Revista Brasileira de Reumatologia (Feb 2013)
Características de atividade das células natural killer em pacientes com esclerose sistêmica Characteristics of NK cell activity in patients with systemic sclerosis
Abstract
INTRODUÇÃO: Estudos têm relatado um aumento da expressão das células natural killer (NK) no sangue periférico de pacientes com esclerose sistêmica (ES). Essas células fazem parte da imunidade inata, reconhecendo células infectadas por meio dos receptores killer immunoglobulin-like receptor (KIR), que apresentam acentuado polimorfismo. Um novo modelo foi proposto prevendo a atividade das células NK, avaliando o excesso de ativação (EA), excesso de inibição (EI) ou se a célula está funcionalmente em equilíbrio (balance, B) (neutra). OBJETIVO: Avaliar a atividade das células NK em pacientes com ES e comparar com grupo-controle. MÉTODO: Cento e dez pacientes com ES e 115 controles foram estudados. Foi aplicado um novo modelo que prevê a atividade das células NK. Para esse método, considerou-se cada célula com seu respectivo ligante KIR/HLA-C e Bw4. A nomenclatura utilizada foi EA, EI e B. RESULTADOS: Nossos resultados mostraram que 63,5% dos controles saudáveis apresentavam o fenótipo KIR caracterizado por EI, em comparação com 39,1% dos pacientes com ES (P = 0,001). Considerando-se somente indivíduos com presença de KIR2DL2 (KIR2DL2+), encontramos 34,7% de EI em controles sadios e 10,9% em pacientes com ES (P INTRODUCTION: Previous studies have shown an increased expression of natural killer (NK) cells in the peripheral blood of patients with systemic sclerosis (SSc). NK cells are part of innate immunity, recognizing infected cells through killer immunoglobulin-like receptors (KIR), which show marked polymorphism. A novel model has been proposed predicting the activity of NK cells, evaluating whether there is excessive activation (EA), excessive inhibition (EI) or balance (B) (neutral). OBJECTIVE: To evaluate the activity of NK cells in patients with SSc and compare it with that of a control group. METHOD: This study comprised 110 patients with SSc and 115 healthy controls. A novel model that predicts the activity of NK cells was used. For that, cells with their respective KIR/HLA-C and Bw4 ligands were considered. The activity of NK cells was defined as EA, EI, or B. RESULTS: Our results showed that 63.5% of healthy controls had the KIR phenotype characterized by EI, as compared with 39.1% of the patients with SSc (P = 0.001). Considering only KIR2DL2-positive individuals, 34.7% of EI was found in healthy controls and 10.9% in patients with SSc (P < 0.001). CONCLUSION: In our study, the model that predicts the action of NK cells showed that healthy controls have higher frequency of EI as compared with SSc patients, suggesting a protective effect of the EI profile against the development of SSc. These results suggest a potential role of NK cells in the pathogenesis of SSc, but further studies should be conducted to confirm our data.
