Immune System Test Now Predicts Early Death
Now early death can be predicted with a blood test that measures a marker of immune-system activity, suggests a new study.
For the study, researchers at the Mayo Clinic tested 15,859 people from Minnesota for the levels of the immune-system molecules known as free light chains. All the people were aged 50 or above. The study found that those whose levels were in the top 10% were four times more likely to die in the next 13 years when compared to others.
Free light chains are generally tested to detect and manage blood disorders and blood-related cancers. This is the first time that the molecules are associated with early death in people without any blood disorder.
Infection fighting antibodies are formed when these light chains bind with heavy chains in our body. Detection of unattached "free" light chains means that there is something wrong with the immune system either due to inflammation, infection, or both, says lead author Vincent Rajkumar, M.D., a hematologist at the Mayo Clinic, in Rochester, Minn.
Free light chain levels are effective in predicting deaths from many causes including cancer, heart disease, lung disease, and diabetes, says the study published this week in the journal Mayo Clinic Proceedings.
It is still unclear as to why exactly free chains are associated with early deaths. One possible explanation given by researchers is that an excessive level of the molecule could mark an inflammation, which is associated with heart disease and many other health problems. Another explanation is that it could be simply a sign of age-related deterioration of the immune system.
Currently the test is not recommended by researchers to be used as a screening instrument, as it might only cause to alarm patients.
Neil Blumberg, M.D., a professor of pathology and laboratory medicine at the University of Rochester Medical Center, in Rochester, N.Y., is skeptical about the test being more powerful than existing tests which determine the functioning of the immune-system.
According to Blumberg, the test has not been compared with other tests and it "may not measure anything that we don't get with white cell count or C-reactive protein or 15 other tests which are cheaper and easier to do."