An Ashkenazi Jewish woman presenting with favism.

The case of a 44 year old Ashkenazi Jewish woman of Russian origin who presented with a typical clinical and haematological picture of favism is reported. There was initial difficulty in confirming glucose-6-phosphate dehydrogenase (G6PD) deficiency because the enzyme concentrations were normal at presentation, but later fell to a concentration compatible with heterozygosity for the Mediterranean type of G6PD deficiency. The diagnosis was also later confirmed by gene analysis. The reasons for the difficulties in the initial confirmation of the diagnosis and the normal G6PD enzyme activity at presentation are discussed.

Detection of mycobacteria in bone marrow biopsy specimens taken to investigate pyrexia of unknown origin.

AIMS: To investigate the value of bone marrow biopsy in the diagnosis of mycobacterial infection. METHODS: The culture results of 433 bone marrow samples taken between 1983 and 1992 were reviewed. The histopathology reports on bone marrow trephine specimens of culture positive samples and all those on HIV positive patients sent in 1992 were also reviewed. RESULTS: Fifty one specimens yielded Mycobacterium spp, 47 were obtained from HIV positive patients. Of the isolates, 42 were Mycobacterium avium-intracellulare (MAI), five were M tuberculosis (MTB), and the remaining four comprised a variety of atypical mycobacteria. All MAI positive samples were obtained from HIV positive patients, with the bone marrow being the only culture positive specimen in one third. Bone marrow yielded MTB only in patients from whom it was also isolated in other specimens. Eleven of 47 trephine specimens from positive bone marrow showed granulomata and nine showed acid-fast bacilli. No acid-fast bacilli were seen in the absence of granulomata. CONCLUSION: Bone marrow biopsy for mycobacterial culture should be reserved for severely immunosuppressed patients and should not be advocated for immunocompetent patients with suspected tuberculosis. Bone marrow biopsy still has a role in the investigation of pyrexia of unknown origin in HIV positive patients, despite the advent of mycobacterial blood culture techniques, particularly if these can be processed safely in automated systems.

Ultrastructure of bone marrow in patients with visceral leishmaniasis.

Ultrastructural studies were performed on bone marrow aspirates from three patients with visceral leishmaniasis. The patients were moderately anaemic but showed a suboptimal increase in the absolute reticulocyte count. Serum and red cell folate concentrations and serum vitamin B12 concentrations were normal in all three cases, and serum ferritin concentrations were normal or increased. The bone marrows were hypercellular and showed erythroid hyperplasia; a high proportion of the erythroblasts showed dyserythropoietic changes. Amastigote forms of Leishmania donovani were found within bone marrow macrophages and within occasional neutrophil and eosinophil granulocytes. Electron microscopy showed the presence of many abnormal cells, which probably represented immature erythroblasts with giant lysosomes. These cells were often large, usually contained immature nuclei with relatively little condensed chromatin, had 1-20 electron dense cytoplasmic granules with an average diameter of 0.5 micron, and regularly displayed substantial rhopheocytotic activity. A few abnormal cells and intermediate and late erythroblasts appeared to have been phagocytosed by macrophages. The data indicate that dyserythropoiesis and ineffective erythropoiesis have a role in the pathogenesis of the anaemia of at least some cases of kala-azar.

Thalidomide in low doses is effective for the treatment of resistant or relapsed multiple myeloma and for plasma cell leukaemia.

Thalidomide is an effective treatment for relapsed multiple myeloma (MM), but is associated with a significant side effect profile at higher doses. In a recent study, only half of the enrolled patients were able to tolerate the maximum dose of 800 mg/day [Singhal, S., et al. (1999) "Antitumor activity of thalidomide in refractory multiple myeloma", New Engl. J. Med. 341, 1565-1571]. Moreover, the dose-response relationship has not been defined. We report our use of low dose thalidomide in a small cohort of 12 patients-eight with relapsed or refractory MM and four with plasma cell leukaemia (PCL). Five of the 12 (42%) patients had a partial response, showing a median fall in their PP/BJP of 80% (63-90%) at a median dose of 175 mg (100-300 mg) with negligible side effects. Three of four patients with PCL showed an impressive response to treatment with thalidomide as a single agent. No patient who failed to show any evidence of response at low dose (<150 mg/day) responded to higher doses. In this study, thalidomide induces a similar rate of response at a lower and better tolerated dose than previously reported and produced "best ever" responses in patients with resistant PCL.

Thrombocytosis with sideroblastic erythropoiesis: a mixed myeloproliferative myelodysplastic syndrome.

Some patients with haematological neoplasms have features which overlap between a myelodysplastic syndrome and a myeloproliferative disorder. Two such patients are reported, both having sideroblastic erythropoiesis and thrombocytosis and one sequentially developing features of atypical chronic myeloid leukaemia, idiopathic myelofibrosis and acute megakaryoblastic leukaemia. The prevalence of thrombocytosis among cases of refractory anaemia with ring sideroblasts may be as high as 15-20% and has implications for choice of therapy.

