曼氏血吸虫感染及其治疗对学龄前儿童麻疹补种免疫抗体反应的影响：一项随机试验。
Effect of Schistosoma mansoni infection and its treatment on antibody responses to measles catch-up immunisation in pre-school children: A randomised trial.
机构信息
Department of Veterinary Pharmacy Clinical and Comparative Medicine, Makerere University, Kampala, Uganda.
Medical Research Council/Uganda Virus Research Institute and London School of Hygiene & Tropical Medicine Uganda Research Unit, Entebbe, Uganda.
出版信息
PLoS Negl Trop Dis. 2019 Feb 14;13(2):e0007157. doi: 10.1371/journal.pntd.0007157. eCollection 2019 Feb.
BACKGROUND
Schistosoma infection is associated with immune modulation that can influence responses to non-schistosome antigens. Vaccine responses may be impaired in S. mansoni-infected individuals. We investigated effects of S. mansoni infection on responses to childhood measles catch-up immunisation and of praziquantel treatment on this outcome in a randomised trial.
METHODOLOGY
The Immune Modulation and Childhood Immunisation (IMoChI) study was based in Entebbe, Uganda. Children aged 3-5 years (193 S. mansoni-infected and 61 uninfected) were enrolled. Infected children were randomised in a 1:1:1 ratio to receive praziquantel 2 weeks before, at time of, or 1 week after, measles catch-up immunisation. Plasma anti-measles IgG was measured at enrolment, 1 week and 24 weeks after measles immunisation. Primary outcomes were IgG levels and percentage of participants with levels considered protective against measles.
RESULTS
Anti-measles IgG levels increased following immunisation, but at 1 week post-immunisation S. mansoni-infected, compared to uninfected, children had lower levels of anti-measles IgG (adjusted geometric mean ratio (aGMR) 0.4 [95% CI 0.2-0.7]) and the percentage with protective antibody levels was also lower (adjusted odds ratio 0.1 [0-0.9]). Among S. mansoni-infected children, anti-measles IgG one week post-immunisation was higher among those treated with praziquantel than among those who were not yet treated (treatment before immunisation, aGMR 2.3 [1.5-4.8]; treatment at immunisation aGMR 1.8 [1.1-3.5]). At 24 weeks post-immunisation, IgG levels did not differ between the trial groups, but tended to be lower among previously-infected children who were still S mansoni stool-positive than among those who became stool-negative.
CONCLUSIONS AND SIGNIFICANCE
Our findings suggest that S. mansoni infection among pre-school children is associated with a reduced antibody response to catch-up measles immunisation, and that praziquantel treatment improves the response. S. mansoni infection may contribute to impaired vaccine responses in endemic populations; effective schistosomiasis control may be beneficial for vaccine efficacy. This should be further explored.
TRIAL REGISTRATION
ISRCTN87107592.
背景
血吸虫感染与免疫调节有关，这种免疫调节可能会影响对非血吸虫抗原的反应。曼氏血吸虫感染的个体可能会对疫苗反应产生损害。我们在一项随机试验中研究了曼氏血吸虫感染对儿童麻疹补种免疫反应的影响，以及吡喹酮治疗对该结果的影响。
方法
免疫调节和儿童免疫接种（IMoChI）研究基于乌干达恩德培。纳入年龄在 3-5 岁之间的儿童（193 名曼氏血吸虫感染和 61 名未感染）。感染的儿童按照 1:1:1 的比例随机分为三组，分别在接种麻疹疫苗前 2 周、接种时或接种后 1 周接受吡喹酮治疗。在接种麻疹疫苗前、接种后 1 周和 24 周测量血浆抗麻疹 IgG 水平。主要结局是 IgG 水平和具有抗麻疹保护水平的参与者比例。
结果
接种麻疹疫苗后，抗麻疹 IgG 水平升高，但在接种后 1 周，与未感染的儿童相比，感染曼氏血吸虫的儿童的抗麻疹 IgG 水平较低（调整后的几何平均比（aGMR）0.4[95%CI 0.2-0.7]），具有保护性抗体水平的比例也较低（调整后的比值比 0.1[0-0.9]）。在感染曼氏血吸虫的儿童中，与未接受治疗的儿童相比，接种前和接种时接受吡喹酮治疗的儿童在接种后 1 周时的抗麻疹 IgG 水平更高（接种前治疗，aGMR 2.3[1.5-4.8]；接种时治疗，aGMR 1.8[1.1-3.5]）。在接种后 24 周时，各组之间的 IgG 水平没有差异，但与仍为曼氏血吸虫粪便阳性的既往感染者相比，粪便转为阴性的感染者的 IgG 水平往往较低。
结论和意义
我们的研究结果表明，学龄前儿童的曼氏血吸虫感染与麻疹补种免疫的抗体反应降低有关，吡喹酮治疗可改善这种反应。曼氏血吸虫感染可能导致流行地区疫苗反应受损；有效的血吸虫病控制可能对疫苗效果有益。这一点需要进一步探讨。
试验注册
ISRCTN87107592。
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