Antimicrobial activity of human ß-defensins against lactic acid bacteria.

In this study, we evaluated the antimicrobial activity of human ß-defensin-1 (hBD-1), human ß-defensin-2 (hBD-2) and human ß-defensin-3 (hBD-3) against three internationally common probiotic strains of lactic acid bacterium. Our results indicated that hBD-1, hBD-2 and hBD-3 at the range of 0.08-10 µg/mL do not have obvious antimicrobial activity against these strains. Viability of Bifidobacterium longum JDM301 (B. longum JDM301), Bifidobacterium lactis HN019 (B. lactis HN019) and Lactobacillus rhamnosus GG (LGG) were still very high even at concentration of 10 µg hBD/mL. Then, we explored the mechanism of resistance by using carbonyl cyanide 3-chlorophenylhydrazone (CCCP) to inhibit efflux pumps. In the presence of CCCP, hBD-1, hBD-2 and hBD-3 exhibited enhanced antibacterial effect against B. longum JDM301 and B. lactis HN019, but not against LGG. Efflux pumps in B. longum JDM301 and B. lactis HN019 may partly contribute to their resistance to hBD-1, hBD-2, and hBD-3.

Epstein-Barr virus induces the differentiation of semi-mature dendritic cells from cord blood monocytes.

BACKGROUND: Epstein-Barr virus (EBV) is a tumorigenic virus which has effectively infected nearly all human beings with over 95% adult being seropositive. The persistence of latent EBV infection is not fully understood. Recent studies point towards a hypothesis of immune suppression and immune evasion involving regulatory T cells (Tregs) and dendritic cells (DCs). We sought to explore the mechanism of EBV suppression and immune evasion. METHODS: We compared the effects of EBV on cord blood (CB) and adult DCs differentiation and maturation including phenotype by flow cytometry, cytokine by ELISA and RT-PCR. And we evaluated the function of DC by co-culture DC and Treg by detection the expression of Foxp3, the phenotype and the cytokine profile of Tregs by flow cytometry. RESULTS: CB DCs derived from EBV-infected CB monocytes or from EBV-infected CB immature DCs (iDCs) displayed distinct phenotypes of "semi-mature" DCs with high expression of co-stimulatory molecules, such as CD40, CD80 and CD86 but low cytokine production, related to immune tolerance and homeostasis. While the EBV-infected adult iDCs resemble that of "pathogen-driven regulatory mature DCs" with high expression of co-stimulatory molecules, down-regulation of IL-12 secretion and up-regulation of IL-10 secretion, related to protection of host and immune evasion of pathogens. EBV infected cord blood monocytes-derived DCs drived Tregs development by driving the expression of Foxp3, increasing the expression of CTLA-4, decreasing the expression of GITR and promoted the generation of intracellular IL-2 and IL-10 by Tregs. CONCLUSION: Epstein-Barr virus induces the differentiation of semi-mature dendritic cells from cord blood monocytes. The differences between CB and adult DCs suggested that the developmental maturity of the cells may affect their immune responses to EBV infection.

Identification of sociodemographic and clinical factors associated with the levels of human ß-defensin-1 and human ß-defensin-2 in the human milk of Han Chinese.

Human milk provides infants with various immune molecules. The objective of the present study was to measure human ß-defensin-1 (hBD-1) and human ß-defensin-2 (hBD-2) levels in the colostrum and mature milk of healthy Han Chinese, to identify factors regulating milk hBD-1 and hBD-2 expression and to explore the potential protective effect of milk hBD-1 and hBD-2 on infants. A total of 100 mothers and their babies were recruited into the study. Sociodemographic characteristics and other factors were obtained by a questionnaire. Babies were followed up for a period of 6 months. Colostrum samples (n 100) and mature milk samples (n 82) were collected by hand expression. The hBD-1 and hBD-2 concentrations were measured by ELISA. The hBD-1 and hBD-2 levels differed in the colostrum and mature milk. In the colostrum, the concentration ranges of hBD-1 and hBD-2 were 1·04-12·81 µg/ml and 0·31-19·12 ng/ml, respectively. In mature milk, the hBD-1 and hBD-2 levels were 1·03-31·76 ng/ml and 52·65-182·29 pg/ml, respectively. Several independent factors influence their production. The multivariable analysis showed a strong association between pre-pregnancy BMI and hBD-1 levels in the colostrum (P=0·001), mode of delivery was significantly associated with hBD-2 levels in the colostrum (P=0·006) and gestational age was significantly associated with hBD-1 levels in mature milk (P= 0·010). During the first 6 months of life, the incidence rate of upper respiratory infection was found to be less in the high-colostrum hBD-1 group than in the low-colostrum hBD-1 group (χ²=4·995, P=0·025). The present study suggested that the abundance of hBD-1 in the colostrum may have a protective function against upper respiratory infection for infants younger than 6 months.

