Experiência da adoção do I e II Consensos Brasileiros de Fator Antinuclear por Imunofluorescência Indireta em Células HEp-2 em um hospital universitário

Abstract

Objective: To evaluate the prevalence of patterns and titers of antinuclear antibodies (ANA) detected by indirect immunofluorescence (IIF) technique on HEp-2 cells in a university hospital following the introduction of I and II Brazilian Consensuses for Standardization of ANA in HEp-2 Cells. Methods: A transversal study was performed between 2002 and 2005 during which all ANA orders to Serviço de Hospital de Clínicas de Porto Alegre (SPC/HCPA) and cognate results were reviewed. Results: 12.095 tests of ANA were revised. The number of positive results during this period was 2.577 (21.30%), annual mean 644 (SD: 233). A marked increase in the number of positive results was observed following the introduction of the Consensuses (p < 0.001). Rheumatology was the medical specialty which requested the highest number of ANA testing per patient although a significant decrease of these numbers was observed after the introduction of the Consensus in 2004 (p < 0,001). Nuclear fine speckled immunofluorescence labeling was the most frequently ANA pattern observed, 52.3% (453/866), and low ANA titers (1/80 and 1/160) more commonly detected (27.8% and 29.4%, respectively). Conclusion: Following the introduction of the Brazilian Consensus for standardization of ANA in HEp-2 cells an increased number of positive results was observed, mostly in low titers and with nuclear fine speckled immunofluorescence pattern. Moreover, there were decreasing numbers of ANA orders by rheumatologists in the same period. Potential causes for these observations are discussed but the real impact in the clinical condition of the patient and therapy deserves to be better studied.

Relevância clínica e frequência de padrões citoplasmático e pontilhado fino denso observados em FAN-HEp-2

“…Each one of them may reflect a given antigen expression recognized by its autoantibody. 10,12 A pioneering study of DFS pattern was performed by Ochs et al 13 and, as already reported by Laurino et al, 14 there is a low prevalence of this fluorescence pattern with positive metaphase plate compared to the other existing patterns. Leser et al 15 demonstrated that DFS pattern showed high rate of association with absence of autoimmunity in low, medium, and high titers.…”

“…Among the patterns found in this study, the frequency of DFS (3.7%) and Cit (3.4%) patterns was lower than that reported in another service, which showed frequency of 6.3% and 9%, respectively. 14 This is probably due to the clinical context of each patient when the examination was requested, especially by the rheumatologists of HUSM, leading to a smaller number of pattern detection linked to specificity. Tampoia et al 16 observed that rheumatologists ordered ANA test with higher frequency in patients with two or more criteria for AID classification, unlike other medical specialties that ordered this test in patients who had only inflammatory conditions.…”