| Part1.The first part of the comparative study of Mycoplasma pneumoniae antibodies and MP-DNA detection.Objective:To explore the clinical significance and value of serum Mycoplasma pneumoniae antibody and nasopharyngeal aspirate(NPA)MP-DNA detection method in respiratory mycoplasma pneumoniae(MP)infection.Methods:Patients who were admitted to the Department of Respiratory Diseases of Children's hospital of soochow university from January 2015 to December 2018 due to respiratory infections and met the following conditions were the subjects of the study conditions:Age 1 month to 14 years Nasopharyngeal aspirate(NPA)specimens were collected after admission and MP-DNA testing was performed using real-time polymerase chain reaction(PCR)technology;titers of MP-IgM and IgG in duplicate serum were measured in the acute and recovery phases;exclusion of immunity Suppressed children and children who have received immunosuppressive treatment.A total of 2839 children were met.All subjects collected peripheral venous blood samples within 24 hours after admission,and collected the second before discharge(when the condition improved after 7-10 days of treatment).Peripheral venous blood samples were tested for serum MP-specific antibodies.NPAl-2mL were collected within 24 hours of admission,and NPA MP-DNA was detected by real-time fluorescent quantitative PCR.Laboratory testing to determine MP positive criteria:(1)Real-time fluorescent quantitative PCR method Detection of NPA MP-DNA,copy number>1x104.(2)The results of semi-quantitative detection of MP-IgM in peripheral and peripheral venous blood within 24 hours of admission,the ratio was>1.1.(3)The detection of MP-IgM and MP-IgG in peripheral and peripheral venous blood before and after discharge from hospital was increased or decreased by 4 or more than 4 times.MP infection diagnosis criteria:NPA MP-DNA copy number>1x104,and NPA MP-DNA copy number is less than 1x104,but the MP-IgM and MP-IgG detection in peripheral and peripheral venous blood before and after discharge from hospital are increased or decreased by 4 or more than 4 times.Collect clinical data of children in the group,Including age,gender,course and clinical symptoms,clinical diagnosis,related laboratory tests,etc.Results:1.2839 cases of NPA specimens collected after admission for MP-DNA testing and detection of MP-IgM and IgG titers in double serum in acute and recovery phases,in which NPA MP-DNA copy number>1x104 In 350 cases of children with NPA MP-DNA copy number less than 1x104,the detection of MP-IgM and MP-IgG in peripheral venous blood before and after admission was 24 hours higher or lower than 4 times.A total of 600 cases were positive for MP,and the total positive rate of MP was 21.13%(600/2839).2.2839 NPA specimens were tested for MP-DNA by real-time fluorescent quantitative PCR,with a positive detection rate of 12.33%(350/2839);24 hours after admission,peripheral blood(first serum)semi-quantitative detection of MP-IgM,positive The detection rate was 23.11%(656/2839);the detection of MP-IgM and MP-IgG in peripheral venous blood(duplicate serum)24 hours before and 24 hours before admission increased or decreased by 4 or more.In 394 cases,the positive rate was 13.88%(394/2839).The positive detection rate of MP-IgM in the first serum was significantly higher than that detected by NPA MP-DNA and double serum MP-IgM and MP-IgG.The difference was statistically significant(?2=140.371,P<0.001).3.A comparison of the positive detection rates of NPA MP-DNA and MP double serum antibody in 600 children with confirmed mycoplasma infection was performed according to age group.The positive detection rate of NPA MP-DNA in the<1 year old group was 71.76%(122/170)was significantly higher than 41.18%(70/170)of MP double serum antibodies,which was statistically significant(x2=32.354,p<0.001);the positive detection rate of NPA MP-DNA was MP duplicate serum antibodies,there is no statistically significant difference between the two(p=0.204),the positive detection rate of NPA MP-DNA in the-6 year old group was 57.14%(84/147)significantly lower than 79.59%of MP duplicate serum antibodies.(117/147),there is a statistically significant difference between the two(x2=17.128,p<0.001);>6-year-old NPA MP-DNA positive detection rate of 40.43%(38/94)is significantly lower than MP double serum antibodies 85.11%(80/94),which is statistically significant(x2=40.149,p<0.001).Compared with different age groups,the MP double serum antibody test and NPA MP-DNA have different positive detection rates.All were statistically significant(p<0.001).4.The course of 600 children with confirmed mycoplasma infection was divided into<3d,?5d,?7d,?10d,?14d,?21d and>21 d 7 In each period group,the positive detection rate of NPA MP-DNA in different course of disease was compared.The detection rate of MP-DNA increased within 10 days of the course of disease and the positive detection rate increased with time.The positive detection rate was the highest,reaching 78.21%.Since then,with the extension of the course of disease,the positive detection rate of NPA MP-DNA has gradually decreased,and the positive detection rate of the group of courses>21d is only 37.5%.The difference in positive detection rate was statistically significant(?2-31.515,P<0.001).5.Among 600 children diagnosed with MP infection,144 were positive for NPA MP-DNA and double seropositive,206 were positive for NPA MP-DNA and 206 were negative for double sera,and 206 were positive for double sera and NPA.There were 250 cases of MP-DNA negative,and the consistency between the sensitivity of the two detection methods was average(Kappa=0.604).6.Among the 350 NPA MP-DNA positive children,the first IgM-positive children were 229(65.43%),and the first IgM-negative children were 