Abolished production of interferon by leucocytes of patients with the acquired cytogenetic abnormalities 5q -- or -- 5 in secondary and de-novo acute non-lymphocytic leukaemia.

Interferon production by leucocytes on stimulation with inactivated antigens from herpes simplex virus, varicella zoster virus and cytomegalovirus was determined in 19 patients with preleukaemia or acute non-lymphocytic leukaemia, in 15 following treatment for other tumours. Production of interferon was abolished in 10 patients and preserved in nine cases after stimulation with herpes simplex antigen. Cytogenetic studies of bone marrow demonstrated an abnormal karyotype in 13/15 patients with secondary preleukaemia or leukaemia. Characteristics were (a) hypodiploid cell lines demonstrated in eight cases, (b) a B-chromosome defect found in five cases and verified as 5q -- in four, and (c) defects in C-group chromosomes in 10, verified as monosomy 7 in nine. All four patients with de-novo preleukaemia or leukaemia had abnormal cytogenetic findings, two B-chromosome abnormalities verified as monosomy 5. A relationship between abnormalities in chromosome no. 5 and abolished production of interferon was demonstrated, as only one of seven patients with 5q --, --5 or --B produced interferon by the leucocytes, compared with eight of a total of 12 patients with other cytogenetic defects or a normal karyotype (P=0.04). The results are remarkable, as chromosome no. 5 has recently been discovered to contain a gene for interferon production. Furthermore abolished production of interferon by leucocytes seemed correlated to previous irradiation and to disease-related fever.