Positive Outlook Promotes Killer Cell Activity, Studies Show
PITTSBURGH (AP) _ A positive outlook on life appears to promote natural killer cell activity for fighting disease in certain cancer patients as well as healthy individuals, according to studies presented today.
″It doesn’t seem to be so much whether one is exposed to stress or not, but how people are reacting to similar types of stress,″ said Dr. Ronald Herberman, director of the Pittsburgh Cancer Institute and part of the research team.
″If they’re not as well adjusted ... we have indication that it has health consequences.″
Herberman and Dr. Sandra Levy, an associate director at the institute, say they have found that colon and skin cancer patients who combine standard medical care with psychotherapy have higher natural killer cell activity than those who do not undergo counseling.
In a separate study being presented at a medical symposium at Johns Hopkins University, they said healthy people with positive outlooks have higher natural killer cell activity than physically fit complainers.
The upbeat subjects suffered fewer colds and other viral infections. Their ailments also did not last as long as illnesses suffered by those expressing ″more hostility and anger about their life,″ said Herberman, who followed the subjects for six months.
These findings, based on an analysis of 120 men and women between ages 18 and 45, confirm the results of a smaller pilot study conducted by Herberman and Levy three years ago at the National Cancer Institute.
″We were looking at how serious the stresses were to them ... their hassles, things that happen to all of us, fights with the boss, that kind of thing,″ Levy said in an interview Tuesday night.
James Zabora, director of patient and family services for the Johns Hopkins Oncology Center in Baltimore and the symposium’s co-director, called the findings ″interesting″ but said they must be kept in perspective.
″They’re moving into a very difficult area,″ Zabora said. ″The immune system is an incredibly complicated system and maybe to this point in time we have examined 1 percent or 0.5 percent of what the immune system is all about.″
Researchers currently can only speculate why happiness seems to promote activity of natural killer cells, which comprise 5 percent to 10 percent of all white blood cells, according to Herberman. One theory is that a positive perception of stress produces certain hormones that affect the body’s immune system.
″It isn’t clear what’s going on,″ Levy said. ″All we’re asking is whether behavior or central nervous system-mediated factors play some role for some tumors. If they do, that’s important because behavior can be changed.″
To test that notion, Herberman, Levy and Dr. Judith Rodin, professor of psychiatry at Yale University, followed 30 people between ages 18 and 45 with colon cancer or malignant melanomas. All had had their tumors surgically removed, and the disease had not reached advanced stages.
Eighteen received individual counseling once a week for eight weeks. The remaining 12 received only standard medical care. Both groups were identical in background.
By the end of psychotherapy, the 18 with counseling showed significantly higher natural killer cell activity than those without, Levy said. The counseled group reported less depression and anger and seemed better able to cope with their lives, she said.
The 12 who did not undergo psychotherapy tended to blame themselves for their problems, Levy said.
″We don’t believe ... that your psychological status is going to make the difference as far as whether the disease is present or not,″ Herberman said. ″But on top of all the physical issues, the nature of the disease and the body’s immune response to it, the psychological factors can have a significant effect.″
Additional studies are needed before any recommendations can be made regarding psychotherapy.
″Time will tell as to how much that is going to make a difference as far as survival or staying tumor-free,″ Herberman said.