Polyclonal T-cell responses to cytochrome P450IID6 are associated with disease activity in autoimmune hepatitis type 2

BACKGROUND & AIMS: Autoimmune hepatitis type 2 (AIH-2), a severe juvenile liver disorder of unknown etiology and pathogenesis, is characterized by liver-kidney microsomal antibody type 1 targeting cytochrome P450IID6 (CYP2D6) and is associated to HLA DRB1*07. Although CYP2D6 B-cell reactivity has been extensively characterized, little is known about CYP2D6-specific T-cell responses. The aim of the present study was to characterize anti-CYP2D6 cellular immune responses and their possible pathogenic role in patients with AIH-2. METHODS: We investigated T-cell reactivity against 61 overlapping peptides spanning the full CYP2D6 protein using ex vivo cultures obtained at diagnosis, remission, and relapse. Moreover, CYP2D6-specific T-cell reactivity was investigated in the context of HLA restriction, peptide-binding affinity to HLA DRB1*07, cytokine profile, disease specificity, and clinical course. RESULTS: Proliferative responses to CYP2D6 cluster to 7 antigenic regions in DRB1*07 and to 4 regions in non-DRB1*07 patients. Whereas distinct peptides induce production of interferon gamma, interleukin-4, or interleukin-10, peptides inducing interferon-gamma and proliferation overlap. There is also an overlap between sequences inducing T- and B-cell responses. The breadth (number of epitopes) and intensity (quantity of cytokine produced) of the T-cell response are directly correlated to disease activity (biochemical and histologic markers). CONCLUSIONS: These data imply that the T-cell response to CYP2D6 in AIH-2 is polyclonal, involves multiple effector types targeting different epitopes, and is associated with hepatocyte damage, knowledge that should form the basis for a more refined therapeutic approach.     

Co-culture of synovial fibroblasts and differentiated U937 cells is sufficient for high interleukin-6 but not interleukin-1beta or tumour necrosis factor-alpha release

Inflamed synovium is characterized by high concentrations of cytokines [interleukin (IL)-6, IL-1beta and tumour necrosis factor (TNF)-alpha] and the abundant presence of infiltrated monocytes, many of which are found adjacent to the resident fibroblast-like synoviocytes. We have used a co-culture of fibroblast-like synoviocytes and differentiated U937 cells to study IL-6, IL-1beta and TNF-alpha release. After a 3 day co-culture, 35% of the U937 cells had adhered and were fully differentiated towards monocytes, as determined by expression of p47phox, CD14, MSE-1, Mac-1, collagenase and NADPH oxidase activity. IL- 6 release from fibroblast-like synoviocytes was induced 4-fold by co- culture with differentiated U937 cells. However, co-culture of differentiated U937 cells with fibroblast-like synoviocytes failed to release detectable levels of IL-1beta and TNF-alpha from the U937 cells. Addition of synovial fluid further increased IL-6 release, but again had no effect on IL-1beta or TNF-alpha, although U937 cells differentiated by phorbol ester were able to release these two cytokines and, in the case of the co-culture, mRNAs for both cytokines were highly expressed in the U937 cells. We postulate that the influx of monocytes into the synovium is instrumental in the elevation of IL-6 levels, but this is not sufficient to explain high levels of IL-1beta or TNF-alpha.      

Comparison of 3‐Year Clinical Outcomes Between Resolute™ Zotarolimus‐ and Sirolimus‐Eluting Stents for Long Coronary Artery Stenosis

Objectives

Long‐term clinical outcomes were evaluated in long coronary artery stenosis treated with different types of drug‐eluting stents.

Background

Long‐term follow‐up data to compare clinical outcomes between Resolute? zotarolimus‐eluting stent (R‐ZES) versus sirolimus‐eluting stent (SES) implantation for long coronary artery stenosis is insufficient.

Methods

A total of 254 patients (307 lesions) treated with R‐ZES and 265 patients (303 lesions) treated with SES for long coronary lesions (total stent length ≥30 mm) were enrolled, and long‐term (3 years) clinical outcomes were compared between the 2 groups. Efficacy (target lesion revascularization [TLR]) and safety (the composite occurrence of cardiovascular death, target lesion–related myocardial infarction, or target lesion–related definite stent thrombosis) were assessed.

Results

The 2 groups had similar baseline characteristics except for the duration of dual antiplatelet therapy (23.4 ± 11.2 months in R‐ZES‐treated patients vs. 27.4 ± 13.9 months in SES‐treated patients, P < 0.001). Total stent length was similar in R‐ZES‐treated patients (45.0 ± 19.0 mm) and SES‐treated patients (45.4 ± 18.6 mm) (P = 0.464). The cumulative TLR rate was 4.6% in R‐ZES‐treated patients versus 4.6% in SES‐treated patients (P = 0.911). For safety parameters, R‐ZES‐treated patients showed a significantly lower rate of the composite occurrence of cardiovascular death, target lesion–related myocardial infarction, or target lesion–related definite stent thrombosis than SES‐treated patients (0.4% vs. 2.4%, P = 0.042). Particularly, the occurrence of target lesion–related definite stent thrombosis was significantly lower in R‐ZES‐treated patients than in SES‐treated patients (0.0% vs. 2.0%, P = 0.028).

Conclusions

R‐ZES stents showed superior long‐term safety than SES for treating long coronary lesions, while maintaining a similar clinical efficacy.