Perfil de índices plaquetários em pacientes com lúpus eritematoso sistêmico

Abstract

Introduction: Systemic lupus erythematosus (SLE) is a chronic autoimmune disease of unknown origin that can cause inflammatory lesions in various organs. In recent years, platelet-related functions have been assigned in the pathophysiology of autoimmunity, inflammation, atherosclerosis and cancer immunology. The role of platelets as a marker of inflammation in SLE is an area of interest today. Mean platelet volume (MPV) has been the most studied index in autoimmune diseases recently, but the use of the immature platelet fraction (IPF) may bring new insights into the knowledge of platelet activity in SLE and we do not yet have a description of its behavior in SLE. Objective: To quantify platelet indexes (platelet, MPV and IPF) in patients with active and inactive SLE compared to healthy blood bank controls. In parallel, correlate the indices with each other and with laboratory abnormalities of the disease. Methods: Cross-sectional, controlled study. Adults with SLE according to the ACR 1997 criteria and healthy blood bank controls made up the groups. The platelet and MPV were obtained in automated counter XE-5000. The IPF was expressed as a percentage by flow cytometry, and cells with fluorescence for cytoplasmic RNA were positive. Results: Forty-five patients with SLE (30 inactive) and 257 controls were evaluated. The median IPF was significantly higher in active SLE than in healthy controls (p = 0.032). There was a significant correlation between IPF and MVP in the lupus population (p <0.001, rs = 0.519) and controls (p <0.001, rs = 0.845). An inverse correlation between IPF and platelet counts was observed in active lupus (p = 0.025; rs = 0.575). There was no association between IPF and presence of anti-DNA. Conclusion: The results of our data point to elevated IPF in patients with active SLE compared to healthy controls. The inverse correlation of IPF with plateletometry in active SLE is instigating finding and may stimulate further research. The role of IPF as an inflammatory marker in SLE demands future confirmation.