The role of regulatory T cells in the acquisition of tolerance to food allergens in children.

Food allergy is a pathological immune reaction that identifies certain harmless food proteins, usually tolerated by the majority of the people, as a threat. The prevalence of these food allergies is increasing worldwide and currently affects 8% of children. Exacerbated reactions to milk, egg and peanut are the most frequent in the pediatric population. It is well known that allergic diseases are a type 2 T-helper (Th2) immune response, characterized by the elevated production of IgE antibodies. However, little is known about the immune mechanisms responsible for the development of clinical tolerance toward food allergens. Recent studies have suggested the key role of regulatory T cells (Tregs) in controlling allergic inflammation. In this review, we discuss the importance of Tregs in the pathogenesis of food allergy and the acquisition of oral tolerance in children. Further investigation in this area will be crucial for the identification of predictive markers and the development of new therapies, which will represent a clinical and social benefit for these allergic diseases.

Colony-level assessment of Brucella and Leptospira in the Guadalupe fur seal, Isla Guadalupe, Mexico.

The relatively small population size and restricted distribution of the Guadalupe fur seal Arctocephalus townsendi could make it highly vulnerable to infectious diseases. We performed a colony-level assessment in this species of the prevalence and presence of Brucella spp. and Leptospira spp., pathogenic bacteria that have been reported in several pinniped species worldwide. Forty-six serum samples were collected in 2014 from pups at Isla Guadalupe, the only place where the species effectively reproduces. Samples were tested for Brucella using 3 consecutive serological tests, and for Leptospira using the microscopic agglutination test. For each bacterium, a Bayesian approach was used to estimate prevalence to exposure, and an epidemiological model was used to test the null hypothesis that the bacterium was present in the colony. No serum sample tested positive for Brucella, and the statistical analyses concluded that the colony was bacterium-free with a 96.3% confidence level. However, a Brucella surveillance program would be highly recommendable. Twelve samples were positive (titers 1:50) to 1 or more serovars of Leptospira. The prevalence was calculated at 27.1% (95% credible interval: 15.6-40.3%), and the posterior analyses indicated that the colony was not Leptospira-free with a 100% confidence level. Serovars Icterohaemorrhagiae, Canicola, and Bratislava were detected, but only further research can unveil whether they affect the fur seal population.

Tratamiento con metformin en pacientes con enfermedad hepática grasa no alcoholica portadores de resistencia a la insulina / Treatment with metformin in patient with nonalcoholic steatohepatitis disease carrier of insuline resistance

Determinar si el tratamiento con metformin modifica los valores de aminotransferasas séricas y la histología hepática en pacientes con enfermedad hepática grasa no alcoholica (EHGNA) y Resistencia a la insulina (RI). 22 pacientes con diagnóstico histológico de EHGNA, RI y transaminasas elevadas recibieron tratamiento con metformin 1000 mg/día. Fueron seguidos por tres meses (n: 4), seis meses (n:4, nueve meses (n:7) y 12 (n:7), con controles trimestrales de aminotransferasas y control histológico al año. Utilizamos t de student pareada y análisis de varianza, p<0.05. La TGo disminuyó en 9 pacientes, y se normalizó en 11; la TGP disminuyó en 9 pacientes y se normalizó también en 9 pacientes, siendo estadísticamente significante en el grupo seguido por seis (p=0,007) y doce meses (p=0.02). Al tercer mes de seguimiento en todos los pacientes disminuyeron la TGO (84,5 a 37,04; p=0,000037) y la TGP (137,27 a 72,95; p=0,0019067). Se repitió la biopsia herpática post-tratamiento en 3 pacientes. En uno disminuyó el grado de 2 a 1 sin cambios en el estadio y en los otros dos no cambió ni el grado ni estadío. El metformin disminuyó las aminotransferasas séricas significatntemente llegando a normalizarse los valores en la mitad de los pacientes tratados. No podemos establecer conclusdiones sobre los efectos del metformin en la histología hepática por el pequeño número de pacientes con biopsia hepática post-tratamiento

Jejunal diverticulosis and gastrointestinal bleeding.

