Immunoglobulin G (IgG) Subclass and IgE Responses in Human Paragonimiases Caused by Three Different Species

In 40 cases of human paragonimiases caused by Paragonimus westermani (20 cases), P. miyazakii (10 cases), and P. skrjabini (10 cases), responses of serum immunoglobulin G (IgG), IgG subclasses, and IgE were analyzed by immunoblotting with crude antigens prepared from egg, 4-week-old juvenile, and adult forms of P. westermani. The 32- and 35-kDa proteins in the adult extracts showed specific reactions regardless of the causative species (39 of 40 cases; 98%). Sera of patients infected with P. westermani and P. miyazakii reacted strongly with the 28-, 46-, and 94-kDa proteins of egg extracts, while those from patients infected with P. skrjabini reacted faintly. No sera from patients with other trematodiases (0 of 15 cases), cestodiases (0 of 20 cases), or lung cancer (0 of 5 cases) or from healthy controls (0 of 10 individuals) showed positive reactions. Analysis by IgG subclass revealed that IgG4 (33 of 40 cases; 83%) and IgG1 (29 of 40 cases; 73%) antibodies in the patient sera recognized the 32- and 35-kDa proteins predominantly. IgG3 reaction was found in 50% (10 of 20 cases) and 30% (3 of 10 cases) of the sera of patients infected with P. westermani and P. miyazakii, respectively. In an IgE immunoblot, 83% (33 of 40 cases) of the sera from paragonimiasis patients reacted with the 32- and 35-kDa proteins while no sera from patients with heterologous diseases and healthy controls showed a positive reaction. Both 32- and 35-kDa proteins in adult extracts of P. westermani were highly reliable for serodiagnosis of human paragonimiases.

本研究纳入40例人类并殖吸虫病病例，其中卫氏并殖吸虫（Paragonimus westermani）感染20例、宫崎并殖吸虫（P. miyazakii）感染10例、斯氏狸殖吸虫（P. skrjabini）感染10例。采用免疫印迹法（immunoblotting），以卫氏并殖吸虫虫卵、4周龄童虫及成虫制备的粗抗原，分析患者血清免疫球蛋白G（IgG）、IgG亚类及免疫球蛋白E（IgE）的应答反应。成虫提取物中32 kDa与35 kDa蛋白可呈现特异性结合反应，覆盖40例病例中的39例（98%），且该反应与致病虫种无关。感染卫氏并殖吸虫与宫崎并殖吸虫的患者血清，可与虫卵提取物中的28 kDa、46 kDa及94 kDa蛋白发生强阳性结合；而感染斯氏狸殖吸虫的患者血清仅呈现微弱结合反应。其余15例其他吸虫病患者、20例绦虫病患者、5例肺癌患者的血清，以及10名健康对照者的血清，均未出现阳性反应。IgG亚类分析结果显示，患者血清中的IgG4（40例中33例，占比83%）与IgG1（40例中29例，占比73%）抗体可主要识别32 kDa与35 kDa蛋白。在感染卫氏并殖吸虫与宫崎并殖吸虫的患者血清中，IgG3阳性率分别为50%（20例中10例）与30%（10例中3例）。IgE免疫印迹检测结果显示，83%的并殖吸虫病患者血清（40例中33例）可与32 kDa及35 kDa蛋白结合，而异源性疾病患者及健康对照者的血清均未呈现阳性反应。卫氏并殖吸虫成虫提取物中的32 kDa与35 kDa蛋白，可作为人类并殖吸虫病血清学诊断的高可靠性标志物。