Browsing by Author "Howell, Michael"

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    Insights into Lichen Planus Pigmentosus Inversus using Minimally Invasive Dermal Patch and Whole Transcriptome Analysis
    (Avens Publishing Group, 2022) Dickman, Jacob; Howell, Michael; Hoopes, Robert; Wang, Yipeng; Dickerson, Tobin J.; Bottomley, Michael; Shamma, H. Nicholas; Rapp, Christine M.; Turner, Matthew J.; Rohan, Craig A.; Travers, Jeffrey B.; Dermatology, School of Medicine
    Lichen Planus Pigmentosus inversus (LPPi) is a rare interface and lichenoid dermatitis (ILD) and supposed variant of lichen planus (LP) that presents as well-demarcated brown to grey macules in flexural and intertriginous areas. LPPi is deemed 'inversus' because its anatomical distribution in skin folds is opposite that seen in lichen planus pigmentosus (LPP) whose pigmented lesions arise on sun-exposed skin. Biopsy is required for the clinical diagnosis of all ILDs. Though multiple clinically-oriented studies have reported differences between LPP, LPPi, and LP, few molecular studies have been performed. In this case study, 3 patients, 2 with LPPi and one with LP, provided samples using minimally invasive whole transcriptome analysis using a dermal biomarker patch. This study confirms the involvement of interferon signaling and T-cell activation in LPPi and suggests an expression profile distinct from LP. Specific genes significantly upregulated in LPPi vs LP include an intergenic splice variant of the primary pigmentation determining receptor in humans and dysregulation of genes essential for ceramide synthesis and construction of the cornified envelope. This work expands upon our knowledge of the pathogenesis of LPPi vs LP, and supports the potential use of this technology in the diagnostic clinical setting to mitigate the need for invasive procedures.
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    Targeting effector memory T cells with alefacept in new onset type 1 diabetes: 12 month results from the T1DAL study
    (Elsevier, 2013-12) Rigby, Mark R; DiMeglio, Linda A; Rendell, Marc S; Felner, Eric I; Dostou, Jean M; Gitelman, Stephen E; Patel, Chetanbabu M; Griffin, Kurt J; Tsalikian, Eva; Gottlieb, Peter A; Greenbaum, Carla J; Sherry, Nicole A; Moore, Wayne V; Monzavi, Roshanak; Willi, Steven M; Raskin, Philip; Moran, Antoinette; Russell, William E; Pinckney, Ashley; Keyes-Elstein, Lynette; Howell, Michael; Aggarwal, Sudeepta; Lim, Noha; Phippard, Deborah; Nepom, Gerald T; McNamara, James; Ehlers, Mario R; Department of Pediatrics, IU School of Medicine
    Background Type 1 diabetes (T1D) results from autoimmune targeting of the pancreatic beta cells, likely mediated by effector memory T cells (Tems). CD2, a T cell surface protein highly expressed on Tems, is targeted by the fusion protein alefacept, depleting Tems and central memory T cells (Tcms). We hypothesized that alefacept would arrest autoimmunity and preserve residual beta cells in newly diagnosed T1D. Methods The T1DAL study is a phase II, double-blind, placebo-controlled trial that randomised T1D patients 12-35 years old within 100 days of diagnosis, 33 to alefacept (two 12-week courses of 15 mg IM per week, separated by a 12-week pause) and 16 to placebo, at 14 US sites. The primary endpoint was the change from baseline in mean 2-hour C-peptide area under the curve (AUC) at 12 months. This trial is registered with ClinicalTrials.gov, number NCT00965458. Findings The mean 2-hour C-peptide AUC at 12 months increased by 0.015 nmol/L (95% CI -0.080 to 0.110 nmol/L) in the alefacept group and decreased by 0.115 nmol/L (95% CI -0.278 to 0.047) in the placebo group, which was not significant (p=0.065). However, key secondary endpoints were met: the mean 4-hour C-peptide AUC was significantly higher (p=0.019), and daily insulin use and the rate of hypoglycemic events were significantly lower (p=0.02 and p<0.001, respectively) at 12 months in the alefacept vs. placebo groups. Safety and tolerability were comparable between groups. There was targeted depletion of Tems and Tcms, with sparing of naïve and regulatory T cells (Tregs). Interpretation At 12 months, alefacept preserved the 4-hour C-peptide AUC, lowered insulin use, and reduced hypoglycemic events, suggesting a signal of efficacy. Depletion of memory T cells with sparing of Tregs may be a useful strategy to preserve beta cell function in new-onset T1D.