Specificity of Tissue Transglutaminase Explains Cereal Toxicity in Celiac Disease

Celiac disease is caused by a selective lack of T cell tolerance for gluten. It is known that the enzyme tissue transglutaminase (tTG) is involved in the generation of T cell stimulatory gluten peptides through deamidation of glutamine, the most abundant amino acid in gluten. Only particular glutamine residues, however, are modified by tTG. Here we provide evidence that the spacing between glutamine and proline, the second most abundant amino acid in gluten, plays an essential role in the specificity of deamidation. On the basis of this, algorithms were designed and used to successfully predict novel T cell stimulatory peptides in gluten. Strikingly, these algorithms identified many similar peptides in the gluten-like hordeins from barley and secalins from rye but not in the avenins from oats. The avenins contain significantly lower percentages of proline residues, which offers a likely explanation for the lack of toxicity of oats. Thus, the unique amino acid composition of gluten and related proteins in barley and rye favors the generation of toxic T cell stimulatory gluten peptides by tTG. This provides a rationale for the observation that celiac disease patients are intolerant to these cereal proteins but not to other common food proteins

Weekly docetaxel in metastatic breast cancer patients:No superior benefits compared to three-weekly docetaxel

Background: In anthracycline-pretreated metastatic breast cancer (MBC) patients, it is unknown whether weekly single-agent docetaxel is preferable to 3-weekly docetaxel regarding its toxicity and efficacy profile. Patients and methods: In this multicenter, randomised, open-label phase III trial, 162 patients were randomised to weekly docetaxel (group A) or 3-weekly docetaxel (group B). The primary end-point was tolerability; secondary end-points were efficacy and quality of life (QoL). Results: Group A (weekly docetaxel, n = 79) experienced less haematological toxicity, with just 1.3% versus 16.9% febrile neutropenia in group B (3-weekly docetaxel, n = 77) (p = 0.001). Not this difference, but fatigue and general malaise foremost led to more patient withdrawals in group A (24 versus 12 patients, p = 0.032), less patients completing treatment (29 versus 43 patients, p = 0.014) and reduced dose-intensity (15.6 versus 26 mg/m(2)/week, 58% versus 70% of projected dose, p = 0.017). As a result, 3-weekly docetaxel was related to better overall survival in multivariate analysis (hazard ratio 0.70, p = 0.036), although in univariate analysis efficacy was similar in both groups. Reported QoL was similar in both groups, but less effective treatment with more general toxicity led to less completed QoL forms in group A (65.4% versus 50%, p = 0.049). Conclusion: Weekly docetaxel is less well tolerated than a 3-weekly schedule, due to more non-haematological toxicity, despite less febrile neutropenia. Also, no efficacy benefits can be demonstrated for weekly docetaxel, which may even be inferior based on multivariate analysis. Therefore, a 3-weekly schedule should be preferred in the setting of MBC. (C) 2011 Elsevier Ltd. All rights reserved