Abstract：
BACKGROUND: Common variable immunodeficiency (CVID) is a rare disease that affects children and adults and is often difficult to diagnose. Despite being one of the most frequent causes of immunodeficiency, involving gastrointestinal (GI), respiratory, and hematological systems, the disease onset can have heterogeneous and intermittent symptoms, frequently leading to diagnostic delay. GI symptoms are common and can include diarrhea, but the asymptomatic periods lead to overlooking the recurrent pattern. The same can occur with respiratory infections, thus delaying CVID suspicion. The starting point for CVID diagnosis is the decreased gamma globulin levels in serum protein electrophoresis (SPE), also observed through direct immunoglobulin\'s dosage.
METHODS: The patient is a 38 years-old man who had intermittent diarrhea and recurrent airway infections for 19 years, but the CVID diagnosis was achieved only after SPE was carried out. At that time, he was already malnourished, and developed other complications related to CVID in a short period.
CONCLUSIONS: SPE is readily available and inexpensive, but is not part of the laboratory approach in diarrhea. According to the case presented herein, it can be useful for patients with recurrent infections or other clues of the disease.
METHODS: The patient is a 38 years-old man who had intermittent diarrhea and recurrent airway infections for 19 years, but the CVID diagnosis was achieved only after SPE was carried out. At that time, he was already malnourished, and developed other complications related to CVID in a short period.
CONCLUSIONS: SPE is readily available and inexpensive, but is not part of the laboratory approach in diarrhea. According to the case presented herein, it can be useful for patients with recurrent infections or other clues of the disease.
摘要：
背景：常见可变免疫缺陷（CVID）是一种罕见的疾病，可影响儿童和成人，通常难以诊断。尽管是免疫缺陷最常见的原因之一，涉及胃肠道（GI），呼吸,和血液系统，疾病发作可以有异质性和间歇性症状，经常导致诊断延迟。胃肠道症状很常见，可能包括腹泻，但是无症状期导致忽略了复发模式。呼吸道感染也会发生同样的情况，从而延缓了对CVID的怀疑。CVID诊断的起点是血清蛋白电泳（SPE）中丙种球蛋白水平降低，也通过直接免疫球蛋白的剂量观察。
方法：患者是一名38岁男性，间歇性腹泻和反复呼吸道感染达19年，但CVID诊断只有在进行SPE后才能实现.当时,他已经营养不良了,并在短时间内出现与CVID相关的其他并发症。
结论：SPE易于获得且价格便宜，但不是腹泻实验室方法的一部分。根据本文提出的情况，它对反复感染或其他疾病线索的患者可能有用。
方法：患者是一名38岁男性，间歇性腹泻和反复呼吸道感染达19年，但CVID诊断只有在进行SPE后才能实现.当时,他已经营养不良了,并在短时间内出现与CVID相关的其他并发症。
结论：SPE易于获得且价格便宜，但不是腹泻实验室方法的一部分。根据本文提出的情况，它对反复感染或其他疾病线索的患者可能有用。
