US researchers say they have found a clue in understanding how an infection can spiral into sepsis by blunting the body’s immune response.
They said their research may help clinicians identify those patients who may need immediate intensive treatment to save their lives.
“The best treatment for sepsis starts with rapid detection”
The team from the Columbia University Irving Medical Center noted that the immune system initially launched a vigorous attack against sepsis, but then the innate immune response shut down.
By analysing the underlying mechanism, they identified two specific molecules – called microRNAs (miR-221 and miR-222) – that were produced in immune cells during prolonged inflammation.
The two microRNAs silence inflammatory gene expression and in a mouse model of sepsis were found to suppress the immune system at a time when the body desperately needed a full response.
Patients with suspected sepsis had a similar reaction. Among 30 hospital patients, those with evidence of organ failure exhibit higher levels of miR-221 and miR-222 in their blood samples.
In septic patients, those with elevated miR-221 and miR-222 also exhibited evidence of immunosuppression, the researchers said in the journal Nature.
They suggested the two microRNAs could be the basis of a test to help clinicians classify patients into those with organ failure who are at high risk of sepsis and death and those with milder infections.
“Any test that can identify the cause of sepsis to guide treatment options is invaluable”
With faster diagnosis, they highlighted that healthcare professionals could start antibiotics and fluids to control the infection more quickly before patients succumbed to organ failure and secondary infections.
However, they noted that clinical trials would now be needed to validate the usefulness of testing patients for these microRNAs as a quick guide to prognosis and treatment.
Lead study author Dr Sankar Ghosh said: “The best treatment for sepsis starts with rapid detection.
“Our results suggest that specific molecules called microRNAs may be potential biomarkers of poor prognosis, indicating the need for more aggressive treatment options,” he said.
Study co-author Dr Daniel Freedberg said that, for clinicians faced with sepsis in hospital, it was “usually a mystery as to what is causing the infection, but they must act quickly”.
He said: “They can choose to use the broadest spectrum of antibiotics for an aggressive approach to cover every bacterial cause of infection, but this may later cause antibiotic resistance, a growing problem.
“Any test that can identify the cause of sepsis to guide treatment options is invaluable,” he added.