The analysis of 288 cases of polycythemia vera (PV) with a minimal follow-up of 10 years enabled us to study the characteristics of acute leukemia as observed in 33 patients (11.4%). In 50% of the patients (16 of 33), the malignant transformation is of the refractory anemia with excess of blasts (RAEB) type. Half of these further transform to acute nonlymphocytic leukemia (ANLL). Their life expectancy is not better than patients who abruptly develop ANLL. Leukemic transformation shows a frequency peak in the eighth year after initial evaluation in PV treated with chemotherapy and in the 11th year in patients treated with radiotherapy. In 30% of the patients myelofibrosis, or the spent phase of PV, is present before the transformation to acute leukemia (AL). This complication is, however, part of the natural history of PV and is observed in 20% of PV patients at 10 years when leukemic transformation is absent. Marrow fibrosis can therefore not be considered as a preleukemic phase. It was also noted that the occurrence of myeloid metaplasia/myelofibrosis is more frequent and begins earlier in patients treated by phlebotomy alone, and who do not transform to leukemia. The clinical characteristics of these AL, including high frequency of partial marrow invasion, difficulties in cytologic classification, a peak incidence similar to that in patients treated by chemotherapy or radiotherapy for a prior malignancy, multiple chromosome abnormalities, and poor response to therapy are all highly suggestive of secondary leukemias.

Scintigraphy of the salivary glands with technetium-sodium pertechnetate (99mTc) was undertaken on 320 patients with oral dryness or connective tissue disease using a computer assisted method that gave quantitative results about the major salivary gland function. Compared with clinical and histological data, scintigraphy provides a sensitive method, even though it is not specific, for detecting minimal injuries to salivary glands in patients suspected of having Sjögen's syndrome. Moreover, it might differentiate between the Sjögen-like syndrome and the sequelae of radiotherapy in patients with bone marrow graft. Scintigraphy of the major salivary glands could therefore form part of the routine investigation of patients with Sjögen's syndrome.

A clinical phase (spent phase) in the course of polycythaemia vera (PV) cases is described as enlargement of the spleen in spite of treatment, frequent cytopenia of one or several lines, persistent red cell hypervolaemia with considerable increase of plasma volume, persistence of myeloid hyperplasia with no collagen myelofibrosis or osteomyelosclerosis, absence of hepatosplenic erythroblastic metaplasia, as shown by radio-iron kinetics and/or 111In-transferrin scintigraphy. The frequency of this phase was 5% in a study where it was not systematically sought, but it could in fact be greater. Its occurrence is not related to the clinical and biological parameters of PV. On the other hand, it is significantly more frequent and earlier in patients treated by phlebotomies than in those treated by myelosuppression (32P). In four of the 12 cases, this phase was rapidly followed by an acute leukaemia. In eight cases there was a 1-5 year interval before a myelofibrosis with splenic myeloid metaplasia. This evolution could at this stage be delayed by chemotherapy. The efficacy of splenectomy should be studied.

Marrow fibrosis is involved in some haematological malignancies. Either because of sampling errors, variations of focal distribution of fibrosis or the discomfort for patients of bone biopsies, conventional histology appears to be unsuitable for the follow‐up of myelofibrosis. During collagen synthesis by marrow fibroblasts, the aminoterminal propeptide is removed from procollagen III and released in the serum. Thus, a sensitive radioimmunoassay of type III aminoterminal propeptide of procollagen (PC III) has been tested in myeloproliferative and lymphoproliferative disorders with a marked bone marrow fibrosis. In polycythaemia vera, PC III level was significantly increased as compared to controls and was related to marrow fibrosis of grade I. The more increased PC III values were observed in spent polycythaemia cases initially treated by phlebotomy alone. Follow‐up showed a transformation into myeloid metaplasia. In contrast, PC III remained stable in patients treated with radiophosphorus 32P or hydroxyurea who did not transform. In myeloid metaplasia, results of PC III were significantly higher than in controls or polycythaemia vera cases. Myelofibrosis of recent onset (< 2 years) gave higher values than chronic myelofibrosis. Increased PC III values were also emphasized in chronic myelocytic leukaemia, and in a few cases of refractory anaemia with excess of blasts, hairy cell leukaemia and chronic lymphocytic leukaemia.

111Indium--transferrin (111In) and 99mTechnetium-colloids (99mTc) bone marrow imaging of 55 myelofibrosis (MF) cases has been compared with clinical, histological, and iron-kinetics data. The best correlations are seen between the splenic uptake of 111In with the spleen/sacrum ratio of 59Fe at the first hour (r = 0.69, P less than 0.001) and also with the splenic erythropoiesis histologically assessed in ten splenectomized patients (r = 0.75, P less than 0.01). Moreover, sacrum uptake of 111In, when compared with sacrum uptake of 59Fe (r = 0.51, P less than 0.001) and with hematopoietic cellularity of the bone marrow (r = 0.57, P less than 0.001) reflects faithfully the hematopoietic cell content of the marrow. Thus, 111In bone marrow imaging provides a noninvasive and useful tool for the diagnosis of myeloid metaplasia in MF. Ferrokinetic studies still appreciate with better insight the amount of ineffective erythropoiesis or hemolysis and remains therefore of great value when splenectomy is discussed.

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Pro‐collagen III (PC III) has been proposed as a useful value for diagnosis and follow‐up of myeloproliferative disorders. A significant difference is observed between polycythaemia vera (PV) and essential thrombocythaemias (ET) on one hand, and the pure erythrocytoses (PE) on the other hand, but a large overlap makes this test of low diagnostic value. High values are observed in primary and post‐PV myelofibrosis, but excessive PC III levels in active PV are not predictive of evolution toward myelofibrosis. PC III level is lower in myelo‐suppressed patients (32P, or hydroxy‐urea) than in active cases or in patients treated by phlebotomies. We conclude that PC III measurement is of low diagnostic value for discriminating PV and PE, does not appear to allow short‐term prediction of evolution to myelofibrosis, but may be useful to evaluate the role of treatment in delaying progression of PV toward myelofibrosis.

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