Annette Larsen

S100A12 is a calcium‐binding protein predominantly found in neutrophil granulocytes and monocytes. Its usefulness in monitoring inflammatory disease states depends on documentation that assay results are reliable. This study aimed at defining guidelines for blood sampling, selection of optimal material handling and reference intervals in healthy controls while taking into account the basic features of S100A12. An enzyme linked immunosorbent assay was developed based upon antibodies induced in rabbits by injection of recombinant S100A12. Our studies confirm that oligomers of S100A12 are generated in the presence of calcium. Structural changes in S100A12 mediated by calcium influence the interaction with antibody. This is proposed as the background for our very low readings of S100A12 in Ethylene Diamine Tetraacetic Acid (EDTA) plasma. Individual S100A12 levels did not change substantially over a 5‐week sampling period. Based upon testing of 150 blood donors we suggest reference intervals of S100A12 in serum to be 49–1340 μg/l for women and 27–1750 μg/l for men. The estimated mean concentrations were 234 μg/l in serum samples (range 12–15791), 114 μg/l (range 3–17282) in re‐calcified EDTA plasma and 48 μg/l (range 2–14843) in heparin plasma. Without adding calcium to EDTA plasma before running the assay, concentrations were around 2 μg/l (16 persons). S100A12 quantification is assumed to become relevant for diagnostic use in many disease states. The importance of the handling and analysing conditions for a reliable result was examined. We recommend serum collected in gel‐containing tubes as the preferred sample material and have suggested reference intervals for healthy individuals.

To assess persistent symptoms and mortality in a cohort of patients with severe (grade 3-4) radiation enteropathy, 59 patients were followed up after 15-18 years. Fifty-nine patients were prospectively enrolled by twelve surgical departments. Primary malignant disease, radiation therapy and surgical management were recorded at inclusion. The cause of death or persistence of symptoms was examined in public death records or by interview of survivors. Thirty-nine patients had received radiation therapy for gynaecological cancers, twelve for urological cancers, four for gastrointestinal cancers and four for other malignancies. Forty-five patients (76%) required surgical intervention. Complications occurred in 11 (25%) operated patients. Forty-seven patients had died at the time of follow-up, seven (12%) died as a direct result of radiation enteropathy, while radiation enteropathy contributed to death in an additional seven patients. Four of the twelve surviving patients suffered from chronic debilitating symptoms of radiation enteropathy, while three had moderate symptoms. Patients with severe delayed radiation enteropathy have a high risk of persistence of symptoms after surgery. At least one in ten patients dies from radiation-induced bowel injury.

Background: Non-invasive diagnostic tools to evaluate the severity of acute, radiation-induced proctitis are not readily available. The faecal excretion of eight markers of gut inflammation was therefore examined. Five proteins and three lipid derivates were analysed in sequential stool samples taken before and during radiation therapy. Methods: Stool samples from 15 patients with prostate cancer scheduled for radiation therapy were examined. Pretreatment and in-treatment samples (2nd and 6th weeks) were measured by enzyme-linked immunosorbent assay (ELISA) (calprotectin, lactoferrin, transferrin, leukotriene B4, prostaglandin E2, thromboxane B2 and TNFα) or nephelometry (α1-antitrypsin). Results: Calprotectin and lactoferrin concentrations increased significantly during radiation treatment (P = 0.0005 and P = 0.019). Transferrin was detected in only 9 out of 45 samples. There were no changes in tumour necrosis factor α (TNFα), leukotriene B4, prostaglandin E2 and thromboxane B2 during treatment. α1-antitrypsin could not be detected in any sample. Conclusions: This study indicates that faecal calprotectin and lactoferrin concentrations could be markers of acute, radiation-induced proctitis. Patient compliance and stability of the markers make this a promising method for clinical research. Eicosanoids could be measured in stool samples, but the concentrations did not increase with increasing radiation dose.