Identification of toxemia in patients with Clostridium difficile infection.

Toxemia can develop in Clostridium difficile-infected animals, and correlates with severe and fulminant disease outcomes. Circumstantial evidence suggests that toxemia may occur in patients with C. difficile infection (CDI), but positive diagnosis is extremely rare. We analyzed the potential for C. difficile toxemia in patients, determined its characteristics, and assessed challenges. C. difficile toxins in serum from patients were tested using an ultrasensitive cell-based assay and further confirmed by Rac1 glucosylation assay. The factors that hinder a diagnosis of toxemia were assessed, including investigation of toxin stability, the level of toxins-specific neutralizing antibodies in sera and its effect on diagnosis limits. CDI patients develop detectable toxemia in some cases (2.3%). Toxins were relatively stable in stored sera. Neutralizing anti-toxin antibodies were present during infection and positively correlated with the diagnosis limits. Thus, the masking effect of toxin-specific neutralizing antibodies is the major obstacle in diagnosing C. difficile toxemia using cell-based bioassays.

Non-high-density lipoprotein cholesterol as a biomarker for nonalcoholic steatohepatitis.

BACKGROUND & AIMS: There are no clinically available biomarkers for nonalcoholic steatohepatitis (NASH); differentiating between steatosis and NASH requires histologic evaluation. Noninvasive methods are needed to replace liver biopsy and its associated risks. Production of very low density lipoprotein (VLDL) contributes to the development of NASH and might be used to distinguish steatosis from NASH. However, it is not possible to measure levels of VLDL directly in the clinic. Non-high-density lipoprotein-cholesterol (non-HDL-C) encompasses all apolipoprotein-B-containing lipoproteins, including VLDL, and can be calculated from standard lipid panels without additional cost. METHODS: We evaluated the ability of non-HDL-C to differentiate steatosis from NASH in a prospective study of 218 patients with suspected NASH (steatosis, n = 100 and NASH, n = 118). RESULTS: Patients with NASH had a trend toward increased levels of non-HDL-C, compared with those with steatosis (P = .08). However, among subjects not on lipid-lowering medications, those with NASH had significantly higher levels of non-HDL-C (144.6 mg/dL) than those with steatosis (129.3 mg/dL; P = .025). This difference remained significant when adjusted for levels of cholesterol and triglycerides, indicating that the difference results from increased levels of apolipoprotein B including VLDL. These findings were validated in a cohort of 40 patients with steatosis or NASH who were not taking lipid-lowering agents. The NASH group had significantly higher levels of non-HDL-C than the steatosis group (162.8 vs 145.9 mg/dL; P = .04). CONCLUSIONS: NASH is associated with significantly higher levels of non-HDL-C than steatosis in patients who do not take lipid-lowering agents. This low-cost biomarker could be used in noninvasive differentiation between steatosis and NASH.

Hepatitis B screening, prophylaxis and re-activation in the era of rituximab-based chemotherapy.

BACKGROUND: Hepatitis B re-activation is a well-described complication in patients with inactive chronic hepatitis B receiving chemotherapy. Screening for HBV and pre-emptive therapy are recommended. However, the rates of HBV screening, prophylaxis and re-activation during rituximab-containing chemotherapy are unknown. PATIENTS AND METHODS: We performed a retrospective study of patients with non-Hodgkin lymphoma (NHL) who received rituximab between August 1997 and September 2009. We evaluated patients for hepatitis B serologies, antiviral prophylaxis and hepatitis B re-activation during or up to 6 months after chemotherapy. RESULTS: One thousand four hundred and twenty-nine patients underwent rituximab-containing chemotherapy for NHL. Hepatitis B serologies were documented in 524 (36.6%) patients. Of these, 20 (3.8%) were HBsAg positive and 10 (50%) experienced HBV re-activation. Only half (5/10) had HBV serology documented before re-activation. Only 3/8 (37.5%) of patients with newly documented HBsAg positivity received antiviral prophylaxis. Virological breakthrough occurred in two of the patients on chronic therapy, in one of three inactive carriers on prophylaxis and in two of five patients not receiving prophylaxis. Re-activation developed in another five patients not screened previously for hepatitis B. One patient developed ALF and died. Re-activation did not occur in 25 patients with isolated positive core antibody. CONCLUSIONS: At tertiary care institutions hepatitis B serologies are infrequently assessed before rituximab-based chemotherapy and prophylaxis is uncommon. Greater adherence to recommendations for screening and prophylaxis is necessary. This suboptimal screening rate could be even lower in community hospitals and could result in significant harm to unscreened and unprophylaxed patients.

Hepatitis C virus regulates transforming growth factor beta1 production through the generation of reactive oxygen species in a nuclear factor kappaB-dependent manner.

BACKGROUND & AIMS: The generation of oxidative stress and transforming growth factor beta1 (TGF-beta1) production play important roles in liver fibrogenesis. We have previously shown that hepatitis C virus (HCV) increases hepatocyte TGF-beta1 expression. However, the mechanisms by which this induction occurs have not been well studied. We explored the possibility that HCV infection regulates TGF-beta1 expression through the generation of reactive oxygen species (ROS), which act through > or =1 of the p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and nuclear factor kappaB (NFkappaB) signaling pathways to induce TGF-beta1 expression. METHODS: We used small molecule inhibitors and short interfering RNAs to knock down these pathways to study the mechanism by which HCV regulates TGF-beta1 production in the infectious JFH1 model. RESULTS: We demonstrated that HCV induces ROS and TGF-beta1 expression. We further found that JFH1 induces the phosphorylation of p38MAPK, JNK, ERK, and NFkappaB. We also found that HCV-mediated TGF-beta1 enhancement occurs through a ROS-induced and p38 MAPK, JNK, ERK1/2, NFkappaB-dependent pathway. CONCLUSIONS: These findings provide further evidence to support the hypothesis that HCV enhances hepatic fibrosis progression through the generation of ROS and induction of TGF-beta1. Strategies to limit the viral induction of oxidative stress appear to be warranted to inhibit fibrogenesis.

Hepatitis C virus infection and its clearance alter circulating lipids: implications for long-term follow-up.

UNLABELLED: Hepatitis C associated hypolipidemia has been demonstrated in studies from Europe and Africa. In two linked studies, we evaluated the relationship between hepatitis C infection and treatment with lipid levels in an American cohort and determined the frequency of clinically significant posttreatment hyperlipidemia. First, a case-control analysis of patients with and without hepatitis C was performed. The HCV Group consisted of 179 infected patients. The Uninfected Control Group consisted of 180 age-matched controls. Fasting cholesterol, low density lipoprotein (LDL), high density lipoprotein and triglycerides were compared. Next was a retrospective cohort study (Treated Hepatitis C Group) of 87 treated hepatitis C patients with lipid data before and after therapy was performed. In the case-control analysis, the HCV Group had significantly lower LDL and cholesterol than the Uninfected Control Group. In the retrospective cohort, patients in the Treated Hepatitis C Group who achieved viral clearance had increased LDL and cholesterol from baseline compared to patients without viral clearance. These results persisted when adjusted for age, sex, and genotype. 13% of patients with viral clearance had increased LDL and 33% experienced increases in cholesterol to levels warranting lipid lowering therapy. CONCLUSION: Hepatitis C is associated with decreased cholesterol and LDL levels. This hypolipidemia resolves with successful hepatitis C treatment but persists in nonresponders. A significant portion of successfully treated patients experience LDL and cholesterol rebound to levels associated with increased coronary disease risk. Lipids should be carefully monitored in persons receiving antiviral therapy.