BIOCHEMICAL MARKERS AS A TRACER IN FOLLOW-UP OF THERAPY EFFECT ON PATIENTS WITH RHEUMATOID ARTHRIT

Abstract

The biochemical markers (urinary enzymes, albuminuria and serum Cystatin C ) was investigated in patients with RA to evaluate the eventually toxicity of non-steroidal anti-inflammatory drugs( NSAIDs). Urinary enzyme activity of b-NAG,AAP, g-GT was determined with standardised kinetic methods. Urinary albumin concentration and serum Cystatin C was measured immunoturbidimetric methods using DAKO tests. Mean +/– SD values of urinary NAG, AAP and g-GT In seropositive (N=56), in seronegative RA(N=32) patients and in normally subjects (N=30) were found to be: b-NAG (2,27+/–0.65, 1.26+/– 0.34,0.75+/–0.43 U/mmol creatinine); AAP(2.98+/–0.36,1.30+/–0.74,0.50+/–0.35 U/mmol creatinine), g-GT(3.84+/– 0.30,1.36+/–0.28,1.32+/–0.50 U/mmol creatinine. The mean urinary NAG and g-GT values in RA patients was found to be a significant higher (p< 0.01) compared to the mean values in seronegative RA patients and normal healthy subjects when analysed by one way ANOVA. In patients who were treated with Methatrexat and Decortin the serum Cystatin C concentration showed significantly elevated values in the therapeutic days (2.85+/– 0.56; v.c.g. 0.70 +/–0.50 mg/L). Urinary albumin concentration increased, but not significantly in the first days of treatment. Determination of the urinary enzymes b-NAG and g-GT, as well as the serum concentration of Cystatin C me therefore serve a more sensitive test for kidney injury in patients with Rheumatoid arthrit.Early detection of high NAG enzymuria and elevated albumin levels in urine before the initiation of MTX therapy could be helpful in predicting possible MTX toxicity probably related to impaired renal clearence of MTX.