Clinical characteristics and genetic profiles of 44 patients with severe combined immunodeficiency (SCID): report from Shanghai, China (2004-2011).

Severe combined immunodeficiency (SCID), a rare type of genetic associated immune disorder, is poorly characterized in mainland China. We retrospectively reviewed 44 patients with SCID who received treatment from 2004 to 2011 in Shanghai, China, and herein summarize their clinical manifestations and immunological and preliminary genetic features. The male-to-female ratio was 10:1. Twenty five patients presented with X-SCID symptoms. Only one patient was diagnosed before the onset of symptoms due to positive family history. The mean time of delay in the diagnosis of X-SCID was 2.69 months (range, 0.5-8.67). Thirty-seven of the 44 patients died by the end of 2011 with the mean age of death being 7.87 months (range, 1.33-31). Six patients received hematopoietic stem cell transplantation (HSCT); only one of them survived, who was transplanted twice. The time between onset and death was shorter in the HSCT-treated group compared with the untreated group (2.87 ± 1.28 and 3.34 ± 0.59 months, respectively), probably due to active infections during transplantation. Bacillus Calmette-Guérin (BCG) complications occurred in 14 of the 34 patients who received BCG vaccination. Transfusion-induced graft-versus-host disease occurred in 5 patients. Total 20 mutations in interleukin-2 receptor subunit gamma (IL2RG) were identified in 22 patients, including 11 novel mutations. Most patients were misdiagnosed before referred to our SCID Center. Therefore, establishing more diagnostic centers dedicated to the care of PID and accessible by primary immunodeficiency patients will facilitate early, correct diagnosis and better care of SCID in China.

Partially hydrolyzed cow's milk formula has a therapeutic effect on the infants with mild to moderate atopic dermatitis: a randomized, double-blind study.

OBJECTIVE: The allergy-preventing effect of partially hydrolyzed cow's milk formula (phCMF) in infants at high risk of atopic dermatitis (AD) has been demonstrated in many studies. However, the therapeutic potential of phCMF in treating the infants with AD has not been reported. We sought to assess such therapeutic efficacy of phCMF in infants with mild to moderate AD. METHODS: From 2006 to 2008, 113 infants <6 months of age with AD were randomized to receive either partially hydrolyzed cow's milk formula (phCMF) or conventional cow's milk formula (CMF) in a double-blind clinical trial. Assessments were made at enrollment and at weeks 4, 8, and 12. The severity of AD was assessed using two scoring systems: Standard guideline for management (diagnosis, severity scoring, and therapy) of AD by the Japanese Dermatological Association Scoring System (JDASS) and the SCORing Atopic Dermatitis (SCORAD). Growth status of the infants was evaluated. Allergy profile was assessed by measuring total blood eosinophils (EOS), total/specific IgE, Th1/Th2 cytokine profiles, and the percentage of regulatory T cells. RESULTS: After follow-up for 12 wk, 27 infants (23.89%) dropped off study. Analysis was performed on 86 infants by the end of 12-wk observation. The AD severity scores were significantly reduced in the phCMF group (n = 56) compared with CMF group (n = 30) after 12 wk (p < 0.05). The severity scores of phCMF group were significantly reduced at weeks 4, 8, and 12 compared to enrollment (p < 0.05). In contrast, no significant improvement was observed for CMF group at any of those time points (p > 0.05). The number of AD flare-ups was significantly decreased in the phCMF group (p = 0.002). Th1/Th2 ratio in phCMF was significantly increased compared with CMF group (p = 0.041). The growth rates did not differ significantly between these feeding groups at any assessed time point (p > 0.05) and were in the normal range. CONCLUSION: This study suggests a novel therapeutic effect of phCMF in treating infants with mild to moderate AD during the first 6 months of their life without affecting their nutritional status.

