Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America.
Southern Iron Disorders Center, Birmingham, Alabama, United States of America.
PLoS One. 2020 Oct 13;15(10):e0240522. doi: 10.1371/journal.pone.0240522. eCollection 2020.
Adults with IgG subclass deficiency (IgGSD) with subnormal IgG2 are inadequately characterized.
We retrospectively analyzed observations in unrelated adults with IgGSD evaluated in a single hematology clinic (1991-2019) and selected those with subnormal serum IgG2 (<117 mg/dL (<1.2 g/L)) without corticosteroid therapy to describe: age; prevalence of women; upper/lower respiratory infection; autoimmune condition(s); atopy; other allergy; frequent or severe respiratory tract infection in first-degree relatives; IgG, IgG subclasses, IgA, and IgM; blood lymphocyte subpopulations; human leukocyte antigen (HLA)-A and -B types and haplotypes; and 23-valent pneumococcal polysaccharide vaccination (PPSV23) responses. We determined the prevalence of subnormal IgG2 among unrelated adults with IgGSD without corticosteroid therapy and compared general characteristics of those with and without subnormal IgG2.
There were 18 patients (94.4% women) with subnormal IgG2. Mean age was 52 ± 11 y. Upper/lower respiratory infection occurred in 94.4%/74.8%, respectively. Autoimmune condition(s), atopy, other allergy, and frequent or severe respiratory infection in first-degree relatives occurred in 44.4%, 44.4%, 61.1%, and 22.2%, respectively. Median IgG2 was 105 mg/dL (83, 116). Subnormal IgG, IgG1, IgG3, IgG4, IgA, and IgM was observed in 66.7%, 50.0%, 100.0%, 5.6%, 33.3%, and 0%, respectively. Lymphocyte subpopulations were normal in most patients. HLA frequencies were similar in patients and controls. Three of 4 patients had no protective S. pneumoniae serotype-specific IgG levels before or after PPSV23. These 18 patients represent 7.6% of 236 adults with IgGSD. Prevalence of subnormal IgG, subnormal IgG3, and subnormal IgA was significantly greater in 18 adults with subnormal IgG2 than 218 adults without subnormal IgG2. Prevalence of subnormal IgM was significantly lower in patients with subnormal IgG2.
Characteristics of adults with IgGSD with subnormal IgG2 include female predominance, other immunologic abnormalities, subnormal IgG3 and/or IgG1, lack of HLA-A and -B association, and suboptimal PPSV23 response.
患有 IgG 亚类缺陷（IgGSD）且 IgG2 水平低于正常值的成年人的特征尚未得到充分描述。
我们回顾性分析了在一家血液科诊所（1991-2019 年）接受评估的、无类固醇治疗的 IgGSD 成年患者的观察结果，并选择了血清 IgG2 水平低于正常值（<117mg/dL（<1.2g/L））的患者，以描述以下特征：年龄；女性患病率；上/下呼吸道感染；自身免疫状况；特应性；其他过敏；一级亲属中频繁或严重的呼吸道感染；IgG、IgG 亚类、IgA 和 IgM；血淋巴细胞亚群；人类白细胞抗原（HLA）-A 和 -B 类型和单倍型；以及 23 价肺炎球菌多糖疫苗（PPSV23）接种反应。我们确定了无类固醇治疗的 IgGSD 成年患者中 IgG2 水平低于正常值的患病率，并比较了 IgG2 水平正常和低于正常值的患者的一般特征。
有 18 例患者（94.4%为女性）的 IgG2 水平低于正常值。平均年龄为 52±11 岁。上/下呼吸道感染的发生率分别为 94.4%和 74.8%。自身免疫状况、特应性、其他过敏和一级亲属中频繁或严重的呼吸道感染的发生率分别为 44.4%、44.4%、61.1%和 22.2%。中位 IgG2 水平为 105mg/dL（83，116）。66.7%、50.0%、100.0%、5.6%、33.3%和 0%的患者分别存在 IgG、IgG1、IgG3、IgG4、IgA 和 IgM 水平低于正常值。大多数患者的淋巴细胞亚群正常。患者和对照组的 HLA 频率相似。4 例患者中有 3 例在接种 PPSV23 前后均未产生针对肺炎链球菌血清型特异性 IgG 水平的保护作用。这 18 例患者占 236 例 IgGSD 成年患者的 7.6%。与 IgG2 水平正常的 218 例患者相比，18 例 IgG2 水平低于正常值的患者中 IgG 水平低于正常值、IgG3 水平低于正常值和/或 IgA 水平低于正常值的患病率显著更高。IgM 水平低于正常值的患者在 IgG2 水平低于正常值的患者中更为常见。
患有 IgG2 水平低于正常值的 IgGSD 成年患者的特征包括女性为主、其他免疫异常、IgG3 和/或 IgG1 水平低于正常值、HLA-A 和 -B 关联缺乏以及 PPSV23 反应不佳。
