Human Anti-Human PTGDR2 monoclonal Antibody, clone SFB609 [APC]

Objective: Adenoids, tubal tonsil, palatine tonsil, and lingual tonsil are immunological organs included in the Waldeyer's ring, the basic function of which is the antibody production to common environmental antigens. Adenoidal hypertrophy (AH) is a major medical issue in children, and adenoidectomy is still the most used treatment worldwide. The response of adenoids to allergens is a good model to evaluate their immunological function. This report assessed the immunological changes in adenoid tissues from children with allergic rhinitis (AR) undergoing sublingual immunotherapy (SLIT). Methods: Adenoid samples from 16 children (seven males, nine females, mean age 7.12 years) with AH and clinical indication to adenoidectomy were collected. Of them, five children were not allergic and 11 had house dust mite and grass pollen-induced AR. Among allergic children, in four AR was treated by antihistamines while in seven AR was treated by high-dose SLIT during 4-6 months. The evaluation addressed the T helper 1 (Th1), Th2, and Th3 cells by performing a PCR array on mRNA extracted from adenoid samples. Results: In non-allergic children, a typical Th1 pattern was found. SLIT induced a strong down-regulation of genes involved in Th2 and Th1 activation and function. In particular, in SLIT-treated allergic children IL-4, CCR2, CCR3, and PTGDR2 (Th2 related genes) and CD28, IL-2, and INHA (Th1 related genes) expression was reduced, compared with children treated with antihistamines. Conclusions: These preliminary findings warrant investigation in trials including larger numbers of patients, but indicate that hypertrophic adenoids of allergic children have the typical response to the specific allergen administered by SLIT. This should suggest that one should reconsider the immunological role of adenoids.

Aims/Hypothesis GPR44 (DP2, PTGDR2, CRTh2) is the receptor for the pro-inflammatory mediator prosta-glandin D-2 (PGD(2)) and it is enriched in human islets. In rodent islets, PGD(2) is produced in response to glucose, suggesting that the PGD(2)-GPR44/DP2 axis may play a role in human islet function during hyperglycemia. Consequently, the aim of this work was to elucidate the insulinotropic role of GPR44 antagonism in vitro in human beta-cells and in type 2 diabetes (T2DM) patients. Methods We determined the drive on PGD(2) secretion by glucose and IL-1 beta, as well as, the impact on insulin secretion by pharmacological GPR44/DP2 antagonism (AZD1981) in human islets and beta-cells in vitro. To test if metabolic control would be improved by antagonizing a hyperglycemia-driven increased PGD(2) tone, we performed a proof-of-mechanism study in 20 T2DM patients (average 54 years, HbA1c 9.4%, BMI 31.6 kg/m(2)). The randomized, double-blind, placebo-controlled cross-over study consisted of two three-day treatment periods (AZD1981 or placebo) separated by a three-day wash-out period. Mixed meal tolerance test (MMTT) and intravenous graded glucose infusion (GGI) was performed at start and end of each treatment period. Assessment of AZD1981 pharmacokinetics, glucose, insulin, C-peptide, glucagon, GLP-1, and PGD(2) pathway biomarkers were performed. Results We found (1) that PGD(2) is produced in human islet in response to high glucose or IL-1 beta, but likely by stellate cells rather than endocrine cells; (2) that PGD(2) suppresses both glucose and GLP-1 induced insulin secretion in vitro; and (3) that the GPR44/DP2 antagonist (AZD1981) in human beta-cells normalizes insulin secretion. However, AZD1981 had no impact on neither glucose nor incretin dependent insulin secretion in humans (GGI AUC (C-peptide 1-2h) and MMTT AUC (Glucose 0-4h) LS mean ratios vs placebo of 0.94 (80% CI of 0.90-0.98, p = 0.12) and 0.99 (90% CI of 0.94-1.05, p = 0.45), despite reaching the expected antagonist exposure. Conclusion/Interpretation Pharmacological inhibition of the PGD(2)-GPR44/DP2 axis has no major impact on the modulation of acute insulin secretion in T2DM patients.