Department of Dermatology, Faculty of Medicine, University of São Paulo, São Paulo, Brazil; Faculty of Medicine ABC, Outpatient Clinic of Recurrent Infections, São Paulo, Brazil.
Scand J Immunol. 2014 Apr;79(4):276-81. doi: 10.1111/sji.12154.
Blood levels of regulators of the complement system in preterm babies were reported in few studies only. The aim of this study was to set up a complement profile in premature and term babies focusing on the development of blood levels of MBL, key regulatory proteins and on classical pathway activity, which may allow an estimation of potential susceptibility to infection. Complement activity (CH50), levels of mannan-binding lectin (MBL), complement regulators (factors H and I, C1 inhibitor, properdin) and C3a as marker of complement activation were assessed in three groups of healthy newborns: (1) prematures (≤34 weeks); (2) late prematures (>34-<37 weeks) and (3) term neonates (≥37 weeks). CH50 increased with gestational age with lower titres in cord blood than in day 5 post-delivery venous blood. MBL concentrations were not significantly different among groups. Quantitative and functional C1 inhibitor were below adult normal range in prematures <34 weeks and lower in cord blood as compared to day 5. Factor I, factor H and properdin remained below adult values in all groups. Low C3a levels excluded that low complement titres were due to activation-induced consumption. These results demonstrate the relative immaturity of the complement system and its regulation, especially in premature infants.
仅有少数研究报道了早产儿补体系统调节因子的血药浓度。本研究旨在建立早产儿和足月儿的补体谱，重点研究MBL、关键调节蛋白和经典途径活性的血药浓度变化，这可能有助于评估潜在的感染易感性。在三组健康新生儿中评估了补体活性（CH50）、甘露聚糖结合凝集素（MBL）水平、补体调节因子（因子 H 和 I、C1 抑制剂、备解素）和 C3a（补体激活的标志物）：（1）早产儿（≤34 周）；（2）晚期早产儿（>34-<37 周）和（3）足月儿（≥37 周）。CH50 随胎龄增加而增加，脐血中的效价低于产后第 5 天静脉血中的效价。各组之间 MBL 浓度无显著差异。<34 周的早产儿的定量和功能性 C1 抑制剂均低于成人正常范围，且脐血中的 C1 抑制剂低于产后第 5 天。所有组中的因子 I、因子 H 和备解素均低于成人值。低 C3a 水平排除了低补体效价是由于激活诱导的消耗所致。这些结果表明补体系统及其调节相对不成熟，尤其是在早产儿中。
