Blood Test Identifies Patients Prone to Serious Illness Post-Surgery

Key differences in a person’s immune system caused by a group of white blood cells called monocytes can be used to predict who will recover well after surgery and who is likely to develop serious illnesses.

Scientists at Queen Mary University (London, UK) took blood samples from 39 patients before surgery on the first and second morning afterward who were undergoing major liver and pancreatic surgery. The team then looked at the patients’ monocytes to see how they respond to fragments of microbes found in the skin or gut that might be released during surgery. The team also examined the level of toll-like receptor proteins in the blood cells. These classes of proteins play a key role in the immune system and are produced by monocytes.

During the study, 12 patients developed serious post-surgery complications and the team found their monocytes behaved very differently to the monocytes found in the blood of the 27 patients who recovered without complication. In addition, by measuring the amount of toll-like receptor proteins in the blood, the team was able to predict with 90% to 100% accuracy that would develop complications compared to 70% with routine tests. These findings were then confirmed in a second group of 30 patients undergoing similar operations.

Serum interleukin (IL)-6 concentration and monocyte Toll-like receptor (TLR)/NF-κB/IL-6 functional pathways were significantly upregulated and overactive in patients who developed systemic inflammatory response syndrome (SIRS). Interferon-α mediated signal transducer and activator of transcription 1 (STAT1) phosphorylation was higher preoperatively in patients who developed SIRS. Increased TLR4 and TLR5 gene expression in whole blood was demonstrated in a separate validation cohort of 30 patients undergoing similar surgery. Expression of TLR4/5 on monocytes, particularly intermediate CD14++CD16+ monocytes, on day one or two predicted SIRS with accuracy of 89% to 100%

William Alazawi, MB, PhD, who led the study said, “This study has given us an important insight into the way in which postoperative complications and infections arise. Patients who develop infections may have an immune system which is predisposed to overreact to surgery or the hospital environment and we need to do further research to fully understand this predisposition. If we can more accurately predict who will run into trouble after an operation, we can tailor personalized treatments to prevent complications and improve survival rates after major surgery. This is particularly the case if we can predict Systemic Inflammatory Response Syndrome before the operation has even taken place.” The study was published on June 7, 2015, in the journal Annals of Surgery.

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