Neopterin, Serum Amyloid A, and Cytokine Monitoring After Renal Transplantation

Abstract

SummaryA reliable and early diagnosis of viral infections and rejection episodes is a major goal of immunologic monitoring in transplantation . Soluble markers like the cytokines, neopterin or serum amyloid A are frequently recommended as diagnostic parameters. However they are not often used routinely in transplant medicine.The study investigates the diagnostic value of plasma (P), serum (S), and urine (U) levels of neopterin (S-/U-NEOP), serum amyloid A (SAA), tumor necrosis factor-a, ( P-/U -TNF-a), soluble interleukin-2 receptor (P-/U -sIL-2R), and interleukin-6 (U -IL-6) in transplant monitoring and describes an approach for their use in the clinical routine decision making.In 29 renal transplant patients blood and urine samples were collected daily during the posttransplant course on ward. The cytokines were measured by ELISAs, neopterin b y RIA, and SAA by immunonephelometry. Descriptive statistics, sensitivity and specificity, day of first significant parameter increase/decrease, receiver operating characteristic curves, and post-test probabilities were calculated for each parameter.12 acute rejection episodes were diagnosed. As rejection markers, S-NEOP and P-TNF-a had the highest sensitivity, U-IL-6 the highest specificity. 8 viral infections occurred. U-NEOP showed values higher than 1000 /-lmol!moICrea. It did not exceed this threshold in case of rejection episodes. SAA and U-IL-6 showed peak. levels during rejections but not during episodes of viral infections. Using the calculated likelihood ratio formulas the probability for the occurrence of an acute rejection could be estimated for the individual, daily parameter measurement. Adding the physician IS rating for rejection posttest probabilities were computed.Immunologic monitoring is possible in transplant medicine. Using daily measurements of serum amyloid A and neopterin facilitates the differential diagnosis of acute rejection episodes and viral infections. The likelihood ratio approach permits an application of the parameter monitoring in the clinical routine.

Pterins as diagnostic markers of exercise-induced stress: a systematic review

“…Second, their concentrations can be measured in several bio-fluids including plasma, serum, CSF, saliva and urine, the latter two of which allows for a non-invasive and stress free collection while CSF can provide quantitative information on several brain cortices associated with injury. Third, pterins are easily measured by commercially available equipment including ELISA, RIA 55 and using reverse phase, 56 cation exchange 50 or amino 36 high-performance liquid chromatography. Because of their natural fluorescence and high absorbance, pterins can be measured in concentrations in the nM range.…”

Neopterin, Inflammation, and Oxidative Stress: What Could We Be Missing?

“…Since then, there has been a plethora of analytical techniques developed and validated for the quantification of neopterin concentrations in a verity of bodily fluids. Serum and plasma neopterin are commonly measured to assess immune activation by radioimmuno assay (RIA), enzyme linked immunosorbent assay (ELISA) [ 49 ], or reverse phase high-performance liquid chromatography (RP-HPLC) coupled with fluorescence detection [ 50 , 51 ]. Levels of neopterin in urine have largely been quantified using RP-HPLC, in part due to the inaccuracy of RIA when analyzing urine [ 52 ].…”