T helper cell polarisation in coeliac disease: any (T-)bet ?

Isotretinoin Exposure and Risk of Celiac Disease

Background

Isotretinoin (13-cis retinoic acid) is a metabolite of vitamin A and has anti-inflammatory and immunoregulatory effects; however, a recent publication by DePaolo et al. demonstrated that in the presence of IL-15, retinoic acid can act as an adjuvant and promote inflammation against dietary proteins.

Objective

To evaluate the risk of overt and latent celiac disease (CD) among users of isotretinoin.

Material and Methods

Medical records of patients from 1995 to 2011 who had a mention of isotretinoin in their records (N = 8393) were searched for CD diagnosis using ICD-09CM codes. Isotretinoin exposure was compared across overt CD patients and their age- and gender-matched controls from the same pool. To evaluate the risk of latent CD with isotretinoin exposure, patients were overlapped with a community-based list of patients with waste serum samples that were tested for CD serology, excluding those with overt CD (2006–2011). Isotretinoin exposure was defined as the use of isotretinoin prior to CD diagnosis or serology.

Results

Of 8393 patients, 25 had a confirmed CD diagnosis. Compared to matched controls (N = 75), isotretinoin exposure was not significantly different between overt CD patients versus controls (36% versus 39%, respectively; P = 0.712). Likewise, latent CD defined as positive serology was not statistically different between isotretinoin exposed (N = 506) versus non-exposed (N = 571) groups (1.8% versus 1.4%, respectively; P = 0.474).

Conclusions

There was no association between isotretinoin use and risk of either overt or latent CD.

Sarcoidosis: Immunopathogenesis and Immunological Markers

Sarcoidosis is a multisystem granulomatous disorder invariably affecting the lungs. It is a disease with noteworthy variations in clinical manifestation and disease outcome and has been described as an “immune paradox” with peripheral anergy despite exaggerated inflammation at disease sites. Despite extensive research, sarcoidosis remains a disease with undetermined aetiology. Current evidence supports the notion that the immune response in sarcoidosis is driven by a putative antigen in a genetically susceptible individual. Unfortunately, there currently exists no reliable biomarker to delineate the disease severity and prognosis. As such, the diagnosis of sarcoidosis remains a vexing clinical challenge. In this review, we outline the immunological features of sarcoidosis, discuss the evidence for and against various candidate etiological agents (infective and noninfective), describe the exhaled breath condensate, a novel method of identifying immunological biomarkers, and suggest other possible immunological biomarkers to better characterise the immunopathogenesis of sarcoidosis.

Celiac disease: pathogenesis of a model immunogenetic disease

Celiac disease is characterized by small-intestinal mucosal injury and nutrient malabsorption in genetically susceptible individuals in response to the dietary ingestion of wheat gluten and similar proteins in barley and rye. Disease pathogenesis involves interactions among environmental, genetic, and immunological factors. Although celiac disease is predicted by screening studies to affect approximately 1% of the population of the United States and is seen both in children and in adults, 10%-15% or fewer of these individuals have been diagnosed and treated. This article focuses on the role of adaptive and innate immune mechanisms in the pathogenesis of celiac disease and how current concepts of immunopathogenesis might provide alternative approaches for treating celiac disease.

Upregulation of T-bet expression in peripheral blood mononuclear cells during Vogt-Koyanagi-Harada disease

AIM

To test the hypothesis that T-bet expression is altered in patients with Vogt-Koyanagi-Harada (VKH) disease.

METHODS

Peripheral blood was withdrawn from 16 VKH patients before and after immunosuppressive treatment and from 16 healthy individuals. IFN-gamma, IL-2, and IL-4 in the serum and the supernatants of peripheral blood mononuclear cells (PBMC) cultured with or without phytohaemagglutinin (PHA) were measured by ELISA. T-bet mRNA and protein expression in PBMC cultured with or without PHA was detected by RT-PCR and western blot, respectively.

RESULTS

The level of IFN-gamma, but not IL-2 and IL-4, was significantly higher in the supernatants of stimulated PBMC in patients than in controls. A significantly increased T-bet mRNA was found in VKH patients during an active uveitis episode, but not in quiescent patients, compared to controls. T-bet protein was detectable in VKH patients during an active uveitis episode, but not in quiescent patients nor in the healthy controls. Stimulation of PBMC with PHA resulted in a marked upregulation of T-bet mRNA and protein expression for both patients and controls with no significant difference between the two groups.

CONCLUSIONS

Upregulation of T-bet may be associated with the development of a Th1 mediated immune response in VKH disease.

T-bet expression patterns in coeliac disease, cryptic and overt enteropathy-type T-cell lymphoma

AIMS

To clarify the distribution and lineage allocation of T-bet-expressing cells in coeliac disease (CD) and in enteropathy-type T-cell lymphoma (ETTCL). The detection of elevated levels of interferon-gamma, interleukin-18 and the key regulator of Th1 helper immune response T-bet in CD biopsies led to the view that CD is the result of a Th1 response to gluten. It remains unknown whether T-bet is expressed in cryptic and overt ETTCL.

METHODS

Specimens from 20 patients with CD, five patients with cryptic and 10 patients with overt ETTCL were analysed by immunohistology employing single and double labellings for T-bet and CD4 or CD8 antigens.

RESULTS

In CD specimens nearly all intraepithelial CD8 cells and many CD4 cells in the lamina propria expressed T-bet. Cryptic ETTCL showed T-bet expression in the intraepithelial neoplastic cells while T-bet+ CD4 cells in the lamina propria were rare. Overt ETTCL showed T-bet expression in cases with non-anaplastic morphology. In addition, a proportion of bystander T cells expressed T-bet.

CONCLUSIONS

Morphological evidence proves that while T-bet orchestrates a CD4- and CD8-based Th1 reaction in CD, its expression shifts to the neoplastic intraepithelial compartment of cryptic ETTCL and becomes absent or lost in anaplastic overt ETTCL.