Study and isolation of human intestinal dendritic cell and macrophage subsets

Dendritic cells and macrophages are the main antigen-presenting cells (APC). In the gut, they control the mechanisms of tolerance toward commensals and nutrients, at the time that they maintain their capacity to trigger immune responses against invading pathogens. Nevertheless, this balance is not perfect as it can get disrupted like in inflammatory bowel disease (where they drive an abnormal immune response against the microbiota) or in coeliac disease (where they trigger an immune response against dietary gluten). Therefore, the study of human intestinal APC subsets is crucial not just to get a deeper insight in the mechanisms of human intestinal homeostasis, but also to understand the pathogenesis of inflammatory bowel disease and coeliac disease. Nevertheless, their study is quite complicated as despite their relevance, their numbers are scare in the intestinal mucosa. Therefore, we hereby describe different approaches to study human intestinal dendritic cell and macrophage subsets in the human intestinal mucosa.

Human intestinal dendritic cell and macrophage subsets in coeliac disease

Dendritic cells (DC) and macrophages (Mϕ) constitute the most abundant antigen presenting cells in the human intestinal mucosa. In resting conditions, they are essential to maintain the mechanisms of immune tolerance toward food antigens and commensals, at the time that they keep the capacity to initiate and maintain antigen-specific pro-inflammatory immune responses toward invading pathogens. Nevertheless, this delicate equilibrium between immunity and tolerance is not perfect, like in coeliac disease (CD), where DC and Mϕ drive the development of antigen-specific immune responses toward dietary gluten peptides. In this review, we provide therefore a comprehensive discussion about CD pathogenesis, the human intestinal immune system and the biology of intestinal DC and Mϕ both in resting conditions and in CD. Last, but not least, we discuss about all the remaining issues pending to be studied regarding DC and Mϕ contribution toward CD pathogenesis. This may allow the identification of unique and specific factors which may be useful in the clinical practice, as well as identify new therapeutic targets in order to reestablish the loss intestinal homeostasis in CD.

Deletions of specific exons of FHOD3 detected by next-generation sequencing are associated with hypertrophic cardiomyopathy

Despite new strategies, such as evaluating deep intronic variants and new genes in whole-genome-sequencing studies, the diagnostic yield of genetic testing in hypertrophic cardiomyopathy (HCM) is still around 50%. FHOD3 has emerged as a novel disease-causing gene for this phenotype, but the relevance and clinical implication of copy-number variations (CNVs) have not been determined. In this study, CNVs were evaluated using a comparative depth-of-coverage strategy by next-generation sequencing (NGS) in 5493 HCM probands and 2973 disease-controls. We detected three symmetrical deletions in FHOD3 that involved exons 15 and 16 in three HCM families (no CNVs were detected in the control group). These exons are part of the diaphanous inhibitory domain of FHOD3 protein, considered a cluster of mutations for HCM. The clinical characteristics of the affected carriers were consistent with those reported in FHOD3 in previous studies. This study highlights the importance of performing CNV analysis systematically in NGS genetic testing panels for HCM, and reinforces the relevance of the FHOD3 gene in the disease.

Comprehensive genomic diagnosis of non-syndromic and syndromic hereditary hearing loss in Spanish patients

BACKGROUND

Sensorineural hearing loss (SNHL) is the most common sensory impairment. Comprehensive next-generation sequencing (NGS) has become the standard for the etiological diagnosis of early-onset SNHL. However, accurate selection of target genomic regions (gene panel/exome/genome), analytical performance and variant interpretation remain relevant difficulties for its clinical implementation.

METHODS

We developed a novel NGS panel with 199 genes associated with non-syndromic and/or syndromic SNHL. We evaluated the analytical sensitivity and specificity of the panel on 1624 known single nucleotide variants (SNVs) and indels on a mixture of genomic DNA from 10 previously characterized lymphoblastoid cell lines, and analyzed 50 Spanish patients with presumed hereditary SNHL not caused by GJB2/GJB6, OTOF nor MT-RNR1 mutations.

RESULTS

The analytical sensitivity of the test to detect SNVs and indels on the DNA mixture from the cell lines was > 99.5%, with a specificity > 99.9%. The diagnostic yield on the SNHL patients was 42% (21/50): 47.6% (10/21) with autosomal recessive inheritance pattern (BSND, CDH23, MYO15A, STRC [n = 2], USH2A [n = 3], RDX, SLC26A4); 38.1% (8/21) autosomal dominant (ACTG1 [n = 3; 2 de novo], CHD7, GATA3 [de novo], MITF, P2RX2, SOX10), and 14.3% (3/21) X-linked (COL4A5 [de novo], POU3F4, PRPS1). 46.9% of causative variants (15/32) were not in the databases. 28.6% of genetically diagnosed cases (6/21) had previously undetected syndromes (Barakat, Usher type 2A [n = 3] and Waardenburg [n = 2]). 19% of genetic diagnoses (4/21) were attributable to large deletions/duplications (STRC deletion [n = 2]; partial CDH23 duplication; RDX exon 2 deletion).

