Mutations in lipopolysaccharide-responsive vesicle trafficking, beach and anchor-containing protein (LRBA) cause immune deficiency and inflammation. Here, we are reporting a novel homozygous mutation in LRBA allele in 7-year-old Omani boy, born to consanguineous parents. He presented with type 1 diabetes, autoimmune haematological cytopenia, recurrent chest infections and lymphocytic interstitial lung disease. The patient was treated with CTLA4-Ig (abatacept) with good outcome every 2 weeks for a period of 3 months. He developed complete IgG deficiency, but remarkably, histological examination revealed germinal centres and plasma cells in lymphoid and inflamed lung tissue. Further charatecterisation showed these cells to express IgM but not IgG. This ex vivo analysis suggests that LRBA mutation confers a defect in class switching despite plasma cell formation.

中文翻译：

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尽管患有新的LRBA突变的患者发生了终末B细胞分化，但血球蛋白血症仍然存在。

脂多糖反应性小泡运输，海滩和含锚蛋白（LRBA）中的突变引起免疫缺陷和炎症。在这里，我们报道了近亲父母出生的7岁阿曼男孩的LRBA等位基因中的一个新的纯合突变。他表现为1型糖尿病，自身免疫性血液细胞减少症，反复发作的胸部感染和淋巴细胞性间质性肺疾病。患者每2周接受CTLA4-Ig（abatacept）治疗，效果良好，持续3个月。他发展出完全的IgG缺乏症，但值得注意的是，组织学检查发现淋巴样和发炎的肺组织中的生发中心和浆细胞。进一步的鉴定表明这些细胞表达IgM，但不表达IgG。