Triplet Leptogenesis in Left-Right Symmetric Seesaw Models

We discuss scalar triplet leptogenesis in a specific left-right symmetric seesaw model. We show that the Majorana phases that are present in the model can be effectively used to saturate the existing upper limit on the CP-asymmetry of the triplets. We solve the relevant Boltzmann equations and analyze the viability of triplet leptogenesis. It is known for this kind of scenario that the efficiency of leptogenesis is maximal if there exists a hierarchy between the branching ratios of the triplet decays into leptons and Higgs particles. We show that triplet leptogenesis typically favors branching ratios with not too strong hierarchies, since maximal efficiency can only be obtained at the expense of suppressed CP-asymmetries.Comment: 16 pages, 5 figures, published versio

Increased mucosal synthesis of rheumatoid factor (RF) in coeliac disease

Increased serum levels of RF have been reported in patients with gluten sensitivity. The objective of this study was to investigate the in vivo secretion of different isotypes of RF in the small bowel in coeliac disease. Nineteen patients were investigated by perfusion of a defined jejunal segment, and the jejunal perfusion fluid was analysed for the presence of IgA and IgM anti-Fc (IgG). Five of the patients studied had serum IgA deficiency. Patients with partial/subtotal villous atrophy but no IgA deficiency (n = 7) had a four-fold increase of IgM-RF (P<0.001) and a three-fold increase of IgA-RF (P<0.001) compared with healthy controls (n = 29). Patients with normal jejunal mucosa but no IgA deficiency (n = 7) had similar IgA-RF and IgM-RF concentrations to healthy controls. Patients with serum IgA deficiency had no IgA-RF detectable in jejunal fluid but the highest IgM-RF concentrations, in particular in active disease. The coeliac patients had serum levels of IgA-RF and IgM-RF within the reference ranges. Jejunal fluid levels of IgA-RF and IgA-anti-gliadin antibodies were significantly correlated (P<0.001). The data indicate that enhanced jejunal mucosal production of RF occurs above all in active coeliac disease. The findings suggest that the immune response to gluten induces a mucosal RF synthesis