Cummins, Nathan W.

Previous studies have shown that human immunodeficiency virus (HIV) protease cleaves procaspase 8 to a fragment, termed Casp8p41, that lacks caspase activity but nonetheless contributes to T cell apoptosis. Herein, we show that Casp8p41 contains a domain that interacts with the BH3-binding groove of pro-apoptotic Bak to cause Bak oligomerization, Bak-mediated membrane permeabilization, and cell death. Levels of active Bak are higher in HIV-infected T cells that express Casp8p41. Conversely, targeted mutations in the Bak-interacting domain diminish Bak binding and Casp8p41-mediated cell death. Similar mutations in procaspase 8 impair the ability of HIV to kill infected T cells. These observations support a novel paradigm in which HIV converts a normal cellular constituent into a direct activator that functions like a BH3-only protein.

SummaryAs invasive mucormycosis (IM) numbers rise, clinicians suspect prior voriconazole worsens IM incidence and severity, and believe combination anti‐fungal therapy improves IM survival. To compare the cumulative incidence (CI), severity and mortality of IM in eras immediately before and after the commercial availability of voriconazole all IM cases from 1995 to 2011 were analysed across four risk‐groups (hematologic/oncologic malignancy (H/O), stem cell transplantation (SCT), solid organ transplantation (SOT) and other), and two eras, E1 (1995–2003) and E2, (2004–2011). Of 101 IM cases, (79 proven, 22 probable): 30 were in E1 (3.3/year) and 71 in E2 (8.9/year). Between eras, the proportion with H/O or SCT rose from 47% to 73%, while ‘other’ dropped from 33% to 11% (P = 0.036). Between eras, the CI of IM did not significantly increase in SCT (P = 0.27) or SOT (P = 0.30), and patterns of anatomic location (P = 0.122) and surgical debridement (P = 0.200) were similar. Significantly more patients received amphotericin‐echinocandin combination therapy in E2 (31% vs. 5%, P = 0.01); however, 90‐day survival did not improve (54% vs. 59%, P = 0.67). Since 2003, the rise of IM reflects increasing numbers at risk, not prior use of voriconazole. Frequent combination of anti‐fungal therapy has not improved survival.

Mucormycosis is a rare and often fatal invasive fungal infection mostly seen in immune-compromised individuals. A high index of clinical suspicion is necessary, so that effective preemptive therapy can be started, as timely intervention is crucial. In this series we present three cases of invasive mucormycosis in patients with underlying inflammatory bowel disease that had received therapy with immunomodulators prior to the infection. All three had varied clinical manifestations. We also review the literature of invasive mucormycosis in patients with inflammatory bowel disease.

Background HIV infection leads to activation of coagulation, which may increase the risk for atherosclerosis and venous thromboembolic disease. We hypothesized that HIV replication increases coagulation potentially through alterations in extrinsic pathway factors. Methods and Results Extrinsic pathway factors were measured among a subset of HIV participants from the Strategies for Management of Anti‐Retroviral Therapy ( SMART ) trial. Thrombin generation was estimated using validated computational modeling based on factor composition. We characterized the effect of antiretroviral therapy ( ART ) treatment versus the untreated state ( HIV replication) via 3 separate analyses: (1) a cross‐sectional comparison of those on and off ART (n=717); (2) a randomized comparison of deferring versus starting ART (n=217); and (3) a randomized comparison of stopping versus continuing ART (n=500). Compared with viral suppression, HIV replication consistently showed short‐term increases in some procoagulants (eg, 15% to 23% higher FVIII ; P <0.001) and decreases in key anticoagulants (eg, 5% to 9% lower antithrombin [ AT ] and 6% to 10% lower protein C; P <0.01). The net effect of HIV replication was to increase coagulation potential (eg, 24% to 48% greater thrombin generation from computational models; P <0.01 for all). The pattern of changes from HIV replication was reversed with ART treatment and consistent across all 3 independent comparisons. Conclusions HIV replication leads to complex changes in extrinsic pathway factors, with the net effect of increasing coagulation potential to a degree that may be clinically relevant. The key influence of changes in FVIII and AT suggests that HIV ‐related coagulation abnormalities may involve changes in hepatocyte function in the context of systemic inflammation. Clinical Trial Registration URL: ClinicalTrials.gov . Unique identifier: NCT 00027352.