Increased mucosal inflammatory cytokines in children with Helicobacter pylori-associated gastritis

The concentrations of tumour necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and IL-1-β in tissue homogenates of gastric mucosal biopsy specimens, and in gastric juice samples from Helicobacter pylori-positive and -negative children, were determined. The study population comprised 30 children with recurrent abdominal pain attending upper gastrointestinal endoscopy. Of these patients 18 were infected with H. pylori. Cytokine concentrations in gastric biopsy homogenate supernatants and in gastric juice were measured by enzyme-linked immunosorbent assay (ELISA). TNF-α levels in gastric juice and in gastric biopsy homogenate supernatants in patients with H. pylori-positive gastritis were found to be significantly higher than those in children without H. pylori infection. IL-6 levels were also higher in H. pylori -infected subjects, but the difference in IL-6 concentrations measured in gastric juice and biopsy homogenate supernatants did not reach statistical significance. IL-1-β concentrations in both specimens showed no significant difference between the two groups of children. It was suggested that increased levels of inflammatory cytokines, especially TNF-α and IL-6 generated locally within the gastric mucosa might be implicated in the pathogenesis of H. pylori-associated gastritis in childhood.     

Influence of Mycobacterium leprae and its soluble products on the cutaneous responsiveness of leprosy patients to antigen and recombinant interleukin 2.

Experiments were carried out in the skin of patients with leprosy to examine whether suppressor cell populations either exist in the skin of multibacillary lepromatous leprosy patients, can be activated with antigen, or are induced to emigrate into a cutaneous site from the circulation. For this purpose, purified protein derivative of tuberculin, a delayed-type antigen that generates a cell-mediated immune response, was introduced into the skin alone or with nonviable Mycobacterium leprae bacilli. Areas of induration and the resulting numbers and phenotypes of emigratory cells were not influenced by M. leprae and its products. Further studies examined the ability of M. leprae and its soluble products to modify the cutaneous response to intradermal injection of recombinant interleukin 2 (IL-2), a lymphokine that mimics a cell-mediated response. Neither the simultaneous injection of M. leprae and IL-2, nor the prior injection of M. leprae followed in 2 days by IL-2, nor the prior administration of IL-2 followed in 4 days by M. leprae, into the same skin site, modified the zone of induration generated by IL-2. In addition, the immunocytochemical and histopathological evaluation of biopsy specimens of skin sites showed no difference between sites injected with IL-2 and sites injected with IL-2 and M. leprae. We conclude that suppressor T cells, if they exist, do not influence the gross or microscopic responsiveness of a cell-mediated skin reaction to antigen and IL-2. IL-2 did, however, enhance the responsiveness of skin-test-positive tuberculoid patients and family contacts to M. leprae antigens by a synergistic effect on the zone of induration and local cell accumulation.     

Cytotoxic T-cell response to ectromelia virus-infected cells. Different H-2 requirements for triggering precursor T-cell induction or lysis by effector T cells defined by the BALB/c-H-2(db) mutation

The T(c)-cell response to ectromelia virus infection was studied in BALB/c-H-2(db) mice which carry a loss mutation in the H-2D region that results in the absence from cell surfaces of a molecule (D’) bearing certain public H-2 specificities. When infected, these mice showed a poor response of T(c) cells that recognize H-2D(d) plus virus-specific determinants on infected macrophage targets, but gave a normal response to H-2K d plus virus-specific antigens. However, their own infected macrophages do display wild-type antigenic patterns involving virus and H-2D(d) since they were killed as efficiently as wild-type (BALB/c,H- 2(d))-infected cells by T(c) cells specific only for H-2D(d) plus viral antigens. When tested in vitro, infected BALB/c-H-2(db) cells stimulated a poor T(c)-cell response to H-2D plus virus-specific antigens, but stimulated a normal response (in comparison with infected BALB/c macrophages) to H-2K(d) plus viral antigens. Uninfected BALB/c-H-2(db) cells stimulated a normal T(c)-cell response to minor H antigens or trinitrophenyl in association with H-2D(d), thus suggesting that the defective response to infection may reside in a failure of the relevant H-2D(d) antigens of mutant cells to physically associate with viral antigens. Close association of viral and H-2D-coded molecules was also suggested by ability of specific anti-H-2K or -H-2D to partially block T(c)-cell-mediated lysis of infected targets. These results were interpreted to mean that H-2Dd-dependent, virus- immune T(c) cells recognized an antigenic pattern consisting of virus- specific and H-2D(d) determinants with the latter borne on an H-2D molecule carrying serologically-defined H-2D(d) private specificities. A second H-2D(d)-coded molecule (D’) was not required for recognition and lysis by activated T(c) cells, but was apparently necessary for efficient stimulation of precursor T(c) cells, perhaps by promoting appropriate physical association of viral and H-2D(d) molecules.     

