The Interdomain Linker of AAV-2 Rep68 Is an Integral Part of Its Oligomerization Domain: Role of a Conserved SF3 Helicase Residue in Oligomerization

The four Rep proteins of adeno-associated virus (AAV) orchestrate all aspects of its viral life cycle, including transcription regulation, DNA replication, virus assembly, and site-specific integration of the viral genome into the human chromosome 19. All Rep proteins share a central SF3 superfamily helicase domain. In other SF3 members this domain is sufficient to induce oligomerization. However, the helicase domain in AAV Rep proteins (i.e. Rep40/Rep52) as shown by its monomeric characteristic, is not able to mediate stable oligomerization. This observation led us to hypothesize the existence of an as yet undefined structural determinant that regulates Rep oligomerization. In this document, we described a detailed structural comparison between the helicase domains of AAV-2 Rep proteins and those of the other SF3 members. This analysis shows a major structural difference residing in the small oligomerization sub-domain (OD) of Rep helicase domain. In addition, secondary structure prediction of the linker connecting the helicase domain to the origin-binding domain (OBD) indicates the potential to form α-helices. We demonstrate that mutant Rep40 constructs containing different lengths of the linker are able to form dimers, and in the presence of ATP/ADP, larger oligomers. We further identified an aromatic linker residue (Y224) that is critical for oligomerization, establishing it as a conserved signature motif in SF3 helicases. Mutation of this residue critically affects oligomerization as well as completely abolishes the ability to produce infectious virus. Taken together, our data support a model where the linker residues preceding the helicase domain fold into an α-helix that becomes an integral part of the helicase domain and is critical for the oligomerization and function of Rep68/78 proteins through cooperative interaction with the OBD and helicase domains

Cost-savings of adalimumab in hidradenitis suppurativa: a retrospective analysis of a real-world cohort

Background: The introduction of adalimumab in the management of hidradenitis suppurativa (HS) raises questions regarding the cost-efficacy of treatment. Objectives: To explore cost-efficacy of treatment with anti-tumour necrosis factor (TNF) agents in a real-world cohort. Methods: Patients with Hurley stage II and III HS with ≥ 1 year of follow-up and at least three visits per year from September 2003 to December 2016 were analysed. Patient visits were divided into two categories – visits for treatment with agents blocking TNF or visits for other therapies. The cost of exacerbations was calculated based on the cost of items provided in current price lists or by the national health insurance agency in cases of hospitalization. Effectiveness of anti-TNF agents was calculated by assessing containment of exacerbations. The primary study end point was the cost-savings achieved using anti-TNF agents. Results: Overall, 1211 patient visits for 250 patients were analysed. Total containment of exacerbations was found in 25·1% of visits involving other therapies and in 63·4% of visits involving anti-TNF agents. The cost-savings per patient visit for patients receiving anti-TNF agents vs. other therapies was €178·92. The odds ratio for the total containment of exacerbations among patients with Hurley stage II and III was 4·86 and 6·03, respectively (P = 0·466). Treatment with anti-TNF agents was an independent variable affecting annual cost as shown by two-way analysis of variance. In Hurley stage III HS, mean annual cost was €8309·60 under other therapies compared with €3264·20 using anti-TNF agents (P = 0·004). Conclusions: Treatment with anti-TNF agents achieves significant cost–benefit through containment of HS exacerbations. The efficacy of anti-TNF agents was similar for both disease stages. © 2018 British Association of Dermatologist

Complement activation in hidradenitis suppurativa: a new pathway of pathogenesis?

Background: Despite the heavy purulence observed in hidradenitis suppurativa (HS), the kinetics of complement anaphylatoxins acting to prime chemotaxis of neutrophils has not been studied. Objectives: To explore complement activation in HS. Methods: Circulating concentrations of complement factor C5a, as well as of membrane attack complex C5b-9, were determined in the plasma of 54 treatment-naïve patients and of 14 healthy controls, as well as in the pus of seven patients. Results were correlated with Hurley stage and International Hidradenitis Suppurativa Severity Score. Peripheral blood mononuclear cells (PBMCs) were isolated from seven patients with Hurley stage III HS and seven healthy volunteers and stimulated in the presence of 25% of plasma for the production of tumour necrosis factor-α (TNF-α). Results: Circulating C5a and C5b-9 were significantly greater in patient than in control plasma; however, concentrations in pus were very low. Circulating C5a levels exceeding 28 ng mL−1 were associated with a specificity > 90% with the occurrence of HS. Circulating levels of C5a and C5b-9 were greater in patients with more severe HS. PBMCs of patients produced high concentrations of TNF-α only when growth medium was enriched with patient plasma; this was reversed with the addition of the C5a blocker IFX-1. Conclusions: Systemic complement activation occurs in HS and may be used as a surrogate biomarker of HS. C5a stimulates overproduction of TNF-α and may be a future therapeutic target. © 2018 The Authors. British Journal of Dermatology published by John Wiley & Sons Ltd on behalf of British Association of Dermatologists

Staphylococcus aureus Carriage in Hidradenitis Suppurativa: Impact on Response to Adalimumab

