Vitamin D is a fat-soluble steroid hormone, which has a wide range of physiological effects in human body.It has been found that vitamin D not only plays an important role in diseases of skeletal system, cardiovascular system and immune system, but also participates in the occurrence and development of infectious diseases.In infectious diseases, vitamin D regulates innate and adaptive immune responses by regulating a variety of immune cells and cytokines, and also plays a bactericidal role by mediating the expression of antimicrobial peptides.This paper briefly introduced the relationship between vitamin D deficiency and infectious diseases in children.

Objective:To analyze the clinical features of convulsion in rotavirus enteritis and the risk factors of multiple convulsion.Methods:The clinical data of children with rotavirus enteritis complicated with convulsion admitted to Xi'an Children's Hospital from January 2018 to March 2021 were retrospectively analyzed. According to whether there was fever during convulsion, they were divided into febrile seizure (FS) group and afebrile seizure (AFS) group.Results:A total of 274 children with rotavirus enteritis accompanied by convulsion were enrolled. The male to female ratio was 2.26∶1 in the FS group, while the male to female ratio was 1∶1.1 in the AFS group. The median number of vomiting in the AFS group was higher than that in the FS group: 4(2, 6) times per day vs. 2(1, 5) times per day, P<0.01. One convulsion was dominant in the FS group (80.68%), and more than two convulsions in the AFS group (62.90%). In the FS group, 60.23% of convulsions occurred on the first day of the course of disease, while in the AFS group,79.57% of convulsions mainly occurred on the second and third day of the course of disease. There was no statistical difference in duration of convulsion and overall course of disease between the two groups ( P>0.05). The median of hypersensitive C-reactive protein (CRP) and procalcitonin (PCT) in FS group were higher than those in AFS group: 5.52(1.45, 15.50) mg/L vs. 0.98(0.50, 3.17) mg/L, 0.17(0.07, 0.46) μg/L vs. 0.06(0.05, 0.15) μg/L. The median of alanine aminotransferase (ALT), aspartate aminotransferase (AST), uric acid (UA) and creatine kinase isoenzyme(CK-MB) in the AFS group were higher than those in the FS group: 28.00(21.00, 34.25) U/L vs. 25.00(19.00, 31.00) U/L, 53.00(45.00, 62.00) U/L vs. 50.00(40.00, 58.00) U/L, 390.00(296.00, 474.25) μmol/L vs. 331.00(250.00, 399.75) μmol/L, 67.00(49.75, 94.25) U/L vs. 59.50(37.25, 78.75) U/L, the differences were statistically significant ( P<0.05). The median age and the median of UA levels in ≥3 convulsions group were higher than those in ≤2 convulsions group: 21(18, 26) months vs. 18(15, 21) months, 411.00(296.50, 496.50) μmol/L vs. 364.00(278.00, 440.50) μmol/L, while the median of serum Na +, the mean value of serum Cl - in the ≥3 convulsions group were lower than those in the ≤2 convulsions group: 135.50(133.75, 137.25) mmol/L vs. 136.60(134.50, 138.20) mmol/L, (103.76 ± 3.26) mmol/L vs. (105.08 ± 4.26) mmol/L, the differences were statistically significant ( P<0.05). The age ≥18 months in children with rotavirus enteritis and convulsion ( OR = 3.359, P = 0.002, 95% CI 1.544 - 7.307) and the serum Cl - < 104.8 mmol/L ( OR = 2.17, P = 0.019, 95% CI 1.138 - 4.138) had an increased risk of convulsions ≥3 times during the course of rotavirus enteritis. Conclusions:Rotavirus enteritis FS mostly occurred on the first day of the course of disease, most of them had convulsion once, hs-CRP and PCT were relatively high. In AFS, convulsions were more than 2 times, and occurred on the 2nd and 3rd day of the course of disease. ALT, AST and UA were relatively high. Children with age ≥18 months and serum Cl - < 104.8 mmol/L had an increased risk of convulsions ≥3 times during the course of the disease.

