我们的目的是确定巴西圣保罗州中部地区患者的二抗缺陷 (SAD) 概况，重点关注传染病。从电子文件中获得人口统计特征以及临床和实验室数据；感染被分类为器官特异性感染，并分为轻度、中度、危及生命和致命。非霍奇金淋巴瘤（NHL）占患者的30%，肾病综合征（NS）占25%，慢性淋巴细胞白血病占20%，多发性骨髓瘤占15%。 NS患者较其他组年轻，94.1%检出低γ球蛋白血症，60.0%检出IgG < 400 mg/dL，55.0%检出IgA < 40 mg/dL，CD19 < 20 cells/mm3 30.0%。发现一百零一例感染； 82.1% 被列为轻度或中度，7.9% 为危及生命，3.0% 为致命。呼吸道感染较多见（41.5%），肺炎占19.8%。与 NHL 患者相比，NS 患者的感染水平较低 (p = 0.0001)。大多数患者在免疫抑制剂治疗后进展为低γ球蛋白血症和SAD，以轻、中度感染为主。这些疗法在患有不同疾病的患者中的应用越来越多；因此，监测低γ球蛋白血症和感染可能有助于识别严重并发症、抗生素预防或治疗以及免疫球蛋白替代的高风险患者。

Our aim was to determine the secondary antibody deficiency (SAD) profiles of patients in a mesoregion of São Paulo state, Brazil, focusing on infectious diseases. Demographic characteristics, and clinical and laboratory data were obtained from electronic files; infections were classified as organ-specific and graded as mild, moderate, life-threatening, and fatal. Non-Hodgkin's lymphoma (NHL) accounted for 30% of patients, nephrotic syndrome (NS) 25%, chronic lymphocyte leukemia 20%, and multiple myeloma 15%. Patients with NS were younger than those in other groups, and hypo-γ-globulinemia was detected in 94.1%, IgG < 400 mg/dL in 60.0%, IgA < 40 mg/dL in 55.0%, and CD19 < 20 cells/mm3 in 30.0%. One hundred and one infections were found; 82.1% were classified as mild or moderate, 7.9% as life-threatening, and 3.0% as fatal. Respiratory tract infections were more prevalent (41.5%), and pneumonia accounted for 19.8%. Lower levels of infections were found in patients with NS compared with NHL (p = 0.0001). Most patients progressed to hypo-γ-globulinemia and SAD after treatment with immunosuppressants, and mild and moderate infections were predominant. These therapies are increasing in patients with different diseases; therefore, monitoring hypo-γ-globulinemia and infections may help to identify patients at high risk for severe complications, antibiotic prophylaxis or treatment, and immunoglobulin replacement.