It has been recognized that some patients with myelodysplastic syndromes (MDS) develop immunologic abnormalities, but little is known of its correlations to MDS-specific disease features. In a retrospective study of 284 MDS patients, we identified 32 patients (11.3%) with clinical or serologic immunological abnormalities (group A) and compared them to the remaining 252 cases (group B). Group A consisted of 20 patients with clinical signs of autoimmune disease and 12 asymptomatic patients with serologic immunological abnormalities only. Apart from significant female predominance in group A (M/F = 2.5 vs M/F = 0.7, p = 0.001), the other clinical and biological features such as median age, distribution of MDS subtypes, incidence of karyotyopic abnormalities, "abnormal" in vitro growth of GM-progenitors and survival times were similar in the two groups. Autoimmune manifestations partially responded to immunosuppressive therapy, with moderate improvement of peripheral cytopenia. In addition, CD3(+), CD4(+), CD8(+), CD19(+), and CD56(+) cells were quantified in peripheral blood of 38 patients. Matched with similarly aged healthy control group, most MDS patients showed significant lymphocytopenia, mainly due to the reduction of T-helper series (in both absolute numbers and percentage). B-cells were reduced in absolute numbers, but their percentage still overlapped with the control. No major abnormalities of natural killer cells (CD56(+)) were seen. We conclude that autoimmune diseases and asymptomatic immunologic abnormalities are common in patients with MDS, but except for female predominance, no correlation between these abnormalities and MDS-specific disease features were found.

The article is concerned with incidence, clinical features, response to therapy, and prognosis of patients with hypocellular myelodysplastic syndromes. Bone marrow (BM) cellularity <30% (or <20% in patients >70 yr) was found in 24 of 236 (10.2%) trephine biopsies. Median age was 61 yr, with significant male predominance (M/F=3.0) At diagnosis, median hemoglobin was 83 g/L, median platelet and neutrofil counts were 31x109/L and 1.2x109/L, respectively. According to FAB classification, 17 patients had RA, 6 had RAEB, and only 1 had RAEB-t. Beside marrow hypoplasia, the most prominent PH finding was megakaryocyte hypoplasia and dysplasia, found in two-thirds of cases, each. Comparison between hypocellular and normo/hypercellular MDS cases regarding clinicopathological features showed younger age, more severe cytopenia, less blood and BM blast infiltration, MK hypoproliferation, and more pronounced stromal reactions in former cases. Karyotypic abnormalities were present in 12.5% hypocellular cases, in contrast to 44.6% normo/hypercellular cases (p=0.0025). Eleven patients were treated with supportive therapy alone, six with danazol or androgens, six with immunosuppressive therapy, and one with LDARAC. However, complete or partial response was achieved in only four patients treated with danazol or androgens. None of the patients developed leukemia. Eleven patients died, so marrow insufficiency was the main cause of death. Median survival was 33 mo for hypocellular MDS, and 19 mo for normo/hypercellular MDS (p=0.09). The results confirm the existence of hypocellular variant of MDS, which seems to have better prognosis than those patients with normo/hypercellular disease.

Spontaneous colony formation from bone marrow megakaryocyte progenitors (BMsCFU-Mk) was studied in 24 patients with essential thrombocythaemia (ET), 20 patients with reactive thrombocytosis (RT), 20 patients with polycthaemia rubra vera with thrombocytosis (PRVtr), 16 patients with chronic myeloid leukaemia with thrombocytosis (CMLtr) and 18 normal control subjects (C). The culture medium which was used in the methylcellulose assay in vitro contained 30% of plasma from a single patient with hereditary haemochromatosis. Remarkable BMsCFU-Mk growth was recorded in all patients with ET but in none with RT or in C. BMs-CFU-Mk were present in 11/20 patients with PRVtr and 7/16 patients with CMLtr. Spontaneous bone marrow erythroid progenitors (BMsBFU-E) were also determined in these patients. BMsBFU-E were found in 21/24 patients with ET and none in the patients with RT and C. All patients with PRVtr and one patient with CMLtr showed BMsBFU-E. We conclude that our implementation of the in vitro methylcellulose assay allows the BMsCFU-Mk to be used as an unequivocal test for discrimination between ET and RT which has not been shown in previously published studies. In addition, we present evidence that in 10 patients BMsCFU-Mk and/or BMsBFU-E growth in the test persisted after long-lasting haematological remission.

The hypothesis that in immune thrombocytopenia, platelet antibody may not only cause destruction of the circulating platelets but also depress platelet production by injuring the megakaryocytes of the bone marrow, was tested experimentally. Sustained thrombocytopenia was produced in rats by titrated injections of a potent heteroimmune antiplatelet serum and megakaryocytopoiesis was then studied by the use of tritiated thymidine and bone marrow autoradiography. Rats in which the platelet count was maintained at a lower than normal level by repeated thrombocytophereses, and other rats injected with platelet antiserum previously absorbed with rat platelets, served as controls. Profoundly altered patterns of megakaryocytopoiesis were found in the rats in which thrombocytopenia was produced by the antiplatelet serum. The data indicated a severely impaired and depressed megakaryocyte maturation and, possibly, destruction of some of the megakaryocytes during their maturation process. In the rats in which the platelet level was maintained low by repeated thrombocytophereses, the pattern of megakaryocytopoiesis indicated accelerated maturation and there was also an increased megakaryocyte mass. No difference from normal was found in the rats receiving the platelet-adsorbed antiserum. It was concluded that the platelet antibody produced an injurious effect on the megakaryocytes in the bone marrow, thereby depressing platelet production, and that the immune thrombocytopenia was the result of both increased platelet destruction and defective platelet production.