Background and aim

The knowledge of dynamics of pertussis toxin (PT)-IgG after pertussis and the appropriate diagnostic cut-off value is limited. We aimed to describe the dynamics of PT-IgG in children and adults up to three years after symptomatic pertussis.

Methods

Patients with persistent cough of unknown aetiology were prospectively enrolled 2012–2014. Pertussis was confirmed by culture, PCR and/or serology. The follow-up samples were taken 4–6 weeks, 1, 2 and 3 years after enrolment. PT-IgG kinetics was described by biexponential model.

Results

Pertussis was diagnosed in 22 patients [median (IQR) age 17.7 (8.4–38.6) years]. Adults compared with children had higher peak of the PT-IgG 397 (IQR 374–518) vs 292 (200–363), p = 0.007, longer time to reach peak PT-IgG 16.4 (IQR 15.6–16.8) days vs 13.3 (13.2–13.4) days, p=<0.001 and shorter PT-IgG half-life 24 days (IQR 20–40) and 364 days (IQR 359–486) p < 0.001.

Conclusion

After symptomatic pertussis, adults and children have different dynamics of PT-IgG.

Clinical trial registry: Not applicable.

中文翻译：

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儿童和成人有症状百日咳后百日咳毒素IgG的动态。

背景和目标

百日咳后百日咳毒素（PT）-IgG动态的知识以及适当的诊断临界值有限。我们旨在描述有症状百日咳症状发生后三年内儿童和成人中PT-IgG的动态。

方法

前瞻性纳入2012-2014年因病因不明而持续咳嗽的患者。通过培养，PCR和/或血清学证实百日咳。入选后4-6周，1、2和3年进行随访。PT-IgG动力学由双指数模型描述。

结果

百日咳被诊断出22例[中位（IQR）年龄17.7（8.4-38.6）岁]。与儿童相比，成人的PT-IgG 397（IQR 374–518）峰值较高，而292（200–363）较高，p = 0.007，达到PT-IgG 16.4（IQR 15.6–16.8）峰值所需时间更长，而13.3（ 13.2–13.4）天，p = <0.001，较短的PT-IgG半衰期24天（IQR 20–40）和364天（IQR 359–486 ） p <0.001。

结论

有症状的百日咳后，成人和儿童的PT-IgG动力学不同。

临床试验注册表：不适用。