Objective:To explore the relationship of Vitamin A and Vitamin D with the incidence and severity of hand, foot and mouth disease(HFMD) as well as with the anti-viral immune index interferon-α(INF-α), and to investigate the role of Vitamin A and Vitamin D in HFMD.Methods:A total of 305 children with Coxsackie virus A6(CA6) HFMD admitted at Xi′an Children′s Hospital from January 2017 to December 2018 were enrolled in the study.One hundred healthy children whose gender and age matched with those of children in the case group were selected as the healthy control group.Serum Vitamin A levels were detected by high performance liquid chromatography.Enzyme-linked immunosorbent assay was used to detect the levels of Vitamin D and IFN-α, and the correlation of the levels of Vitamin A and Vitamin D with the severity of HFMD was analyzed.Results:The levels of serum Vitamin A[(0.96±0.39) mg/mol] and Vitamin D [(42.14±15.13) μg/L] in patients with CA6 HFMD were lower than those of the healthy control group[(1.26±0.29) mg/mol, (49.63±8.86) μg/L], and the differences were statistically significant(all P<0.05). Logistic multivariate regression analysis showed that WBC>15×10 9/L, blood sugar>8.3 mmol/L, the deficiency of Vitamin A level and Vitamin D level were all risk factors for severe CA6 HFMD in children( OR=2.303, 4.622, 7.346, 5.211; all P<0.05). According to the receiver operating characteristic curve analysis, the Youden index was the largest at a Vitamin A level of 0.725 mg/mol, and the corresponding sensitivity and specificity were 82.0% and 64.8%, respectively.When Vitamin D level was 32.88 μg/L, the Youden index was the highest, and the sensitivity and specificity were 84.5% and 61.9%, respectively.The serum IFN-α concentration of patients with CA6 HFMD [(84.44±26.28) ng/L] was higher than that of the healthy control group [(36.58±14.39) ng/L], and the difference was statistically significant( P<0.05). In addition, the serum IFN-α concentration in severe HFMD children [(71.48±18.34) ng/L] was significantly lower than that in the common HFMD children [(91.25±27.27) ng/L], and the difference was statistically significant( P<0.05). The results of correlation analysis showed that serum IFN-α concentration is positively correlated with Vitamin A and Vitamin D levels ( r=0.783, 0.239; all P<0.001). Conclusions:The levels of serum Vitamin A and Vitamin D decreased in children with HFMD.WBC>15×10 9/L, blood sugar>8.3 mmol/L, the deficiency of Vitamin A level and Vitamin D level are related to severe HFMD.The se-rum IFN-α concentration is positively correlated with the levels of Vitamin A and Vitamin D. The deficiency of Vitamin A and Vitamin D is one of the early warning factors of severe HFMD.

Objective To analyze the changes of levels of plasma diamine oxidase(DAO),D-lactate and endotoxin in children with different severity of hand-foot-mouth disease(HFMD),explore the changes of the function of intestinal mucosal barrier in children with HFMD,and investigate the sensitivity and early warning effect of the indexes described previously on the damage of intestinal mucosal barrier in children with severe HFMD.Methods Four hundred and seventy inpatient children in Xi′an Children′s Hospital from March 2016 to June 2017 suffered from HFMD were selected as the study group,and one hundred healthy children were selected as the control group in the same period.Children in the study group were divided into common group(n=300),severe group(n=110)and critical condition group(n=60)according to the sever-ity of the disease.The levels of plasma DAO,D-lactate and endotoxin from children in each group were com-pared.Results The plasma D-lactate level of the children in the study group was significantly higher than that in the control group,and the difference was statistically significant[(27.670 ± 6.273)mg/L vs.(25.585 ± 5.177)mg/L;t=3.515,P<0.05];but the differences of DAO and endotoxin compared with the control group were not statistically significant[(3.205 ± 0.956)U/L vs.(3.135 ± 0.884)U/L,P>0.05;(1.186 ± 0.486)U/L vs.(1.091 ± 0.494)U/L,P>0.05].The comparison of multiple groups showed that the differ-ence of plasma D-lactate levels was statistically significant(F=33.488,P<0.05),while the differences of the levels of DAO and endotoxin were not statistically significant among different severity groups(F=0.709, F=2.296,P>0.05).The level of plasma D-lactate in critical condition group[(32.502 ± 4.756)mg/L]was significantly higher than those in the severe group[(29.872 ± 6.468)mg/L],the common group [(25.896 ± 5.691)mg/L] and the control group,and the differences were statistically significant(P <0.05);the difference in plasma D-lactate levels in the severe and non-severe groups was statistically signifi-cant(P<0.05),and the difference between common group and control group was not statistically significant (P>0.05).Conclusion The intestinal permeability and intestinal mucosal barrier are impaired in children with severe and critical HFMD.Plasma D-lactate is significantly elevated in the early stage of intestinal barri-er injury.Compared with DAO and endotoxin,D-lactate is a sensitive and early warning index suggesting the impaired intestinal mucosal barrier function in severe and critical cases of HFMD.

