Deleterious mutations in LRBA are associated with a syndrome of immune deficiency and autoimmunity.

Most autosomal genetic causes of childhood-onset hypogammaglobulinemia are currently not well understood. Most affected individuals are simplex cases, but both autosomal-dominant and autosomal-recessive inheritance have been described. We performed genetic linkage analysis in consanguineous families affected by hypogammaglobulinemia. Four consanguineous families with childhood-onset humoral immune deficiency and features of autoimmunity shared genotype evidence for a linkage interval on chromosome 4q. Sequencing of positional candidate genes revealed that in each family, affected individuals had a distinct homozygous mutation in LRBA (lipopolysaccharide responsive beige-like anchor protein). All LRBA mutations segregated with the disease because homozygous individuals showed hypogammaglobulinemia and autoimmunity, whereas heterozygous individuals were healthy. These mutations were absent in healthy controls. Individuals with homozygous LRBA mutations had no LRBA, had disturbed B cell development, defective in vitro B cell activation, plasmablast formation, and immunoglobulin secretion, and had low proliferative responses. We conclude that mutations in LRBA cause an immune deficiency characterized by defects in B cell activation and autophagy and by susceptibility to apoptosis, all of which are associated with a clinical phenotype of hypogammaglobulinemia and autoimmunity.

Astragaloside IV induces endothelial progenitor cell angiogenesis in deep venous thrombosis through inactivation of PI3K/AKT signaling.

BACKGROUND: Deep vein thrombosis (DVT), referred to as venous thromboembolism, is the third most frequent cardiovascular disease. Endothelial progenitor cells (EPCs) contribute to the recanalization of DVT. Astragaloside IV (AS-IV) has been suggested to have angiogenesis-enhancing effects. Here, we investigate the roles and mechanisms of AS-IV in EPCs and DVT. METHODS: The experimental DVT model was established by inferior vena cava stenosis in rats. EPCs were collected from patients with DVT. Transwell assays were performed to detect cell migration. Tube formation was determined using Matrigel basement membrane matrix and ImageJ software. The thrombus weight and length were measured. Pathological changes were examined by hematoxylin-eosin staining. The production of proinflammatory cytokines was estimated by ELISA. The level of PI3K/AKT-related proteins was measured by western blotting. RESULTS: AS-IV administration facilitated the migrative and angiogenic functions of human EPCs in vitro. Additionally, AS-IV inhibited thrombosis and repressed the infiltration of leukocytes into the thrombus and the production of proinflammatory cytokines in rats. Mechanistically, AS-IV inactivated PI3K/AKT signaling in rats. CONCLUSION: AS-IV prevents thrombus in an experimental DVT model by facilitating EPC angiogenesis and decreasing inflammation through inactivation of PI3K/AKT signaling.

Anti-inflammatory effects of reticuline on the JAK2/STAT3/SOCS3 and p38 MAPK/NF-κB signaling pathway in a mouse model of obesity-associated asthma.

BACKGROUND: Asthma associated with obesity is a chronic disease characterized by earlier airway remodeling, severe wheezing, and increased insensitivity to hormone therapy. Reticuline, a bioactive compound of Magnoliae Flos, exerts anti-inflammatory activity and can inhibit neutrophil recruitment. Thus, this study investigated the role of reticuline in obesity-related asthma. METHODS: The BALB/c mice fed a low-fat diet (LFD) and high-fat diet (HFD) were intranasally challenged with house dust mites (HDMs) or ovalbumin (OVA). Reticuline (0.25 mg/kg) was administrated into mice by intragastrical gavage. Airway hyper-responsiveness was examined after the final challenge. Body weight was measured, and bronchoalveolar lavage fluid (BALF) and lung tissues were collected. The number of inflammatory cells in BALF was estimated. Histological changes were assessed by performing hematoxylin-eosin staining, and production of proinflammatory cytokines and IgE was examined by ELISA kits. Related pathways were studied with western blotting. RESULTS: Reticuline suppressed airway resistance and inflammatory infiltration in lung tissue and reduced inflammatory cell recruitment in BALF in obesity mice with asthma. Additionally, the levels of IL-17A, IL-1ß, IL-5, macrophage inflammatory protein 2, and regulated on activation, normal T cell expressed and secreted in the lung were reduced by reticuline. Mechanistically, reticuline inactivated the JAK2/STAT3/SOCS3 and p38 MAPK/NF-κB signaling pathways in obesity-related asthma. CONCLUSION: Reticuline alleviates airway inflammation in obesity-related asthma by inactivating the JAK2/STAT3/SOCS3 and p38 MAPK/NF-κB signaling pathways.