Background: Several patients with hidradenitis suppurativa (HS) present flare-ups during treatment with adalimumab (ADA), the cause of which is not clear. ADA is the only FDA-approved biologic for the therapy of moderate-to-severe HS. A previous study of our group has shown that Staphylococcus aureus stimulation of whole blood affects the production of human β-defensin 2 and modulates HS severity. It is, therefore, hypothesized, that carriage of S. aureus may drive HS flare-ups. Objective: To explore the association between carriage of S. aureus and loss of response to ADA. Patients and Methods: Among patients with moderate-to-severe HS without carriage of S. aureus at start of treatment with ADA, we investigated for carriage of S. aureus from the nares when flare-ups occurred. Flare-ups were pre-defined as at least 25% increase of inflammatory lesions (sum of inflammatory nodules and abscesses) from baseline. Samplings were also done after completion of 12 weeks of ADA treatment from all patients who did not present flare-ups. Clinical response to ADA was assessed by the HS Clinical Response score (HiSCR). Results: Thirty-nine patients were studied; 24 with Hurley II stage HS and 15 with Hurley III stage HS. Twenty-nine patients achieved HiSCR after 12 weeks of treatment without any flare-ups; 10 patients had flare-ups and failed HiSCR. Three (10.3%) and 5 (50%) patients, respectively, had nasal carriage of S. aureus (odds ratio 8.67; 95% CI 1.54-48.49; p = 0.014). Among 32 patients reaching follow-up week 48, 20 patients achieved HiSCR and 12 had flare-ups leading to ADA failure; 2 (10%) and 5 (41.7%) patients, respectively, had positive culture for S. aureus (odds ratio 6.42; 95% CI 1.00-41.20; p = 0.05). Conclusion: Nasal carriage of S. aureus may be associated with loss of response to ADA. Findings need confirmation in larger series of patients. © 202

Staphylococcus aureus Carriage in Hidradenitis Suppurativa: Impact on Response to Adalimumab

Background: Several patients with hidradenitis suppurativa (HS) present flare-ups during treatment with adalimumab (ADA), the cause of which is not clear. ADA is the only FDA-approved biologic for the therapy of moderate-to-severe HS. A previous study of our group has shown that Staphylococcus aureus stimulation of whole blood affects the production of human β-defensin 2 and modulates HS severity. It is, therefore, hypothesized, that carriage of S. aureus may drive HS flare-ups. Objective: To explore the association between carriage of S. aureus and loss of response to ADA. Patients and Methods: Among patients with moderate-to-severe HS without carriage of S. aureus at start of treatment with ADA, we investigated for carriage of S. aureus from the nares when flare-ups occurred. Flare-ups were pre-defined as at least 25% increase of inflammatory lesions (sum of inflammatory nodules and abscesses) from baseline. Samplings were also done after completion of 12 weeks of ADA treatment from all patients who did not present flare-ups. Clinical response to ADA was assessed by the HS Clinical Response score (HiSCR). Results: Thirty-nine patients were studied; 24 with Hurley II stage HS and 15 with Hurley III stage HS. Twenty-nine patients achieved HiSCR after 12 weeks of treatment without any flare-ups; 10 patients had flare-ups and failed HiSCR. Three (10.3%) and 5 (50%) patients, respectively, had nasal carriage of S. aureus (odds ratio 8.67; 95% CI 1.54-48.49; p = 0.014). Among 32 patients reaching follow-up week 48, 20 patients achieved HiSCR and 12 had flare-ups leading to ADA failure; 2 (10%) and 5 (41.7%) patients, respectively, had positive culture for S. aureus (odds ratio 6.42; 95% CI 1.00-41.20; p = 0.05). Conclusion: Nasal carriage of S. aureus may be associated with loss of response to ADA. Findings need confirmation in larger series of patients. © 202

MABp1 Targeting IL-1α for Moderate to Severe Hidradenitis Suppurativa Not Eligible for Adalimumab: A Randomized Study

Patients with moderate to severe hidradenitis suppurativa failing adalimumab therapy, or those ineligible to receive it, remain a population with an unmet need. Twenty patients not eligible for adalimumab were randomized to receive 12 weeks of blind treatment with placebo or MABp1, a true human antibody targeting IL-1α. Hidradenitis suppurativa clinical response score at week 12 was the primary endpoint. The primary endpoint was met in 10% and 60% of placebo- and MABp1-treated patients, respectively (odds ratio = 13.50, 95% confidence interval = 1.19–152.51). Clinical efficacy was maintained at 24 weeks in 0% and 40%. Improvement in the visual analog scale was reported by 20% and 85.7%, respectively, of patients failing previous anti-TNF treatment. Ultrasonography showed decreased neovascularization and lesion skin depth in the MABp1 group. MABp1 treatment was associated with decrease of circulating IL-8 and of stimulated production of IL-8 by whole blood. Whole blood production for hBD-2 was negatively associated with changes on ultrasonography in the placebo group but not in the MABp1 group. MABp1 is a promising treatment for patients with hidradenitis suppurativa not eligible for adalimumab. Inhibition of neovascularization and modulation of the production of IL-8 and hBD-2 are suggested mechanisms of action. © 2017 The Author