Bone marrow findings in acquired immunodeficiency syndrome (AIDS)

HIV-1 Nef Induces Hck/Lyn-Dependent Expansion of Myeloid-Derived Suppressor Cells Associated with Elevated Interleukin-17/G-CSF Levels

Human immunodeficiency virus (HIV) or simian immunodeficiency virus (SIV) infection causes myelodysplasia, anemia, and accumulation of inflammatory monocytes (CD14⁺ CD16⁺) through largely unknown cellular and molecular pathways. The mouse cells thought to be equivalent to human CD14⁺ CD16⁺ cells are CD11b⁺ Gr1⁺ myeloid-derived suppressor cells (MDSC). We used HIV transgenic (Tg) mouse models to study MDSC, namely, CD4C/Nef Tg mice expressing nef in dendritic cells (DC), pDC, CD4⁺ T, and other mature and immature myeloid cells and CD11c/Nef Tg mice with a more restricted expression, mainly in DC and pDC. Both Tg strains showed expansion of granulocytic and CD11b⁺ Gr1^low/int cells with MDSC characteristics. Fetal liver cell transplantation revealed that this expansion was stroma-independent and abrogated in mixed Tg/non-Tg 50% chimera. Tg bone marrow (BM) erythroid progenitors were decreased and myeloid precursors increased, suggesting an aberrant differentiation likely driving CD11b⁺ Gr1⁺ cell expansion, apparently cell autonomously in CD4C/Nef Tg mice and likely through a bystander effect in CD11c/Nef Tg mice. Hck was activated in Tg spleen, and Nef-mediated CD11b⁺ Gr1⁺ cell expansion was abrogated in Hck/Lyn-deficient Nef Tg mice, indicating a requirement of Hck/Lyn for this Nef function. IL-17 and granulocyte colony-stimulating factor (G-CSF) were elevated in Nef Tg mice. Increased G-CSF levels were normalized in Tg mice treated with anti-IL-17 antibodies. Therefore, Nef expression in myeloid precursors causes severe BM failure, apparently cell autonomously. More cell-restricted expression of Nef in DC and pDC appears sufficient to induce BM differentiation impairment, granulopoiesis, and expansion of MDSC at the expense of erythroid maturation, with IL-17→G-CSF as one likely bystander contributor. IMPORTANCE HIV-1 and SIV infection often lead to myelodysplasia, anemia, and accumulation of inflammatory monocytes (CD14⁺ CD16⁺), with the latter likely involved in neuroAIDS. We found that some transgenic (Tg) mouse models of AIDS also develop accumulation of mature and immature cells of the granulocytic lineage, decreased erythroid precursors, and expansion of MDSC (equivalent to human CD14⁺ CD16⁺ cells). We identified Nef as being responsible for these phenotypes, and its expression in mouse DC appears sufficient for their development through a bystander mechanism. Nef expression in myeloid progenitors may also favor myeloid cell expansion, likely in a cell-autonomous way. Hck/Lyn is required for the Nef-mediated accumulation of myeloid cells. Finally, we identified G-CSF under the control of IL-17 as one bystander mediator of MDSC expansion. Our findings provide a framework to determine whether the Nef>Hck/Lyn>IL-17>G-CSF pathway is involved in human AIDS and whether it represents a valid therapeutic target.

Potential Mechanisms for Altered Iron Metabolism in Human Immunodeficiency Virus Disease

Recently, anemia associated with human immunodeficiency virus (HIV) disease has received more attention as our understanding of the significance of anemia in this population has grown and more emphasis is placed on the quality of life of people living with HIV/AIDS. Although the diagnosis and treatment of anemia in HIV disease has been discussed in great detail, the prevalence and pathophysiology of the two most common forms of anemia, iron deficiency anemia (IDA) and the anemia of chronic disease (ACD), have not received much attention despite the difficulty and importance of differentiating between these two anemias. In addition, little attention has been given to iron overload, which has serious implications in individuals with HIV disease. This article proposes a model of altered iron metabolism in HIV disease as a basis for explaining the pathophysiology and implications of IDA, ACD, and iron overload in this population. Implications for clinical practice and recommendations for future research are discussed.

Bone marrow macrophage iron grade and survival of HIV-seropositive patients

OBJECTIVE

Increased iron stores predispose to certain microbial infections. This association might be especially important in patients whose immune system is impaired by HIV. This study examined the relationship between iron stores and the survival times of patients with HIV infection.

DESIGN

Retrospective analysis of iron stores, as determined directly in bone marrow aspirates, and of hospital records.

SETTING

The George Washington University Hospital, an urban academic tertiary care institution.