Characterization of immunocompetent cells in human milk of Han Chinese.

Immunocompetent cells in colostrum and mature breast milk (42 days after delivery) of 64 Chinese females of Han ethnic background were characterized. The total cell numbers in colostrum and mature breast milk were 593 ± 205 × 10(6)/L and 1.74 ± 0.97 × 10(6)/L, respectively. NK cell is the predominant lymphocyte subtype (12.69%). T cells in colostrum express CD40L and CD25 without stimulation, indicating memory T cells in nature. The CD45RA( +)CD45RO(+) subsets of CD4(+) T cells are present in both colostrum and mature human milk. The percentage of NK cells and the absolute number of CD4(+)CD45RO(+) T cells in colostrum of atopic mothers were significantly lower than those of mothers without atopy (P = .006 and .026, respectively). The absolute numbers of CD4( +) T lymphocytes and their expression of CD40L were significantly reduced in breast milk of mothers who had undergone cesarean section versus vaginal delivery (P < .05), indicating that atopy and cesarean delivery are associated with the phenotypes of lymphocytes in colostrum.

Distribution and clinical features of primary immunodeficiency diseases in Chinese children (2004-2009).

Two hundred and one patients have been diagnosed with primary immunodeficiency diseases (PIDs) in our center from January 2004 to December 2009. The male-to-female ratio was 5.29:1. Spectrums of PIDs were as follows: predominantly antibody deficiency disease was the most common category (94 patients, 48.2%), followed by other well-defined immunodeficiency syndromes (40 patients, 20.5%), combined T and B cell immunodeficiencies (33 patients, 16.9%), congenital defects of phagocyte number and/or function (21 patients, 10.8%), and diseases of immune dysregulation (six patients, 3.1%). Agammaglobulinemia was the most frequent disease type. The median of diagnosis lag was 18.0 months. Pneumonia was the most common manifestation of PID patients. Some manifestations were prone to concentrate in certain diseases. As for therapy, 99 patients (50.8%) received intravenous immunoglobulin replacement therapy; 13 patients received hematopoietic stem cell transplantation and nine of them were still alive. In this study, we sought to describe and analyze the distribution, clinical features, and therapy methods of PIDs among children diagnosed in our country and to compare with reports from other countries and regions.

A novel point mutation in CD18 causing leukocyte adhesion deficiency in a Chinese patient.

BACKGROUND: Leukocyte adhesion deficiency type 1 (LAD-1) is a rare, autosomal recessive inherited immunodeficiency disease characterized by recurrent severe bacterial infection, impaired pus formation, poor wound healing, associated with the mutation in the CD18 gene responsible for the ability of the leucocytes to migrate from the blood stream towards the site of inflammation. Correct and early diagnosis of LAD-1 is vital to the success of treatment and prevention of aggressive infections. The purpose of this study was to collect the clinical findings of the disease and to identify the genetic entity. METHODS: CD18 expression in the peripheral blood leukocytes from the patient, his parents and normal control was measured with flow cytometry. The entire coding regions of the CD18 gene were screened with direct sequencing genomic DNA. RESULTS: CD18 expression level on this patient's leukocyte surface was significantly decreased, with normal level in control group, his father and mother. Gene analysis revealed that this patient had a homozygous c.899A > T missense mutation in exon 8 of CD18 gene, causing the substitution of Asp to Val at the 300 amino acid. His parents were both heterozygous carriers while no such mutation was found in 50 normal controls. CONCLUSION: This study disclosed a novel point mutation Asp 300 Val located in a highly conserved region (HCR) of CD18 and confirmed the heterogeneity of the mutations causing LAD-1, indicating it was quite beneficial to establish correct and early diagnosis in children with severe LAD-1.