Opsonizing and agglutinating antibodies against Plasmodium falciparum schizont-infected erythrocytes in Gambian sera.

The presence of an IgG antibody to autologous schizont-infected red blood cells (SIRBC) in the sera of Gambian children with acute malaria and a positive direct anti-globulin test (DAT) was demonstrated by two methods: IgG quantitation using 125I-labelled anti-IgG and phagocytosis of these SIRBC. A similar antibody could not be demonstrated in sera of children with acute malaria and a negative DAT. When a laboratory strain of parasite was used there was a more variable pattern of IgG uptake but the highest was from sera of immune adult Gambians and Gambian children with acute malaria and a positive DAT. The uptake of IgG by SIRBC may be a useful test to determine the specificities of antibodies against different isolates of P. falciparum.

Human monocyte activation by supernatants from continuous cultures of Plasmodium falciparum.

When mononuclear cells derived from the blood of unsensitized adult Caucasians are incubated for 22 hours with supernatants from cultures of Plasmodium falciparum, there is a substantial stimulation of the phagocytic capacity of the adherent monocytes for anti-D sensitized red cells. This stimulatory effect is dependent on (i) a heat-stable factor in such supernatants, (ii) the presence of T lymphocytes in the mononuclear cell preparations and (iii) the occurrence of DNA synthesis in the mononuclear cell cultures. It is proposed that the malaria culture supernatant contains a mitogen which acts on non-allergized T lymphocytes and that the stimulation of such lymphocytes probably causes the release of a lymphokine which enhances the phagocytic activity of cells of the mononuclear phagocyte system.

The coombs direct antiglobulin test in Kenyans.

The direct antiglobulin test (DAT) was performed on 243 subjects in Kenya. A high incidence of positive DAT was found in children with malaria of whom 70% had RBCs coated with IgG, C3 and C4 either separately or together. Only 12% of paediatric patients with conditions other than malaria had a positive DAT. Most positive DATs in association with malaria occurred in children between 18 months and five years of age. There was a lower incidence of positive DAT in Kikuyu children from an area of low malarial transmission than in children from other tribal groups who reside in areas of high malaria endemicity. A high rate of positive DAT was also found in patients with visceral leishmaniasis. Interestingly there was an association of IgG and C4 but without C3 on red cells of five patients with visceral leishmaniasis and two schoolchildren from an area endemic for visceral leishmaniasis. This combination was not found on other patients.

The deoxyuridine suppression test in severe anaemia following Plasmodium falciparum malaria.

Haematological studies in a group of Gambian children with severe anaemia due to Plasmodium falciparum malaria revealed marked dyserythropoietic changes in erythroblasts and evidence of increased ineffective erythropoiesis. In some cases, the bone marrow also showed a few giant metamyelocytes and ring sideroblasts. The results of deoxyuridine suppression tests indicated that these haematological disturbances were not a consequence of vitamin B12 or folate deficiency within marrow cells.

Severe megaloblastic anaemia due to vitamin B12 deficiency in The Gambia.

Five cases of severe megaloblastic anaemia in Gambians are described. Three of the patients were found to have pernicious anaemia. The difficulties in diagnosis and the various features of pernicious anaemia in Negroes are discussed. A brief review of the literature is included.

Iron and folate status in Gambian children with malaria.

Iron and folate status were evaluated in a group of 106 Gambian children with malaria and variable degrees of anaemia. In children with malaria, normal or increased levels of red cell folate were found in 75 patients at presentation and in 15 patients 1-2 weeks after treatment with anti-malarials alone, despite the presence of giant metamyelocytes and megaloblasts in the bone marrow in some cases. Twenty-eight per cent of patients were found to have deficient bone marrow iron stores but malaria could not be directly implicated as the cause of this deficiency. Iron deficiency could also not be implicated as the sole cause of dyserythropoiesis in patients with malarial anaemia. Excess storage iron and the presence of ring sideroblasts were found in the bone marrow in some cases. It is concluded that the morphological changes including dyserythropoiesis, occasional megaloblasts, giant metamyelocytes and ring sideroblasts seen in the bone marrows of these children are manifestations of disturbed marrow function in malaria and are not related to haematinic deficiency. Because of the high rate of iron deficiency found in these patients it is recommended that Gambian children with severe anaemia should receive iron therapy after adequate treatment of malaria.

Peripheral blood and bone marrow leucocytes in Gambian children with malaria: numerical changes and evaluation of phagocytosis.