PATIENTS

Three hundred and forty-eight HIV-seropositive adults who had diagnostic bone marrow aspirates between January 1985 and June 1996.

MEASUREMENTS

Bone marrow macrophage iron stores were graded on a scale of 0 to 5. For analysis of the influence of iron stores on survival, we compared patients with grades 4-5 iron stores (markedly or massively increased; n = 188) to those with grades 0-2 iron stores (normal or decreased; n = 130).

RESULTS

Infections caused by Candida spp., Pneumocystis carinii, and Mycobacterium spp. were more common in patients with high macrophage iron grades than in patients with low or normal iron grades (P < or = 0.006). The adjusted estimated rate of death (hazards ratio) was higher in patients with high iron stores compared with patients with low or normal iron stores, both from the time of the bone marrow study (ratio of 2.1; 95% confidence interval 1.3-3.5; P = 0.003) and the determination of HIV-seropositivity (ratio of 2.8; 95% confidence interval 1.4-4.9; P = 0.001).

CONCLUSION

High iron stores, as determined by bone marrow macrophage iron grade, may be associated with shorter survival times in patients with HIV infection.

Utility of bone marrow culture and biopsy in the diagnosis of disseminated infections in AIDS

Bone marrow examination (BME) has been used as a diagnostic test of last resort in HIV infected patients. Identifying factors that would increase the diagnostic yield of BME would be useful. A retrospective cohort study was done to determine the predictive value of BME for disseminated infection in 133 patients with HIV infection in a 4-year period at an active HIV clinical center. Thirty-two percent of the cases had evidence of a disseminated infection on BME but only 10% of cases had a diagnosis made exclusively by BME. Multivariate analysis demonstrated that a positive result was more likely in those patients with fewer than 50 CD4 cells/mm3 and those with a hematocrit of less than 25% (P<0.01). BME can be a useful, low-risk diagnostic procedure in selected patients with HIV infection who are ill with a low CD4 count and/or have a hematocrit less than 25%. A diagnosis can usually be made by other means, suggesting that this test should be limited to those in whom other diagnostic modalities have been exhausted.

Bone marrow involvement by disseminated toxoplasmosis in acquired immunodeficiency syndrome: the value of bone marrow trephine biopsy and immunohistochemistry for the diagnosis

A bone marrow biopsy was performed on four patients with acquired immune deficiency syndrome (AIDS) for a long-running course fever of unknown origin associated with a recent pancytopenia. In the four cases, striking histological similarities, such as interstitial edema, foci of necrosis and only few scattered or clustered histiocytes, were found. Near or in the foci of necrosis, free forms, and pseudocysts of Toxoplasma gondii were observed not only in the cytoplasm of macrophages and of some granulocytes, but also within megakaryocytes. No sign of other parasitic, bacterial, or fungus infection has been found. The diagnosis was confirmed by immunohistochemistry in the four cases and ultrastructural examination in one case. This case study stresses the importance of bone marrow histological changes for the diagnosis of severe toxoplasmosis in AIDS patients and particularly the localization of T gondii within the cytoplasm of megakaryocytes.

Bone marrow morphologic findings in patients with human immunodeficiency virus (HIV) infection

The hematologic, histologic and morphologic bone marrow findings of 18 patients with human immunodeficiency virus (HIV) infection were reviewed. The mean age of the patients studied was 27 years; age range was six to 63 years. The main bone marrow morphologic finding was hypercellularity (72%), which was mainly due to megakaryocytic hyperplasia with or without granulocytic or erythrocytic hyperplasia. Naked (denuded) megakaryocytic nuclei, which are considered an indicator of HIV infection, were present in 72% of the bone marrows examined. Reticuloendothelial iron blockade was identified in 78% of cases. Other less frequent findings included erythrocytic dysplasia (44%), plasmacytosis (28%), nonspecific granulomas (17%), Hodgkin's and non-Hodgkin's lymphoma (17%), lymphocytic aggregates (11%) and histiocytosis (6%) . The bone marrow findings in this series of HIV patients appear to be similar to what has been previously reported from other countries.

Dysplastic haemopoiesis following orthotopic liver transplantation: comparison with similar changes in HIV infection and primary myelodysplasia

To validate scientifically our prior empiric observations that patients develop significant haemopoietic dysplasia following solid organ transplantation, we developed a quantitative lineage-specific scoring system to evaluate dysplastic features of bone marrow aspirates and core biopsies. We used this scoring system to compare retrospectively randomly selected bone marrow aspirates and core biopsies from 19 patients undergoing orthotopic liver transplantation (OLT), 21 with a known history of human immunodeficiency virus (HIV) infection, and 18 with primary or chemotherapy-related myelodysplastic syndromes (MDS). Our results show that the OLT patient group developed significant but milder haemopoietic dysplastic changes than the HIV or MDS groups, and that the MDS group developed more severe dysplasia of the myeloid lineage than the other groups. The possible roles for drugs and infectious agents in the pathophysiology of dysplastic changes are discussed.

