Enzyme-linked immunosorbent assay ( ELISA) was applied to detect the antibody against CoxA16 and EV71 among 0~14 age groups. In 1 000 cases of children, the total positive rate of anti-EV71 IgM was 19. 9%, the total positive rate of anti-EV71 IgG was 47. 7%, the total positive rate of anti-CoxA16 IgM was 22. 8%, the to-tal positive rate of anti-CoxA16 IgG was 51. 3%. There was a negative correlation between positivity for EV71 IgM and positivity for CoxA16 IgM(χ2 =2. 794,P>0. 05). There was also a negative correlation between positivity for EV71 IgG and positivity for CoxA16 IgG(χ2 =2. 793,P>0. 05). The positive rate of IgG antibody against CoxA16 and EV71 was higher in neonatal group in which anti-EV71 IgG was 41 . 5% and anti-CoxA16 IgG was 49 . 5%. The lowest positive rate of IgG antibody against CoxA16 and EV71 was in infant group in which anti-EV71 IgG was 38. 0% and anti-CoxA16 IgG was 43. 5%. Except for neonatal group,the positive rate of IgG antibody against Cox-A16 and EV71 increased gradually with the age growth, there were statistical differences among the age groups (χ2=27. 04 and 19. 98,P<0. 01). With the age growth,the positive rate of IgM antibody against EV71 and CoxA16 increased,there were statistical differences among the age groups(χ2 =41. 12 and 37. 13,P<0. 01). There were not statistical differences between gender groups (χ2 =0. 51,1. 77,0. 36 and 2. 12,P>0. 05).

Objective To investigate the diagnostic value of neutrophil CD64 expression for bacterial infection in children . Methods 168 children were divided into the infection group (n=133) and non-infection group(n=35) according to the results of bacterial culture .CD64 reagents from Beckman company and BD company were employed to detect CD 64 in neutrophils and lym-phocytes .Flow cytometry was used to assay their average fluorescence intensity and the CD 64 indexes were calculated .Receiver operator characteristic(ROC) curve was adopted to analyze the diagnostic performance of CD64 indexes .Results Average fluores-cence intensity of neutrophil CD64 detected by CD64 reagents from Beckman company and BD company were 46 .16 ± 29 .21 , 28 .11 ± 17 .90 ,respectively ,with statistical difference(P<0 .01) ,and their CD64 indexes were 4 .98 ± 3 .09 ,4 .89 ± 3 .53 ,respective-ly ,without statistical difference(P>0 .05) .The CD64 index of children in infection group (7 .06 ± 4 .20) was higher than that in the non-infection group(2 .93 ± 0 .79)(P<0 .01) .When CD64 index cut-off point was 3 .37 ,the sensitivity and specificity for bacterial infection diagnosis of CD64 were 93 .2% and 82 .9% ,respectively .Conclusion CD64 index may be served as an effective indicator for early diagnosis of bacterial infection in children .

Objective To study the value of MP-DNA in the early diagnosis of pneumonia by analyzing the result of MP-DNA in bronchoalveolar lavage fluid(BALF) and MP-IgM antibodies in serum.Methods 103 hospitalized children were detected for MP-DNA in BALF(positive:DNA copies ＞ 102/ml) and MP-IgM antibodies in serum.Results The MP-DNA positive in BALF and the MP-IgM positive in serum in children with pneumoina were significantly higher than those in children with foreign body in bronchus (x2 =13.00,4.11,all P ＜ 0.05).33.01％ of 103 children was MP-DNA positive,19.43％ of 103 children was MP-IgM positive.The MP-DNA positive in BALF was significantly higher than the MP-IgM positive in serum(x2 =4.92,P ＜0.05).Conclusion The samples of MP-DNA in BALF were collected more difficulty than the samples of MP-IgM in serum,but the detection of MP-DNA can avoid the false negative,which may be of value in the diagnosis and therapy of MPP.

