HMOX1 Gene Promoter Alleles and High HO-1 Levels Are Associated with Severe Malaria in Gambian Children

Heme oxygenase 1 (HO-1) is an essential enzyme induced by heme and multiple stimuli associated with critical illness. In humans, polymorphisms in the HMOX1 gene promoter may influence the magnitude of HO-1 expression. In many diseases including murine malaria, HO-1 induction produces protective anti-inflammatory effects, but observations from patients suggest these may be limited to a narrow range of HO-1 induction, prompting us to investigate the role of HO-1 in malaria infection. In 307 Gambian children with either severe or uncomplicated P. falciparum malaria, we characterized the associations of HMOX1 promoter polymorphisms, HMOX1 mRNA inducibility, HO-1 protein levels in leucocytes (flow cytometry), and plasma (ELISA) with disease severity. The (GT)n repeat polymorphism in the HMOX1 promoter was associated with HMOX1 mRNA expression in white blood cells in vitro, and with severe disease and death, while high HO-1 levels were associated with severe disease. Neutrophils were the main HO-1-expressing cells in peripheral blood, and HMOX1 mRNA expression was upregulated by heme-moieties of lysed erythrocytes. We provide mechanistic evidence that induction of HMOX1 expression in neutrophils potentiates the respiratory burst, and propose this may be part of the causal pathway explaining the association between short (GT)n repeats and increased disease severity in malaria and other critical illnesses. Our findings suggest a genetic predisposition to higher levels of HO-1 is associated with severe illness, and enhances the neutrophil burst leading to oxidative damage of endothelial cells. These add important information to the discussion about possible therapeutic manipulation of HO-1 in critically ill patients

Hepatitis B and C Co-Infections in Some HIV-Positive Populations in Cameroon, West Central Africa: Analysis of Samples Collected Over More Than a Decade

<div><p>As people infected with the human immunodeficiency virus (HIV) in Sub-Saharan Africa live longer due to availability of antiretroviral treatment (ART), so is the rise of associated infections with their burdens on patients. But reliable data on the prevalence of co-infection with hepatitis B (HBV) or C (HCV) still remains sparse and many individuals with HIV do not know their co-infection status. This study attempted to estimate the seroprevalence and identify risk factors associated with hepatitis B and/or C co-infections in HIV-infected individuals from five Regions of Cameroon by screening 531 HIV infected subjects for the presence of HBV surface antigen (HBsAg) and antibodies to HCV (HCV-Ab). A Screening and a confirmatory Enzyme linked immunosorbent assay were used to detect presence of markers of infection. CD4 count levels were also examined. The results indicate that of the 531 participants, 68% were females and 32% males. Mean CD4 count was ~400 cells/μl. Seroprevalence rates for HBsAg and HCV-Ab were 23.7%, and 7.2%, respectively. Associations assessed using logistic regression revealed that HBsAg but not HCV-Ab positivity was linked to age, lower CD4 count and residing in an urban rather than in a rural setting. This high prevalence of co-infection with HBV raises the urgent need to systematically screen all newly diagnosed HIV cases for co-infection in Cameroon and other regions of sub-Saharan Africa where HIV accounts for the majority of the global infection, so as to improve management strategies for HBV infection and ART implementation.</p></div

Age-specific prevalence for co-infection with HBV or HCV.

<p>Prevalence rates were calculated based on the proportion of study participants at risk of co-infection in a given age group.</p

Region-specific prevalence for co-infection with HBV or HCV.

<p>Prevalence rates were calculated based on the proportion of study participants at risk of co-infection in a given region.</p

Viral testing algorithm.

<p>¹HBsAg: confirmatory test for HBsAg. Confirmatory test for HCV-Ab was the same test as for the screening for HCV-Ab.</p

Baseline characterization of HBV and HCV markers by sex.

<p>P-values for age and CD4 cell counts represent differences in mean between males and females. Other P-values stand for trend across categories of infection type. For viral markers of infection, % column was calculated as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0137375#pone.0137375.t001" target="_blank">Table 1</a>.</p><p>SE, Standard error of the mean; HBsAg, Hepatitis B surface antigen; HBeAg, Hepatitis B e antigen; HCV-Ab, Antibodies to Hepatitis C.</p><p>Baseline characterization of HBV and HCV markers by sex.</p

Associations of demographic and serological markers with risk of infection with HBV or HCV.

<p>Percentages (%) in columns were calculated by dividing the number of participants with a particular outcome by the total number of participants with the outcome of interest *100. Adjustments were made for age, sex, CD4 count, residence, region and number of sexual partners.</p><p>HBV, Hepatitis B virus; HCV, Hepatitis C virus</p><p>Associations of demographic and serological markers with risk of infection with HBV or HCV.</p

Association of the IFNL4-ΔG Allele With Impaired Spontaneous Clearance of Hepatitis C Virus.

Interferon lambda 4 protein can be generated in IFNL4-ΔG carriers but not IFNL4-TT homozygotes. We studied 890 anti-hepatitis C virus (HCV)-positive participants in the Women's Interagency HIV Study. Among blacks (n = 555), HCV was more often cleared for those with genotype IFNL4-TT/TT (32.6%; odds ratio [OR], 3.59; P = 3.3 × 10(-5)) than IFNL4-TT/ΔG (11.3%; OR, 0.95; P = .86) or IFNL4-ΔG/ΔG (11.9%; referent). Pooling these data with published results in blacks (n = 1678), ORs were 3.84 (P = 8.6 × 10(-14)) for IFNL4-TT/TT and 1.44 (P = .03) IFNL4-TT/ΔG, and the area under the curve was 0.64 for IFNL4-ΔG genotype and 0.61 for rs12979860 (IL28B). IFNL4-ΔG is strongly associated with impaired spontaneous HCV clearance