An autopsy case of acquired immune deficiency syndrome (AIDS) with preceding aplastic anemia

A case of acquired immunodeficiency syndrome (AIDS) with preceding aplastic anemia is reported. The patient was a 36 year old female who had been diagnosed as having aplastic anemia 10 years before and thereafter had received multiple transfusions. Human immunodeficiency virus (HIV)-seropositivity was revealed 10 months prior to her death, but no particular clinical signs indicating HIV infection, pre-AIDS or onset of AIDS were recognized before serological diagnosis, although the slow progression of leukopenia was noted along with thrombocytopenia. Her general condition deteriorated during the last 10 months accompanied by an acute decrease in the CD4/CD8 ratio. Autopsy revealed full-blown AIDS: systemic aspergillosis, progressive multifocal leukoencephalopathy, Epstein-Barr virus-related B cell lymphoma arising in the diaphragm and severe lymphocyte depletion in the lymph nodes and spleen. Markedly hypoplastic bone marrow was considered to be primarily attributable to the aplastic anemia but the affection of AIDS was not excluded. The possible transmission route of HIV and the effect of the preceding aplastic anemia on the infection and clinical course of AIDS are discussed.

Proliferating cell nuclear antigen (PCNA) expression of megakaryocytopoiesis in normal human bone marrow and reactive lesions with special emphasis on HIV-myelopathy

A morphometric analysis was performed on bone marrow trephine biopsies using sequential double-immunostaining, to evaluate endoreduplicative activity of megakaryocytopoiesis. A total of 104 marrow specimens were studied with employment of monoclonal antibodies PC10 (anti-proliferating cell nuclear antigen-PCNA) and Y2/51-CD61 (anti-platelet glycoprotein IIIa). In addition to the control group patients included non-specific inflammatory changes, HIV-myelopathy with normal or decreased platelet counts, idiopathic thrombocytopenic purpura (ITP), and finally reactive thrombocytosis (TH). To exclude an undue overexpression of PCNA, in a comparative pilot study we also applied MIB1 (Ki-67 antigen) on normal bone marrow specimens. In accordance with the various modalities of cell-cycle marker expression, no significantly different findings were disclosed. PCNA-labelling index was relatively low, ranging from 0.8 to 1.7% of the total megakaryocytopoiesis (promegakaryoblasts to mature platelet-shedding megakaryocytes). A significant relationship between megakaryocyte size and PCNA-expression was determinable. This implies that some of the cases with a prevalence of small megakaryocytes, like ITP, have the tendency to show a higher proportion of positively-stained cells. Moreover, this feature confirms a hypothesis postulating a decrease in the time for DNA-synthesis (S-phase) and a relative prolongation of the G1/G2-phases of the cell-cycle at higher ploidy levels (large-sized megakaryocytes). On the other hand, it may be speculated that some of the hyperpolyploid giant megakaryocytes may have reached their endstage of endoreduplication and enter into G0-phase. In comparison with the control group and the other entities under study, a significant reduction of PCNA-reactivity was recognizable in HIV-myelopathy accompanied by thrombocytopenia.(ABSTRACT TRUNCATED AT 250 WORDS)

Megakaryocytopoiesis in bone marrow biopsies of patients with acquired immunodeficiency syndrome (AIDS). An immunohistochemical and morphometric evaluation with special emphasis on myelodysplastic features and precursor cells

In 25 patients (22 males, 3 females--median age 39 years) with AIDS (CDC stages IV A-D) and no preceding myelotoxic therapy, morphometry and immunohistochemistry (CD 61-Y 2/51) was performed on trephine biopsies of the bone marrow to evaluate the megakaryocytic lineage. In comparison with megakaryocytes in the myelodysplastic syndromes (MDS) significant differences were evident. In AIDS this cell population revealed a size distribution within the normal range (control group) and no predominance of micromegakaryocytes characteristic for MDS. Furthermore, by determination of the form factors more irregular shapes of cell and nuclear perimeters could be shown. Finally, a not-evaluated number of precursors (promegakaryoblasts) was calculable. Particularly in those patients (n = 15) with AIDS-related severe thrombocytopenia the missing increase in the relative amount of promegakaryoblasts was conspicuous. This result was strikingly different from findings in idiopathic (autoimmune) thrombocytopenia and suggested an impairment of progenitor cell proliferation and differentiation in the acquired immunodeficiency syndrome. In conclusion, morphometry in combination with immunohistochemistry failed to establish characteristic myelodysplastic aspects of the megakaryocytic lineage in AIDS. For this reason, bone marrow lesions in this disorder should be properly termed HIV-myelopathy and not myelodysplasia.