CONCLUSIONS

In the era of precision medicine, obtaining an etiologic diagnosis of SNHL is imperative. Here, we contribute to show that, with the right methodology, NGS can be transferred to the clinical practice, boosting the yield of SNHL genetic diagnosis to 50-60% (including GJB2/GJB6 alterations), improving diagnostic/prognostic accuracy, refining genetic and reproductive counseling and revealing clinically relevant undiagnosed syndromes.

New IL-15 receptor-α splicing variants identified in intestinal epithelial Caco-2 cells

IL-15 is a pleiotropic cytokine related to IL-2 which acts at a broader level than its counterpart. It is presented through its specific high-affinity receptor, IL-15Rα. Both cytokine and receptor are tightly regulated at multiple levels and are widely distributed. Thus, deregulation of their expression leads to an inflammatory immune response. Variants of splicing of IL-15Rα have been described in immune and barrier cells; however, their presence has not been focused on intestinal epithelial cells. In this study, we describe five new alternative variants of splicing of IL-15Rα in Caco-2 cells. Four of them were expressed into proteins inside Caco-2 cells, but these were unable to bind IL-15 or to follow the secretory pathway. However, the expression of mRNA itself might be relevant to diseases such as celiac disease, inflammatory bowel disease or colorectal cancer.

Detection of specific IgA antibodies against a novel deamidated 8-Mer gliadin peptide in blood plasma samples from celiac patients

We studied whether celiac disease (CD) patients produce antibodies against a novel gliadin peptide specifically generated in the duodenum of CD patients by a previously described pattern of CD-specific duodenal proteases. Fingerprinting and ion-trap mass spectrometry of CD-specific duodenal gliadin-degrading protease pattern revealed a new 8-mer gliadin-derived peptide. An ELISA against synthetic deamidated 8-mer peptides (DGP 8-mer) was used to study the presence of IgA anti-DGP 8-mer antibodies in plasma samples from 81 children (31 active CD patients (aCD), 17 CD patients on a gluten-free diet (GFD), 10 healthy controls (C) and 23 patients with other gastrointestinal pathology (GP)) and 101 adults (16 aCD, 12 GFD, 27 C and 46 GP-patients). Deamidation of the 8-mer peptide significantly increased the reactivity of the IgA antibodies from CD patients against the peptide. Significant IgA anti-DGP 8-mer antibodies levels were detected in 93.5% of aCD-, 11.8% of GFD- and 4.3% of GP-patients in children. In adults, antibodies were detected in 81.3% of aCD-patients and 8.3% of GFD-patients while were absent in 100% of C- and GP-patients. Duodenal CD-specific gliadin degrading proteases release an 8-mer gliadin peptide that once deamidated is an antigen for specific IgA antibodies in CD patients which may provide a new accurate diagnostic tool in CD.

Percutaneous liver biopsy: patients' point of view

INTRODUCTION

Hepatic fibrosis can be assessed through serum markers or by the implementation of new non-invasive techniques, such as elastography. We must know patients' opinion on percutaneous liver biopsy (PLB) when it comes to comparing it with other procedures.

AIMS

To know the point of view of patients undergoing a PLB with regard to information provided to them, as well as the procedures and biopsy consequences.

PATIENTS AND METHODS

A questionnaire was sent by mail to 178 patients who underwent PLB from April 2006 to May 2010. Answers were analyzed. Results are expressed in percentages and compared based on gender and age (younger or older than 47 years of age) (Chi-square test).

RESULTS

Ninety patients of the group answered, 44 females, mean age 47 ± 12 years. The answers revealed that 93% of patients rated the information concerning the reasons for a PLB as adequate (86% women and 100% men). As for the information concerning the objective of the procedure, 88% of patients regarded it as adequate (81% of women vs. 93% of men, p = 0.08). As for the information concerning the risks of a biopsy, 77.7% see it as sufficient. About 12.20% of patients did not receive any information on the physician who asked for the PLB, or who performed it. PLB was considered very painful by 14% of patients, painful by 21%, bothersome by 41.1% and barely bothersome by 23% of patients. Thirty-five percent of patients required analgesia after the puncture. Even though 92% of patients regard PLB as a useful procedure, 46% of them have not received any treatment or a different nutritional regime (55.8%, among those older than 47 years of age, p = 0.03). Eighty percent of patients think that PLB has more benefits than drawbacks, although 87% would have opted for a less aggressive technique as long as it would have provided the same information. But 21% of patients would have also preferred a less aggressive technique, even though it provided fewer details.

CONCLUSIONS

In general, PLB is widely approved by patients and is also regarded as a useful procedure. One out of six patients would rather choose a less-aggressive technique even if it provided less information. PLB does not involve changes in the treatment in around a half of patients.

