S ummary . A 57‐year‐old female patient, admitted for an acute abdominal syndrome, was found to have an extensive proliferation of mast cells both in the peripheral blood and the bone marrow. Cytochemical studies confirmed the mast cell characteristics of the pathological cell population, while the immuno‐phenotype strongly suggested a bone marrow origin of this malignancy. The course of the disease was not affected by antiproliferative treatment and the patient, after progressive general deterioration, died of intractable haemorrhage. On both clinical and haematological criteria it seems possible to distinguish this rare case of primary mast leukaemia from the more common form of tissue mastocytosis with secondary leukaemia.

Summary In a group of 14 patients with primary thrombocythaemia (PT) the study of erythropoietic colony formation in vitro showed the development of so‐called ‘endogenous’colonies, namely colonies with no added erythropoietin (Ep), in all but one case. In the presence of added Ep the colony formation increased slightly in the PT group, but the rise in the control group was so pronounced that any statistical difference between the two groups disappeared. No ‘endogenous’colonies were observed in cases of secondary thrombocytosis. This finding reinforces the view that PT is a myeloproliferative disorder and establishes that some erythroid progenitors show the same high sensitivity to Ep as that found in polycythaemia vera; it is of interest that, in the patients studied, there was no apparent involvement of erythropoiesis.

Colony formation in vitro from bone marrow haemopoietic progenitors was studied in a group of patients with acute myeloblastic leukaemia and acute lymphoblastic leukaemia at presentation of the disease and, in a few cases, during complete remission. Both granulocytic-macrophagic (CFU-GM) and erythropoietic (CFU-E) colonies were studied. A sharp contrast was observed between CFU-GM and CFU-E formation at presentation of the disease: while the former was markedly depressed, with considerable increase of the cluster colony ratio, CFU-E production was not significantly affected, with only a reduced sensitivity to low-dose erythropoietin. CFU-GM formation returned to normal in the early stages of complete remission, but showed a progressive decline in the course of time; the process of cell differentiation was not significantly impaired, although minor changes were observed. It appears that the leukaemic process has much greater impact altogether on CFU-GM than on CFU-E colony formation, the latter being only marginally affected, even in the presence of a high proportion of blast cells.

This is a study of in vitro production of erythropoietic colonies from peripheral blood and bone marrow of normal subjects and patients with different polycythaemic conditions. Proliferative stimuli included: 1. Fetal calf serum (FCS) only. 2. FCS plus a source of erythropoietic-stimulating activity (ESA). 3. FCS + ESA + erythropoietin (Ep). It was found that normal subjects and patients with secondary polycythaemia (SP) exhibited full colony growth only in the presence of both ESA and Ep, while patients with primary proliferative polycythaemia (PPP) showed colony production with FCS alone, further enhanced in the presence of ESA and Ep. A group of patients with idiopathic erythrocytosis (IE), namely with an increase of red cell mass not accompanied by other signs of myeloproliferative disorder, and without underlying cause, showed a heterogeneous response to ESA which in some patients was significantly greater than in normal subjects or in SP patients. It appears therefore that sensitivity of erythropoietic colony formation to Ep and ESA may be helpful in differentiating among various forms of polycythaemia; this study also establishes the heterogenicity of the IE group.

Lymphocyte subpopulations from peripheral blood of normal subjects and patients with primary proliferative polycythaemia (PPP), idiopathic erythrocytosis (IE) and essential thrombocythaemia (ET) were separated using antihuman immunoglobulin antiserum for B lymphocytes and the following monoclonal antibodies: OKT3, directed against the general T-lymphocyte subpopulation, OKT4 and OKT8, detecting respectively T-helper and T-suppressor lymphocyte subpopulations, OKM1 reacting mainly with monocytes. A decrease in the number of OKT3+ cells was observed both in PPP and IE, with a particular fall of the OKT8+ (suppressor) cells, so that the T4/T8 ratio was significantly increased (P less than 0.03 in PPP and P less than 0.0005 in IE). The ratio remained normal in samples from ET. OKM1+ cells were significantly increased in PPP (P less than 0.04), but not in IE, while in ET there was a rise in a few cases only. The present data point out some definite changes in the circulating lymphomonocytic cell subsets, which may be of interest in the study of this group of myeloproliferative disorders.

British Journal of HaematologyVolume 55, Issue 3 p. 557-558 Free Access ERYTHROPOIETIC ACTIVITY IN PRIMARY PROLIFERATIVE POLYCYTHAEMIA S. Eridani, S. Eridani Department of Haematology, St Thomas' Hospital and Medical School, London SE1 7EHSearch for more papers by this authorE. Batten, E. Batten Department of Haematology, St Thomas' Hospital and Medical School, London SE1 7EHSearch for more papers by this authorB. Sawyer, B. Sawyer Department of Haematology, St Thomas' Hospital and Medical School, London SE1 7EHSearch for more papers by this author S. Eridani, S. Eridani Department of Haematology, St Thomas' Hospital and Medical School, London SE1 7EHSearch for more papers by this authorE. Batten, E. Batten Department of Haematology, St Thomas' Hospital and Medical School, London SE1 7EHSearch for more papers by this authorB. Sawyer, B. Sawyer Department of Haematology, St Thomas' Hospital and Medical School, London SE1 7EHSearch for more papers by this author First published: November 1983 https://doi.org/10.1111/j.1365-2141.1983.tb02171.xCitations: 9AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat No abstract is available for this article. REFERENCES Douer, D., Fabian, I. & Cline, M. (1983) Circulating pluripotent haemopoietic cells in patients with myeloproliferative disorders. British Journal of Haematology, 54, 373–381. Eridani, S., Pearson, T.C., Sawyer, B., Batten, E. & Wetherley-Mein, G. (1983) Erythroid colony formation in primary proliferative polycythaemia, idiopathic erythrocytosis and secondary polycythaemia: sensitivity to erythropoietic stimulating factors. Clinical and Laboratory Haematology, 5, 121–129. Fauser, A.A. & Messner, H.A. (1981) Pluripotent hemopoietic progenitors (CFU-GEMM) in polycythaemia vera: analysis of erythropoietin requirement and proliferative activity. Blood, 58, 1224–1227. Citing Literature Volume55, Issue3November 1983Pages 557-558 ReferencesRelatedInformation