Rps14, Csnk1a1 and miRNA145/miRNA146a deficiency cooperate in the clinical phenotype and activation of the innate immune system in the 5q- syndrome

RPS14, CSNK1A1, and miR-145 are universally co-deleted in the 5q- syndrome, but mouse models of each gene deficiency recapitulate only a subset of the composite clinical features. We analyzed the combinatorial effect of haploinsufficiency for Rps14, Csnk1a1, and miRNA-145, using mice with genetically engineered, conditional heterozygous inactivation of Rps14 and Csnk1a1 and stable knockdown of miR-145/miR-146a. Combined Rps14/Csnk1a1/miR-145/146a deficiency recapitulated the cardinal features of the 5q- syndrome, including (1) more severe anemia with faster kinetics than Rps14 haploinsufficiency alone and (2) pathognomonic megakaryocyte morphology. Macrophages, regulatory cells of erythropoiesis and the innate immune response, were significantly increased in Rps14/Csnk1a1/miR-145/146a deficient mice as well as in 5q- syndrome patient bone marrows and showed activation of the innate immune response, reflected by increased expression of S100A8, and decreased phagocytic function. We demonstrate that Rps14/Csnk1a1/miR-145 and miR-146a deficient macrophages alter the microenvironment and induce S100A8 expression in the mesenchymal stem cell niche. The increased S100A8 expression in the mesenchymal niche was confirmed in 5q- syndrome patients. These data indicate that intrinsic defects of the 5q- syndrome hematopoietic stem cell directly alter the surrounding microenvironment, which in turn affects hematopoiesis as an extrinsic mechanism.

Hematological findings and antibody responses in Syrian hamster (Mesocricetus auratus) infected with Babesia microti

Hematological findings during the course of infection and the antibody response in Syrian hamsters infected with Babesia microti were examined. A macrocytic hypochromic anemia with an increase of the reticulocyte count was detected as a rise in the parasitized erythrocyte rate. White blood cell counts also remarkedly increased with the increases of both neutrophils and active-shaped monocytes, and thus they particularly play an important role in eliminating the parasite. In Western blotting with the sera from the hamsters infected with B. microti, a 38 kDa protozoan antigen reacted to the early-term sera, and additionally 28, 32, and 34 kDa antigens also reacted to the medium- and latter-term, and convalescent sera. These antigens were immunodominant and the antibodies against these antigens had also important roles for inhibition of this parasite.

Susceptibility of multipotent haemopoietic stem cell deficient W/Wv mice to Plasmodium berghei-infection

The susceptibility of haemopoietic stem cell deficient W/Wv mice to infection with Plasmodium berghei was examined. The mean survival time of W/Wv mice after the infection was shorter than that of the +/+ mice. Splenomegaly, a characteristic pathological change of the host after infection with malaria parasites was not observed in W/Wv mice. When haemopoietic activity of the infected mice was examined, a substantial increase in number of multipotent haemopoietic stem cells (CFU-S) and the committed stem cells for granulocytes and macrophages (CFU-GM) or for erythrocytes (CFU-E) was observed in the bone marrow and spleen of +/+ but not of W/Wv mice. CFU-S were not detected in W/Wv mice before or after infection. The number of CFU-GM and CFU-E in bone marrow and spleen of W/Wv mice decreased after infection. Bone marrow grafting from +/+ to W/Wv mice 8 weeks before infection prolonged the mean survival time of the mice and effectively restored the number of CFU-S in the spleen of W/Wv mice. These results indicate that multi-potent haemopoietic stem cells play an important role in the host's defence mechanisms against P. berghei-infection.

Lymphocyte subpopulations in megaloblastic anaemia due to vitamin B-12 deficiency

Lymphocyte subpopulations were measured in the blood of 17 patients with megaloblastic anaemia due to vitamin B-12 deficiency. 14 patients had pernicious anaemia and 3 others were gastrectomized. By using monoclonal antibodies recognizing T cell surface markers and immunofluorescence microscopy, we found a significant decrease in the number of circulating suppressor T cells and an increase in the ratio of helper to suppressor T lymphocytes in pernicious anaemia patients. This finding may be related to other immune abnormalities found in pernicious anaemia, e.g. the presence of multiple autoantibodies.

B lymphocyte precursors in embryonic and adult W anemic mice

Mice homozygous for mutations at the dominant spotting or W locus on chromosome 5 have been extensively used as models of severe macrocytic anemia caused by defective hemopoietic stem cells. We examined cells of the developing B lineage in adult and embryonic W anemic mice both by phenotypic analyses and by three distinctly different functional assays for B lymphocyte precursors. Adult W/Wv mice had normal numbers of B cells in the spleen and bone marrow, and normal numbers of pre-B cells and cells identified by a monoclonal antibody directed to a B lineage cell surface antigen (14.8) in the bone marrow. Embryonic W/Wv and Wx/Wx mice had hypoplastic liver development at 16 days gestation with a corresponding reduction in absolute numbers of pre-B cells, 14.8+ cells, and clonable granulocyte-macrophage progenitor cells, although their frequencies were normal. As expected, spleen colony-forming units were greatly reduced both in absolute number and frequency. Adult bone marrow cells and fetal liver cells from W anemic mutants generated B cells in vitro as well as did cells from normal littermates, but W anemic cells failed to generate B lymphocytes as well in vivo. These observations likely reflect differences in precursor cells that contribute to B cell formation in these assays, and suggest that early B lineage precursors are reduced or defective in W anemic mice.

