Acute myeloid leukaemia relapsing following interleukin-2 treatment expresses the alpha chain of the interleukin-2 receptor.
Immunotherapy with recombinant human Interleukin-2 (rhIL-2) was given to nine patients in first complete remission from acute myeloid leukaemia (AML). Five patients relapsed. The median time to relapse after commencing rhIL-2 was 26 weeks (range 2-44). Four patients were studied at relapse. The morphological and cytochemical features at relapse and presentation were similar. Cytogenetic analysis at relapse in patients 1 and 3 showed a normal karyotype. At relapse, patient 4 had the abnormality 46,XY, t(2;3). Patient 2 had the chromosomal abnormality t(8;21) at presentation and relapse. Patients 3 and 4 with M5 AML relapsed rapidly at 2 and 9 weeks after starting rhIL-2 treatment. Relapse leukaemia cells had features normally associated with lymphoid development. Patient 3 was TdT positive, with rearranged immunoglobulin genes, and a proportion of cells expressing the CD7 antigen; patient 4 also expressed the CD7 antigen. Relapse leukaemic cells from three of four patients expressed the alpha chain of the IL-2 receptor as assessed by flow cytometry. After overnight incubation and removal of T-lymphocytes the proportion of cells from these patients expressing the alpha chain increased from 15% to 61% (P less than 0.01). Using tritiated thymidine uptake to assess cell proliferation, two of three patients who expressed the IL-2 receptor alpha chain proliferated in response to 1000 u/ml of rhIL-2 in vitro, with a stimulation index greater than 1.95 (P less than 0.05). Following rhIL-2 immunotherapy for AML, relapse cells may express an inducible form of the alpha chain of the IL-2 receptor, which can mediate a proliferative response. It is possible that rhIL-2 when administered to AML patients in remission, may induce relapse. This may be a particular risk in patients with the M5 subtype.
Macdonald
D
D
Department of Haematology, Royal Postgraduate Medical School, Hammersmith Hospital, London.
Jiang
Y Z
YZ
Swirsky
D
D
Vulliamy
T
T
Morilla
R
R
Bungey
J
J
Barrett
A J
AJ
D000328:Adult; D005260:Female; D015321:Gene Rearrangement / Q000502:physiology; D006801:Humans; D007376:Interleukin-2 / Q000627:therapeutic use*; D007951:Leukemia, Myeloid / Q000235:genetics / Q000276:immunology / Q000628:therapy*; D008875:Middle Aged; D010641:Phenotype; D010865:Pilot Projects; D015375:Receptors, Interleukin-2 / Q000032:analysis*; D011994:Recombinant Proteins / Q000627:therapeutic use; D012008:Recurrence
D007376:Interleukin-2; D015375:Receptors, Interleukin-2; D011994:Recombinant Proteins