Definition, frequency (epidemiology) and causes (etiology)

Hodgkin lymphoma (also known as Hodgkin’s lymphoma, Hodgkin’s disease, morbus Hodgkin and lymphogranulomatosis,) is a malignant disease of the lymphatic system. In comparison to other malignant tumors it occurs only rarely, but among malignant lymphomas, it is relatively common. Every year, approximately 2-3 among 100,000 people get Hodgkin lymphoma. Men are more affected than women (in a ratio of 3:2). There are two peaks of incidence regarding the age of affected patients in the industrial world, a large one in patients between 20 and 30 years of age and a smaller one in patients over 65. However, Hodgkin lymphoma may principally affect patients of all age.

In 1832, the English physician Sir Thomas Hodgkin was the first to describe this lymphoma as an independent disease, and so it was named after him.

The characteristic histologic changes that are associated with Hodgkin lymphoma, the disease-defining Hodgkin cells and Reed-Sternberg cells, were first described in 1898 by Carl Sternberg and in 1902 by Dorothy Reed.

Since then and until today, different causes and potential mechanisms for the development of the lymphoma have been under discussion.

Only recently, new molecular-biological methods provided evidence that malignant Hodgkin cells originate from B lymphocytes (small white blood cells) that are produced in the germinal center of lymph nodes.

The Epstein-Barr virus (EBV) is supposed to promote the development of Hodgkin lymphoma because patients who once had an EBV infection, which appears as an acute feverish lymph node swelling, are more often affected by Hodgkin lymphoma as patients who never had this kind of infection. This is supported by a detection made at the end of the 1980s, when the genetic code of the Epstein-Barr virus was found in Hodgkin cells and Sternberg-Reed cells.

However, there are also malignant Hodgkin and Reed-Sternberg cells in which no EBV DNA can be detected. In addition, more than 95% of the population become infected with the Epstein-Barr virus during the first 30 years of their life (most of them without showing any clinical signs), and the great majority of these cases does not develop Hodgkin lymphoma. For these reasons, there must be other essential factors causing or contributing to the development of Hodgkin lymphoma that have not been revealed yet

Potential factors might be a disturbance in the regulation of the immune system as well as genetic aspects or environmental influences.