Hypogammaglobulinemia is a complication of B-cell targeting therapies (BCTT), used in vasculitis, rheumatoid arthritis and systemic lupus erythematosus (SLE). Since autoimmune diseases are associated with underlying and induced immune abnormalities, several societies recommend assessing immune function before and during rituximab treatment. In SLE, polyclonal hypergammaglobulinemia is the typical alteration of gammaglobulins, though hypogammaglobulinemia has also been reported. This is a cross-sectional study describing immunoglobulin levels measured as part of routine care in patients with lupus nephritis, a group with multiple factors contributing to immunoglobulin abnormalities, including immune dysregulation, immunosuppression and nephrotic syndrome. Polyclonal hypergammaglobulinemia occurred in 15/83 (18.1%) patients. In contrast, low levels of immunoglobulins were found as follows: selective IgA deficiency 2/83 (2.4%), reduced IgG levels 7/83 (8.4%), reduced IgM 14/83 (16.9%). Only 1 patient required immunoglobulin replacement. Immunoglobulin abnormalities are frequently found in lupus nephritis, ranging from polyclonal hypergammaglobulinemia to hypogammglobulinemia. Consequently, immunoglobulin levels should be assessed prior to commencing BCTT.

中文翻译：

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狼疮性肾炎患者常出现免疫球蛋白异常

低丙种球蛋白血症是 B 细胞靶向治疗 (BCTT) 的并发症，用于血管炎、类风湿性关节炎和系统性红斑狼疮 (SLE)。由于自身免疫性疾病与潜在的和诱发的免疫异常有关，一些协会建议在利妥昔单抗治疗之前和期间评估免疫功能。在 SLE 中，多克隆高丙种球蛋白血症是丙种球蛋白的典型改变，但也有报道低丙种球蛋白血症。这是一项横断面研究，描述了作为狼疮肾炎患者常规护理的一部分测量的免疫球蛋白水平，狼疮肾炎患者有多种因素导致免疫球蛋白异常，包括免疫失调、免疫抑制和肾病综合征。15/83 (18.1%) 患者发生多克隆高丙种球蛋白血症。相比之下，发现低水平的免疫球蛋白如下：选择性 IgA 缺乏 2/83 (2.4%)，IgG 水平降低 7/83 (8.4%)，IgM 降低 14/83 (16.9%)。只有 1 名患者需要更换免疫球蛋白。免疫球蛋白异常常见于狼疮性肾炎，范围从多克隆高丙种球蛋白血症到低丙种球蛋白血症。因此，应在开始 BCTT 之前评估免疫球蛋白水平。