Endomyocardial biopsy remains the most reliable method of detecting rejection following cardiac transplantation. Despite numerous attempts to detect rejection using a blood assay, none have proved reliable enough to replace the biopsy. Here, we have investigated the hypothesis that proteomics has the potential to reveal many molecules which are upregulated in the heart during rejection, some of which may serve as novel blood markers of rejection. Initially, sequential cardiac biopsies (33 in total) from 4 patients were analysed by two-dimensional gel electrophoresis according to whether they showed rejection (n = 16) or no rejection (n = 17); over 100 proteins were found to be upregulated by between 2- and 50-fold during rejection. Of these, 13 were identified and were found to be cardiac specific or heat shock proteins. Two of these (alphaB-crystallin, tropomyosin) were measured by ELISA in the sera of 17 patients followed for 3 months after their transplants. Mean levels of alphaB-crystallin and tropomyosin were significantly higher in sera associated with biopsies showing 1A (p = 0.007) or all grades of rejection (p = 0.022) compared to no rejection. These studies demonstrate that proteomics is a powerful method that can be used to identify novel serum markers of human cardiac allograft rejection.

Cytokines play an important role in the pathogenesis of systemic lupus erythematosus (SLE) and lupus nephritis. This is currently a very active area of research. Of particular interest is the use of cytokines as biomarkers of disease activity in SLE and lupus nephritis. Can cytokine measurements assist in early detection of renal flare in known lupus nephritis? Can such measurements be used to distinguish between flare and chronic damage? Or help to confirm renal remission? Could they be used to help assess the required duration of immunosuppression and reduce the need for invasive renal biopsy? This review discusses limitations of current laboratory methods in monitoring SLE, how measurements of cytokines may contribute in relation to following disease activity and summarizes what is known about cytokines as biomarkers in SLE and lupus nephritis.

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