OBJECTIVEThe development of recurrent respiratory tract infection (RRTI) is related to vitamin A deficiency and immune function abnormality in children. This study examined serum levels of IgG subclasses and vitamin A in children with recurrent respiratory tract infection.

METHODSSerum IgG subclasses levels (IgG1, IgG2, IgG3, IgG4) were detected using ELISA and serum vitamin A levels were detected using high performance liquid chromatography-Miller method in 80 children with RRTI (ranged from 2-10 years old). The values were compared with those from 80 aged-matched healthy children.

RESULTSSerum levels of IgG2 (1.52 +/- 0.18 g/L) and IgG4 (0.22 +/- 0.12 g/L) in children with RRTI were significantly lower than controls (IgG2: 2.23 +/- 0.08 g/L; IgG4: 0.28 +/- 0.01 g/L) (P < 0.05). Serum vitamin A levels in children with RRTI were also significantly lower than controls (1.16 +/- 0.22 micromol/L vs 1.56 +/- 0.12 micromol/L; P < 0.05). IgG2 and IgG4 deficiency (27%) was the most common in 22 RRTI children with vitamin A deficiency.

CONCLUSIONSSerum levels of IgG subclasses, IgG2 and IgG4, and vitamin A decrease in children with RRTI. There might be some relationship between the decreased IgG2 and IgG4 levels and vitamin A deficiency.

Child ; Child, Preschool ; Female ; Humans ; Immunoglobulin G ; blood ; classification ; Male ; Respiratory Tract Infections ; blood ; Vitamin A ; blood

OBJECTIVETo explore the relationship between the major allergens of 6 common allergic foods and IgA nephropathy.

METHODSA sensitive sandwich enzyme-linked immunosorbent assay (ELISA) was used to detect the serum levels of food-specific IgA1, IgG and IgE in 31 patients with IgA nephropathy and 80 healthy volunteers. All the patients were examined for a history of food allergy using a questionnaire.

RESULTSSerum levels of IgA1 and IgG against the major allergens of the 6 common allergic foods were significantly higher in patients with IgA nephropathy than in healthy volunteers (P<0.05). There was no detectable food-specific IgE antibodies in the two groups. No patients had a clear history of food allergy. All the patients with increased IgG levels specific to 4 or more foods simultaneously had proteinuria.

CONCLUSIONSSome foods especially the highly allergic ones may participate in the pathogenesis and progression of IgA nephropathy.

Adult ; Antibody Specificity ; Case-Control Studies ; Female ; Food Hypersensitivity ; classification ; immunology ; Glomerulonephritis, IGA ; blood ; immunology ; Humans ; Immunoglobulin A ; blood ; Immunoglobulin E ; blood ; Immunoglobulin G ; blood ; Male ; Young Adult

OBJECTIVE: To explore the role of IL-21 in the pathogenesis of myasthenia gravis (MG) and its influence on the the class switch of anti-AChR antibodies. METHODS: Blood was taken from 26 patients and 18 healthy controls, and the expression of IL-21R mRNA in peripheral blood mononuclear cells (PBMCs) was detected by RT-PCR. The expression of IL-21R on B lymphocytes was measured by flow cytometry, while the concentrations of serum IL-21 and the levels of anti-AChR-IgG and its isotype IgG(1), IgG(2), and IgG(3) were tested by ELISA. RESULTS: The serum concentration of IL-21 in the MG group was higher than that in the control group (31.686±8.499 pg/mL, 15.147±6.366 pg/mL) and the difference was significant (P<0.01). IL-21R mRNA expressed on PBMCs in the MG group was higher than that in the control group (0.139±0.052, 0.101±0.022), and the difference was significant (P<0.05). There was no difference between ocular MG and generalized MG subgroup (P>0.05). Compared with the control group, the expression of IL-21R on B lymphocytes also increased in the MG group (P<0.05). In the anti-AChR-Ab positive MG group, the serum concentration of IL-21 showed positive correlation with anti-AChR-IgG(P<0.05),but no correlation with its isotype IgG(1), IgG(2), and IgG(3), respectively(P>0.05). Expression of IL-21R mRNA in the PBMCs showed no correlation with the level of serum anti-AChR-IgG and its isotype IgG(1), IgG(2), and IgG(3), respectively(P>0.05); however the expression of IL-21R in B lymphocytes showed positive correlation with anti-AChR-IgG and it's isotype IgG(1) and IgG(3) (P<0.05,P<0.01,P<0.05), but no correlation with IgG(2) (P>0.05). CONCLUSION IL-21 might induce the class switch of anti-AChR antibodies to IgG(1) and IgG(3) isotype through IL-21R on B lymphocytes which promotes the pathogenesis of the MG.
Adolescent ; Adult ; Autoantibodies ; classification ; immunology ; Female ; Humans ; Immunoglobulin Class Switching ; immunology ; Immunoglobulin G ; classification ; Interleukins ; blood ; genetics ; Male ; Middle Aged ; Myasthenia Gravis ; blood ; immunology ; RNA, Messenger ; blood ; genetics ; Receptors, Cholinergic ; immunology ; Receptors, Interleukin-21 ; blood ; genetics ; Young Adult

