeloperoxidase, C-reactive protein, and alpha2-macroglobulin in the urine.
Previous investigations have shown that the determination of two acute-phase proteins in the urine, C-reactive protein (CRPu) and alpha2-macroglobulin (alpha2-MGu), allows a noninvasive diagnosis of acute renal graft dysfunction. A reliable differentiation between rejection and urinary tract infection can be made only when considering the C-reactive protein in serum and urine at the same time (CRPs:CRPu ratio). Therefore, a diagnostic procedure independent of parameters other than urinary proteins is needed. As granulocytes play only a minor role in graft rejection but are a common feature in urinary tract infection, we determined a marker of granulocytes (myeloperoxidase) in urine (MPOu). Eighty-nine renal transplant recipients were included in the study. In normal courses, CRPu, alpha2-MGu, and MPOu were within the normal range. In 15 cases of acute interstitial rejection, an increased excretion of CRPu and alpha2-MGu could be confirmed, but MPOu could not be detected. On the occasion of acute vascular rejection (n=6), with the exception of one case, MPOu could not be observed. The pattern of the three urinary proteins differed in urinary tract infections (n=40): MPOu could be detected in all cases, CRPu in 50% of cases, and alpha2-MGu in 73% of cases. In patients with cytomegalovirus infection (n=7), no MPOu, CRPu, or alpha2-MGu was found. In conclusion, the simultaneous measurement of the three proteins allows a complete, noninvasive, differential diagnostic procedure of renal graft dysfunction.
Steinhoff
J
J
Department of Internal Medicine I, University of Lübeck, Germany.
Einecke
G
G
Niederstadt
C
C
de Groot
K
K
Fricke
L
L
Machnik
H
H
Sack
K
K
D015415:Biomarkers / Q000652:urine; D002097:C-Reactive Protein / Q000652:urine; D003586:Cytomegalovirus Infections / Q000652:urine; D003937:Diagnosis, Differential; D006084:Graft Rejection / Q000175:diagnosis / Q000652:urine; D006098:Granulocytes / Q000737:chemistry; D006801:Humans; D016030:Kidney Transplantation / Q000276:immunology*; D009195:Peroxidase / Q000652:urine; D014552:Urinary Tract Infections / Q000175:diagnosis* / Q000652:urine*; D000511:alpha-Macroglobulins / Q000652:urine
D015415:Biomarkers; D000511:alpha-Macroglobulins; D002097:C-Reactive Protein; D009195:Peroxidase