Interplay between human leukocyte antigen genes and the microbial colonization process of the newborn intestine

Coeliac disease (CD) development involves genetic (HLA-DQ2/DQ8) and environmental factors. Herein, the influence of the HLA-DQ genotype on the gut colonization process of breast-fed children was determined. A cohort of 20 newborns, with at least one first-degree relative with CD, were classified according to their HLA-DQ genotype into high, intermediate and low genetic risk groups, showing 24-28%, 7-8% and less than 1% probability to develop CD, respectively. Faecal microbiota was analysed at 7 days, 1 and 4 months of children's age by fluorescence in situ hybridization. When considering all data, Gram-negative bacteria and Bacteroides-Prevotella group proportions were higher (P<0.05) in the high than in the intermediate and low genetic risk groups. E. coli, Streptococcus-Lactococcus, E. rectale-C. coccoides, sulphate-reducing bacteria, C. lituseburense and C. histolyticum group proportions were also significantly higher (P<0.05) in the high than in the low genetic risk group. Correlations between these bacterial groups and the genetic risk were also detected (P<0.05). In addition, the number and type of CD relative seemed to influence (P<0.050) these bacterial proportions in children at CD risk. At 4 months of age, similar relationships were established between the high genetic risk to develop CD and the proportions of Streptococcus-Lactococcus (P<0.05), E. rectale-C. coccoides (P<0.05), C. lituseburense (P<0.05), C. histolyticum (P<0.05), Bacteroides-Prevotella (P<0.10) groups and total Gram-negative bacteria (P<0.05). The results suggest a relationship between HLA-DQ genes and the gut microbial colonization process that could lead to a change in the way this disorder is investigated.

[Interleukin 18 (IL-18) and other immunological parameters as markers of severity in acute pancreatitis]

OBJECTIVE

Our aim was to prospectively compare the behavior of interleukin 18 (IL-18) levels and other immunological parameters during the first week of hospitalization between acute pancreatitis patients with and without severity criteria, as well as between patients with and without late pseudocyst development.

PATIENTS AND METHODS

In 36 patients with acute pancreatis we compared sTNF-RI, IL-1Ra, IL-6, and IL-18 levels at days 1, 2, 3 and 7 after hospitalization between mild pancreatitis, severe pancreatitis, and a "control" group (13 patients) with uncomplicated biliary colic, as well as between patients with and without pseudocyst.

RESULTS

On comparing mild to severe pancreatitis, IL-18 was significantly higher only the first day in severe pancreatitis, while the other parameters were steadily higher after the second day. In patients developing pseudocyst, IL-18 was also noticeably higher the first day.

CONCLUSIONS

IL-18 appears to be the earliest marker of complications and severity in acute pancreatitis at both the systemic and local level (pseudocyst).

Higher constitutive IL15R alpha expression and lower IL-15 response threshold in coeliac disease patients

The IL-15 triggering effect of gliadin is not exclusive to coeliac disease (CD) patients, whereas the secondary response is CD specific. We have studied the expression of the IL-15 receptor, and the IL-15 response upon stimulation, in non-CD and CD patients, and the possible existence of a lower immunological threshold in the latter. Forty-two CD patients (20 on a gluten-containing diet, GCD, and 22 on gluten-free diet, GFD) and 24 non-CD healthy individuals were studied. IL15R alpha mRNA expression, and tissue characterization, were assayed in the duodenum. Biopsies from six CD patients on GFD and 10 non-CD individuals were studied in vitro using organ culture in basal conditions, as well as after IL-15 stimulation discarding basal IL-15 production. Secretion of immune mediators was measured in the culture supernatants. IL15R alpha mRNA expression was increased in CD patients, as compared with non-CD controls (on GFD P = 0.0334, on GCD P = 0.0062, respectively), and confirmed also by immunofluorescence. No differences were found between CD patients on GFD and on GCD. After in vitro IL-15 stimulation, IL15R alpha expression was only triggered in non-CD controls (P = 0.0313), though it remained increased in CD patients. Moreover, IL-15 induced a more intense immunological response in CD patients after triggering the production of both nitrites and IFN gamma (P = 0.0313, P = 0.0313, respectively). Gliadin-induced IL15 has a lower response threshold in CD patients, leading to the production of other immune mediators and the development of the intestinal lesion, and thus magnifying its effects within the CD intestine.

[Cytokines and other immunological parameters as markers of distant organ involvement in acute pancreatitis]

BACKGROUND AND OBJECTIVE

There is a role of immunologic proinflammatory mediators in pathogenesis of distant organ disfunction in acute pancreatitis (AP). The aim is to evaluate the relationship between those mediators and liver, kidney and lung disfunction in patients with AP.

PATIENTS AND METHOD

On the day of admission in 34 patients with AP, biochemical parameters of liver function, creatinine and arterial partial pressure of oxygen (PO2) were determined, and cut points were established. Soluble tumor necrosis factor receptor I (sTNFRI), interleukin (IL) 1 receptor antagonist (IL-1Ra), IL-6, soluble IL-6 receptor (sIL-6R), IL-18, and intercellular adhesion molecule-1 (ICAM-1) were determined on days 1, 2, 3 and 7, and were compared between patients with biochemical parameters and PO2 on admission higher or lower than an established cut point.

