In previous phases of this project, proteinase 3 (PR3) and myeloperoxidase (MPO), the main antigenic target molecules of antineutrophil cytopiasmic antibodies, were isolated and applied in standardized ELISAs.In this study, standardized ELISAs with three PR3 preparations (from Copenhagen (CO), Raisdorf (RS) and Leiden (LF)) and one MPO preparation (from Copenhagen), were evaluated in a large retro-and prospective clitiical study.New patients (n=174) with primary systemic vasculitis (Wegener's granulomatosis, microscopic polyangiitis and idiopathic rapidly progressive glomerulonephritis, classical PAN and Churg-Strauss Syndrome) were included. Retrospectively, another 190 patients were evaluated. Furthermore control sera were obtained from patients with other forms of vasculitis, glomerulonephritis or granulomatous diseases (disease controls, n = 184) and healthy donors (healthy controls, n = 728). All patients were categorized by a system based on clinical and histoiogical data. Patients were followed up for at least 1 year after diagnosis in order to evaluate a possible correlation between ANCA levels and disease activity.The sensitivity of the anti-PR3 assays for histologically proven WG was between 59% and 69% in new patients, with a sensitivity of 22% for the anti-MPO assay. Similar figures were found for patients with clinically suspected WG. This was comparable with the results of the IIF test. In MPA and IRPGN a larger percentage of patients had anti-MPO antibodies than in WG. Only a few patients with PAN and CSS were investigated, and most of these were negative in the ELISAs.The specificity ofthe assays for disease controls was 89-91% for the anti-PR3 assays and 95% for the anti-MPO assay. In the healthy controls the specificity was 98-99%. The specificity of the IIF test was 97% for a cANCA pattern and 81 % for a pANCA pattern in disease controls. The combination of cANCA with anti-PR3 and pANCA with anti-MPO both had a specificity of 99%.Further details will be presented during the meeting, in addition to the results of a follow-up study with correlation ofdisease activity and ANCA level. From this study we can conclude that ELISAs using purified PR3 or MPO are not more sensitive than the IIF test. However, the anti-MPO assay is more specific for systemic vascuitis as compared to disease controls with related diseases. Furthermore, the combination of the IIF test with antigen-specific ELISAs is very specific for the diagnosis Wegetier's granulomatosis, microscopic polyangiitis and idiopathic rapidly progressive gtomerulonephritis.

Some patients with undiagnosed celiac disease have minor mucosal lesions that may not be apparent during routine histological analysis. Twenty-five such patients of our institution were discharged to their primary-care physicians despite having positive endomysial antibody serology. To re-evaluate diagnosis for these patients, immunohistological staining with antibodies to CD2, CD3, CD7, CD8, CD69, and Ki67 was conducted on original biopsies from twenty patients. Clinical, serological, and histological investigations were offered to all fourteen patients who attended for review. We observed a significantly greater (P < 0.0001) numbers of intraepithelial lymphocytes and Ki67-positive enterocytes in sections from these twenty patients than for normal controls. Of the fourteen patients who attended for further review, firm diagnosis of celiac disease was made for seven patients and diagnosis was likely for another two. Our study clearly revealed that over-reliance on standard histological findings results in failure to diagnose celiac disease.

The majority of patients in this cohort did not have IgE-mediated allergic disease. Increased awareness of the features that differentiate allergy from non-allergic conditions such as food intolerance or chronic spontaneous urticaria is required. The allergy advice email service should be developed further to play a key role in education and care delivery in partnership primary care.

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