PMID- 37493768
OWN - NLM
STAT- MEDLINE
DCOM- 20230727
LR  - 20230729
IS  - 1414-431X (Electronic)
IS  - 0100-879X (Print)
IS  - 0100-879X (Linking)
VI  - 56
DP  - 2023
TI  - Improvement of indirect immunofluorescence technique to detect antineutrophil 
      cytoplasmic antibodies and its impact on test positivity rate.
PG  - e12636
LID - S0100-879X2023000100647 [pii]
LID - 10.1590/1414-431X2023e12636 [doi]
LID - e12636
AB  - 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.
FAU - Zarur, E B
AU  - Zarur EB
AUID- ORCID: 0000-0002-1057-2104
AD  - Divisao de Reumatologia, Departamento de Medicina, Escola Paulista de Medicina, 
      Universidade Federal de Sao Paulo, Sao Paulo, SP, Brasil.
FAU - Rodrigues, S H
AU  - Rodrigues SH
AUID- ORCID: 0000-0001-5005-2771
AD  - Divisao de Reumatologia, Departamento de Medicina, Escola Paulista de Medicina, 
      Universidade Federal de Sao Paulo, Sao Paulo, SP, Brasil.
FAU - Ambrogini, O Jr
AU  - Ambrogini O Jr
AUID- ORCID: 0000-0003-3318-6246
AD  - Divisao de Gastroenterologia, Departamento de Medicina, Escola Paulista de 
      Medicina, Universidade Federal de Sao Paulo, Sao Paulo, SP, Brasil.
FAU - Ferraz, M L G
AU  - Ferraz MLG
AUID- ORCID: 0000-0001-8992-8494
AD  - Divisao de Gastroenterologia, Departamento de Medicina, Escola Paulista de 
      Medicina, Universidade Federal de Sao Paulo, Sao Paulo, SP, Brasil.
FAU - Mastroianni-Kirsztajn, G
AU  - Mastroianni-Kirsztajn G
AUID- ORCID: 0000-0003-1317-4109
AD  - Divisao de Nefrologia, Departamento de Medicina, Escola Paulista de Medicina, 
      Universidade Federal de Sao Paulo, Sao Paulo, SP, Brasil.
FAU - Andrade, L E C
AU  - Andrade LEC
AUID- ORCID: 0000-0001-8742-9931
AD  - Divisao de Reumatologia, Departamento de Medicina, Escola Paulista de Medicina, 
      Universidade Federal de Sao Paulo, Sao Paulo, SP, Brasil.
FAU - Souza, A W S de
AU  - Souza AWS
AUID- ORCID: 0000-0001-7681-6215
AD  - Divisao de Reumatologia, Departamento de Medicina, Escola Paulista de Medicina, 
      Universidade Federal de Sao Paulo, Sao Paulo, SP, Brasil.
LA  - eng
PT  - Journal Article
DEP - 20230721
PL  - Brazil
TA  - Braz J Med Biol Res
JT  - Brazilian journal of medical and biological research = Revista brasileira de 
      pesquisas medicas e biologicas
JID - 8112917
RN  - 0 (Antibodies, Antineutrophil Cytoplasmic)
RN  - EC 3.4.21.76 (Myeloblastin)
RN  - EC 1.11.1.7 (Peroxidase)
SB  - IM
MH  - Humans
MH  - *Antibodies, Antineutrophil Cytoplasmic
MH  - Fluorescent Antibody Technique, Indirect
MH  - Cross-Sectional Studies
MH  - Myeloblastin
MH  - Enzyme-Linked Immunosorbent Assay
MH  - *Peroxidase
PMC - PMC10361643
EDAT- 2023/07/26 13:07
MHDA- 2023/07/27 06:42
PMCR- 2023/07/21
CRDT- 2023/07/26 11:11
PHST- 2023/03/17 00:00 [received]
PHST- 2023/05/10 00:00 [accepted]
PHST- 2023/07/27 06:42 [medline]
PHST- 2023/07/26 13:07 [pubmed]
PHST- 2023/07/26 11:11 [entrez]
PHST- 2023/07/21 00:00 [pmc-release]
AID - S0100-879X2023000100647 [pii]
AID - 10.1590/1414-431X2023e12636 [doi]
PST - epublish
SO  - Braz J Med Biol Res. 2023 Jul 21;56:e12636. doi: 10.1590/1414-431X2023e12636. 
      eCollection 2023.