RESULTS

Levels of sTNFRI, IL-18 and ICAM-1 were significantly higher and sustained, and IL-6 only the first day, in patients with parameters of liver function above the cut point. sTNFRI, IL-1Ra and ICAM-1 early showed significantly higher levels in relation with serum creatinine, and these and also IL-6 in those with PO2 below 60 mmHg.

CONCLUSIONS

sTNFRI, IL-6, IL-18 and ICAM-1 behaved as early markers of hepatic alteration, sTNFRI, IL-1Ra and ICAM-1 of renal disfunction and these and IL-6 of lung injury.

Interleukin 18 maintains a long-standing inflammation in coeliac disease patients

Dietary gluten induces an early response in the intestine of coeliac disease patients (CD), within a few hours, and this is driven by high levels of proinflammatory cytokines, including IFNgamma and IL-15, as has been thoroughly shown by gluten stimulation of biopsy explants. Our aim was to identify the immune mediators involved in the long-standing inflammation in untreated CD patients at diagnosis. mRNA and protein levels of TNFalpha, IL-12(p35), IL-12(p40), IL-15, IL-18 and IL-23(p19) were quantified in biopsies from active CD patients, CD patients on a gluten-free diet (GFD), healthy controls, and patients with non-CD inflammation and mild histological changes in the intestine. Biopsies from CD patients on a GFD were also stimulated in vitro with gliadin, and protein expression of IL-15 and IL-18 was analysed. Levels of IL-12 and IL-23 mRNA are nearly absent, and TNFalpha levels remain unchanged among different groups. Both the active and inactive forms of IL-18 protein have been found in all samples from active CD, and protein expression was only localized within the crypts. Levels of IL-15 mRNA remain unchanged, and protein expression, localized within the lamina propria, is found in a small number of samples. In vitro stimulation with gluten induces the expression of IL-15 and IL-18. In active CD, the early response following gluten intake characterized by high IFNgamma levels is driven by IL-18, and probably IL-15, and this alternates with periods of long-standing inflammation with moderate IFNgamma levels, maintained by IL-18 alone.

Citocinas en la patogenia de la enfermedad celíaca

Celiac disease is manifested by an enteropathy caused by intolerance to gluten, a family of proteins found in wheat and other cereals. Following intestinal T-cell activation in predisposed individuals, different inflammatory mechanisms are triggered under the control of the cytokine balance including those with a pro-inflammatory Th1 pattern such as IFNgamma, TNFalpha, IL-15 and IL-18; and regulatory cytokines such as TGFbeta and IL-10. These cytokines, besides increasing the intensity of the activation and the number of immune cells within the intestinal mucosa, regulate the activity of epithelial growth factors and metalloproteinases, a group of molecules involved in the maintenance and turnover of the intestinal mucosa structure; in inflammatory conditions, they also induce the intestinal lesion responsible for malabsorption syndrome.

IL6, IL10 and TGFB1 gene polymorphisms in coeliac disease: differences between DQ2 positive and negative patients

Predisposition to coeliac disease (CD) might be partially due to an individual pattern of hyper-inflammatory biased immune response. One of these patterns of intense response may be linked to the haplotype carrying HLA-DQ2 alleles and TNF -308A allele. However, 10 % of CD patients do not express the DQ2 heterodimer and these do not usually carry the TNF -308A allele. A similar response might be achieved by genes codifying other cytokines.

OBJECTIVES

To study biallelic polymorphisms in genes codifying for TNFalpha, IL10, IL6 and TGFbeta1 in DQ2 negative CD patients and to compare the results with DQ2 positive patients and healthy controls, in order to establish whether any of these polymorphisms have a role in CD susceptibility.

METHODS

TNF -308 (G > A), IL-6 -174 (G > C) and TGFB1 codon 10 (+ 869, T > C) and codon 25 (+ 915, G > C) polymorphisms and IL-10 haplotype of polymorphisms in positions -1082 (G > A), -819 (C > T) and -592 (C > A) were typed by a SSP-PCR technique.

RESULTS

The distribution of allele frequencies for TNF -308 is different between DQ2 positive CD patients and controls and the same occurs for haplotype frequencies of the IL10 promoter (-1082, -819, -592): The frequencies of the TNF -308A allele (p = 0.027), TNF -308A carriers (p = 0.031) and of IL10GCC haplotype are increased (p = 0.013) in DQ2 positive CD patients. However, the IL6 -174 allele G is more frequent in DQ2 negative patients than in healthy controls (p = 0.018), DQ2 negative controls (p = 0,018), and DQ2 positive patients (p = 0.008).

CONCLUSIONS

DQ2 negative CD patients show an increased frequency of genotypes associated to IL6 high production. These were mainly allele G homozygous for the IL6 gene (-174) polymorphism. The IL6 -174GG genotype (homozygous) may be an additional risk marker for CD in DQ2 negative patients, representing an alternative susceptibility factor for CD when TNF -308A is negative.

