Co-infection with <i>Plasmodium</i> and HBV alters plasma cytokine profile.

<p>Plasma levels of IFN-γ, IL-10 and TNF-alpha were compared between individuals currently infected with HBV (n = 29) and those co-infected with HBV and malaria (n = 32). Lines and boxes represent median and interquartile range, and whiskers represent minimum and maximum values. Data were compared using a Mann-Whitney test. P values are shown in each graph.</p

Screening and enrollment.

<p>The study participants were stratified according to the clinical presentation of <i>Plasmodium sp</i>. infection (non-infected, asymptomatic and symptomatic malaria). Simultaneously, the presence of HBV infection was verified to identify co-infections.</p

Baseline characteristics of the subjects.

<p>A Chi-square test was performed to compare the distribution of each variable between the groups.</p><p>Individuals presenting AgHBS⁻/anti-HBS⁺/anti-HBc⁺ with no HBV DNA amplification by quantitative RT-PCR (qPCR) were considered to have previous HBV infection, those presenting AgHBS⁺/anti-HBS⁻ and detectable viremia by qPCR were considered currently infected with HBV and those with AgHBS⁻/anti-HBS⁺/anti-HBc⁻ were considered vaccinated against the virus.</p><p>‡Malaria diagnosis was based on light microscopy and confirmed by a nested RT-PCR molecular test, as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0019841#s2" target="_blank">methods</a>.</p><p>§Cut-off IL-10 and IFN- γ plasma levels were determined by choosing the values that implied the highest likelihood ratio in discriminating asymptomatic from symptomatic malaria infection using a ROC analysis.</p

Adjusted multinomial logistic regression analysis of risk factors for asymptomatic malaria infection or for no malaria infection compared to symptomatic malaria.

<p>Symptomatic malaria infection was considered the primary outcome. Adjustment was performed for all variables presented. CI: Confidence interval. Individuals presenting AgHBS⁻/anti-HBS⁺/anti-HBc⁺ with no HBV DNA amplification by quantitative RT-PCR (qPCR) were considered to have previous HBV infection, those presenting AgHBS⁺/anti-HBS⁻ and detectable viremia by qPCR were considered currently infected with HBV and those with AgHBS⁻/anti-HBS⁺/anti-HBc⁻ were considered vaccinated against the virus. The statistical significance was estimated through multinomial logistic regression.</p

Baseline characteristics of the subjects, considering only <i>Plasmodium vivax</i> infections.

<p>A Chi-square test was performed to compare the distribution of each variable between the groups.</p><p>Individuals presenting AgHBS⁻/anti-HBS⁺/anti-HBc⁺ with no HBV DNA amplification by quantitative RT-PCR (qPCR) were considered to have previous HBV infection, those presenting AgHBS⁺/anti-HBS⁻ and detectable viremia by qPCR were considered currently infected with HBV and those with AgHBS⁻/anti-HBS⁺/anti-HBc⁻ were considered vaccinated against the virus.</p><p>§Cut-off IL-10 and IFN- γ plasma levels were determined by choosing the values that which implied the highest likelihood ratio in discriminating asymptomatic from symptomatic malaria infection using a ROC analysis.</p

Individuals co-infected with <i>Plasmodium sp.</i> and HBV present lower parasitemia and higher viremia.

<p>(A) Individuals presenting with symptomatic or asymptomatic malaria were stratified according to the HBV status, and parasitemia levels were determined by light microscopy as described in the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0019841#s2" target="_blank">methods</a>. The number of participants in each group is described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0019841#pone-0019841-t001" target="_blank">Table 1</a>. Values were compared by the Kruskal-Wallis test with Dunn's multiple comparisons posttest. (B) HBV viremia was estimated by real-time PCR in both HBV infected (n = 29) or HBV-malaria co-infected (n = 32) individuals using the Mann-Whitney test and the percentage of HBeAg positive cases was also compared to these groups (C) using Fisher's exact test. Lines and boxes represent medians and interquartile ranges, and whiskers represent minimum and maximum values. (D) Spearman correlation between <i>Plasmodium</i> parasitemia and HBV viremia in co-infected individuals (n = 32). A non-linear curve fit was used to illustrate the general trend of the correlation. *P<0.05; ***P<0.0001.</p

HBV infection did not alter either laboratory markers of organic dysfunction or the prevalence of symptoms in malaria cases.

<p>The study participants were stratified according to the clinical presentation of <i>Plasmodium</i> infection and also according to the HBV natural exposure and plasma levels of (A) alanine-aminotransferase (ALT), (B) total bilirubin, (C) C-reactive protein and (D) fibrinogen were compared using a Kruskal-Wallis test with Dunn's multiple comparisons. Lines and boxes represent medians and interquartile ranges, while whiskers represent minimum and maximum values. (E) The prevalence of diverse malaria-related symptoms was measured in individuals presenting with symptomatic malaria and compared between those with previous or current HBV infection and those with no markers of HBV exposure. The values were compared using Chi-square test and no significant differences were found.</p