Autophagy-enhancing drug carbamazepine diminishes hepatocellular death in fibrinogen storage disease

Fibrinogen storage disease (FSD) is a rare autosomal-dominant hereditary disorder characterized by hypofibrinogenemia and accumulation of fibrinogen aggregates within the hepatocellular endoplasmatic reticulum (ER). Some FSD patients present with elevated amino-transferases and fibrosis/cirrhosis similar to alpha-1-antitrypsin deficiency (ATD), also an ER storage disease. Pharmacological stimulation of autophagy has been shown to mediate clearance of protein aggregates and halt progression of liver fibrosis in in vivo models of ATD. Our aim was to evaluate the presence of autophagy and a possible response to autophagy-enhancing therapy in patients with FSD. Hepatic fibrosis was assessed by transient elastography in 2 newly identified FSD families with fibrinogen Aguadilla and Brescia mutations, encompassing 8 affected members. Available liver biopsies were assessed for autophagy. Two patients, who had had elevated alanine amino-transaminase levels (2-5 above upper limit of normal), were treated with the autophagy enhancer carbamazepine (CBZ). Transient elastography did not show evidence of significant fibrosis in any affected family members. Quantitative electron microscopy of one patient showed a 5.15-fold increase of late stage autophagocytic vacuoles compared to control livers. CBZ at low anticonvulsive treatment levels led to rapid normalization of alanine-aminotransferase and decrease of caspase-cleaved and uncleaved cytokeratin-18 fragments (M30 and M65). These effects reversed after discontinuation of treatment. Response to CBZ may be mediated by pharmacologically enhanced autophagy resulting in reduction of aggregate-related toxicity in FSD. These results suggest clinical applicability of pharmacological stimulation of autophagy in FSD, but potentially also in other related disorders.

Would CLSI M53-A have helped in the diagnosis of HIV in Canada? Results of the performance of Canadian laboratories participating in a recent NLHRS proficiency testing panel containing HIV-1 antigen positive (antibody negative) and HIV-2 samples

INTRODUCTION

The Clinical and Laboratory Standards Institute recently published M53-A, Criteria for Laboratory Testing and Diagnosis of Human Immunodeficiency Virus (HIV) Infection; Approved Guideline (2011), which includes a state of the art algorithm for identifying HIV-1 acute and HIV-2 infections. To assess the ability of Canadian laboratories to detect these sample types and the impact of M53-A, the National Laboratory for HIV Reference Services distributed a special proficiency testing panel.

METHODS

HIVS425-2012Nov22 was sent to 42 laboratories across Canada. It contained one HIV negative sample (B), two HIV-1 positive samples (A and E), one HIV-2 positive sample (C) and one HIV-1/2 antibody negative-HIV-1 antigen positive sample (D). Data was collected and analyzed using DigitalPT; a standardized on-line tool.

RESULTS

Forty-one laboratories returned results. Sample B (HIV negative) was identified by 95% of laboratories (39/41) and samples A and E (HIV-1 positive) by 98% (40/41). No laboratory identified sample C as HIV-2 positive, although 85% (35/41) detected reactivity prompting a referral for further testing. The remaining laboratories identified sample C as HIV-1 positive (4), indeterminate (1) or gave no final status (1). Sample D (HIV antibody negative-antigen positive) was correctly identified by two laboratories as HIV-1 antigen positive while 78% (32/41) detected reactivity, recommending further testing. One laboratory did not provide a final status. Alarmingly, six laboratories called this sample HIV negative.

CONCLUSION

Although there is a high quality of HIV testing across Canada, introduction of the M53-A guideline would further improve the ability of laboratories to diagnose HIV-1 acute and HIV-2 infection.

Analysis of HHV-6 mutations in solid organ transplant recipients at the onset of cytomegalovirus disease and following treatment with intravenous ganciclovir or oral valganciclovir

BACKGROUND

Human herpesvirus 6 (HHV-6) and human cytomegalovirus (HCMV) are major opportunistic pathogens in solid organ transplant (SOT) recipients. The use of antivirals for the treatment of HCMV disease can result in the development of drug resistance mutations in HCMV and also potentially in HHV-6.

OBJECTIVES

The emergence of HHV-6 drug resistance mutations was evaluated in SOT recipients at the onset of HCMV disease and following treatment with ganciclovir (GCV) or valganciclovir (VGCV).

STUDY DESIGN

Detection of HHV-6 was performed by real-time PCR from whole blood samples serially obtained from SOT recipients treated for HCMV disease with an induction dose of intravenous GCV or oral VGCV for 21 days followed by VGCV maintenance for 28 days in both arms. Baseline and last positive HHV-6 samples were tested for mutations in the genes encoding the protein kinase (U69) and the DNA polymerase (U38).

RESULTS

The rate of HHV-6 viraemia among SOT patients with HCMV disease at baseline was 3.2% (5/155). All isolates belonged to the HHV-6B species. Mutations L213I and Y479H were detected at baseline and at later times in the U69 kinase. Mutation L213I was previously reported as polymorphism whereas the role of mutation Y479H in drug resistance is unknown. Mutations D854E and E855Q found in the DNA polymerase were known as natural variants.

CONCLUSIONS

The incidence of HHV-6 viraemia in SOT recipients with established HCMV disease before initiation of antiviral therapy was low. Treatment with GCV or VGCV did not induce the emergence of HHV-6 drug resistance mutations.