Asynchronous expression of granulocyte membrane receptors in megaloblastic anaemia

The expression of Fc(IgG) and C3b membrane receptors by granulocytes and their precursors was examined in 23 cases of megaloblastic anaemia which were graded I-III according to morphological severity. Fractionated bone marrow and peripheral blood granulocyte receptors were assessed by rosette formation with optimally sensitized ox erythrocytes and the results compared with those found in 14 normal marrows. Promyelocyte Fc and C3b receptor activities in megaloblastic anaemia did not differ from normal whilst the number of Fc receptor positive myelocytes and later cells showed a significant increase (P less than 0.05 in Grade I, P less than 0.01 in Grades II and III) proportional to the severity of megaloblastosis. An increase in the number of C3b receptor positive granulocytes was seen in early megaloblastic anaemias and, in contrast to Fc receptor expression, showed the highest receptor activities in the Grade II cases. The most significant changes in receptor expression were seen at the metamyelocyte stage and appear to be related to the numbers of these cells found in the megaloblastic marrows. It is suggested that these alterations are primarily related to asynchronous granulocyte maturation and the application of these findings to the study of granulocytic disorders is discussed.

Experimental production of possible autoimmune castritis followed by macrocytic anemia in athymic nude mice

A specific gastritis was induced in BALC/c (+/?) mice by thymectomy within 3 days after birth (25 to 45 per cent) or in BALB/c (nu/nu) mice by the injection of spleen cells (10(7)) from neonatally thymectomized mice (70 per cent). Normal peripheral lymphoid cells, irrespective of the sex and dose, were generally ineffective in inducing gastritis in nude mice, while thymus cells were partially effective (30 per cent). The induced gastritis was characterized by a loss of chief and parietal cells and by varying degrees of lymphoid cell infiltration along thickened muscularis mucosa. The fundic mucosa was replaced by mucous necklike immature cells, and there was a rise of pH of the gastric juice. Argyrophilic endocrine cells escaped the inflammation and increased in number. The gastritis induced in nude mice was generally more severe and was often followed by severe macrocytic anemia. Megaloblast-like large immature erythroid cells were numerous in the spleens of affected mice. Antiparietal cell antibodies (IgG) were always demonstrated by an indirect immunofluorescence test in the sera of gastritis-developing mice, but were absent in sera of normal or untreated conventional nude mice. These findings suggest a new animal model of pernicious anemia in man.

Humoral and cellular immunity to intrinsic factor in myasthenia gravis

Myasthenia gravis (MG) is an autoimmune disease often associated with other autoimmune disorders. A case history of MG with a coexisting atypical megaloblastic anaemia with vitamin B12 deficiency and anti Intrinsic Factor (IF) antibodies, led to a study of humoral and cellular immunity to IF in 81 MG patients. Within this series, 3 other patients had a disturbed humoral and cellular immunity to IF. These 3 patients presented no other features of pernicious anaemia. The possible origins and significance of the anti IF antibodies in MG patients are discussed.

Reversible C3 hypocomplementaemia in megaloblastic anaemia due to vitamin B12 deficiency

Serum C3 and C4 levels have been determined in patients with Addisonian pernicious anaemia (PA) and megaloblastic anaemia due to vitamin B12 deficiency from other causes, before and after treatment, in order to study the interaction between vitamin B12 deficiency and complement and the role of complement in the pathogenesis of the gastric lesion of PA. C3 levels are significantly reduced in vitamin B12 deficiency and return to normal on treatment; C3 levels correlate with the degree of anaemia but not with serum vitamin B12 levels at diagnosis. C4 levels are normal. These observations suggest that the observed C3 hypocomplementaemia is not a consequence of immune mechanisms, but may be due to altered synthesis of C3 complement component.

Colony-forming ability of bone marrow cells of W anaemic mice on macrophage layer formed in peritoneal cavity of mice

The colony-forming ability of haematopoietic cells of W anaemic mice was examined on the macrophage layer formed in the peritoneal cavity of mice. Bone marrow cells of W anaemic mice formed a considerable number of colonies on the macrophage layer, notwithstanding they did not form any colonies in the spleen of the same recipients. As the colony-forming ability of the bone marrow cells was not reduced by the incubation with 3-H-thymidine, most of the cells which formed colonies on the macrophage layer seemed to stay in G0 state. The interrelationship between the spleen colony-forming cells, the macrophage-layer colony-forming cells, and in vitro colony-forming cells was discussed.

Depressed cell-mediated immunity in megaloblastic anemia due to folic acid deficiency

Cell-mediated immunity has been studied in patients with 1) megaloblastic anemia of folic acid deficiency, 2)megaloblastic anemia of pregnancy, or 3) iron-deficiency anemia. Using dinitrochlorobenzene skin tests, phytohemagglutinin-stimulated lymphocyte transformation, and rosette inhibition by antilymphocyte globulin, we have shown that cell-mediated immunity is depressed in megaloblastic anemia due to folate deficiency; this depression was reversed by folate treatment. Cell-mediated immunity was not impaired by iron-deficiency anemia. Suggested interactions between iron deficiency and folate metabolism were not clarified by these studies.

Erythrocyte chimerism after injection of spleen cells into anemic mice of the W-series

Anemic mice (W(v)W(v)) when injected at birth with a mixture of isologous (genotype W(v)w) and homologous spleen cells, showed an improvement in their peripheral blood picture when adult. Red blood counts, red cell size, and electrophoresis of the hemoglobins indicated that, in some cases, the homologous tissue had become implanted and, in others, the isologous tissue was functioning.