RESUMO
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.
RESUMO
Regulatory T (TREG) cells play an important role in maintaining immune tolerance and avoiding autoimmunity. We analyzed the expression of membrane molecules in TREG and effector T cells in systemic lupus erythematosus (SLE). TREG and effector T cells were analyzed for the expression of CTLA-4, PD1, CD28, CD95, GITR, HLA-DR, OX40, CD40L, and CD45RO in 26 patients with active disease, 31 with inactive disease, and 26 healthy controls. TREG cells were defined as CD25+/highCD127Ø/lowFoxP3+, and effector T cells were defined as CD25+CD127+FoxP3Ø. The ratio of TREG to effector T cells expressing GITR, PD1, HLA-DR, OX40, CD40L, and CD45RO was determined in the three groups. The frequency of TREG cells was similar in patients with SLE and controls. However, SLE patients had a decreased frequency of CTLA-4+TREG and CD28+TREG cells and an increased frequency of CD40L+TREG cells. There was a decrease in the TREG/effector-T ratio for GITR+, HLA-DR+, OX40+, and CD45RO+ cells, and an increased ratio of TREG/effector-T CD40L+ cells in patients with SLE. In addition, CD40L+TREG cell frequency correlated with the SLE disease activity index (P=0.0163). In conclusion, our findings showed several abnormalities in the expression of functionally critical surface molecules in TREG and effector T cells in SLE that may be relevant to the pathogenesis of this disease.
Assuntos
Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Antígenos de Superfície/metabolismo , Leucócitos Mononucleares/metabolismo , Lúpus Eritematoso Sistêmico/imunologia , Linfócitos T Reguladores/imunologia , Análise de Variância , /análise , /análise , /análise , /análise , /análise , Citometria de Fluxo , Fatores de Transcrição Forkhead/análise , Proteína Relacionada a TNFR Induzida por Glucocorticoide/análise , Antígenos HLA-DR/análise , /análise , /análise , Lúpus Eritematoso Sistêmico/metabolismo , Lúpus Eritematoso Sistêmico/fisiopatologia , Receptor de Morte Celular Programada 1/análise , /análise , Estatísticas não ParamétricasRESUMO
OBJECTIVE: The identification of regulatory T cells (Treg cells) as CD4(+)CD25(high) cells may be upset by the increased frequency of activated effector T cells (Teff cells) in inflammatory diseases such as systemic lupus erythematosus (SLE). This study aimed to evaluate the frequency of T-cell subsets according to the expression of CD25 and CD127 in active (A-SLE) and inactive SLE (I-SLE). METHODS: Peripheral blood mononuclear cells (PBMCs) from 26 A-SLE patients (SLE Disease Activity Index (SLEDAI) = 10.17 ± 3.7), 31 I-SLE patients (SLEDAI = 0), and 26 healthy controls (HC) were analysed by multicolour flow cytometry. RESULTS: CD25(high) cell frequency was increased in A-SLE (5.2 ± 5.7%) compared to I-SLE (3.4 ± 3.4%) and HC (1.73 ± 0.8%) (p < 0.01). However, the percentage of FoxP3(+) cells in the CD25(high) subset was decreased in A-SLE (24.6 ± 16.4%) compared to I-SLE (33.7 ± 16) and HC (45 ± 25.1%) (p < 0.01). This was partly due to the increased frequency of Teff cells (CD25(high)CD127(+)FoxP3(Ø)) in A-SLE (10.7 ± 7.3%) compared to I-SLE (8.5 ± 6.5) and HC (6.1 ± 1.8%) (p = 0.02). Hence the frequency of Treg cells (CD25(+/high)CD127(low/Ø)FoxP3(+)) was equivalent in A-SLE (1.4 ± 0.8%), I-SLE (1.37 ± 1.0%), and HC (1.13 ± 0.59%) (p = 0.42). A-SLE presented an increased frequency of CD25(+)CD127(+)FoxP3(+) and CD25(Ø)FoxP3(+)CD127(low/Ø) T cells, which may represent intermediate phenotypes between Treg and Teff cells. CONCLUSIONS: The present study has provided data supporting normal Treg cell frequency in A-SLE and I-SLE as well as increased frequency of Teff cells in A-SLE. This scenario reflects a Treg/Teff ratio imbalance that may favour the inflammatory phenotype of the disease. In addition, the increased frequency of T cells with putative intermediate phenotypes may be compatible with a highly dynamic immune system in SLE.