Neutrophilia, monocytosis, eosinopenia and reactive lymphocytes were found in the peripheral blood of infants and children with acute malaria at presentation. These changes were mostly reversed by days 3 and 7 after starting treatment. Mild rebound eosinophilia was seen in three cases after starting treatment. In patients with low grade malaria and anaemia, peripheral blood counts did not alter significantly after treatment. Two patients with mild eosinophilia at presentation were subsequently found to have strongyloidiasis and the eosinophil count rose markedly in one after treatment of malaria. Bone marrows were hypercellular in all cases. There was a low mean percentage of myeloid precursors in the marrow of all children as compared with the normal. This was due to increased lymphocyte percentage in those with acute malaria and to marked erythroid hyperplasia in those with low grade malaria. Phagocytosis of parasitized and non-parasitized red cells by bone marrow macrophages was seen most frequently in children with high parasitaemias, but erythroblast phagocytosis was more commonly seen in those with low grade malaria. There was no absolute correlation between the presence or absence of erythrophagocytosis in marrow macrophages and the presence or absence of a positive direct antiglobulin test (DAT) in children with malaria. This indicates that immunological mechanisms cannot be implicated as the sole cause of erythrophagocytosis in these bone marrows.

Red cell associated IgG in patients suffering from Plasmodium falciparum malaria.

Quantitation of red cell associated IgG in 62 Gambian patients with P. falciparum malaria and 23 normal adult controls was carried out, using a purified 125I-labelled anti IgG. The number of IgG molecules per red cell was found to be between 90-897 molecules for patients with malaria and 100-233 for controls. 12 patients with malaria had raised levels of RBC associated IgG. There was no correlation between severity of anaemia and RBC associated IgG levels in patients with malaria nor was there a correlation between reticulocytosis and RBC associated IgG levels. It is concluded that although immune haemolysis may occur in some patients with malaria who have high levels of IgG or activated complement components on their red cells, other factors such as marrow suppression or ineffective erythropoiesis play an important role in the pathogenesis of the post-malaria anaemia.

Hematopoiesis in human malaria.

This paper presents changes in the bone marrow of patients with malaria; it is based primarily on observations of bone marrows of 89 Gambian children with P. falciparum malaria and includes a review of the literature. Erythroid hyperplasia with dyserythropoiesis was found to be more common in patients with severe anemia and low grade parasitemia than in those with acute malaria. The dyserythropoietic changes are illustrated both with light photomicropraphs and with electron micrographs. The significance of the dyserythropoiesis and possible causes are discussed. Other changes in these patients with acute malaria include lymphocytosis in the bone marrow and reactive lymphocytes, monocytosis and mild neutrophilia in the peripheral blood. Giant metamyelocytes were also commonly seen in bone marrow of patients but were thought to be part of dysmyelopoiesis and not due to B12 or folate deficiency. Phagocytosis of erythrocytes, parasitized cells and nucleated cells was more commonly seen in macrophages in acute malaria, while phagocytosis of small particles such as merozoites was observed in neutrophils. Megakaryocytes were found to be increased in number in patients with acute malaria; a proportion of these cells had rounded nuclei, probably indicating accelerated platelet turnover.

A study of erythroid progenitor cells in the bone marrow of Gambian children with falciparum malaria.

There was a wide variation in the number of BFUe and CFUe in the bone marrow of Gambian children with falciparum malaria and moderate or severe anaemia. However, such children were often not deficient in these erythroid progenitors. The number of BFUe in patients who had parasitaemias greater than 1% was significantly lower than that in patients with parasitaemias less than 1%. There was also a statistically significant negative correlation between the number of BFUe and CFUe in the entire group of children studied. When autologous serum (30%, v/v) was used in the culture system, CFUe growth was observed even in the absence of added erythropoietin (EPO), indicating the presence of high levels of EPO or an EPO-like substance in the anaemic sera. It is concluded that children with Plasmodium falciparum malaria show no major abnormality in their erythroid progenitor cells and that the perturbation of erythropoiesis in such children occurs mainly in the morphologically recognizable erythroid precursor cells. The wide variation observed in the number of CFUe and BFUe in different patients, and the correlations between the number of BFUe and parasitaemia and the number of BFUe and CFUe are all probably largely related to the changing clinicopathological situation in patients with malaria and anaemia.

Blood and bone marrow changes in malaria.

A variety of abnormalities in the number, morphology and function of blood and bone marrow cells may be found in Plasmodium falciparum and P. vivax malaria. In a non-immune individual, the nature of such abnormalities depends on the time after infection. In others it is determined by the pattern and intensity of malaria transmission in the area and the extent of host immunity. Severe anaemia may occur in children with chronic falciparum malaria and low parasitaemia as well as in patients with complicated acute falciparum malaria with high parasitaemia. However, the mechanisms underlying the anaemia in these two situations appear to be different. The possible roles of parasite products, T-cell-derived cytokines produced in response to the infection, macrophage activation and hyperplasia, macrophage-derived factors such as tumour necrosis factor-alpha, and macrophage dysfunction in the pathogenesis of the haematological abnormalities are discussed.