Objective

Mast cell (MC) activation (MCA) defines the mechanism by which certain patients have symptoms owing to the effect of a wide range of mediators released from MCs upon their activation, when triggered by different stimuli. When these symptoms are severe and recurrent, the diagnosis of MCA syndrome (MCAS) might be considered. Here, we review the relevant aspects related to the pathogenesis of MCAS, with special emphasis on the prevalence and diagnostic relevance of KIT mutations.

Data Sources

PubMed was searched between 1980 and 2021 using the following terms: mast cell activation syndromes, mast cell activation, anaphylaxis, KIT mutations, KIT D816V, indolent systemic mastocytosis, bone marrow mastocytosis, cutaneous mastocytosis, IgE anaphylaxis, and idiopathic anaphylaxis.

Study Selections

Only articles published in English were selected based on their relevance to MCAS or severe and recurrent anaphylaxis.

Results

MCAS can be classified as clonal MCAS and nonclonal MCAS depending on the presence vs absence of an underlying KIT mutation (mostly KIT D816V), respectively. In contrast to clonal MCAS in which MCA is associated with a primary MC disorder (ie, primary MCAS) such as mastocytosis or monoclonal MCAS, nonclonal MCAS can be secondary to known or unidentified triggers (ie, secondary and idiopathic MCAS, respectively).

Conclusion

The clinical heterogeneity and complexity of the molecular assays needed for the study of patients with MCAS might lead to misdiagnosis, particularly when patients are evaluated at nonspecialized centers. Thus, referral of patients having clinical manifestations suggestive of MCAS to reference centers on mastocytosis and MC diseases is strongly recommended.

中文翻译：

---

KIT 在原发性肥大细胞活化障碍中的致病和诊断相关性

客观的

肥大细胞 (MC) 激活 (MCA) 定义了某些患者出现症状的机制，这是由于当由不同刺激触发时从 MC 释放的多种介质对其激活的影响。当这些症状严重且反复出现时，可能会考虑 MCA 综合征 (MCAS) 的诊断。在这里，我们回顾了与 MCAS 发病机制相关的相关方面，特别强调了KIT突变的流行和诊断相关性。

数据源

1980 年至 2021 年期间，使用以下术语对 PubMed 进行了搜索：肥大细胞激活综合征、肥大细胞激活、过敏反应、KIT突变、KIT D816V、惰性系统性肥大细胞增多症、骨髓肥大细胞增多症、皮肤肥大细胞增多症、IgE 过敏反应和特发性过敏反应。

研究选择

仅根据与 MCAS 或严重和复发性过敏反应的相关性选择以英文发表的文章。

结果

根据潜在KIT突变（主要是KIT D816V）的存在与否，MCAS 可分为克隆性 MCAS 和非克隆性 MCAS 。与其中 MCA 与原发性 MC 疾病（即原发性 MCAS）相关的克隆性 MCAS 不同，例如肥大细胞增多症或单克隆性 MCAS，非克隆性 MCAS 可继发于已知或未确定的触发因素（即，分别为继发性和特发性 MCAS）。

结论

研究 MCAS 患者所需的分子检测的临床异质性和复杂性可能会导致误诊，尤其是在非专科中心对患者进行评估时。因此，强烈建议将具有提示 MCAS 临床表现的患者转诊至肥大细胞增多症和 MC 疾病的参考中心。