抗体延迟产生的肺炎支原体肺炎患儿临床特征分析

The clinical characteristics of delayed antibody production in mycoplasma pneumoniae pneumonia in children

目的了解抗体延迟产生的肺炎支原体肺炎(MPP)患儿的临床特征及其相关因素。方法选取2019年1月1日至12月31日苏州大学附属儿童医院住院治疗的MPP患儿285例,将病程14 d内血清抗体IgM 2次检测均为阴性,且IgG 2次检测抗体滴度无4倍及以上增高或减低的36例患儿设为抗体延迟产生组;将14 d内血清抗体检测IgM阳性或IgG 2次检测抗体滴度呈4倍及以上增高或减低的患儿249例设为抗体阳性组。对比分析两组的临床表现、免疫学及影像学特征。结果抗体延迟产生组中位年龄0.75(0.30,2.78)岁,显著小于抗体阳性组5.50(3.73,7.20)岁(P<0.001)。血清免疫球蛋白IgG低水平是造成患儿肺炎支原体抗体延迟产生的独立影响因素(P=0.037),当血清免疫球蛋白IgG低于7.155 mmol/L时,预测发生肺炎支原体抗体延迟产生的敏感度为0.819,特异度为0.833。与抗体延迟产生相关基础疾病主要为新生儿期住院病史(P=0.007)和先天性心脏病(P=0.001)。抗体延迟产生组11.11%(4/36)发生痉挛性咳嗽、41.67%(15/36)发生喘息及33.33%(12/36)发生腹泻,显著高于抗体阳性组的0.40%(1/249)、24.50%(61/249)和9.64%(24/249)(P<0.05)。抗体延迟产生组63.89%(23/36)出现发热,显著低于抗体阳性组的92.37%(230/249)(P<0.001),发热持续天数[2.50(0.00,4.75)d]也显著低于抗体阳性组[7.00(5.00,8.50)d](P<0.001)。抗体延迟产生组19.44%(7/36)发生大叶性肺炎,无一例发生肺外表现,显著低于抗体阳性组的75.50%(188/249)和14.86%(37/249)(P<0.05)。结论MPP患儿抗体延迟产生多见于血清免疫球蛋白IgG水平低于7.155 mmol/L的患儿,尤其当存在新生儿期住院病史及先天性心脏病时。该类患儿临床表现主要以痉挛性咳嗽、喘息为主要特征,出现发热、大叶性肺炎和肺外表现概率低。

Objective To clarify the clinical characteristics and related fators of children with delayed antibody production of mycoplasma pneumoniae pneumonia(MPP).Methods Two hundreds and eithty-five cases of children hospitalized at Children′s Hospital of Soochow University with MPP(positive for nucleic acid testing of respiratory secretion)were chosen from January 1st,2019 to September 31st,2019.Delayed antibody production group included 36 cases,who were tested for negative IgM antibody meanwhile the titer of IgG antibody changed less than 4 folds within 14 days.Positive group included 249 cases who were tested for positive IgM antibody or the titer of IgG antibody changed over 4 folds within 14 days.The characteristics of clinical manifestation,immunology and radiology were comparatively analyzed.Results The medium age of delayed antibody production group was 0.75(0.30,2.78)years old,which was obviously younger than that from positive group[5.50(3.73,7.20)years old](P<0.001).Low level of serum immunoglobulin IgG was the independent effect factor of delayed production for Mycoplasma pneumoniae antibody(P=0.037).When the serum immunoglobulin IgG level was lower than 7.155mmol/L,the sensitivity of predicting delayed production for mycoplasma pneumoniae antibody would be 0.819 and the specificity was 0.833.The underlying diseases associated with delayed antibody production were hospitalization history during neonatal period(P=0.007)and congenital heart disease(P=0.001).There were 11.11%(4/36)of children appearing spasmodic cough,41.67%(15/36)of children showing wheezing and 33.33%(12/36)showing diarrhea in delayed antibody group,which were significantly higher than those in positive group[0.40%(1/249),24.50%(61/249)and 9.64%(24/249),respectively,P<0.05].The incidence of fever in delayed antibody group were 63.89%(23/36),which was lower than that in positive group[92.37%(230/249)](P<0.001),meanwhile,the fever last time was 2.50(0,4.75)days in delayed antibody group,which was shorter than that in positive group[7(5.00,8.50)days](P<0.001).In the delayed antibody group,there was 19.44%(7/36)of children sufferring from lobar pneumonia,and no extrapulmonary manifestations occurred,which were significantly lower than those in positive group[75.50%(188/249),14.86%(37/249)](P<0.05).Conclusion Delayed antibody production in children with MPP is more common when serum immunoglobulin IgG level is lower than 7.155 mmol/L,especially in the presence of neonatal hospital history and congenital heart disease.The clinical manifestations of these children are mainly characterized by spasmodic cough and wheezing,with low probability of fever,lobular pneumonia and extrapulmonary manifestations.