HKU finds high blood sugar in diabetics weakens immune response to respiratory infections

High blood sugar in patients with type 2 diabetes weakens their immune response to respiratory viral infections, as the functionality of immunity cells can be reduced by as much as 40 per cent compared with healthy individuals, research by the University of Hong Kong (HKU) has found.

Researchers from the LKS Faculty of Medicine at HKU, examined 40 blood samples from type 2 diabetes patients at Queen Mary Hospital in 2022 and 2023. The samples were divided into two groups: patients with poor blood glucose control and patients with well-controlled blood glucose. A control group of healthy individuals was also included.

According to the findings, published in the Cell Metabolism journal early this month, revealed that Th1 cells, which play a crucial role in initiating the inflammatory response needed to combat infections, showed a 40 per cent reduction in functionality in patients with poor blood glucose control. This deficiency increased their vulnerability to respiratory viral infections.

Heidi Ling Guang-sheng, assistant professor at the School of Biomedical Sciences at HKU, said the research highlighted the importance of maintaining good blood glucose level in type 2 diabetes patients.

“We can see that if the patients control the blood glucose well, their Th1 cells functionality would be the same as a healthy person. Which means there is no fear of losing immunity even if you have diabetes,” he said.

Dr Paul Lee Chi-ho, clinical associate professor at the School of Clinical Medicine at HKU, said previous research found the risk of Covid-19-related deaths in infected patients was 10 times higher among type 2 diabetes patients with poorly controlled blood glucose compared with those with well-controlled levels.