[Celiac disease. New therapeutic alternatives based on a better knowledge of molecular pathogenesis]

Coeliac disease is a chronic autoimmune-like gastrointestinal disorder triggered by a known exogenous antigen (gluten). The disease is strongly linked to the HLA system, though other genetic, environmental and immunologic factors, may determine the type and timing of presentation. The immune response within the intestinal mucosa is characterized by a well defined TH1 response, where IFNgamma secreted by specific T cells is the predominant cytokine, as well as an innate immune response to certain gluten-derived peptides, mediated by IL-15. The strict gluten-exclusion diet is the best way of reversing both the symptoms and the histological changes in the intestinal mucosa. However, the frequency of transgressions and a low dietary compliance had led to the description of new therapeutic alternatives discussed in this review.

High cord blood IL-10 levels in preterm newborns with respiratory distress syndrome

BACKGROUND

The development of respiratory distress syndrome (RDS) is closely related to fetal immaturity, although the participation of inflammatory mechanisms also seems to be likely. We previously reported high interleukin-10 (IL-10) levels in cord blood from preterm infants. In the present study, we investigate the possible role of IL-10 and IL-12 in preterm newborns with RDS, a disease that is also closely related to gestational age.

PATIENTS AND METHODS

Cord blood levels of IL-10 and IL-12 (p70 + p40) were determined by ELISA in 20 preterm infants who later developed RDS, in 21 preterm infants without RDS and in 31 full term newborns. In 11 patients follow-up samples could be also obtained between 2 and 14 days of life.

RESULTS

Preterm infants with RDS showed higher IL-10 (27 vs 10.8 pg/mL; p: 0.0003) and lower IL-12 (188 vs 384; p: 0.002) levels in cord blood than premature infants without RDS and full term newborns (IL-10: 3.2 pg/mL, p: 0.0001; IL-12: 352 pg/mL; p: 0.002). The differences remained statistically significant after correction for the effect of gestational age between both preterm groups.

CONCLUSIONS

The results obtained may be related to an immature cytokine response in premature infants, but the IL-12/IL-10 imbalance found in our patients also supports the hypothesis that inflammation plays a role in RDS.

Hypogalactosylation of serum IgG in patients with coeliac disease

Coeliac disease (CD) is described as an autoimmune enteropathy associated with the presence of IgG and IgA antigliadin and antitransglutaminase autoantibodies. While of diagnostic significance, the role of these autoantibodies in the immunopathogenesis of CD is elucidated. An inappropriate T cell immune response to gluten is also involved in the pathogenesis of CD, as evidenced by autoantibody switching. The N-glycans released from serum IgG of CD patients and three groups of healthy controls, of differing age ranges, were analysed by NH2-high performance liquid chromatography (HPLC). The fucosylated biantennary N- glycans were the most abundant neutral oligosaccharides; in particular, the agalacto form (G0F) showed a mean value of 42% (s.d. +/- 7.4), 30% (s.d. +/- 5.9), 26% (s.d. +/- 4.2) and 35% (s.d. +/- 6.8) for CD patients, healthy children, healthy adults under 40 and healthy adults over 40 years old, respectively. The ratio of asialo agalacto fucosylated biantenna to asialo monogalacto fucosylated biantenna (G0F)/(G1F) for CD patients showed a significant increase compared to healthy children (P < 0.0002), healthy adults under 40 (P < 0.0002) and healthy adults over 40 years old (P < 0.01). Hypogalactosylation was more pronounced for CD patients than for the patients with other autoimmune diseases such as rheumatoid arthritis or psoriatic arthritis.

Influence of leptin levels and body weight in survival of children with sepsis

High levels of serum leptin (LPT) were reported in adult patients with sepsis and a protective role was suggested. LPT was determined in sera from 55 children with severe sepsis at admission (0 h), 6, 24 and 48 h. LPT levels were higher at 0 h than at 24 h (2.80 vs 1.61 ng/ml; p = 0.009) and a negative correlation was found with IL-13 (p = 0.009), and granulocyte counts (p = 0.035), but not with other factors. Infants younger than 12 mo of age had higher LPT levels than older infants (5.88 vs 2.38 ng/ml; p = 0.0005). The increase in LPT levels was higher in non-survivor patients than in survivors, with a maximum difference at 24 h (5.30 vs 1.45 ng/ml; p = 0.0042). However, LPT levels were not associated with shock, multiorgan failure or the severity score. Children who died showed higher percentiles of weight than survivors (p = 0.025). A subgroup with higher LPT (> Pc75) included mainly patients with weight > Pc50 (p = 0.0065), low IL-13 levels (p = 0.007) and low granulocyte counts (p = 0.013), Neisseria meningitidis B being the most frequently isolated germ (p = 0.022).

CONCLUSION

Using a model of severe infection, mainly meningococcal, in young children (median 3 y 6 mo old), it was not possible to confirm previous results in adults. A general protective role for LPT in sepsis seems unlikely.

