Tag Archives: infection

Racial background affects risk of severe sepsis

High infection rates and increased risk of acute organ dysfunction in black individuals explains why people from this racial background are more likely to have (and die from) severe sepsis than white individuals, according to a new study published in JAMA.

Severe sepsis (when the body has a systemic inflammatory response to infection that can lead to multiple organ failure and death) is well-known to be more frequent in black individuals than white people. However, just why the incidence of severe sepsis is higher in this racial group is unknown and it is particularly important to investigate whether these racial disparities are because of different susceptibilities to infection or organ failure—a critical distinction that could influence treatment. High infection rates can be combated with vaccination programmes in at-risk individuals whilst high incidence rates of organ failure can be improved with better care in hospitals.

In what can only be described as a mammoth retrospective study (that included data from all hospitalisations across seven US states, that is, a potential total number of over 63 million people in the study), Florian B. Mayr and colleagues wanted to examine exactly why black people have a higher incidence of severe sepsis than white people.

The researchers found that of more than 8.6 million hospital admissions (not related to childbirth) in black and white individuals, over 2.2 million of the cases were because of infection and 381,787 of these cases (67,812 black patients; 313,975 white patients) had severe sepsis. They found that black patients had 67% higher hospitalization rates (after standardising for both age and sex) because of severe sepsis than did white patients. Furthermore, black patients also had both increased infection rates, risk of developing organ dysfunction and mortality compared with white patients. Differences in infection-related hospitalisations between the races were especially pronounced in younger adults (20–65 years old).

Findings from this large, retrospective cohort study clearly demonstrate that high severe sepsis rates in black people are because of a “higher likelihood of being hospitalised with infection and a higher risk of developing acute organ dysfunction”. These results have implications for public health; interventions to reduce infection (such as vaccinations) and better quality of care and management of hospitalised patients should be promoted, especially in healthcare providers that serve black communities. Furthermore, more research is needed to investigate risk of severe sepsis in people from other racial groups.

ResearchBlogging.orgMayr, F., Yende, S., Linde-Zwirble, W., Peck-Palmer, O., Barnato, A., Weissfeld, L., & Angus, D. (2010). Infection Rate and Acute Organ Dysfunction Risk as Explanations for Racial Differences in Severe Sepsis JAMA: The Journal of the American Medical Association, 303 (24), 2495-2503 DOI: 10.1001/jama.2010.851

Leave a comment

Filed under Infectious Disease, Medicine, Public Health

IL-33—a new treatment against sepsis?

New research shows that the novel cytokine interleukin (IL)-33 reduces sepsis and has “therapeutic potential” to treat this often fatal inflammatory condition. According to the study published this week in Nature Medicine, IL-33 promotes neutrophil recruitment to the site of infection, which is a critical host defence response, and the levels of the decoy IL-33 receptor soluble ST2 in serum could affect whether people recover from sepsis.

Sepsis is a serious illness in which the body has a massive inflammatory response to an infection. Severe sepsis and septic shock can affect multiple organs in the body including the heart, lungs, liver and brain, and is life-threatening (30–50% of people with severe sepsis or septic shock die) and requires treatment in intensive care.

Jose Alves-Filho and colleagues used experimental models of sepsis (using cecal ligation and puncture or CLP) to investigate the role of IL-33 during sepsis. The scientists induced sepsis in mice and then treated them with recombinant IL-33; IL-33-treated mice had a marked reduction in mortality compared to untreated controls and IL-33 protected mice from sepsis for 3h after CLP. The researchers found that IL-33 treatment increased the number of neutrophils migrating to the site of infection (by increasing the expression of the chemokine receptor that is crucial for neutrophil recruitment, CXCR2). This neutrophil recruitment promoted clearance of the bacterial infection and IL-33 also reduced the systemic proinflammatory cytokines (e.g. IL-6, tumour necrosis factor α and CXCL2) that occurred in response to the infective bacteria. Furthermore, the scientists analysed blood serum from healthy individuals and people who had sepsis. They found that people with sepsis had higher levels of IL-33 than healthy people, and that serum levels of soluble ST2 (the decoy receptor of IL-33) were substantially higher in people who did not survive sepsis compared to those who recovered from the disease (soluble ST2 serum levels were negligible in healthy individuals).

The research reveals a “previously unknown mechanism of action of IL-33” and further studies will show whether IL-33 could be used as a potentially novel therapy for sepsis.

ResearchBlogging.orgAlves-Filho, J., Sônego, F., Souto, F., Freitas, A., Verri, W., Auxiliadora-Martins, M., Basile-Filho, A., McKenzie, A., Xu, D., Cunha, F., & Liew, F. (2010). Interleukin-33 attenuates sepsis by enhancing neutrophil influx to the site of infection Nature Medicine DOI: 10.1038/nm.2156

Leave a comment

Filed under Immunology, Infectious Disease, Medicine, Uncategorized