Department of Hematology, Xuzhou Children's Hospital, Xuzhou, Jiangsu, China.
Eur Rev Med Pharmacol Sci. 2017 Oct;21(19):4322-4326.
Juvenile rheumatoid arthritis (JRA), also known as juvenile idiopathic arthritis (JIA), is a rare autoimmune joint disorder of children. The concrete causes for the prevalence of the above pathological state are still unknown. In other words, it is an arthritis affecting mainly children and adolescents. Clinically, it has 3 different clinical subtypes. JRA patients are often noticed with some confirmed symptoms including coagulopathy, disseminated intravascular coagulation (DIC) with hepatosplenomegaly, fall in erythrocyte sedimentation rate and higher levels of liver enzymes leading to a life-threatening outcome. The above complications of JRA are recognized as a macrophage activation syndrome (MAS), which is similar to hemophagocytic lymphohistiocytosis (HLH). Pathogenesis of JRA manly involves deregulation of immunological processes with excessive and persistent activation of antigen presenting cells and T-lymphocytes. Further, abnormalities in the functioning of NK cells are often observed in JIA cases. Also, 40% of patients with these abnormalities are habitually associated with perforin gene mutations. Today, MAS remains a clinical and diagnostic challenge.
The diagnosis of MAS is mainly based on clinical grounds. However, laboratory evidence of macrophages in the bone marrow performing phagocytosis of variable hematopoietic cells also help in diagnosis. For confirmation of MAS, there must be present either of two clinical or laboratory criteria. Further, laboratory criteria often appear late and are unable to diagnose the complication right at the beginning stage. Important laboratory findings in macrophage activation syndrome associated with JIA include hypertriglyceridemia, anemia, low erythrocyte sedimentation rate, elevated alanine aminotransferase level, higher than normal bilirubin levels, presence of fibrin degradation products, high lactate dehydrogenase level, low sodium, low albumin, and hyperferritinemia.
MAS is a confirmed life threatening complication of patients with JIA. Further, an early diagnosis and treatment of MAS could be a life-saving mode for this syndrome.
幼年特发性关节炎（JRA），也称幼年型特发性关节炎（JIA），是一种罕见的儿童自身免疫性关节疾病。这种病理状态流行的确切原因尚不清楚。换句话说，这是一种主要影响儿童和青少年的关节炎。临床上，它有 3 种不同的临床亚型。JRA 患者常出现一些明确的症状，包括凝血功能障碍、弥漫性血管内凝血（DIC）伴肝脾肿大、红细胞沉降率下降和肝酶水平升高，导致危及生命的后果。JRA 的上述并发症被认为是一种巨噬细胞活化综合征（MAS），类似于噬血细胞性淋巴组织细胞增生症（HLH）。JRA 的发病机制主要涉及免疫过程失调，抗原呈递细胞和 T 淋巴细胞过度和持续活化。此外，JIA 病例中常观察到 NK 细胞功能异常。此外，40%的此类异常患者习惯性地与穿孔素基因突变相关。如今，MAS 仍然是一个临床和诊断挑战。
MAS 的诊断主要基于临床依据。然而，骨髓中巨噬细胞吞噬各种造血细胞的吞噬作用的实验室证据也有助于诊断。为了确诊 MAS，必须存在两种临床或实验室标准中的一种。此外，实验室标准通常出现较晚，无法在疾病早期诊断并发症。与 JIA 相关的巨噬细胞活化综合征的重要实验室发现包括高甘油三酯血症、贫血、红细胞沉降率低、丙氨酸氨基转移酶水平升高、胆红素水平高于正常、纤维蛋白降解产物存在、乳酸脱氢酶水平升高、低钠、低白蛋白血症和铁蛋白血症。
MAS 是 JIA 患者的一种明确的危及生命的并发症。此外，MAS 的早期诊断和治疗可能是这种综合征的一种救生模式。
