Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0042384 (vasculitis)
 20,525 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Antineutrophil cytoplasmic antibodies (ANCA) are directed against enzymes found in the granules of the polymorphonuclear (PMN) leukocytes. They are detected by indirect immunofluorescence microscopy assays on human ethanol fixed neutrophils. Three different fluorescence patterns can be distinguished: a cytoplasmic pattern (cANCA), a perinuclear pattern (pANCA), and an atypical pattern (aANCA). The use of other fixatives, e.g., formalin and methanol, allows differentiation between the pANCA and the antinuclear antibodies. ANCA specificity is determined by solid phase assays (ELISA, immunodot, and multiplex assay). ANCA with high titres and defined specificities (antiproteinase 3 [PR 3] or antimyeloperoxidase [MPO]) are proven to be good serological markers of active primary systemic vasculitis: c/PR 3-ANCA for Wegener's granulomatosis and p/MPO-ANCA for microscopic polyangiitis. The former have higher sensitivity and specificity for Wegener's granulomatosis than the latter for microscopic polyangiitis. ANCA with low titres and unknown specificity have been detected in a wide range of inflammatory and infectious diseases leading to a critical reappraisal of the diagnostic significance of ANCA testing. Physicians must keep in mind the possible occurrence of infectious diseases like subacute endocarditis that could be dramatically worsened by irrelevant immunosuppressive therapy. ANCA findings in certain manifestations, such as the pulmonary-renal syndrome in which massive pulmonary hemorrhage can quickly be life-threatening, warrant ANCA testing as an emergency test for patient care.
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PMID:Antineutrophil cytoplasmic autoantibodies: how should the biologist manage them? 1817 46

In adults, anti-neutrophil cytoplasmic antibodies (ANCA) are considered as serological markers of several diseases, especially vasculitis and glomerulonephritis. Since ANCA are rarely positive in children, few data about the clinical relevance of these auto-antibodies in pediatric population have been reported. Therefore, our study aims to describe the spectrum of disorders associated with positive ANCA in Tunisian children. This study had been carried out over a period of 12 years and a half. All patients under the age of 15 for whom ANCA screening was performed in our laboratory were included. Clinical data were collected retrospectively. Indirect immunofluorescence (IFI) technique for ANCA detection was performed using PNN smears fixed with ethanol, formalin and, if necessary, methanol. Positive results were tested using immunodot to characterize the antigenic targets (myeloperoxydase (MPO) and proteinase 3 (PR3)). Our results showed that 410/5,990 (6.8%) laboratory requests for ANCA screening were for children. Forty (9.7%) requests were positive (24 children). Clinical data were available for 19 patients only. Sex-ratio (F/M) was 1.25. The mean age was 9 years and a half (3-15 years). The most frequent IIF patterns were x-ANCA (n=12) and p-ANCA (n=7). In our patients, the most frequent conditions associated to ANCA were treatment with benzylthiouracil for hypothyroidism (n=6), inflammatory bowel disease (n=4) and hemolytic anemia (n=4). In conclusion, the positivity of ANCA in children seems to be a rare event. Associated conditions include clinical disorders specific to the pediatric population. Treatment with benzylthiouracil is an etiology to be taken into consideration.
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PMID:Positivity of antineutrophil cytoplasmic antibodies in children: prevalence and etiologies. 2938 46