Occult gastrointestinal bleeding frequently frustrates clinicians' attempts to locate the source. Foci of hemorrhage within the small bowel are often found only at laparotomy and can be attributed to Meckel's diverticula, carcinomas, or less frequently, pulsion-type diverticula. We report our experience with two patients whose jejunal diverticula resulted in recurrent episodes of massive gastrointestinal hemorrhage.

Carcinosarcoma of the esophagus--pattern of recurrence.

Carcinosarcoma of the esophagus is a rare malignant neoplasm, predominantly affecting men in their seventh decade of life. While presenting symptoms and anatomic location of squamous cell and carcinosarcoma of the esophagus are similar, the latter often presents as a large intraluminal polypoid mass on barium esophagram. The more favorable prognosis associated with carcinosarcoma versus other esophageal neoplasms has been attributed to early onset of symptoms, resulting in prompt diagnosis, and a lower propensity for tumor invasion. We report the case of an elderly woman presenting with dysphagia who was initially diagnosed with esophageal leyomyosarcoma. Final tumor pathology showed esophageal carcinosarcoma.

HGV RNA sequences in liver and PBMC.

HGV has been identified in patients with chronic hepatitis of unknown aetiology and the possibility that HGV may be the cause has been raised. We have analysed liver biopsies and PBMC (peripheral blood mononuclear cells) from 80 patients with chronic hepatitis and HGV-RNA in serum by PCR. In ten patients HGV-RNA was detected in liver, in five patients it was detected in PBMC and seven were positive in both specimens by PCR. Whether this agent resides and replicates in hepatocytes remains controversial and needs more studies.

Detection of mycobacterial DNA in papulonecrotic tuberculid lesions by polymerase chain reaction.

Tuberculids are a heterogeneous group of cutaneous lesions. Recent discoveries of M. Tuberculosis DNA in these lesions by PCR suggest that M. tuberculosis could play a role in their pathogenesis. The aim of this study was to demonstrate the presence of M. tuberculosis DNA by polymerase chain reaction in papulonecrotic tuberculid lesions. Skin biopsy specimens from ten patients with papulonecrotic tuberculid lesions (histopathologic features) were studied. All of them tested solidly positive in a tuberculin intradermal test. A gene-amplification PCR, using primers capable of amplifying DNA in the M. tuberculosis complex, was performed to detect M. tuberculosis DNA in the lesions. A 285-bp sequence specific of M. tuberculosis complex was amplified and confirmed by Southern-blot hybridation with a 32 p 5'-labelled internal probe. No inhibitors were detected in the negative PCR samples. The PCR technique makes the detection of mycobacterial DNA in tuberculids a possibility, and therefore provides a rational basis for antituberculous therapy and for the clinical management of these disorders.

GB virus C in patients with liver disease of unknown etiology.

To assess the prevalence of GBV-C in patients suffering unknown liver disease we have investigated the GBV-C-RNA in serum of 54 patients: 10 with acute and 32 with chronic non-A-E hepatitis (16 active and 16 persistent), 10 with hepatocellular carcinoma, 2 diagnosed with hepatic fulminant failure, and 91 healthy blood donors (control). PCR with primers from NS3 helicase region was performed and the product was identified by a double strand DNA enzyme immunoassay. GBV appears to infect 40 and 31% of acute or chronic non-A-E hepatitis respectively. Also the GBV genome was found in 1 in 10 samples of hepatocarcinoma, in 2 cases of fulminant hepatitis, and in 1 in 91 of the control group. In spite of these results the role of GBV in the etiology of liver diseases has to be analyzed in more comprehensive studies.

GBV-C RNA presence in several high-risk groups of Spain.