TNF alpha and LT alpha gene polymorphisms as additional markers of celiac disease susceptibility in a DQ2-positive population

TNFalpha and TNFbeta, or linfotoxin (LTalpha), are two molecules playing an important role in inflammation. Their genes map on Chromosome 6, between the HLA class II and class I loci. Polymorphisms in, or near, TNF genes have been associated with susceptibility to several autoimmune diseases. Studies of TNF genes in celiac disease (CD) have presented contradictory results. We have assessed the role of TNFalpha and linfotoxin alpha (TNFbeta) in CD and their relative value as CD markers in addition to the presence of DQ2. The TNFA -308 polymorphism and the polymorphism at the first intron of the LTA gene were typed in CD patients and healthy controls and the results were correlated with the presence of DQ2. Significant differences were found in genotype and allele frequencies for the TNFA and LTA genes between CD patients and controls, with an increase in the presence of the TNFA*2 and LTA*1 alleles in CD patients. These differences increase when DQ2-positive CD patients and DQ2-positive controls are compared. In DQ2-positive individuals, allele 2 (A) in position -308 of the promoter of TNFA and allele 1 (G) of the NcoI RFLP in the first intron of LTA are additional risk markers for CD.

The HLA-DRB4 gene is present in half of the Spanish HLA-DQ2-negative celiac patients

We studied nine consecutive DQ2-negative celiacs [from a group of 186 consecutive celiac disease (CD) patients] for the presence of the HLA-DQB1, DRB1, and DRBx alleles. HLA-DR53 was present in only 5 out of 9 (55%) of DQ2-negative patients. DRB4 (DR53) positivity -39% of chromosomes--among Spanish DQ2-negative CD patients is due to both DR4- and DR7-positive cases. Spanish DQ2-positive patients show a high frequency of DR7/DR11 heterozygous carriers of DRB4 (DR53). One-third of our DQ2-negative celiac patients have DRB1*04 (DR4). Six patients are DR4 negative: at least one of the DQ2 alleles (DQA1*0501/DQB1*02) is present in four cases, but none of the alleles of risk, including DR53, were found in the remaining two cases, both of whom carry DQB1*06 alleles (*0602/3 and 0604). The fact that half of our DQ2-negative patients lack DRB4 (DR53) leads us to believe that this gene is not an essential factor to confer CD susceptibility.

A novel visual immunoassay for coeliac disease screening

BACKGROUND

To date, the most commonly accepted techniques for the screening of coeliac disease are indirect immunofluorescence and enzyme-linked immunosorbent assay (ELISA), which reveal antiendomysium and antigliadin antibodies respectively. We report the use of a simple visual system for coeliac disease screening based on the use of Staphylococcus aureus protein A, which binds to both IgG and IgA, thus avoiding the need for two parallel immunoassays.

MATERIALS AND METHODS

Opaque polystyrene microwell strips coated with a wheat gliadin extract were incubated with sera followed by incubation with protein A-colloidal gold conjugate. The resulting colour was compared with that of positive and negative control sera. The procedure took less than an hour.

RESULTS

One hundred and forty-five biopsy-proven sera, 94 from active coeliac patients and 51 from non-coeliac patients with diverse gastrointestinal pathologies or diabetes mellitus, were assayed. Ninety of the 94 sera from the active coeliac patients were positive, whereas only 3 of the 51 non-coeliac control subjects were positive. The technique has a sensitivity of 95.7% and a specificity of 94.1%.

CONCLUSIONS

The sensitivity and specificity of the visual system are greater than those of most ELISA systems and are similar to those observed with IgA antiendomysium antibodies when tested in the same population. Moreover, it is inexpensive, quick, simple to perform and easy to interpret, i.e. it requires no qualified personnel. It is for these features, together with the outstanding sensitivity and specificity, that we propose this immunoassay as a new test for reliable coeliac disease screening.

Markers of pulmonary inflammation in tracheobronchial fluid of premature infants with respiratory distress syndrome

To asses the role of pulmonary inflammation in the outcome of preterm neonates with respiratory distress syndrome (RDS) we measured soluble intercellular adhesion molecule-1 (ICAM-1), interleukin-8 (IL-8), eosinophil cationic protein (ECP) and transforming growth factor beta-1 (TGF beta 1) in tracheobronquial lavage (TBL) fluid of 15 preterm infants; 9/15 completely recovered from RDS and 6/15 developed chronic lung disease (CLD). ICAM-1 (p: 0.001) and TGF beta 1 (p: 0.04) levels increased in TBL fluid during the first days of life. The values of ICAM-1 were correlated to the days of 0(2) and mechanical ventilation dependency. At 3 days of age, ICAM-1 levels in TBL fluid were higher in infants who later developed CLD compared to infants without CLD (24.5 vs 8.3 micrograms/ml; p: 0.02). Thereafter no significant differences were found although the CLD group had higher values. IL-8 levels showed a fall, specially from 1 to 3 days of age in children without CLD (77.0 to 41.7 ng/ml) although not significant. No difference in TGF beta 1 values were found between both groups, but the TGF beta 1 levels were lower in patients with CLD and they showed undetectable values in 8 samples. ICAM-1 is a major factor associated with airways inflammation whereas IL-8 is not a good marker during the first days of life to predict the RDS outcome. A defect of TGF beta 1 in the smallest premature infants may delay the lung repair process which occurs after tissue injury. High ICAM-1 levels and low TGF beta 1 levels in lung fluid are related to oxygen dependency at 28 days of age.

