Department of Nephrology, Tianjin Medical University General Hospital, Tianjin, China.
Department of Haematology, Tianjin Medical University General Hospital, Tianjin, China.
Clin Exp Rheumatol. 2018 Jul-Aug;36(4):603-611. Epub 2018 Jan 15.
Hypoalbuminaemia has been proved to be a biomarker of poor prognosis in many diseases. The objective of this study was to investigate the significance of hypoalbuminaemia in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV).
Data of 117 AAV patients were analysed retrospectively. The relationship between hypoalbuminaemia and disease severity were studied. The influence of albumin on the pathogenetic role of ANCA was investigated in vitro.
Among all patients, 52 had light hypoalbuminaemia (30g/L<=albumin<35g/L) and 40 had nephrotic hypoalbuminaemia (albumin <30g/L). Patients with hypoalbuminaemia had higher inflammation levels and more severe kidney injury than patients without hypoalbuminaemia, but no significant difference of the urinary protein levels were found between patients with nephrotic and light hypoalbuminaemia. Multivariate analysis showed serum albumin correlated with age (r=-0.566, p=0.018), C-reactive protein (r=-0.521, p=0.032) and haemoglobin (r=0.512, p=0.036). Patients with nephrotic hypoalbuminaemia had higher incidence of infection, end stage renal disease and all cause mortality during treatment than patients with light hypoalbuminaemia or normal serum albumin. In vitro study indicated albumin could inhibit the binding between ANCA and neutrophils in a concentration dependent manner. Albumin also inhibited the ANCA-induced respiratory burst and neutrophil extracellular traps formation.
Serum albumin have an inhibitory effect on the binding between ANCA and its antigen. The incidence of hypoalbuminaemia in AAV with kidney involvement is high but is not caused by heavy proteinuria. Hypoalbuminaemia is correlated with the high inflammation level and poor prognosis of AAV. Therapy targeting hypoalbuminaemia might benefit patients with AAV.
低白蛋白血症已被证实是许多疾病预后不良的生物标志物。本研究旨在探讨低白蛋白血症在抗中性粒细胞胞浆抗体（ANCA）相关性血管炎（AAV）中的意义。
回顾性分析 117 例 AAV 患者的数据。研究低白蛋白血症与疾病严重程度的关系。在体外研究白蛋白对 ANCA 致病作用的影响。
所有患者中，52 例为轻度低白蛋白血症（30g/L<=白蛋白<35g/L），40 例为肾病性低白蛋白血症（白蛋白<30g/L）。低白蛋白血症患者的炎症水平和肾脏损伤程度均高于无低白蛋白血症患者，但肾病性低白蛋白血症与轻度低白蛋白血症患者的尿蛋白水平无显著差异。多变量分析显示，血清白蛋白与年龄（r=-0.566，p=0.018）、C 反应蛋白（r=-0.521，p=0.032）和血红蛋白（r=0.512，p=0.036）呈负相关。肾病性低白蛋白血症患者在治疗过程中感染、终末期肾病和全因死亡率的发生率高于轻度低白蛋白血症或正常血清白蛋白患者。体外研究表明，白蛋白可呈浓度依赖性抑制 ANCA 与中性粒细胞的结合。白蛋白还抑制了 ANCA 诱导的呼吸爆发和中性粒细胞胞外陷阱的形成。
血清白蛋白对 ANCA 与其抗原的结合有抑制作用。伴有肾脏受累的 AAV 患者低白蛋白血症的发生率较高，但并非由大量蛋白尿引起。低白蛋白血症与 AAV 的高炎症水平和不良预后相关。针对低白蛋白血症的治疗可能有益于 AAV 患者。