PURPOSE: A possible involvement of autoimmune mechanism in the pathogenesis of bronchial asthma has been proposed. Recently, alpha-enolase protein was identified as a major autoantigen recognized by circulating IgG autoantibodies in patients with severe asthma. To evaluate a possible pathogenetic significance of these autoantibodies in severe asthma, isotype (IgG, IgA, IgM, and IgE) and IgG subclass (IgG1, IgG2, IgG3, and IgG4) distributions of autoantibodies to recombinant human alpha-enolase protein were analyzed. PATIENTS AND METHODS: We examined serum samples from 10 patients with severe asthma and 7 patients with mild-to-moderate asthma, and 5 healthy controls by immunoblot analysis. Severe asthma was defined as patients having at least 1 severe asthmatic exacerbation requiring an emergency department visit or admission in the last year despite continuous typical therapies. RESULTS: IgG1 was the predominant IgG subclass antibody response to alpha-enolase protein in patients with severe asthma. IgG1 autoantibody to alpha-enolase protein was detected in 7 of 10 patients with severe asthma (70%), 1 of 7 patients with mild-to-moderate asthma (14.3%), and none of 5 healthy controls (0%) (chi-square test; p < 0.05). IgA, IgM, and IgE autoantibodies to alpha-enolase protein could not be detected in patients with severe asthma. CONCLUSION: IgG1 subclass was the predominant type of autoantibody response to alpha-enolase protein in patients with severe asthma, suggests a possibility of IgG1 autoantibody- mediated complement activation in the pathogenesis of severe asthma.
Adult ; Aged ; Asthma/*enzymology/*immunology ; Autoantibodies/*blood/classification ; Autoantigens ; Case-Control Studies ; Complement Activation ; Female ; Humans ; Immunoglobulin G/blood/classification ; Immunoglobulin Isotypes/blood ; Male ; Middle Aged ; Phosphopyruvate Hydratase/*immunology ; Recombinant Proteins/immunology ; Young Adult

OBJECTIVETo investigate status of infection with severe acute respiratory syndrome coronovirus (SARS-CoV) in traders of wild animals wholesale markets in Guangzhou.

METHODSSerum antibody against SARS-CoV IgG was determined cross-sectionally and symptoms of respiratory infection were investigated retrospectively for part of traders of three wholesale markets for wild animals in Guangzhou.

RESULTSOverall rate of infection with SARS-CoV in 635 traders was 16.69%, varying in three different markets. Infection rate in market A mainly engaging in wild animals ranked the highest of 25.61%, significantly higher than that in markets B and C engaging in domestic fowls and snakes. Infection rate in traders only engaging in civet cats was 58.54%, significantly higher than that in traders engaging in snakes only (9.46%). In market A, infection rate varied in different persons, 59.34%, 20.59%, 16.00%, 15.22%, 10.40% and 9.68% in traders engaging in wild animals, managers, children of the traders, traders engaging in domestic fowls, traders engaging in snakes, and traders engaging in frozen food, respectively, in a decreasing pattern as their contact opportunities. During the period of SARS epidemic, detection rate of SARS-CoV antibody in people with symptoms of acute respiratory infection was higher (30.70%) than that in those without such symptoms (20.08%). Prevalence of symptoms of acute upper respiratory infection in people with positive antibody against SARS-CoV was higher (49.28%) than that in those with negative antibody (30.35%).

