The Changes Of Immune Function In Children With Mycoplasma Pneumoniae Pneumonia And Its Significance

Background:Mycoplasma pneumoniae(MP)is one of the most common pathogens causing community acquired pneumonia in children and adolescents.Mycoplasma pneumoniae is mainly transmitted by respiratory droplets,and its pathological changes are mainly interstitial pneumonia,especially in children and adolescents.The incubation period of mycoplasma pneumoniae infection is more than 2 to 3 weeks before clinical symptoms appear,and less than 30% cases can be asymptomatic.Symptoms vary after onset,mycoplasma pneumoniae pneumonia starts slowly,at first,there are more pharynx,fever,headache,anorexia,fatigue and other symptoms.The temperature of fever is from 38? to 41?,most of them are about 39?,and a small number of children only have low fever or no fever.After 2 to 3 days,there were obvious respiratory symptoms,mainly paroxysmal irritating dry cough,night cough,late sputum cough,mostly mucilage sputum or purulent sputum,and occasionally blood filaments could be seen in sputum.The incidence of mycoplasma pneumoniae pneumonia is high,the mortality rate is high,and it is easy to appear more extrapulmonary complications.Therefore,it is necessary to give a reasonable and effective treatment plan for children with mycoplasma pneumoniae pneumonia in time.At present,the pathogenesis of Mycoplasma pneumoniae pneumonia is not very clear.More and more studies show that immune disorders,including cellular immunity and humoral immunity,play an important role in the pathogenesis of Mycoplasma pneumoniae pneumonia.Methods:To collect one hundred children with MPP in hospitalized children from January 2017 to January 2018.They were divided into two groups: MPP group(n=50)and severe MPP group(n=50).At the same time,50 healthy children in the same period of outpatient examination in our hostipal were collected as the control group.The CD4+?CD8+?CD4+/CD8+?IgG?IgA?IgM values in peripheral blood of 150 children were collected and the immunological indexes were compared.In addition,the values of CRP and PCT were collected and compared between the two groups of MPP children.Results:1?Age difference : the age of MPP group with pleural effusion was significantly hinger than that of simple MPP gruop,and the difference was statistically significant(P<0.05).2?Humoral immunity dysfunction: The level of IgG in MPP children in both groups was significantly lower than in the control group(P<0.05).The decrease of IgG in MPP group with pleural effusion was more obvious than that in control group(P<0.01).The level of IgA in MPP children in both groups was significantly lower than in the control group(P<0.01).The level of serum IgM in MPP group was lower than that in control group,but the difference was not statistically significant.3?Cellular immune dysfunction: The level of CD3+ in simple MPP groups was lower than that in the control group,but the difference was not statistically significant(P>0.05).The level of CD3+ in MPP group with pleural effusion was significantly lower than that in the control group(P<0.05).The level of CD4+ in MPP children in both groups was significantly lower than in the control group(P<0.01).There was no significant difference in CD4+ between MPP group with pleural effusion and simple MPP group(P>0.05).The level of CD8+ in MPP children in both groups was higher than in the control group,the difference is not statistically significant(P>0.05).There was no significant difference in CD4+/CD8+ among the three groups(P>0.05).4?Comparison of inflammatory makers: The level of CRP in the MPP group with pleural effusion was higher than that in the simple MPP group,and the difference was statistically significant(P<0.05).The level of PCT in the MPP group with pleural effusion was higher than that in the simple MPP group,but the difference was statistically significant(P>0.05).Conclusion:1?Children with mycoplasma pneumoniae infection complicated with pleural effusion are older than those with simple mycoplasma pneumoniae infection.It may be suggested that the immune system is relatively perfect and the immune system is relatively stronger with the increase of age,so the stronger the immune response is,the more obvious is the immune disorder in the body.2?Humoral immune dysfunction exists in children with MPP,and the more serious the condition,the more obvious the disorder of humoral immunity.The main manifedtation is the decrease of IgG?IgA level.These results suggest that the B lymphocytes are over-activated after MP infection.The decrease of immunoglobulin indicates of immune factor and the low immune function of the body.3?Cellular immune dysfunction exists in children with MPP.And the more serious the condition,the more significant the decrease in CD3+?CD4+ value.It is suggested that with the exacerbation of the disease,the decrease of mature T lymphocytes is more obvious.The immune function of helper T cells is decreased,which leads to the disorder of immunomodulation function in children.4?Compaerd with simple MPP,MPP in children with pleural effusion was significantly higher than that in children with MPP alone,suggesting that there was a more severe inflammatory reaction in children with MPP complicated with pleural effusion.