Interleukin-21 restores immunoglobulin production ex vivo in patients with common variable immunodeficiency and selective IgA deficiency.

Interleukin-21 (IL-21) is an important promoter for differentiation of human B cells into immunoglobulin (Ig)-secreting cells. The objective of this study was to evaluate an IL-21-based approach to induce immunoglobulin production in B cells from patients with common variable immunodeficiency (CVID) or selective IgA deficiency (IgAD). We show that a combination of IL-21, IL-4, and anti-CD40 stimulation induces class-switch recombination to IgG and IgA and differentiation of Ig-secreting cells, consisting of both surface IgG(+) (sIgG(+)) and sIgA(+) B cells and CD138(+) plasma cells, in patients with CVID or IgAD. Stimulation with IL-21 was far more effective than stimulation with IL-4 or IL-10. Moreover, spontaneous apoptosis of CD19(+) B cells from patients with CVID or IgAD was prevented by a combination of IL-21, IL-4, and anti-CD40 stimulation. Analysis of IL-21 and IL-21 receptor (IL-21R) mRNA expression upon anti-CD3 stimulation of T cells, however, showed no evidence for defective IL-21 expression in CVID patients and sequencing of the coding regions of the IL21 gene did not reveal any mutations, suggesting a regulatory defect. Thus, our work provides an initial basis for a potential therapeutic role of IL-21 to reconstitute immunoglobulin production in CVID and IgAD.

Novel mutations in TACI (TNFRSF13B) causing common variable immunodeficiency.

INTRODUCTION: Common variable immunodeficiency (CVID) is a heterogeneous syndrome characterized by impaired immunoglobulin production. The disorder is also characterized by co-occurrence of autoimmune, lymphoproliferative, and granulomatous diseases. Mutations in the gene encoding TACI (Transmembrane Activator and CAML Interactor, TNFRSF13B) were previously found to be associated with CVID. MATERIALS AND METHODS: We therefore sequenced TNFRSF13B gene in a cohort of 48 Iranian CVID patients. Expression of TACI and binding of A proliferation-inducing ligand (APRIL) were tested by FACS. RESULTS: We identified one patient with a homozygous G to T substitution in the TNFRSF13B gene at the splice site of intron 1 (c.61+1G>T), which abolished expression of the TACI molecule and binding capacity of APRIL. This represents the second CVID patient in the world with a complete absence of TACI expression. B cell lines from family members carrying the same mutation in a heterozygous form showed a reduced level of TACI expression and APRIL-binding capacity, suggesting a gene dosage effect. In addition, we found the previously recognized C104R and C172Y mutations in a heterozygous form in two patients with CVID and one, novel, heterozygous P42T mutation. CONCLUSION: TACI mutations were observed in Iran CVID patients in a similar frequency as in other Caucasian populations. The novel mutations identified in this study support the notion of a crucial role for TACI in B cell differentiation.

Cernunnos influences human immunoglobulin class switch recombination and may be associated with B cell lymphomagenesis.

Cernunnos is involved in the nonhomologous end-joining (NHEJ) process during DNA double-strand break (DSB) repair. Here, we studied immunoglobulin (Ig) class switch recombination (CSR), a physiological process which relies on proper repair of the DSBs, in B cells from Cernunnos-deficient patients. The pattern of in vivo generated CSR junctions is altered in these cells, with unusually long microhomologies and a lack of direct end-joining. The CSR junctions from Cernunnos-deficient patients largely resemble those from patients lacking DNA ligase IV, Artemis, or ATM, suggesting that these factors are involved in the same end-joining pathway during CSR. By screening 269 mature B cell lymphoma biopsies, we also identified a somatic missense Cernunnos mutation in a diffuse large B cell lymphoma sample. This mutation has a dominant-negative effect on joining of a subset of DNA ends in an in vitro NHEJ assay. Translocations involving both Ig heavy chain loci and clonal-like, dynamic IgA switching activities were observed in this tumor. Collectively, our results suggest a link between defects in the Cernunnos-dependent NHEJ pathway and aberrant CSR or switch translocations during the development of B cell malignancies.

