We all know that stress suppresses immunity and, therefore, inflammation, right? For example, one of the very well-known side effects of corticosteroid medications is suppression of the immune system, which can leave patients more vulnerable to infections. It turns out that it is not that simple and now there is considerable evidence that chronic stress actually boosts "humoral immunity," and nasty systemic inflammation along with it. 
Humoral immunity is the part of your immune system that deals with antibodies and fighting against foreign invaders such as germs. Of course, this is critical for our survival against infections of all sorts, but the problem is that humoral immunity is also associated with increased inflammation. For example, we know of a number of infections that likely to lead to heart disease, including urinary tract infections, influenza and possibly periodontal disease. This link between infection, inflammation and heart disease has been noted many times in the research of the last twenty years and is now widely accepted. Inflammation has also been linked to erectile dysfunction! See my page on Inflammation and Erectile Dysfunction for more information.
But a connection between stress and inflammation seems much more subtle. How could stress, especially the chronic, day-to-day kind, trigger such a silent, background process as inflammation that is designed to work against foes such as diptheria, west nile virus and malaria?
The answer is that the body does not really differentitate that well between a deadly superpathogen and the worry we experience night after night about your mortgage payment. These both trigger a very similar inflammatory response as I will show below, and it can be deadly.
Has this been verified in humans? One study monitored medical students under psychological stress and found that the following inflammatory cytokines increased: 
NOTE: Furthermore, some students had a lower response of the immunoregulatory cytokines IL-10 and IL-4, so, basically, the brakes were removed and the accelerator pushed full throttle in some students.
The importance of the above cannot be overestimated. Inflammation is considered the "root of all evil" by many authorities. It has been found to be a root cause of many cancers, autoimmune diseases including diabetes and arthritis, heart disease, Alzheimers - the list goes on and on. Almost all of the nasty chronic medical conditions that plague us in Western societies have inflammation as a root cause. You can read about all of this in more detail in my link on The Evils of Inflammation. TNF alpha can also downregulate eNOS, which will leave you with much less nitric oxide according one one study.  Yes, this helps explain why an increase in inflammation can lead to a loss in erectile strength.
NOTE: I have a link on How to Lower Your TNF Alpha Naturally for those interested.
The study above  was also instructive, because it was on medical students before and after exams. Basically, it was covering the kinds of everyday stress that we experience as human beings in modern societies: worrying about how we're going to pay the mortgage; worrying about a relationship that is falling apart; worrying about medical bills that we can pay; worrying about losing your job, etc. These kind of seeming "do or die" situations can really take a toll on us, not just psychological but physically as the above study shows us.
The same study had the foresight to study two very important psychological states that were found to really increase inflammatory cytokine levels: 1) high stress perception and 2) a high anxiety response. Some men "just roll with the punches." Some guys can sleep like a baby even when the pressure is on. But most of us cannot and so, if you were one of those guys who is actually the opposite, you are probably sending these inflammatory messengers through the roof.
And the studies have looked at a little older crowd as well. One study on seniors contrasted caregivers - those who were taking care of a very sick spouse - with those who weren't. What they found was incredible: "caregivers' average rate of increase in IL-6 was about four times as large as that of noncaregivers."  Again, IL-6 can kill you in a dozen different ways and is a huge source of chronic disease. So, ironically, the task of caring and empathizing over the health of a loved one can destroy your own
So what can you do about stress? Much, much more than you might think. Of course, time and people management skills can help tremendously. But one thing that many men do not realize is that there are ways to actually manage the stress (and cortisol) throught simple techniques that you can do at home.. Basically, you can teach your mind not to overreact during times of stress through a variety of techniques, which I cover on these pages: (Non-religious) Mindfulness Meditation, Progressive Muscle Relaxation and Secular Meditation.
There are many other techniques that work. There is a study that shows that self-hypnosis lowers the humoral immunity that I mentioned above  or you can go with your wife to her yoga classes, since it is a proven stress buster. There is also guided imagery, biofeedback, Tai Chi, etc. However, I prefer the above, because you can do them in your home in perfect privacy - no one really has to know - and they do not require another person. You can start today after doing just 20 minutes of reading.
In addition, 1) progressive muscle relaxation almost forces your body to relax and is easy to do and 2) meditation forces you to learn how to control your mind and many men struggle with stray and repetitive thoughts under stress. Again, read the above links and you will find that these techniques can actually 1) grow back parts of your brain, 2) lower cortisol, 3) lower blood pressure, 4) improve many psychological issues including anxiety and depression.
NOTE: The research also shows that depression is linked to inflammation. One of the cytokines, for example, has been found to actually induce depression! 
1) Trends in Endocrinology & Metabolism, Nov 1 1999, 10(9):359-368, "Stress Hormones, Th1/Th2 patterns, Pro/Anti-inflammatory Cytokines and Susceptibility to Disease"
2) Cytokine, April 1998, 10(4):313 318, "THE EFFECTS OF PSYCHOLOGICAL STRESS ON HUMANS: INCREASED PRODUCTION OF PRO-INFLAMMATORY CYTOKINES AND Th1-LIKE RESPONSE IN STRESS-INDUCED ANXIETY"
3) Eur Heart J, 2007, "The role of infection in cardiovascular disease: more support but many questions remain"
4) International Journal of Psychophysiology, Aug 2001, 42(1):55-71, "Cellular and humoral immunity, mood and exam stress: the influences of self-hypnosis and personality predictors"
5) Circulation Research, 1993, 73:205-209, "Tumor necrosis factor downregulates an endothelial nitric oxide synthase mRNA by shortening its half-life"
6) Trends in Immunology, Jan 2006, 27(1):24-31, Cytokines sing the blues: inflammation and the pathogenesis of depression"
7) PNAS, Jul 22 2003, 100(15):9090-9095, "Chronic stress and age-related increases in the proinflammatory cytokine IL-6"