The cause and pathogenesis of lymphoma

The cause and pathogenesis of lymphoma are still unclear, among which the viral theory is highly valued.

1. Virology

Most of the studies on the etiology of lymphoma started from high-incidence areas or high-incidence populations. In 1964, Epstein et al. first isolated Epstein-Barr (EB) virus from the subculture of Burkitt lymphoma tissue in African children and found that this DNA herpes virus can cause human B lymphocyte malignancy and lead to Burkitt lymphoma. Burkitt lymphoma has obvious local prevalence. More than 80% of such patients have significantly increased titers of EB virus antibodies in their serum, while only 14% of patients without Burkitt lymphoma have increased titers of EB virus antibodies in their serum. The chances of developing Burkitt lymphoma in the general population with high titers are also significantly increased. The above studies all suggest that EB virus may be the cause of Burkitt lymphoma. The serum of HL patients was tested by immunofluorescence, and some patients had high titers of EB virus antibodies. EB virus particles can be found in the lymph nodes of HL patients by electron microscopy. EB virus can be found in RS cells of 20% HL, and the relationship between EB virus and HL is extremely close. At the same time, EB virus may also be the cause of post-transplant lymphoma and AIDS-related lymphoma. However, my country is a high-infection area of ​​EB virus, and the infection rate of EB virus in the normal population is very high, with no significant difference from lymphoma patients.

Another important discovery in recent years is the viral etiology of T-cell lymphoma. In 1976, Japanese scholars found that adult T-cell lymphoma/leukemia had a clear familial concentration trend and was seasonal and regionally prevalent. Gallo in the United States and Yoshida in Japan discovered a retrovirus, which they called T-cell lymphoma/leukemia virus (HTLV-I). HTLV-I was proven to be the cause of this type of T-cell lymphoma. Another retrovirus, HTLV-Ⅱ, has recently been considered to be related to the onset of T-cell cutaneous lymphoma (mycosis fungoides). Kaposi sarcoma virus is also considered to be the cause of lymphoma originating in the body cavity.

(II) Immunodeficiency

The occurrence of lymphoma is closely related to immunosuppression, and the host's immune function determines the host's susceptibility to lymphoma. Recent studies have found that people with hereditary or acquired immunodeficiency and lymphoma are more likely to have lymphoma than normal people; one-third of malignant tumors caused by long-term use of immunosuppressants after organ transplantation are lymphoma; the incidence of lymphoma in patients with Sjögren's syndrome is higher than that in the general population. Under immunodeficiency, repeated infections, allogeneic organ transplantation, and antigenic stimulation of lymphocytes to the host can all cause a proliferation reaction of lymphoid tissue. Due to the absence or dysfunction of T suppressor cells, the body lacks automatic feedback control, and lymphoid tissue proliferates indefinitely, eventually leading to the occurrence of lymphoma.

3. Chemical and physical factors

In the early years, the United States reported that farmers in the Midwest of the United States had a lymphoma incidence rate several times higher than the normal population due to the use of insecticides and pesticides, but the mechanism is still unclear. The incidence of ML in Hiroshima atomic bomb victims who had received more than 1Gy of radiation and patients who had received radiation therapy for spondylitis was twice that of the normal population. Chemical drugs, benzene, asbestos and arsenic can all lead to an increase in the incidence of ML.

(IV) Others

Long-term use of certain drugs can induce lymphoma, such as phenytoin sodium can induce ML, etc. Chronic infection of Helicobacter pylori is closely related to gastric mucosa-associated lymphoid tissue lymphoma. Not only can evidence of bacteria be found in serum and gastroscopy, but antibiotic treatment can also achieve good therapeutic effects for most Helicobacter pylori-positive gastric mucosa-associated lymphoid tissue lymphomas.