CONCLUSIONSInfection with SARS-CoV in traders of animal markets possibly related to their direct exposure to wild animals, particularly to civet cats. During the period of SARS epidemic, some of the traders did infect with SARS-CoV, but they were neglected due to clinically inapparent manifestations.

Animals ; Antibodies, Viral ; blood ; China ; Contact Tracing ; Family ; Humans ; Immunoglobulin G ; blood ; Occupational Exposure ; Occupations ; classification ; Retrospective Studies ; SARS Virus ; immunology ; Severe Acute Respiratory Syndrome ; immunology ; transmission

OBJECTIVETo understand antibody responses to and RNA sequences of Hantavirus in patients with hemorrhagic fever renal syndrome (HFRS) in Yantai areas and to demonstrate the type of the prevalent viruses caused HFRS.

METHODSSerum specimens collected at acute and convalescent stages from 90 patients with HFRS and IgM and IgG antibodies against Hantavirus were detected with ELISA, and cross plaque reduction neutralizing tests were performed to detect neutralizing antibody. Viral RNA was extracted from the patients? sera by using Trizol method and nested PCR was utilized to amplify the specific segments of the viral cDNA and the products of the PCR were TA cloned and then the nucleotide sequences were determined.

RESULTSThe IgM antibody was positive in 82.2% (88/107) of the patients while the IgG antibody was positive in 85.7% (66/77) of the patients. Both the serologic and sequence analyses demonstrated that the epidemic of HFRS in Yantai areas was caused by mixed types of Hantavirus. The prevalent strains of Hantavirus had higher homology with the strains isolated in Korea than with those isolated previously in China.

CONCLUSIONSThe serologic and sequencing analyses indicated that the epidemic of HFRS in Yantai areas was caused by mixed types of Hantavirus dominated by type SEO.

Antibodies, Viral ; blood ; Base Sequence ; China ; DNA, Viral ; analysis ; Disease Reservoirs ; Hantaan virus ; classification ; genetics ; immunology ; Hemorrhagic Fever with Renal Syndrome ; virology ; Humans ; Immunoglobulin G ; blood ; Immunoglobulin M ; blood ; Molecular Sequence Data ; Sequence Analysis, DNA ; Serotyping

This study was performed to characterize the humoral immune responses with isotype profiles in Mycobacterium tuberculosis infection. PPD-Specific IgG and IgG subclasses were measured using ELISA in 212 patients with pulmonary tuberculosis. The values of PPD-specific IgG were significantly higher in pulmonary tuberculosis patients than those in the control group, and were correlated to the severity of illness (P < 0.01). The specificity and sensitivity of ELISA for IgG antibodies were 1.0 and 0.81, respectively as determined in 212 sera from tuberculosis patients and 44 from healthy controls. The positive predictive value was 1.0 (171/171), while negative predictive value was 0.52 (44/85). The values of PPD-specific IgG were significantly decreased after 2-4 months of treatment. Among the moderately and far advanced pulmonary tuberculosis patients, the values of PPD-specific IgG were significantly decreased in responders after 6 months of treatment. However, PPD-specific IgG in nonresponders was increased (P < 0.01). PPD-specific IgG subclass responses were evident to all four IgG subclasses. No changes of isotype response according to the severity of the disease were observed.
Adolescent ; Adult ; Aged ; Child ; Child, Preschool ; Enzyme-Linked Immunosorbent Assay ; Female ; Humans ; Immunoglobulin G/*blood/classification ; Infant ; Infant, Newborn ; Male ; Middle Aged ; Tuberculin/*immunology ; Tuberculosis, Pulmonary/*immunology

