Hodgkin's Disease - Introduction

Highlights	Outlook	Transplantation
Introduction	Staging and Treatment Guidelines	Immunotherapy
Risk Factors	Treatment Options by Stage	Resources
Symptoms	Radiation Treatments	References
Diagnosis	Other Treatments

Introduction

Hodgkin's disease is a type of lymphoma. Lymphomas are cancers of the lymphatic system. They are generally subdivided into two groups: Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL). NHL is discussed in another report. [See In-Depth Report #84: Non-Hodgkin's Lymphomas.]

The lymphatic system filters fluid from around cells. It is an important part of the immune system. When people refer to swollen glands in the neck, they are usually referring to swollen lymph nodes. Common areas where lymph nodes can be easily felt, especially if they are enlarged, are: the groin, armpits (axilla), above the clavicle (supraclavicular), in the neck (cervical), and the back of the head just above hairline (occipital).

Hodgkin's Disease and Biologic Process Involved in Malignancy

HD is the major tumor in a group known as malignant lymphomas. Most often HD starts in B-cell lymphocytes located in lymph nodes in the neck area, although any lymph node may be the site of initial disease.

Click the icon to see an image of the lymph nodes in the head and neck.

The following is a possible description of the process leading to HD:

In early development, B cells normally undergo a series of genetic rearrangements until they create immunoglobulins, which are proteins that act as antibodies.
Antibodies are produced by the immune system. They contain receptors that match and bind to a wide array of foreign substances (such as viral proteins) called antigens. Antibodies help launch an immune attack against antigens.
B cells normally undergo limited cycles of genetic rearrangement that result in immunoglobulin production. In rare cases, however, the genetic arrangements create a mutation that does produce immunoglobulins. The results are large, abnormal cells referred to as Reed-Sternberg cells.
Without immunoglobulin, Reed-Sternberg cells can be infected by certain viruses (notably the Epstein-Barr virus--the cause of infectious mononucleosis). Genetic byproducts of these viruses appear to inhibit a natural process of self-destruction (called apoptosis) that would normally kill off these natural cells. Instead, the abnormal B cells grow non-stop, causing most forms of HD.

Click the icon to see an image of an antibody.

It should be noted that only a very small percentage (about 1%) of cells found in the affected lymph tissues of HD are actually Reed-Sternberg cells. Researchers are unable to completely explain why so few cells can cause such severe symptoms. One explanation is that these cells trigger production very powerful immune systemproteins called cytokines (including those known as interleukin-1, interleukin-6, and tumor necrosis factor). These cytokines produce an inflammatory response that can cause local pain, fever, and other symptoms typical of HD. The dominance of different kinds of cytokines may also explain why HD takes different forms.