Immunotolerant indoleamine-2,3-dioxygenase is increased in condyloma acuminata.

BACKGROUND: The tryptophan-depleting enzyme indoleamine-2,3-dioxygenase (IDO) is critical for the regulation of immunotolerance and plays an important role in immune-associated skin diseases. OBJECTIVES: To analyse the level of IDO in condyloma acuminata (CA) and its role in this condition. METHODS: IDO expression was assessed in the skin and peripheral blood of healthy controls and patients with CA. To assess the role of skin IDO in immunity, the ability of isolated epidermal cells to metabolize tryptophan and the influence on polyclonal T-cell mitogen (PHA)-stimulated T-cell proliferation were explored. RESULTS: IDO median fluorescence intensities in peripheral blood mononuclear cells from patients with CA were similar to those from healthy controls. Immunohistochemistry showed that IDO+ cells were rare in normal skin and the control skin of patients with CA, but were greatly accumulated in wart tissue. Most fluorescence signals of IDO+ cells did not overlap with those of CD1a+ Langerhans cells. Human papillomavirus (HPV) DNA probe in situ hybridization showed a large number of IDO+ cells in the HPV- site. Keratinocytes in the skin of healthy controls and the circumcised skin of patients with CA could minimally transform tryptophan into kynurenine, but IDO-competent epidermal cells from warts could transform tryptophan. In addition, these IDO-competent epidermal cells could inhibit PHA-stimulated T-cell proliferation. The addition of an IDO inhibitor, 1-methyl-d-tryptophan, restored the inhibited T-cell proliferation. CONCLUSIONS: Abnormally localized high IDO expression might be involved in the formation of a local immunotolerant microenvironment.

T-cell activation Rho GTPase-activating protein expression varies with inflammation location and severity in Crohn's disease.

BACKGROUND: The T-cell activation Rho GTPase-activating protein (TAGAP) gene has a regulatory role in T cell activation. We have previously suggested a correlation between the TAGAP-associated single nucleotide polymorphism rs212388 and protection from anal sepsis in Crohn's disease (CD) patients. The present study sought to evaluate TAGAP's expression in colonic tissue of CD patients with varying disease severity and location. MATERIALS AND METHODS: Five transverse, 17 left, and five sigmoid colectomy specimens from 27 CD patients with varying disease severity (16 male, mean age at diagnosis 26.4 ± 2.2 y) were evaluated for TAGAP messenger RNA expression. Fisher exact, Mann-Whitney, and Welch two-sample t-tests were used for statistical evaluation. Immunohistochemistry confirmed results. RESULTS: Patients with tissue demonstrating lower TAGAP messenger RNA expression (less than the overall mean) were younger at diagnosis (mean age 21.1 ± 6.3 versus 32.5 ± 13 y, P = 0.009). Increased TAGAP expression was seen in moderate or severely diseased tissue versus tissue with no or mild disease (RQ = 1.3 ± 0.34 versus 0.53 ± 0.09, P = 0.050). This was the most dramatic in the sigmoid colon (P = 0.041). TAGAP expression was increased in more distal tissue with a significant difference seen when comparing transverse versus sigmoid colon with moderate or severe disease (0.51 ± 0.14 versus 1.9 ± 0.37, P = 0.049). CONCLUSIONS: Colonic expression of TAGAP in CD patients varied according to disease severity and location, being the most elevated in patients with severe disease in the sigmoid colon. Whether changes in TAGAP expression are a result of disease response or inherent to the disease pathophysiology itself remains to be determined. This gene warrants further investigation for its role in CD.

Matrix metalloproteinase mRNA expression in canine anal furunculosis lesions.

Although the aetiology of anal furunculosis (AF) in dogs is poorly understood, there is evidence for an underlying immune dysfunction. This is illustrated by the presence of a T helper type 1 cytokine mRNA profile in AF lesions and the clinical response to ciclosporin therapy. Expression of MMPs 2, 9 and 13 were evaluated in AF lesional biopsies by real-time quantitative RT-PCR. There was significantly increased expression of both MMP-9 and MMP-13 mRNA in AF biopsies compared to controls (p<0.001) but no significant difference in MMP-2 mRNA expression. Since MMP-9 and MMP-13 are primarily produced by macrophages, these data suggest that ulceration could be the result of aberrant activation of this cell type in the tissues. It is feasible that such pathological macrophage activity occurs in response to interferon-gamma secreted by T helper type 1 cells. This could explain why the lesions resolve following treatment with the immunosuppressive drug ciclosporin.

Absence of NADPH-diaphorase activity in internal anal sphincter (IAS) achalasia.

We studied the internal anal sphincter (IAS) muscle from 10 patients with achalasia and five normal controls using histochemical staining for NADPH-diaphorase and acetylcholinesterase (AChE). Normal control IAS muscle contained occasional AChE-positive nerve fibers, whereas IAS achalasia specimens demonstrated prominent AChE-positive nerve fibers in muscle layers. NADPH-diaphorase activity was strongly expressed in nerves in the normal IAS muscle but was absent or scanty in the muscle of patients with IAS achalasia. Our findings of increased AChE-positive nerves and the absence of NADPH-diaphorase activity taken in conjunction with reports of abnormal peptidergic innervation indicate that complex neural abnormalities occur in IAS achalasia. The primary event remains obscure, but it is possible that a single defect, such as nitrergic nerve depletion, may lead to compensatory changes in the other nerve fibers.