Non-homologous end joining in class switch recombination: the beginning of the end.

Immunoglobulin class switch recombination (CSR) is initiated by a B-cell-specific factor, activation-induced deaminase, probably through deamination of deoxycytidine residues within the switch (S) regions. The initial lesions in the S regions are subsequently processed, resulting in the production of DNA double-strand breaks (DSBs). These breaks will then be recognized, edited and repaired, finally leading to the recombination of the two S regions. Two major repair pathways have been implicated in CSR, the predominant non-homologous end joining (NHEJ) and the alternative end-joining (A-EJ) pathways. The former requires not only components of the 'classical' NHEJ machinery, i.e. Ku70/Ku80, DNA-dependent protein kinase catalytic subunit, DNA ligase IV and XRCC4, but also a number of DNA-damage sensors or adaptors, such as ataxia-telangiectasia mutated, gammaH2AX, 53BP1, MDC1, the Mre11-Rad50-NBS1 complex and the ataxia telangiectasia and Rad3-related protein (ATR). The latter pathway is not well characterized yet and probably requires microhomologies. In this review, we will focus on the current knowledge of the predominant NHEJ pathway in CSR and will also give a perspective on the A-EJ pathway.

[Effect of neonatal BCG vaccination on phenotype and function of splenic dendritic cells of BALB/c mice].

OBJECTIVE: The impact of dendritic cells (DCs) and regulatory T cells (Tr) on the pathogenesis of asthma have been investigated over the past decades. As the professional antigen presenting cells, DCs not only prime immune response directing Th0 cells toward different T subtypes but also induce immune tolerance. As an immunoregulator, Bacillus Calmette-Guerin (BCG) has potential to be applied in allergic diseases such as asthma for prevention. Previous study showed that neonatal BCG vaccination could induce Th1/Tr1 development in mice in vivo. To further identify the mechanism of neonatal BCG vaccination on T cell subsets differentiation, the present study was designed to investigate the impact of BCG vaccination on splenic DCs development in neonatal mice. METHODS: Neonatal specific pathogen free (SPF) BALB/c mice (2-3 days) were divided into intraperitoneal BCG-treated group, subcutaneous BCG-treated group and control group; simultaneously adult SPF BALB/c mice (6-8 weeks) were divided into intraperitoneal BCG-treated and control group. The BCG-treated mice were inoculated with 1 x 10(5) CFU BCG, the mice in control group were not inoculated with any vaccine. Four weeks post BCG vaccination, spleen cells were isolated. With flow cytometry, subtype and maturity of splenic DCs were analysed. Moreover, cells were further separated into mononuclear cell by Ficoll solution. The mononuclear cells were stimulated by 1 microg/ml lipopolysaccharide (LPS) for 18 or 10(5) CFU /ml BCG for 48 hours at 37 degrees C in a humidified atmosphere containing 5% CO2 and cytokines concentration was detected by ELISA. RESULTS: (1) CD11c(+) CD8alpha(+) and CD11c(+) CD8alpha(-) DCs were found in spleen cells of the BALB/c mice. In comparison with the control group, the percent of CD11c(+) CD8alpha(-) DCs in intraperitoneal BCG group significantly declined (P < 0.01) and that of CD11c(+) CD8alpha(+) DCs significantly increased (P < 0.01), there were no significant difference in DC subtypes between intraperitoneal and subcutaneous BCG-vaccinated mice. In contrast, the percent of CD11c(+) CD8alpha(-)DCs markedly increased (P < 0.01) and that of CD11c(+) CD8alpha(+)DCs noticeably reduced (P < 0.01) in adult BCG-vaccinated mice. The percent of CD11c(+)CD8alpha(-)DC was significantly higher and that of CD11c(+) CD8alpha(+)DC was significantly lower in adult-vaccinated BALB/c mice than that of neonatal-vaccinated ones. (2) The expression of costimulatory molecules CD40 on CD11c(+) CD8alpha(-) DCs and CD86 on CD11c(+) CD8alpha(+) DCs in neonatal BCG-treated BALB/c mice was higher than the controls. There were no significant difference in expression of costimulatory molecules on DC between neonatal BCG-vaccinated mice. Compared with the control group, expression of CD40 and MHC-II molecules on CD11c(+) CD8alpha(-) and CD11c(+) CD8alpha(+)DC was significantly higher and that of CD86 was significantly lower in adult BCG-vaccinated mice. The expression of costimulatory molecules on DC had no significant difference between neonatal and adult BCG vaccinated BALB/c mice. (3) As compared with the control mice, concentration of IL-12p70 induced by LPS and IL-10 induced by BCG in vitro from spleen cells culture supernatant was noticeably elevated (P < 0.05) in neonatal BCG-treated BALB/c mice, but that of IL-6 did not change by LPS or BCG stimulation. CONCLUSION: (1) By up-regulating splenic CD8alpha(+)DCs and inducing IL-12p70 and IL-10 production in BALB/c mice, neonatal BCG vaccination promoted Th1/Tr1 development. (2) The effect of BCG vaccination on DC was different between neonates and adult BALB/c mice.