Advances in the immunogenetics of coeliac disease. Clues for understanding the pathogenesis and disease heterogeneity

Recent studies using the technique of the human genome screening in families with multiple siblings suffering from coeliac disease have suggested the presence of at least four different chromosomes in the predisposition to suffer from coeliac disease. Two loci in chromosome 6 appear to be important in disease susceptibility. Other studies based on cytokine gene polymorphisms have found a strong association with a particular haplotype in the TNF locus. This haplotype carries a gene for a high secretor phenotype of TNFalpha. The finding may be important in understanding the heterogeneity of inflammatory response. Evidence has been presented in favour of a predominantly Th1 pattern of cytokine production by the coeliac disease associated HLA-DQ restricted T cell clones. HLA-DQ2 and -DQ8 restricted gliadin-specific T cells have been shown to produce IFN-gamma, which appears to be an indispensable cytokine in the damage to enterocytes encountered in the small intestine, since the histological changes can be blocked by anti-IFN-gamma antibodies in vitro. TNF-alpha, also produced by several T cell clones, may in conjunction with IFN-gamma have a toxic effect or enhance the IFN-gamma-induced increase of HLA-class II expression on surface enterocytes. In the lamina propria this leads to an increased expression of adhesion molecules such as ICAM-1 on T lymphocytes and macrophages. Th1 cells also activate cytotoxic CD8+ T cells that migrate in the epithelial layer, and stimulate further LPL macrophages to produce IFN-gamma and TNF-alpha enhancing the inflammatory response. During this process autoreactive T cells proliferate, creating a situation which is very similar to the process that takes place in autoimmune diseases. Occasionally, this inflammatory destruction of the small intestinal integrity initiated by gluten peptides goes further and develops into a proper autoimmune disease which requires the use of immunosuppressive drugs in addition to a gluten-free diet.

Lack of correlation between soluble CD14 and IL-6 in meningococcal septic shock

Meningococcal sepsis is a good model to study the dynamic response of cytokines and other soluble factors in vivo in the early stages of the disease. Levels of soluble CD14, interleukin-6 (IL-6), IL-6 receptor (IL-6R), and C-reactive protein (CRP) have been measured in plasma from 26 children with septic shock (nine of whom had disseminated intravascular coagulation) and from ten control children. All samples were collected at the onset, before treatment, and, when possible, 24 and 48 hours later. At admission, patients had significantly higher levels of IL-6 (p < 0.001) and CRP (p < 0.001), and lower levels of IL-6R (p < 0.005) than normal controls. After 24 hours, there was a significant increase of sCD24 (p < 0.05) and CRP (p < 0.001). Although IL-6 showed a progressive decline since the onset, its levels were always higher than controls. There was an inverse correlation between IL-6 and both IL-6R (p < 0.001) and CRP (p < 0.001), probably due to the later increase of CRP. Nevertheless, sCD14 did not correlate with IL-6 levels. We have confirmed the finding of IL-6 as a sensitive and reliable inflammatory marker in septic shock. Moreover, the ratio IL-6/IL-6R may have a prognostic value, given a putative role of IL-6R in modulating the effects of IL-6 in meningococcal sepsis.

[Radiofrequency treatment of tachyarrhythmias in children and adolescents]

INTRODUCTION

Radiofrequency ablation has been extensively used in adults to treat supraventricular and ventricular tachycardia. In children and adolescents few data are available on its safety and efficacy.

METHODS

28 patients (mean age 12.8) with symptomatic tachyarrhythmias underwent catheter ablation; 21 children had atrioventricular accessory pathways (11 right connections, 9 lef connections and one midseptal pathway), 3 had intranodal tachycardia, 2 had ventricular tachycardia and 2 had atrial tachycardia. Only four patients had associated structural anomalies.

RESULTS

Success rate was 71.4% (20 patients). The success per cents in each group were: in intranodal tachycardias 100%; we failed in the two patients with ventricular tachycardias; in accessory pathways 76.1% and 50% in atrial tachycardia. There were no recurrences of arrhythmia in a mean chase period of 24 months (12-46). Major complications were only observed in one patient who developed a Wallenberg syndrome after ablation.

CONCLUSIONS

Radiofrequency catheter ablation appears to be a safe and effective method to treat arrhythmias in children and adolescents, which in most cases can supersede surgery. Alow incidence of complications is reported, although long term damage on endocardial structures remains yet to be determined.

