Lonely white cells.

The white blood cells of chronically lonely people display abnormal patterns of gene activation, according to a new report.

Study leader Steve Cole of the University of California, Los Angeles says the findings may indicate that the "biological impact of social isolation reaches down into some of our most basic internal processes."

Many studies have found that lonely people have increased rates of infectious diseases, cardiovascular problems, and even cancer. But the reason for the connections has been unclear. The new study hints that an altered immune response may play a key role.

Published online in Genome Biology, the study looked at patterns of gene activation--which genes were turned on and off, and to what degree--in the white blood cells of six chronically lonely and eight nonlonely middle-aged adults. Degrees of isolation were assessed by a standard questionnaire, and each participant ranked in the same category for 3 consecutive years.

In the lonely people, 208 genes were activated much more or much less than the same genes in the nonlonely individuals. Many of the genes abnormally expressed in the isolated people are involved in immune processes such as inflammation, response to viruses, and antibody production.

Although the study was small, the authors say it provides an early window into understanding how social factors affect health.--B.V.