Animals ; Antibodies, Viral ; blood ; Cytokines ; blood ; Female ; Immunoglobulin G ; blood ; classification ; Membrane Glycoproteins ; immunology ; Mice ; Mice, Inbred BALB C ; Recombinant Proteins ; immunology ; Severe Acute Respiratory Syndrome ; immunology ; Spike Glycoprotein, Coronavirus ; T-Lymphocyte Subsets ; immunology ; Viral Envelope Proteins ; immunology

OBJECTIVETo characterize the immune response induced by SAG1 encoding plasmid combined with IL-2 gene adjuvant in mice and to assess the protective effect of this vaccination against toxoplasmosis.

METHODSMice were co-injected intramuscularly with plasmid encoding Toxoplasma gondii SAG1 plus murine IL-2 expression vector at a dose of 100 microg. Booster immunizations were employed 2 more times at 3-week interval. As controls, mice were inoculated with PBS or empty plasmid pcDNA3. Humoral and cellular responses were assayed using ELISA for the determination of Ab, Ab isotype and IFN-gamma, as well as IL-4. To detect the integration and dissemination of DNA in the injected mice, PCR and in situ hybridization were performed. All mice were then infected with highly virulent RH tachyzoites of Toxoplasma gondii intraperitoneally.

RESULTSSignificant increases in specific IgG levels were observed in mice after immunization three times with SAG1 expression plasmid. With respect to the IgG isotype, co-inoculation of IL-2 expression plasmid enhanced the level of IgG2a and the production of IFN-gamma. Challenging mice by vaccinating with combined plasmids with RH tachyzoites resulted in prolonged survival.

CONCLUSIONHumoral and cytokine responses elicited by SAG1 DNA immunization can be modulated by co-inoculation with IL-2 expression plasmid. The use of DNA vaccine in combination with an appropriate cytokine gene to prevent T. gondii infection warrants further investigation.

Animals ; Antibodies, Protozoan ; blood ; Antigens, Protozoan ; Cytokines ; biosynthesis ; Female ; Immunization ; Immunoglobulin G ; blood ; classification ; Interleukin-2 ; genetics ; Mice ; Protozoan Proteins ; genetics ; Protozoan Vaccines ; immunology ; Toxoplasma ; immunology ; Toxoplasmosis, Animal ; prevention & control ; Vaccines, DNA ; immunology

OBJECTIVESTo investigate HEV infection in swine and the genotype relationship between swine and human HEV.

METHODSAnti-HEV IgG antibody was detected in the sera of swine using enzyme linked immunoassay (EIA), and HEV RNA was amplified by reverse transcription nested polymerase chain reaction (RT-nPCR). The Vector NTI Suite 7 and TreeView softwares were used for nucleotide sequences phylogenetic analysis of HEV isolated from human and swine.

RESULTSThe anti-HEV IgG positive rate was 16.67% (18/108). Among the 18 anti-HEV IgG positive sera, 2 sequences (11.11%, called S18 and S43, respectively) of HEV ORF1 (102-387bp) were amplified, with the identity of 99% between them. They had 76% to 77%, 78%, 76% to 79%, 85% to 86%, 77%, 80%, 79% and 75% - 79% homology at the nucleotide level with human HEV genotypes 1 to 8, respectively. One (S18) of them was also amplified out in ORF2 region (5,994-6 297bp) and showed 76% to 78%, 74%, 74% to 77%, and 85% to 94% identity with human HEV genotypes 1 to 4 at the nucleotide level, respectively.

CONCLUSIONHEV sequences isolated from swine belong to human HEV genotype 4.

Animals ; Antibodies, Viral ; blood ; Base Sequence ; Hepatitis E ; transmission ; veterinary ; Hepatitis E virus ; classification ; genetics ; Immunoglobulin G ; blood ; Molecular Sequence Data ; RNA, Viral ; chemistry ; Reverse Transcriptase Polymerase Chain Reaction ; Swine ; Swine Diseases ; virology