121(34.57%);the first In the first IgM-positive children,54(15.43%)had a 4-fold increase or decrease after re-examination of the second serum antibody,and in the first IgM-negative children,90 cases(25.71%)has a 4-fold change,so the total number of double seropositive children among the 350 patients was 144(41.14%).7.According to the course of 350 cases of children with positive NPA MP-DNA detection method based on the clinical course of clinically obtained laboratory test specimens of children with respiratory infections,they were divided into<3 d,?5 d,?7d,?10d,?14d,?21d and>21d 7 time period groups,comparing the positive detection rate of the first IgM positive in different course of disease.The positive detection rate of MP-IgM increased significantly at?7d,peaked at?10d,and then slowly decreased;during the course of During the 10d period,the consistency of the NPA MP-DNA test and the MP single serum IgM positive was the best,reaching 91.80%.The positive detection rate of MP single IgM in different courses was significantly different(x2=65.812,P<0.001).Conclusion:1.The positive detection rate of NPA MP-DNA was high in the group? 1 years old,and the positive detection rate of MP double serum antibody was high in the group?6 years old and over 6 years old,while the positive detection rate of NPA MP-DNA and MP double serum antibody was similar in the group?3 years old.2.The positive detection rate of NPA MP-DNA increased with the increase of time within 10 days of course of disease,and the positive detection rate was the highest between 7 and 10 days of course of disease.3.NPA MP-DNA and single serum IgM of MP method had the best consistency in the period of disease course?10d.4.In clinic,single serum MP-IgM positive was used as an indicator of MP recent infection with the risk of false positive.Part2.The second part Influencing factors of antibody production after Mycoplasma pneumoniae infection.Objective:To detect nasopharyngeal aspirate in children with MP-DNA positive,but the first serum MP-IgM and double serum MP antibodies were negative,and to explore the possible reasons for the inability to produce antibodies after MP infection.Method:Thirty-one children with NPA MP-DNA>1×104 and negative serum MP-IgM and double serum MP antibodies were selected from 600 children diagnosed with recent mycoplasma infection in the first part,and NPA MP-DNA 144 children with>lxl04 and double serum MP antibody positives were the study subjects.Grouped according to age:?1 year old group and>1 year old group.Collected clinical history data of children in the group and within 24 hours of admission 2.The results of double blood routine and lymphocyte subsets,immunoglobulin test results of peripheral venous blood discharged from hospital,clinical and experimental tests were performed on children with negative serum MP-IgM and double serum MP antibodies and children with double serum MP antibodies.Comparative study of laboratory testing.Result:1.Children with negative serum MP-IgM and double serum MP antibodies were both 80.65%in the ?1 year old group and significantly more than 6.25%in the double seropositive group.There was a statistically significant difference between the two.2.The ratios of CD3+,CD3+,CD8+in the first serum MP-IgM and double serum MP antibodies were 66.6(61.2-73.6)and 25.2(21.2-29.9),which were higher than those in the double serum MP antibodies.Positive group 62.6(60.1-70.3),19.5(17.0-23.0);the first serum MP-IgM and double serum MP antibodies were negative CD3+CD4+,CD3-CD19+,CD 1 9+CD23+and CD3-CD(16+56+)are 34.8(30.1-40.9),17.2(13.4-24.7),7.9(5.8-11.7),10.2(6.8-16.7).In the double seropositive group 41.1(33.6-45.0),21.3(13.1-24.7),13.5(13.1-24.7),13.5(13.1-24.7).The first serum MP-IgM and the double serum MP antibody were negative in the ratio of CD4+/CD8+was 1.4(1.0-1.8),which was significantly lower than that of the double serum MP antibody positive group 2.0(1.7-2.7),and the differences were statistically significant,P<0.001.3.The first serum MP-IgM and the double serum MP antibody negative groups had a quantitative IgA of 0.14(0.04-0.42),which was significantly lower than that of the double serum MP antibody positive group 1.17(0.84-1.49),and the difference was statistically significant(Z=-17.519,P<0.001);the IgG quantification of the first serum MP-IgM and the double serum MP antibody negative group was 5.29(4.30-7.19),which was significantly lower than the double serum MP antibody positive group of 9.22(7.9-11.00),The difference between the two was statistically significant(Z=-14.654,P<0.001);the first serum MP-IgM and the double serum MP antibodies were negative.The IgM quantification of the group was 0.77(0.41-1.17),which was significantly lower than the double serum MP antibody positives.Group 1.13(0.88-1.45),he difference between the two was statistically significant(Z=-9.497,P<0.001).4.In the first serum MP-IgM and double serum MP antibody negative groups,the increase in the percentage of routine blood platelet counts was 65.52%,which was significantly lower than the 93.62%of the double serum MP antibody positive group.The difference was statistically significant(P<0.001).Conclusion:1.The first serum MP-IgM and the double serum MP antibodies were negative,more common in younger age groups,and mainly?1 year old infants.2.First MP IgM and double serum MP antibody all negative group of children,the comparison of peripheral blood lymphocyte subsets and double routine blood platelet count dynamic tip percentage increase immune system development is not perfect and existing immunity by the inhibition of children,can show the MP infection after infection with specific antibodies cannot normal expression and rising phenomenon. |
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