Unidad de Alergia, Hospital de Fuenlabrada, Madrid, Spain.
Immunotherapy. 2011 May;3(5):637-51. doi: 10.2217/imt.11.44.
Systemic mastocytosis (SM) is typically suspected in patients with cutaneous mastocytosis (CM). In recent years, the presence of clonal mast cells (MCs) in a subset of patients with systemic symptoms associated with MC activation in the absence of CM has been reported and termed monoclonal MC activation syndromes or clonal systemic MC activation syndromes. In these cases, bone marrow (BM) MC numbers are usually lower than in SM with CM, there are no detectable BM MC aggregates, and serum baseline tryptase is often <20 µg/l; thus, diagnosis of SM in these patients should be based on careful evaluation of other minor WHO criteria for SM in reference centers, where highly sensitive techniques for immunophenotypic analysis and investigation of KIT mutations on fluorescence-activated cell sorter-purified BM MCs are routinely performed. The prevalence of hymenoptera venom anaphylaxis (HVA) among SM patients is higher than among the normal population and it has been reported to be approximately 5%. In SM patients with IgE-mediated HVA, venom immunotherapy is safe and effective and it should be prescribed lifelong. Severe adverse reactions to hymenoptera stings or venom immunotherapy have been associated with increased serum baseline tryptase; however, presence of clonal MC has not been ruled out in most reports and thus both SM and clonal MC activation syndrome might be underdiagnosed in such patients. In fact, clonal BM MC appears to be a relevant risk factor for both HVA and severe reactions to venom immunotherapy, while the increase in serum baseline tryptase by itself should be considered as a powerful surrogate marker for anaphylaxis. The Spanish Network on Mastocytosis has developed a scoring system based on patient gender, the clinical symptoms observed during anaphylaxis and serum baseline tryptase to predict for the presence of both MC clonality and SM among individuals who suffer from anaphylaxis.
系统性肥大细胞增多症（SM）通常在伴有肥大细胞活化的系统性症状而无皮肤肥大细胞增多症（CM）的患者中怀疑。近年来，已报道并命名为单克隆肥大细胞活化综合征或克隆系统性肥大细胞活化综合征，在一组具有系统性症状的患者中存在克隆肥大细胞（MC）。在这些情况下，骨髓（BM）MC 数量通常低于伴有 CM 的 SM，不存在可检测到的 BM MC 聚集，且血清基础 tryptase 通常<20μg/l；因此，这些患者的 SM 诊断应基于在参考中心仔细评估其他用于 SM 的 WHO 次要标准，在这些中心，常规进行用于免疫表型分析和研究荧光激活细胞分选纯化的 BM MC 中 KIT 突变的高度敏感技术。SM 患者中的蜂螫过敏（HVA）发生率高于普通人群，据报道约为 5%。在 IgE 介导的 HVA 的 SM 患者中，毒液免疫疗法是安全有效的，应终生规定。对蜂螫或毒液免疫疗法的严重不良反应与血清基础 tryptase 增加有关；然而，在大多数报告中并未排除克隆 MC 的存在，因此在这些患者中可能漏诊了 SM 和克隆 MC 活化综合征。实际上，克隆 BM MC 似乎是 HVA 和对毒液免疫疗法的严重反应的一个相关危险因素，而血清基础 tryptase 的增加本身应被视为过敏的有力替代标志物。西班牙肥大细胞网络已制定了一个评分系统，基于患者性别、过敏期间观察到的临床症状和血清基础 tryptase，用于预测发生过敏的个体中 MC 克隆性和 SM 的存在。