Pathophysiological mechanisms of HIV-induced defects in haematopoiesis: pathology of the bone marrow

Bone marrow biopsies of 96 HIV1-infected patients were analysed histologically and by immuno- and enzyme histochemical techniques. Independently of the stage of disease, the bone marrow frequently exhibits hypercellularity and features of dysplastic haemopoiesis combined with mesenchymal alterations. In situ immunohistochemical analysis shows that there is a marked reduction in expression of the proliferation-associated nuclear antigen recognized by the Ki67 antibody. Comparison with non-infected controls reveals that there is a reduction in CD34+/myeloperoxidase-/naphthol AS-D chloroacetate- progenitor cells and an overproportional decrease in CD8+ lymphocytes in the bone marrow. Double staining revealed the presence of gag-coded HIV1 proteins in the above-mentioned CD34+ progenitor cells, in myelopoiesis cells, megakaryocytes and above all, in CD68+/acid phosphatase+ and alkaline phosphatase+ bone marrow reticular cells. From the latter results, it was concluded that HIV1-infected reticular cells may be disturbed in their ability to produce factors responsible for the short-range regulation of haemopoietic activity.

The aetiology of severe anaemia in pregnancy in Ndola, Zambia

The aetiology of severe anaemia (haemoglobin less than 7.0 g dl-1) has been studied in 37 pregnant Zambians. Aetiology was usually multiple; 31 (84%) had Plasmodium falciparum malaria, 23 (62%) were folate deficient, 13 (35%) were iron deficient, one had sickle-cell anaemia and one had the acquired immunodeficiency syndrome (AIDS). Folate deficiency was most often secondary to malarial haemolysis: iron deficiency was nutritional, but hookworm was contributory in about one-third of patients. The anaemia of malaria and folate deficiency was both more common and more severe than anaemia due to iron deficiency; it was seen in younger women although primigravidae were not over-represented, it occurred earlier in pregnancy, and was associated with low birthweight. AIDS must now be included in the differential diagnosis of anaemia in pregnancy. Vigorous antimalarial treatment and prophylaxis are essential in the management and prevention of anaemia in pregnancy. Total dose iron infusion is indicated only when severe iron deficiency anaemia has been proven, and must be accompanied by antimalarial therapy and folic acid supplements. Because of the risk of transmission of human immunodeficiency virus, it is more important than ever to prevent anaemia and malaria in pregnancy, and to give blood transfusion only as a life-saving treatment.

Hematologic aspects of human immunodeficiency virus infection: laboratory and clinical considerations

Hematologic abnormalities are common in patients with HIV infection. This review will focus on HIV-associated cytopenias and coagulation abnormalities. Their occurrence, laboratory evaluation, and clinical significance and the mechanisms underlying their development are discussed. Therapeutic modalities are presented, with an emphasis on treatment strategies for HIV-associated thrombocytopenia.

Haematological abnormalities in human immunodeficiency virus (HIV) disease

Peripheral blood and bone marrow changes are commonly seen in disease associated with human immunodeficiency virus (HIV). This annotation aims to summarise these changes and to suggest possible factors entailed in their occurrence.

Histopathology of bone marrow in human immunodeficiency virus infection

The clinical and haematological findings in 18 patients with human immunodeficiency virus (HIV) infection were correlated with the histological features of plastic embedded bone marrow biopsies. Fifteen patients presented with peripheral cytopaenia of one or several cell lines. Twelve (66%) of the 18 patients exhibited bone marrow findings including normo- to hypercellularity, myelodysplasia, lymphocytosis with or without plasmacytosis and fibrosis of the reticulin type. Seventeen patients had myelodysplastic features, 5 of the 3 haematopoietic lines, 10 of 2 lines and 2 of 1 line. Dysmegakaryocytopoiesis and dyserythropoiesis, seen in 88% and 83% of the 18 patients respectively, were the most common myelodysplastic features. Bone marrow gelatinous transformation (serous atrophy) was a conspicuous finding in 7 (38%) of the 18 patients. The constellation of histological features here described, although not pathognomonic, is highly suggestive of HIV infection. The pathogenesis of the haematological abnormalities in HIV infection is discussed.