The identification of lymphocyte clones, with chromosome structural aberrations, in irradiated men and women

Cytogenetic studies in patients previously treated for Hodgkin's disease

A cytogenetic study was made of bone marrow cells and lymphocytes from patients who had been successfully treated with various regimens for Hodgkin's disease. Most of the patients had been off treatment for at least 3 years before the study began. They were divided into three groups according to the intensity of the therapy received. The frequency of gaps and breaks in the chromosomes of lymphocytes was above normal limits and similar in the three treatment groups. In contrast, the frequency of both lymphocytes and bone marrow cells with rearranged karyotypes was correlated with the intensity of treatment. Clones of cells with an abnormal karyotype were found in only two patients, both of whom were in the group receiving the most intensive therapy, i.e., chemotherapy and total nodal irradiation.

Chromosomes and transformation of lymphocytes in lymphoproliferative disorders

In chronic lymphocytic leukaemia the majority of circulating lymphocytes which responded to phytohaemagglutinin in vitro were found to have normal karyotypes. A minor population of cells in patients treated with chemotherapy had an increased number of chromosomal rearrangements as compared with cells from normal controls and untreated patients with chronic lymphocytic leukaemia. Probably bonemarrow and lymph-node cells also had a normal karyotype.In the other lymphoproliferative disorders the peripheral blood lymphocytes had either normal karyotypes or chromosomal abnormalities attributable to treatment, even in those cases where the tumour cells of involved lymph nodes were known to have abnormal karyotypes.It was possible that circulating tumour cells were present in one case.