Familial hemophagocytic lymphohistiocytosis (HLH) is

No abstract

Objective. Macrophage activation syndrome is characterized by an overwhelming inflammatory reaction driven by excessive expansion of T cells and hemophagocytic macrophages. Levels of soluble interleukin-2 receptor ␣ (sIL-2R␣) and soluble CD163 (sCD163) may reflect the degree of activation and expansion of T cells and macrophages, respectively. This study was undertaken to assess the value of serum sIL-2R␣ and sCD163 in diagnosing acute macrophage activation syndrome complicating systemic juvenile idiopathic arthritis (JIA).Methods. Enzyme-linked immunosorbent assay was used to assess sIL-2R␣ and sCD163 levels in sera from 7 patients with acute macrophage activation syndrome complicating systemic JIA and 16 patients with untreated new-onset systemic JIA. The results were correlated with clinical features of established macrophage activation syndrome, including ferritin levels.Results. The median level of sIL-2R␣ in the patients with macrophage activation syndrome was 19,646 pg/ml (interquartile range [IQR] 18,128), compared with 3,787 pg/ml (IQR 3,762) in patients with systemic JIA (P ‫؍‬ 0.003). Similarly, the median level of sCD163 in patients with macrophage activation syndrome was 23,000 ng/ml (IQR 14,191), compared with 5,480 ng/ml (IQR 2,635) in patients with systemic JIA (P ‫؍‬ 0.017). In 5 of 16 patients with systemic JIA, serum levels of sIL-2R␣ or sCD163 were comparable with those in patients with acute macrophage activation syndrome. These patients had high inflammatory activity associated with a trend toward lower hemoglobin levels (P ‫؍‬ 0.11), lower platelet counts, and significantly higher ferritin levels (P ‫؍‬ 0.02). Two of these 5 patients developed overt macrophage activation syndrome several months later.Conclusion. Levels of sIL-2R␣ and sCD163 are promising diagnostic markers for macrophage activation syndrome. They may also help identify patients with subclinical macrophage activation syndrome.In pediatric rheumatology the term "macrophage activation syndrome" refers to a set of symptoms caused by excessive activation and proliferation of T cells and well-differentiated macrophages (1,2). Such activation leads to a potentially fatal overwhelming inflammatory reaction. The pathognomonic feature of macrophage activation syndrome, the presence of numerous, welldifferentiated macrophages (histiocytes) actively phago-

No abstract

No abstract