BTLA and systemic lupus erythematosus: There were neither significantly different percentages in expression of BTLA between healthy controls and active SLE patients (40.2% ± 19.8% vs. 64.4% ± 31.3%, p = 0.12) nor between healthy controls and inactive SLE patients (40.2% ± 19.8% vs. 28.8% ± 23.1%, p = 0.13).