The majority of cases of lymphoma arise out of the blue and we really have no idea what the cause is. And in fact in most cases there probably isn't a specific cause. One of the features of the immune system is that it has to be ready to fight off thousands upon thousands of different types of pathogens that are in the environment. And to achieve this the immune cells have a special system when, when they are developing, there is a series of enzymes in the cell that come along, chop up the DNA controlling the production of antibodies and receptors on T-cells that recognise pathogens. It chops them up, changes them and sticks them back together in a different way to create unique entities, this is how the immune system creates diversity. But actually chopping up DNA, altering it and putting it back together is a recipe for creating cancer, and so one could argue that lymphomas are the cost of mankind being able to cope with infections, and that the real issue is not why do people get lymphoma, but why in fact so few people get lymphomas.
Now, in any system where the immune system is chronically stimulated, the immune cells will undergo more divisions, and as a consequence of that, they are going to be more prone to random changes that could cause lymphomas. So it's well recognised that some chronic infections can lead to an increased risk of lymphoma. And probably the most notable of those is individuals who have chronic gastritis from a particular organism, heliocobacter, and in those individuals there is a greater incidence of getting a lymphoma affecting the stomach. Likewise in Rheumatoid Arthritis and some allied conditions, particularly Sjorgren's disease, which affects the parotid gland, there is chronic immune stimulation, you tend to get slightly swollen glands, the lymphocytes are turning over more frequently, and this leads to an increased risk of lymphoma. It's not a great increased risk, the vast majority of people with Rheumatoid Arthritis, for instance, will not get lymphoma, but there is a statistically increased risk. |