[Allergic airway response associated with the intestinal microflora disruption induced by antibiotic therapy].

OBJECTIVE: Over the past several decades, there has been a significant increase in allergy and asthma in the world, which correlates with alterations in microflora and widespread use of antibiotics. The authors have developed a mouse model of antibiotics-induced microbiota disruption. In that model, mice were challenged by intranasal exposure to Aspergillus fumigatus allergens to explore the relation of allergic airway response and intestinal microflora disruption. METHODS: Sixty female BALB/c mice were divided at random into 6 groups with 10 mice in each. (1) First antibiotic therapy group: the mice were given oral cefoperazone for 7 days, on day 7, mice were inoculated with Candida albicans (10(9)/ml, 50 microl) orally. (2) First control group: the mice were treated as first antibiotic therapy group, but cefoperazone and Candida albicans were replaced by saline. The mice in groups (1) and (2) were sacrificed on day 8, and cecal contents were collected for quantitative analysis of the intestinal bacterial flora. (3) Antibiotic therapy and challenge group: the mice were treated as the first antibiotic therapy group, then challenged (day 9 and 16) by intranasal exposure to Aspergillus fumigatus allergen. (4) Second antibiotic therapy group: the mice were treated as the first antibiotic therapy group, then challenged (day 9 and 16) by intranasal exposure to saline. (5) Challenge group: the mice were treated as the first control group, then challenged (day 9 and 16) by intranasal exposure to Aspergillus fumigatus allergen. (6) Second control group: the mice were treated as the first control group, then challenged (day 9 and 16) by intranasal exposure to saline. The mice in (3) - (6) group were killed for analysis of allergic airway response on day 19. RESULTS: The quantity of Enterobacteriaceae, Enterococcus, Bifidobacterium and Lactobacillus in first antibiotic therapy group was significantly lower than that in the first control group, the quantity of Candida albicans increased in the first antibiotic therapy group as compared with the first control group. Mice intestinal microflora were disrupted with weight reduction and increased moisture in feces. After challenging with Aspergillus fumigatus allergens via intranasal inhalation, the total cell count, eosinophils, lymphocytes and neutrophils increased in BALF, especially in bronchoalveolar lavage fluid (BALF) from the mice in antibiotic therapy and challenge groups. IL-4 level in BALF from antibiotic therapy and challenge group (45.35 +/- 2.36) pg/ml was higher than that in the second control group (35.32 +/- 2.53) pg/ml. The expression of GATA-3 mRNA in the mice lung tissue (0.569 +/- 0.023) was higher than that in the second control group (0.410 +/- 0.020), and the ratios of T-bet/GATA-3 (0.578 +/- 0.021) decreased as compared with that in the second control group (0.804 +/- 0.035). IFN-gamma level in BALF from any group was not significantly different. In the absence of antibiotics, mice exposed to Aspergillus fumigatus allergen did not develop an allergic response in the airways. CONCLUSIONS: The allergic (Th2) immune response can be induced by airway challenge with Aspergillus fumigatus allergen in the mice in which the intestinal microflora disruption resulted from antibiotic therapy, this result suggests that the intestinal microflora disruption resulted from antibiotic therapy is a risk factor for allergy and asthma.