Improvement of indirect immunofluorescence technique to detect antineutrophil cytoplasmic antibodies and its impact on test positivity rate
The indirect immunofluorescence (IIF) technique for antineutrophil cytoplasmic antibodies (ANCA) detection is subject to substantial differences across laboratories. This study aimed to assess the impact of improvements in the IIF-ANCA technique on the positivity rate of ANCA tests. A cross-sectiona...
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| Format: | Article |
| Language: | English |
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Associação Brasileira de Divulgação Científica
2023-07-01
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| Series: | Brazilian Journal of Medical and Biological Research |
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| Online Access: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2023000100647&tlng=en |
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| author | E.B. Zarur S.H. Rodrigues O. Ambrogini Jr M.L.G. Ferraz G. Mastroianni-Kirsztajn L.E.C. Andrade A.W.S. de Souza |
| author_facet | E.B. Zarur S.H. Rodrigues O. Ambrogini Jr M.L.G. Ferraz G. Mastroianni-Kirsztajn L.E.C. Andrade A.W.S. de Souza |
| author_sort | E.B. Zarur |
| collection | DOAJ |
| description | The indirect immunofluorescence (IIF) technique for antineutrophil cytoplasmic antibodies (ANCA) detection is subject to substantial differences across laboratories. This study aimed to assess the impact of improvements in the IIF-ANCA technique on the positivity rate of ANCA tests. A cross-sectional study was performed with serum samples from patients with ANCA-associated vasculitis (AAV), autoimmune hepatitis (AIH), and ulcerative colitis (UC). A paired analysis was performed for IIF-ANCA results using the traditional method and a modified protocol after a series of specific adjustments in the technique based on the protocol of IIF-ANCA test performed at a nation-wide private laboratory in Brazil. ANCA specificity was assessed by ELISA for anti-proteinase 3 (PR3) and anti-myeloperoxidase (MPO) antibodies. Sixty-one patients were evaluated. The positivity rate of IIF-ANCA tests at disease presentation performed at the University reference laboratory was 32.3% in AAV, AIH, and UC patients, whereas the positivity rates of IIF-ANCA and ELISA tests in other laboratories were 75.0 and 72.7%, respectively. After modifications in the IIF-ANCA technique, there was a significant increase in the positivity rate (14.8 vs 34.3%; P=0.0002) and in median titers [1/40 (1/30-1/160) vs 1/80 (1/40-1/80); P=0.0003] in AAV, AIH, and UC patients. UC had the highest increment in positive results from 5.3 to 36.8%. There was poor agreement between MPO- or PR3-ANCA and both IIF-ANCA techniques. In conclusion, modifications in the IIF-ANCA protocol led to a significant improvement in its positivity rate and titers. |
| first_indexed | 2024-03-12T22:01:03Z |
| format | Article |
| id | doaj.art-68587672b3394e6995110c73182235fe |
| institution | Directory Open Access Journal |
| issn | 1414-431X |
| language | English |
| last_indexed | 2024-03-12T22:01:03Z |
| publishDate | 2023-07-01 |
| publisher | Associação Brasileira de Divulgação Científica |
| record_format | Article |
| series | Brazilian Journal of Medical and Biological Research |
| spelling | doaj.art-68587672b3394e6995110c73182235fe2023-07-25T07:42:41ZengAssociação Brasileira de Divulgação CientíficaBrazilian Journal of Medical and Biological Research1414-431X2023-07-015610.1590/1414-431x2023e12636Improvement of indirect immunofluorescence technique to detect antineutrophil cytoplasmic antibodies and its impact on test positivity rateE.B. Zarurhttps://orcid.org/0000-0002-1057-2104S.H. Rodrigueshttps://orcid.org/0000-0001-5005-2771O. Ambrogini Jrhttps://orcid.org/0000-0003-3318-6246M.L.G. Ferrazhttps://orcid.org/0000-0001-8992-8494G. Mastroianni-Kirsztajnhttps://orcid.org/0000-0003-1317-4109L.E.C. Andradehttps://orcid.org/0000-0001-8742-9931A.W.S. de Souzahttps://orcid.org/0000-0001-7681-6215The indirect immunofluorescence (IIF) technique for antineutrophil cytoplasmic antibodies (ANCA) detection is subject to substantial differences across laboratories. This study aimed to assess the impact of improvements in the IIF-ANCA technique on the positivity rate of ANCA tests. A cross-sectional study was performed with serum samples from patients with ANCA-associated vasculitis (AAV), autoimmune hepatitis (AIH), and ulcerative colitis (UC). A paired analysis was performed for IIF-ANCA results using the traditional method and a modified protocol after a series of specific adjustments in the technique based on the protocol of IIF-ANCA test performed at a nation-wide private laboratory in Brazil. ANCA specificity was assessed by ELISA for anti-proteinase 3 (PR3) and anti-myeloperoxidase (MPO) antibodies. Sixty-one patients were evaluated. The positivity rate of IIF-ANCA tests at disease presentation performed at the University reference laboratory was 32.3% in AAV, AIH, and UC patients, whereas the positivity rates of IIF-ANCA and ELISA tests in other laboratories were 75.0 and 72.7%, respectively. After modifications in the IIF-ANCA technique, there was a significant increase in the positivity rate (14.8 vs 34.3%; P=0.0002) and in median titers [1/40 (1/30-1/160) vs 1/80 (1/40-1/80); P=0.0003] in AAV, AIH, and UC patients. UC had the highest increment in positive results from 5.3 to 36.8%. There was poor agreement between MPO- or PR3-ANCA and both IIF-ANCA techniques. In conclusion, modifications in the IIF-ANCA protocol led to a significant improvement in its positivity rate and titers.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2023000100647&tlng=enAntineutrophil cytoplasmic antibodiesANCA-associated vasculitisAutoimmune hepatitisUlcerative colitisPR3-ANCAMPO-ANCA |
| spellingShingle | E.B. Zarur S.H. Rodrigues O. Ambrogini Jr M.L.G. Ferraz G. Mastroianni-Kirsztajn L.E.C. Andrade A.W.S. de Souza Improvement of indirect immunofluorescence technique to detect antineutrophil cytoplasmic antibodies and its impact on test positivity rate Brazilian Journal of Medical and Biological Research Antineutrophil cytoplasmic antibodies ANCA-associated vasculitis Autoimmune hepatitis Ulcerative colitis PR3-ANCA MPO-ANCA |
| title | Improvement of indirect immunofluorescence technique to detect antineutrophil cytoplasmic antibodies and its impact on test positivity rate |
| title_full | Improvement of indirect immunofluorescence technique to detect antineutrophil cytoplasmic antibodies and its impact on test positivity rate |
| title_fullStr | Improvement of indirect immunofluorescence technique to detect antineutrophil cytoplasmic antibodies and its impact on test positivity rate |
| title_full_unstemmed | Improvement of indirect immunofluorescence technique to detect antineutrophil cytoplasmic antibodies and its impact on test positivity rate |
| title_short | Improvement of indirect immunofluorescence technique to detect antineutrophil cytoplasmic antibodies and its impact on test positivity rate |
| title_sort | improvement of indirect immunofluorescence technique to detect antineutrophil cytoplasmic antibodies and its impact on test positivity rate |
| topic | Antineutrophil cytoplasmic antibodies ANCA-associated vasculitis Autoimmune hepatitis Ulcerative colitis PR3-ANCA MPO-ANCA |
| url | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2023000100647&tlng=en |
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