Because of their roles as both sentinels and effectors of the innate and adaptive immune system, white blood cells (leukocytes) are frequently measured and monitored in clinical practice. An increased white blood cell count (leukocytosis) is one of the most common signs of infectious and inflammatory diseases.
Neoplasms of immune cells, which include the leukemias, the lymphomas, and the plasma cell tumors, are less common but much more important clinically. Hodgkin lymphoma (the first of these tumors to be described) came to attention in 1832 in a paper entitled "On Some Morbid Appearances of the Absorbent Glands and Spleen" by Thomas Hodgkin. The photograph on the right illustrates the natural history of Hodgkin lymphoma, which includes the inexorable development of massively enlarged lymph nodes and eventual spread of the disease to the liver, spleen, bone marrow, and other tissues. Little could be done for such unfortunate souls.
This sad state has changed dramatically. Beginning in the latter half of the 20th century, white cell neoplasms have been on the leading edge of advances in oncology; indeed, Hodgkin lymphoma was the first human cancer to be cured with radiation and combination chemotherapy. The field now finds itself at the forefront of a genomic revolution that is laying the groundwork for increasingly precise molecular diagnoses and more effective, less toxic targeted cancer therapies.
Hodgkin lymphoma, duration 6 months.
From Cabot's "Physical Diagnosis," fifth edition, New York, William Wood and Company, published in 1914.