Objective To detect the cellular immune and humoral immune function in infants with Mycoplasma pneumoniae(Mp) infection,and to study its change regularity and the related clinical indexes.Methods The peripheral blood samples were collected from infantile patients with MP infection.The expression of CD3,CD4 and CD8 on the surface of T lymphocyte(T-cell)were detec-ted by the flow cytometry and the concentrations of IgG,IgA and IgM in serum were detected by the automatic biochemistry analy-zer.At the same time the normal control group was set up.Results The proportion of CD3 + and CD4 + T-cell,CD4 +/CD8 + ratio and the concentration of IgG,IgA in the patient group were significantly lower than those in the control group,while the concentra-tion of IgM in the patient group were significantly lower than those in the normal children.The concentration of IgM was higher than that in the normal children;the proportion of peripheral blood CD4 + T-cell and the concentration of IgM in the low-copy group were significantly lower than those in the high-copy group.Conclusion The immune status in children with Mp infection has obvi-ous change.The immune function of T-cell is suppressed.the humoral immune function has certain turbulence.

Objective:This study evaluates the performance of chemiluminescence assay, which is designed to detect Hepatitis D Virus (HDV) Immunoglobulin G (IgG) antibodies.Methods:A comparative analysis was conducted among chemiluminescence anti-HDV IgG reagent, the magnetic particle-based domestic reagent A and domestic reagent B, and the Robo Gene HDV RNA kit, using 1909 HBsAg-positive plasma samples. This comparison aimed to delineate clinical specificity and detection accuracy. The anti-HDV IgG reagent precision was assessed at three different concentration levels following the Clinical Laboratory Standards Institute EP5-A2 guidelines. The specificity of the assay was validated using 200 HAV IgM positive, 545 HBsAg-positive but anti-HDV IgG-negative, 350 anti HCV positive plasma samples and 200 healthy human blood samples. Additionally, a concordance study was conducted with 545 HBsAg-positive and 37 anti-HDV IgG-positive plasma samples, comparing the anti-HDV IgG reagent against reagent A.Results:1 909 HBsAg-positive plasma samples were tested using 3 anti HDV IgG reagent and 1 HDV RNA reagent, 19 samples were identified as anti-HDV IgG-positive. The anti-HDV IgG demonstrated superior accuracy and specificity. The assay exhibited excellent precision, with intra-assay coefficient of variation (CV) values ranging from 1.57% to 4.30%, and inter-assay CV values between 1.71% and 4.67% for detecting samples at high, medium, and low concentration levels. Concordance with Reagent A showed consistent results in both positive and negative detections.Conclusion:In this study, the anti-HDV IgG reagent (chemiluminescence method) displayed outstanding specificity in detecting clinical samples and exhibited a high conformity rate with commercialized reagents, making it potentially suitable for screening anti-HDV IgG in HBsAg-positive samples.

Objective:This study aims to evaluate the quality and explore the preliminary clinical applications of a domestically developed hepatitis D virus nucleic acid quantification reagent (abbreviated as"domestic HDV RNA reagent").Methods:The sensitivity and accuracy of the reagent were evaluated in accordance with the WHO HDV RNA international standard, employing the Bio-Rad CFX Opus 96 real-time fluorescence quantitative PCR analysis system. Serial dilutions of pseudo-viruses or cell culture-derived virus were used to determine the linear range of the domestic HDV RNA reagent. Specificity was assessed using positive samples of HAV, HBV, HCV infection, and HEV national reference materials. Precision was evaluated with samples at both high and low concentrations. In a comparative analysis, 30 HDV IgG positive samples were tested using both the domestic HDV RNA reagent and the RoboGene HDV RNA kit based on the ABI 7500 FAST DX system. The Pearson correlation coefficient (r) was used to examine the correlation between the two reagents.Results:The domestic HDV RNA reagent demonstrated a high sensitivity of up to 6 IU/ml, consistent with that of the comparator reagent. The calibration curve for WHO HDV RNA standards had a slope of -3.286, with an amplification efficiency of 101.6%. The linear detection range spanned from 10 to 10 8 IU/ml for eight HDV genotypes. The domestic HDV RNA reagent exhibited exceptional specificity, without cross-reactivity observed with HAV, HBV, HCV, or HEV. Accuracy assessments at five concentration levels met the required standards, with intra-assay precision coefficient of variation ( CV) ranging from 1.20% to 4.20%, and inter-assay precision CV from 1.20% to 7.90%. The detection results for HDV IgG positive samples were highly correlated with the comparator reagent ( r=0.984, P<0.001), achieving a diagnostic accuracy of 100% compared to sequencing results. Conclusion:In this study, the domestic HDV RNA reagent possesses excellent specificity, accuracy, precision, and a broad linear range, attaining a sensitivity level on par with international reagents of the same type.