Two novel AIRE mutations in autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) among Indians

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is a rare recessive disorder resulting from mutations in the autoimmune regulator ( AIRE ) gene. There is no information on AIRE mutations in Indians. In a cross-sectional study, nine patients (eight families), from four referral hospitals in India, were studied for AIRE mutations by direct sequencing. We screened for new mutations in 150 controls by allele-specific PCR. The patients had 1–7 known components of APECED. Three patients had unusual manifestations: presentation with type 1 diabetes; chronic sinusitis and otitis media; and facial dysmorphism. All patients carried homozygous, probably recessive, AIRE mutations. Two unrelated patients from a small in-bred community (Vanika Vaisya) in south India carried an unreported missense mutation, p.V80G, in the N-terminal caspase recruitment domain. Another unique mutation, p.C302X, resulting in a truncated protein with deletion of both zinc-finger domains, was detected in a patient from Gujarat. Neither mutation was detected in controls. Other mutations, previously described in Caucasians, were: 13 base pair deletion (p.C322fsX372) in 4 (38%), and Finn-major (p.R257X) and p.R139X (Sardinian) mutation in one subject each. In conclusion, in this first series of APECED in Indians, we detected AIRE mutations previously reported in Caucasians, as well as unique mutations. Of these, p.V80G is possibly an ancestral mutation in an in-bred community.     

Evaluation of four semi-synthetic Mycobacterium leprae antigens with sera from healthy populations in endemic and non-endemic areas.

In order to determine the frequency of occurrence of antibodies to semisynthetic antigens of Mycobacterium leprae in clinically healthy nonpatient populations and to establish a 'baseline' for comparison with antibody frequencies in both patients with a history of leprosy and their contacts, ELISAs were conducted using representative sera from two areas: a leprosy endemic area, Cebu City, Philippines and a nonendemic area for leprosy Chicago, Illinois, USA. These sera were tested, by an indirect IgM ELISA, for the presence of antibodies reacting with four semisynthetic antigens based on the phenolic glycolipid I antigen of M. leprae: ND-O-BSA (natural disaccharide with octyl linkage to bovine serum albumin), NT-O-BSA (natural trisaccharide with octyl linkage to BSA), ND-P-BSA (natural disaccharide with phenolic ring linkage to BSA) and NT-P-BSA (natural trisaccharide with phenolic ring linkage to BSA). Using an OD reading > or = 0.16 as positive, the antigen with the lowest background seroreactivity was ND-O-BSA, which reacted with 5/398 (1.3%) sera from Cebu, and 3/426 (0.7%) sera from Chicago. A total of 10 (2.5%) of 398 sera from the endemic area reacted with at least one antigen and 5 (1.3%) sera reacted with all four semisynthetic antigens. Of the 426 sera from Chicago, 12 (2.8%) were reactive with at least one antigen and 3 (0.7%) were reactive with all four semisynthetic antigens. Mean ELISA values for the 22 positive sera for each antigen ranged from 0.17 to 0.3 OD units, while the mean values for all sera in each area ranged from 0.01 to 0.04 OD units for all four antigens. Reactivity of 14 of the positive sera to some antigens, but not all four semisynthetic antigens, indicated that the carrier and linker arms might be associated with this background reactivity. Investigation of alternative linker arms and carriers is warranted. We conclude that nonspecific background reactivity to the semisynthetic antigens representing the PG-I molecule of M. leprae is 0.7-1.3%, based on a > or = 0.16 OD cutoff value. From these data it was concluded that reactivity in individuals free of leprosy was low enough to warrant use of these antigens in a diagnostic setting, such as screening household contacts and highly endemic populations. When incidence and prevalence of leprosy are low, testing with these antigens would not be cost effective, unless applied to high risk individuals.(ABSTRACT TRUNCATED AT 400 WORDS)