Objective:To summarize the clinical characteristics, causes of misdiagnosis and preventive measures of infectious mononucleosis (IM) in children, and to improve the ability of clinicians in early diagnosis of IM in children.Methods:The clinical data of 468 children with IM in Xi′an Children′s Hospital from January 2018 to December 2021 were retrospectively analyzed, including general situation, disease onset, diagnosis and misdiagnosis.Results:Among the 468 children, 33 cases were clinically diagnosed and 435 cases were a definitely diagnosed; 281 males (60.04%) and 187 females (39.96%); the incidence rate was highest in preschool children (43.80%, 205/468) and in autumn (33.12%, 155/468). The first symptoms were fever (52.99%, 248/468), eyelid edema (15.38%,72/468) and neck mass (14.96%, 70/468). The fever rate was 90.38% (423/468), and the median time of first fever appearance was on the first (first, second) day of disease course, and the median duration of fever was 6 (4, 8) d. The median time of first visit was on the third (first, fifth) day of disease course, and the time of diagnosis was on the seventh (fifth, ninth) day of disease course. Blood routine examination showed that the proportion of white blood cell count increased was 51.92% (243/468), the proportion of lymphocytes increased was 61.75% (289/468), and the proportion of abnormal lymphocytes increased (≥10%) in peripheral blood was 58.97% (276/468). The lymphocyte subsets of 364 children were detected, the rate of helper T lymphocytes (Th cells) decreased was 80.22% (292/364), the rate of suppressor T lymphocytes (Ts cells) increased was 99.45% (362/364), the value and decreased rate of Th cells/Ts cells were 0.24 (0.16, 0.40) and 100.00% (364/364), rate of B lymphocytes decreased was 93.96% (342/364), rates of natural killer cells decreased and increased were 35.16% (128/364) and 0.55% (2/364). The misdiagnosis rate was 55.13% (258/468), and the misdiagnosis time was on the fifth (fourth, seventh) day of disease course. Among the 258 misdiagnosed children, 105 cases (40.70%) were misdiagnosed as upper respiratory tract infection, 65 cases (25.19%) as acute suppurative tonsillitis, 27 cases (10.47%) as acute cervical lymphadenitis or neck mass.Conclusions:Due to the complex and diverse clinical manifestations of IM in children, it is easy to be misdiagnosed in the early stage of the disease. So, it is necessary for clinicians to master the clinical characteristics of IM in children, constantly improve the level of diagnosis and treatment, and reduce the misdiagnosis rate.

