StlmmaryWe have previously demonstrated that bacterial lipopolysaccharide (LPS) is capable of promoting Coxsackie B3 (CB3)-induced myocarditis in genetically resistant B10.A mice. Because LPS is known to increase production of various cytokines, we tested CB3-infected, LPS-treated mice for the presence of interleukin 1 (II.-1) and tumor necrosis factor (TNF). We found significantly increased amounts of both cytokines in the sera of CB3/LPS-treated mice compared with animals treated only with LPS. We also found immunohistochemical evidence for local production of these cytokines in the cardiac tissue of CB3/LPS-treated mice. Treatment with IL-1 or TNF alone promoted CB3-induced autoimmune myocarditis in resistant B10.A mice. Myocarditis was also observed when uninfected mice were immunized with syngeneic heart extract in the presence of 1I.-1 or TNF.

BackgroundChronic mucocutaneous candidiasis disease (CMCD) may result from various inborn errors of interleukin (IL)-17-mediated immunity. Twelve of the 13 causal mutations described to date affect the coiled-coil domain (CCD) of STAT1. Several mutations, including R274W in particular, are recurrent, but the underlying mechanism is unclear.ObjectiveTo investigate and describe nine patients with CMCD in Eastern and Central Europe, to assess the biochemical impact of STAT1 mutations, to determine cytokines in supernatants of Candida-exposed blood cells, to determine IL-17-producing T cell subsets and to determine STAT1 haplotypes in a family with the c.820C>T (R274W) mutation.ResultsThe novel c.537C>A (N179K) STAT1 mutation was gain-of-function (GOF) for γ-activated factor (GAF)-dependent cellular responses. In a Russian patient, the cause of CMCD was the newly identified c.854 A>G (Q285R) STAT1 mutation, which was also GOF for GAF-dependent responses. The c.1154C>T (T385M) mutation affecting the DNA-binding domain (DBD) resulted in a gain of STAT1 phosphorylation in a Ukrainian patient. Impaired Candida-induced IL-17A and IL-22 secretion by leucocytes and lower levels of intracellular IL-17 and IL-22 production by T cells were found in several patients. Haplotype studies indicated that the c.820C>T (R274W) mutation was recurrent due to a hotspot rather than a founder effect. Severe clinical phenotypes, including intracranial aneurysm, are presented.ConclusionsThe c.537C>A and c.854A>G mutations affecting the CCD and the c.1154C>T mutation affecting the DBD of STAT1 are GOF. The c.820C>T mutation of STAT1 in patients with CMCD is recurrent due to a hotspot. Patients carrying GOF mutations of STAT1 may develop multiple intracranial aneurysms by hitherto unknown mechanisms.

Heart-reactive antibodies are commonly observed in patients with myocarditis or cardiomyopathy. Such antibodies may be important in the pathogenesis of these disorders, yet the specific antigens recognized have not been studied systematically. This report characterizes circulating heart autoantibodies from patients with myocarditis (n = 17) or idiopathic cardiomyopathy (n = 71) and from healthy volunteers (n = 15). Indirect immunofluorescence demonstrated that high titer (greater than or equal to 1:20) immunoglobulin G (IgG) antibody activity occurred in 59% of the myocarditis samples, 20% of the cardiomyopathy samples and none of the normal samples. All samples were tested by Western immunoblotting for IgG activity against a normal human heart extract. The number of antigens recognized by each sample was enumerated and the molecular weight of each antigen estimated; the prevalence of reactivity against antigens in selected molecular weight classes was determined. There was no difference in the mean number of heart antigens recognized by serum from each group. For most weight classes, prevalence either did not differ significantly among the various groups or subgroups or was greatest among samples from healthy volunteers. Prevalence of reactivity with 190 to 199 kilodalton (kd) antigens was greatest (p less than 0.05) among low titer serum samples from patients with myocarditis. High titer cardiomyopathy serum differed from normal serum by an increased (p less than 0.05) prevalence of antibodies to 40 to 49 and 100 to 109 kd antigens. These results suggest that western immunostaining may ultimately contribute substantively to identifying patients with myocarditis or cardiomyopathy.

X-linked lissencephaly with abnormal genitalia (XLAG) is a distinct form of lissencephaly associated with absent corpus callosum. Recently, forms of syndromic and nonspecific X-linked mental retardation have been found to be associated with mutations in the Aristaless-related homeobox gene ARX. The authors assessed ARX as a candidate gene for XLAG in a genetic analysis of neuronal migration disorders and found two different point mutations in two XLAG pedigrees affecting the homeodomain of the protein, confirming that ARX is a causative gene for XLAG.

Growth hormone (GH) insensitivity syndrome (GHIS) is a rare clinical condition in which production of insulin-like growth factor 1 is blunted and, consequently, postnatal growth impaired. Autosomal-recessive mutations in signal transducer and activator of transcription (STAT5B), the key signal transducer for GH, cause severe GHIS with additional characteristics of immune and, often fatal, pulmonary complications. Here we report dominant-negative, inactivating STAT5B germline mutations in patients with growth failure, eczema, and elevated IgE but without severe immune and pulmonary problems. These STAT5B missense mutants are robustly tyrosine phosphorylated upon stimulation, but are unable to nuclear localize, or fail to bind canonical STAT5B DNA response elements. Importantly, each variant retains the ability to dimerize with wild-type STAT5B, disrupting the normal transcriptional functions of wild-type STAT5B. We conclude that these STAT5B variants exert dominant-negative effects through distinct pathomechanisms, manifesting in milder clinical GHIS with general sparing of the immune system.

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Advances in genetic engineering have created opportunities for improved understanding of the molecular basis of carcinogenesis. Through selective introduction, activation, and inactivation of specific genes, investigators can produce mice of unique genotypes and phenotypes that afford insights into the events and mechanisms responsible for tumor formation. It has been suggested that such animals might be used for routine testing of chemicals to determine their carcinogenic potential because the animals may be mechanistically relevant for understanding and predicting the human response to exposure to the chemical being tested. Before transgenic and knockout mice can be used as an adjunct or alternative to the conventional 2-year rodent bioassay, information related to the animal line to be used, study design, and data analysis and interpretation must be carefully considered. Here, we identify and review such information relative to Tg.AC and rasH2 transgenic mice and p53 +/-and XPA -/-knockout mice, all of which have been proposed for use in chemical carcinogenicity testing. In addition, the implications of findings of tumors in transgenic and knockout animals when exposed to chemicals is discussed in the context of human health risk assessment.

Although endoscopic examination in patients with bleeding of the upper gastrointestinal tract has improved diagnostic accuracy, it has not been useful in predicting clinical outcome and has not been shown to improve the patients' prognoses. This article describes a subgroup of patients with acute upper gastrointestinal bleeding whose clinical outcome can be predicted at the time of endoscopy. In 28 of 317 patients who underwent endoscopy, a "visible vessel" was seen in an ulcer presumed to be the bleeding site. All 28 were later recommended for operation because of recurrent (86 per cent) or uncontrolled (14 per cent) hemorrhage. In contrast, 75 per cent of the remaining 289 patients in whom vessels were not seen, whether or not bleeding from ulcers, had single bleeding episodes managed medically. Since patients with a "visible vessel" can be expected to have uncontrolled or recurrent hemorrhage, surgical treatment should be considered at the time of endoscopy if such a vessel is seen.