Study of HLA-DQA1 alleles in celiac children

The familial incidence of celiac disease (CD) confirms its genetic basis, although acquired factors are also involved. Many authors have reported a linkage between celiac disease and HLA antigens, but there are differences which depend on geographical areas, and nowadays the study must be done at the genetic level. Thirty-eight celiac children and 52 normal controls were included in this study. All individuals were chosen from the Castilla and Leon area. We used the reverse ¿dot block¿ technique, using sequence-specific oligonucleotide DNA probes (Cetus, USA) to determine the HLA-DQA1 alleles in DNA samples previously amplified by PCR (polymerase chain reaction). The different frequency of alleles in patients and controls was assessed by 3 statistical tests: chi square (chi(2)), relative risk (RR) and etiologic fraction (EF). A very high frequency of DQA1*0201 (chi(2):p <0.0001) and DQA1*0501 (chi(2): p <0.0001) alleles was observed in patients; all but one (97%) had the DQA1*0501 allele vs. 40% of controls (RR: 37.00; EF: 0.955). The DQA1*0201 allele also had a high prevalence in celiacs (58%)(RR: 1.375: EF:0.438). The DQA1*01 allele was only found in 10.5% of patients compared to 79% of controls (chi(2): p <0.0001) and the DQA1*03 allele was also decreased in celiacs. There was only one celiac girl without the DQA1*0501 allele. She had no other clinical or serological differences, as compared to the other patients. In the study of allele subtypes, among the DQA1*01 allele, 50% of patients were positive for DQA1*101 and the remaining 50% had DQA1*0102, but none of the individuals were positive for DQA1*0103. Among normal controls, 32 individuals (61.5%) expressed the DQA1*0102 subtype, 15 (28.9%) the DQA1*0101 subtype and 5 (9.6%) the DQA1*0103 subtype. All positive cases for DQA1-*05 belong to the DQA1* 0501 subtype, in both celiac and control groups. There were 10 possible combinations of HLA-DQA1 genes, but we found a very unequal distribution in both celiacs and controls. Only 4 genotypes were found in patients (DQA1*01/1*0501, DQA1* 0201/1*0501, DQA1*03/1*0501 and DQA1*0501/1*0501) and 8 in controls. The DQA1*0201/1*-0501 genotype was the most discordant, being positive in 55.3% of patients vs. 3.8% of controls (chi2:p < 0.001; RR: 1.235; EF:0.534). None of the 90 individuals studied expressed the DQA1*0311*03 genotype. The DQA1*0201/1*03 genotype was not shown by any control and by only 1 celiac patient. It is noteworthy that the DQA1*0201/1*0501 genotype was more frequent than the homozygous genotype DQA1*0501/1*0501. Our results do not suggest a dosage effect for the DQA1*0501 allele. The determination of the HLA-DQA1 gene is a helpful tool for the screening of individuals with a high risk of being celiacs.

Report of six cases of human infection by Serratia plymuthica

Serratia plymuthica is an uncommon cause of human infection. Only one case of chronic osteomyelitis and two cases of sepsis secondary to central venous catheter infection have been documented. We report the isolation of S. plymuthica from six patients. The organism was recovered from blood cultures in three cases in which the patients had lymphoblastic leukemia, lymphoma, or stroke. Two isolates were recovered from exudates (following knee and abdominal surgery). In the last case, the organism was isolated from the peritoneal fluid of a patient with cholecystitis. The infection was considered nosocomial in five cases and community acquired in the other.

Increased serum IL-2R levels in coeliac disease are related to CD4 but not CD8 antigens

Forty-three coeliac children, ranging from 1 year and 3 months to 14 years and 9 months, were studied. Twenty-eight patients were in an active phase of the disease, and 15 were in remission. The criteria of coeliac disease (CD) activity were established according to the results of IgA anti-endomysial antibodies (IgA-AEm). Interleukin 2 receptor (IL-2R) and CD4 and CD8 antigens were measured in serum samples by an ELISA technique using two noncompetitive monoclonal antibodies. Antigliadin antibodies of IgG (IgG-AGA) and IgA (IgA-AGA) classes were also measured. The AEm-positive coeliac patient group showed values of 1,860 +/- 948 U/ml for IL-2R, 430 +/- 228 U/ml for CD8, and 36.8 +/- 25.1 U/ml for CD4. AEm-negative patients showed values of 980 +/- 436 U/ml, 350 +/- 243 U/ml, and 24.1 +/- 20 U/ml, respectively. IL-2R levels were the only ones significantly elevated (p < 0.005) in the active coeliac group. On the other hand, IgG-AGA and IgA-AGA were both clearly increased (p < 0.001). IL-2R levels in active coeliac patients correlated with CD4 levels (p < 0.05), but not with CD8, IgG-AGA, and IgA-AGA levels. We also found a surprising negative correlation between AEm antibodies of IgA2 class with both IL-2R (r = 0.471; p < 0.05) and CD8 (r = 0.616; p < 0.05). The results show that in CD there is a lymphocyte activation affecting mainly CD4+ cells and not correlated with serum AGA levels, suggesting an independence of both immunological phenomena and probably with different locations of origin.