GB virus C subtype (GBV-C) seems to share the same routes of transmission as other parenteral transmitted viruses. We have evaluated the prevalence of GBV-C in 247 patients with potential risk for GBV-C infection and in 91 healthy blood donors. The presence of GBV-C RNA was examined by polymerase chain reaction in serum samples. The 23.6% of parenteral drug users were GBV-C positive, 36.3% of them were also HIV infected. Moreover, 22.5 and 19% of sera from patients with HBV and HCV chronic hepatitis, respectively, but without apparent risk factors seemed GBV-C infected. Finally, the 6% of patients on hemodialysis were also positive. Therefore, these results suggest that GBV-C is transmitted by parenteral routes but other non-parenteral routes shared with HBV or HCV must be considered.

GBV-RNA detection by polymerase chain reaction with several primer pairs.

The identification of specific genomic sequences of GB viruses (GBV) has made it possible to utilize the polymerase chain reaction (PCR) for evaluation of the viraemia. Several studies have demonstrated the RNA-GBV presence in sera from different patients amplifying several portions of the virus. In this investigation the PCR results when different regions of GBV (NS3, UTR and putative CORE and E1) were amplified in the same sample. In 245 samples studied there were two (0.8%) discordant results and the NS3 primer showed the greatest sensitivity. The lowest percentage of positivity was obtained with CORE-E1 primers. These results could be because the nucleocapside/E1 region was extremely variable in length and sequences, although degenerated primers and probes were used. Discordances were attributable to laboratory errors, variability in the viral genome, the presence of primer inhibitors in samples or a low viral load.

Detection of enteroviral RNA by a new single-step PCR.

In this study we present a modified diagnostic routine PCR (polymerase chain reaction) technique for the detection of specific enteroviral nucleic acid sequences in human body fluids, the use of which would reduce the number of false-positive results, the costs and the concentration of reagents required in PCR. Cerebrospinal samples, pharyngeal swabs and faeces were tested. To this end, general primers, selected in the highly conserved 5' non-coding region were used, with a closed-tube RT semi-nested PCR protocol, and the PCR product was analysed using a hybridization in solid phase. A total of 32 patients with suspected enteroviral infection, 17 with suspected viral meningitis and 15 with a possible acute enteroviral infection different from meningitis were analysed, and 80% of the patients with possible acute enteroviral infection were PCR-positive. A broad range of enteroviruses can be detected and false-positive results can be reduced. The availability of results in less than 12 h and the lack of need for radiolabelled probes also increase the convenience of this protocol.

Diagnosis of cutaneous tuberculosis in biopsy specimens by PCR and southern blotting.

AIMS: To evaluate the use of a gene amplification and hybridisation method for detecting mycobacterial nucleic acid as a possible diagnostic method for cutaneous tuberculosis infection. METHODS: Biopsy specimens from 20 patients with various skin conditions of possible tuberculous aetiology were studied. Six patients had ulcerative nodules, seven lupiform lesions, two non-necrotic granulomas, one scrofulous lichen, one impetigo, one erythematosus lesions, one warty lesions, and one suspected tuberculous lipoma. Biopsy specimens were stained using Ziehl-Neelsen stain and cultured in Lowenstein-Jensen medium. DNA was extracted and then amplified by PCR using primers specific for the Mycobacterium tuberculosis complex. Specificity was confirmed by Southern blotting. RESULTS: Of the specimens, 30% were positive for mycobacteria on staining with Ziehl-Neelsen stain, 60% were culture positive and 85% PCR positive. Only 35.2% of specimens were positive with all three techniques. A further 32.5% were both culture and PCR positive. All PCR negative samples were also negative when cultured or stained with Ziehl-Neelsen stain. Of the PCR positive specimens, 29.4% were negative when cultured or stained. CONCLUSIONS: PCR, using suitable primers, is an efficient and sensitive method for the diagnosis of cutaneous tuberculosis.