Objective To analyze the clinical characteristics in children with pertussis,and to provide a scientific basis for treatment of pertussis.Methods Retrospective analysis of general data,symptoms,signs,auxiliary examinations,treatment and prognosis was performed on the patients with pediatric pertussis in Xi'an from January 2015 to December 2016;the epidemiological data were analyzed by using descriptive approach.Results In a total of 857 patients with pertussis,there were 469 males and 388 females (the gender ratio of 1.21 ∶ 1.00),183 cases (21.3％) from the urban areas and 674 cases (78.7％) from the rural areas.The cases were reported throughout the year,indicating 2 peak times of onset:355 cases (41.5％) from July to September and 218 cases (25.4％) from February to April.And 473 cases (55.2％) were younger than 6 months;479 cases (55.9％) were inoculated with diphtheria,tetanus and pertussis combined vaccine(DTP) vaccine;492 cases (57.4％) were exposed to their family members who coughed at that time.Cough was the main symptom,and the median duration of pertussis from onset to diagnosis was 20 days.Concomitant symptoms included spasmodic cough was relieved in 836 cases (97.5 ％),facial suffusion in 806 cases (94.0％),peri-oral cyanosis in 308 cases (35.9％),asthma in 269 cases (31.4％),crow-like echo in 248 cases (28.9％),and apnea in 46 cases (5.4％);pulmonary moist rale was found by check-up in 761 cases (88.8％),and fever was observed in 159 cases (18.5％).The increased proportion of the peripheral blood lymphocytes was found in 702 cases (81.9％),the increased total count of leukocytes in 505 cases (58.9％),the increased procalcitonin(PCT) in 36 cases (4.2％) and the elevated level of high sensitivity C reactive protein(hsCRP) in 17 cases (2.0％);pneumonia was suggested by chest radiography in 673 cases (78.5％);in the blood-gas analysis,hypoxemia was suggested in 50 cases (5.8％) and respiratory failure in 9 cases (1.1％).In the 857 patients with pertussis,59 cases (6.9％) were with severe-type pertussis.At 1 week of the treatment,no spasmodic cough was reported in 515 cases (60.1％) and obviously relieved spasmodic cough in 198 cases (23.1％),and no deaths occurred.Conclusions The cases of pertussis occur throughout the year in Xi'an,predominately from July to September and February to April.A higher incidence is reported in the rural areas,compared with the urban areas,particularly in those younger than 6 months with incomplete DTP vaccination,who usually have severe conditions.In many cases,those with pediatric pertussis are infected by family members;most of them have spasmodic cough with good prognosis,without typical clinical signs.

Objective To detect the plasma calcitonin gene-related peptide ( CGRP ) in children with enterovirus 71(EV71) infected hand foot and mouth disease(HFMD),and explore the relationship be-tween CGRP and the severity of EV71 infected HFMD. Methods Two hundred children with EV71 infected HFMD in Xi'an Children's Hospital from January 2017 to December 2017 were selected as the research group,and 50 healthy children were selected as control group in the same period. According to the severity of the disease,the research group was divided into the mild group (n=142) and the severe group (n=58). The level of plasma CGRP was detected by ELISA. Results In acute stage,the level of CGRP in children with EV71 infected HFMD was lower than that in control group, and the difference was statistically significant (t=4. 235,P<0. 001). The level of CGRP in acute stage in severe group[(29. 90 ± 5. 10)pg/ml] was sig-nificantly lower than that of the mild group[(35. 51 ± 5. 48)pg/ml],and the difference was statistically sig-nificant (t=6. 615,P=0. 001). The level of CGRP in mild group[(35. 51 ± 5. 48)pg/ml] was slightly low-er than that of the control group[(36. 63 ± 5. 65)pg/ml],but the difference was insignificant (t=1. 120, P=0. 086). In recovery stage,the level of CGRP in the severe group was obviously higher than that in the acute stage(t=5. 924,P=0. 003). According to the ROC curve of CGRP in mild and severe EV71 infected HFMD,the critical value of CGRP in mild and severe HFMD was 28. 12 pg/ml, and the sensitivity was 80. 0％ and the specificity was 50. 0％. Conclusion The CGRP is associated with the progression of EV71 HFMD,and when CGRP is lower than 28. 12 pg/ml,suggesting the possibility of severe HFMD. The decrease of plasma CGRP may be a risk factor for the progression of EV71 infected HFMD.