Angiogenesis in B-chronic lymphocytic leukemia

Increased microvascular network in bone marrow of HIV-positive haemophilic patients

OBJECTIVES

Angiogenesis has been associated with the pathogenesis of myelodysplastic syndromes (MDSs). However, less is known about the significance of this process in the bone marrow of HIV-positive patients with myelodysplastic features (MDF).

METHODS

Trephines from 22 HIV-positive haemophilic patients were immunostained for CD34 antigen, and the microvessel density (MVD) was quantitatively evaluated and compared with that of 21 biopsies from patients with primary MDS and with that of 12 control bone marrows with no evidence of marrow disease.

RESULTS

Bone marrow MVD in HIV-positive haemophilic patients was similar to that in patients with MDS; however, both groups revealed significantly higher MVD counts than those of control bone marrows (P=0.002). Mean MVD counts of HIV-positive haemophilic patients were significantly associated with HIV RNA levels (P=0.008). In contrast, no correlation was found between MVD and clinical HIV stage or CD4 counts at the time of biopsy.

CONCLUSIONS

These results suggest a direct involvement of HIV in the pathogenesis of MDF in HIV infection. Elucidation of the mechanisms underlying bone marrow angiogenesis in HIV-positive patients may provide further insights into the pathobiology of AIDS.

A morphometric study of bone marrow angiogenesis in hairy cell leukaemia with clinicopathological correlations

Bone marrow angiogenesis has recently been implicated in the pathophysiology and course of various haematological malignancies. Little is known, however, about the significance of this phenomenon in hairy cell leukaemia (HCL). We evaluated various morphometric characteristics of microvessels, highlighted by means of anti-CD34 immunohistochemistry, in the bone marrow of 44 patients with typical HCL, before and after treatment with interferon-alpha (IFN-alpha). Overall, bone marrow from 103 HCL patients and 20 controls was examined. Microvessel density (MVD) and several size- and shape-related parameters were quantified in the region of most intense vascularization using image analysis. MVD, size-related parameters and the percentage of branching microvessels were higher in HCL than in controls. Likewise, perimeter counts were higher in partial/non-responders than in complete responders. Achievement of complete response was accompanied by smaller calibre microvessels. IFN-alpha induced a decrease in MVD and branching values in cases with diffuse marrow involvement. In univariate analysis, progression-free survival was adversely affected by MVD, branching and major axis length. Multivariate analysis indicated that MVD/branching independently affected progression-free survival and the likelihood of complete response. Our data suggest that the generation of bone marrow microvessels indicated an increased risk of progression and IFN-alpha treatment failure in HCL. Furthermore, the prognostic significance of angiogenesis requires the concomitant assessment of MVD and the complexity of the microvascular network.

Increased angiogenesis in the bone marrow of HIV-positive patients with myelodysplasia

AIM

Little is known about the significance of angiogenesis in the bone marrow of HIV-positive patients with myelodysplastic features (MDF). However, this process has been associated with the pathogenesis of primary myelodysplastic syndromes (MDS). The aim of the study was to investigate angiogenesis in the bone marrow of HIV-positive patients.

METHODS

Bone marrow biopsies from 28 HIV-positive patients were immunostained for factor VIII and the microvessel density (MVD) was quantitatively evaluated and compared with that of 32 biopsies from patients with primary MDS and to 18 control bone marrows from patients with no evidence of bone marrow disease.

RESULTS

Bone marrow MVD in HIV-positive patients was similar to that of MDS. However, both groups revealed significantly higher MVD counts compared to those of control bone marrows (MDF vs controls P=0.022, MDS vs controls P=0.001).

CONCLUSIONS

Bone marrow from HIV-positive patients with MDF reveals similar microvessel counts compared to those with primary MDS, although both differ significantly from that of control bone marrow. Elucidation of the mechanisms underlying bone marrow angiogenesis in HIV-positive patients, may provide further insights into the pathobiology of AIDS and might be of value for the development of new therapeutic strategies for this disease.