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Anti-Saccharomyces cerevisiae antibodies (ASCA), anti-nuclear associated anti-neutrophil antibodies (NANA) and antibodies to exocrine pancreas (PAB), are serological tools for discriminating Crohn's disease (CrD) and ulcerative colitis (UC). Like CrD, coeliac disease (CoD) is an inflammatory bowel disease (IBD) associated with (auto) antibodies. Performing a multicenter study we primarily aimed to determine the performance of ASCA, NANA and PAB tests for IBD diagnosis in children and adults, and secondarily to evaluate the prevalence of these markers in CoD.Sera of 109 patients with CrD, 78 with UC, 45 with CoD and 50 healthy blood donors were retrospectively included. ASCA, NANA and PAB were detected by indirect immunofluorescence (IIF).ASCA+/NANA- profile displayed a positive predictive value of 94.2% for CrD. Detection of ASCA was correlated with a more severe clinical profile of CrD and treatment of the disease did not influence their serum levels. ASCA positivity was found in 37.9% of active CoD. PAB were found in 36.7% CrD and 13.3% CoD patients and were not correlated with clinical features of CrD, except with an early onset of the disease. Fifteen CrD patients were ASCA negative and PAB positive.ASCA and PAB detected by IIF are specific markers for CrD although their presence does not rule out a possible active CoD. The combination of ASCA, NANA and PAB tests improves the sensitivity of immunological markers for CrD. Repeating ASCA, NANA, and PAB testing during the course of CrD has no clinical value.

Background The nucleosome is considered as a major antigen in SLE and nucleosome-specific antibodies (Ab) seem to be the most specific and the earliest markers of SLE. Objectives To evaluate different methods of detecting anti-nucleosome Abs and determine the diagnostic value of these Abs in recently active SLE. Methods A 2 year (1998–99) prospective multicenter study in 13 European Immunopathology Centres (Groupe d’Etude de l’Auto-Immunite). Patients: (i) 55 cases of recently active SLE (evolution IgG anti-nucleosome Abs were detected by ELISA or immunodot using different nucleosome preparations. IgG anti-ds DNA Abs were detected by ELISA (calf thymus and human recombinant plasmid DNA). Results 34/55 SLE patients had anti-nucleosome Abs reacting with 4 kits. 16/55 SLE patients had anti-nucleosome Abs reacting with 1 to 3 kits. 5/55 SLE patients were negative for anti-nucleosome Abs. 5/50 patients with other autoimmune diseases had anti-nucleosome Abs. Conclusion 50/55 (91%) of patients with recently active SLE had anti-nucleosome Abs (by at least 1 method), 46/55 (84%) also had anti-ds DNA Abs (by ELISA). The sensitivity and the specificity of the anti-nucleosome Abs for SLE depend on the method and the nucleosome preparation.