Müller H

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.

Distribution and infection of Langerhans cells in the skin of HIV-infected healthy subjects and AIDS patients

The in situ content of cells of the reticuloendothelial system and lymphatic cells was examined in the skin of eight symptom-free HIV-positive individuals, three AIDS patients and eleven healthy immunocompetent volunteers. The epidermis was obtained in vivo by the suction blister technique. The numbers of CD68+, CD3+, CD8+, CD25-(IL2R)+ and HLA-DR+ intraepidermal cells proved to be independent of the number of CD4+ peripheral blood lymphocytes. At the same time, the intraepidermal concentrations of these cells were generally low in symptom-free HIV-infected individuals. The strong inverse correlation between the number of epidermal Langerhans cells (LC) and the severity of immunodeficiency was quantitatively confirmed; an increase in LC in symptom-free HIV-infected individuals was found. Thus, the reduction in these cells which was observed in the epidermis of AIDS patients began at a significantly elevated level. In contrast to results from other studies, in AIDS patients, in the present study, the concentration of epidermal LC did not differ significantly from that of healthy immunocompetent volunteers. The immunohistochemical technique can be as effective as in situ hybridization for the detection of HIV in the skin. Our results suggest that the viral load of the skin is rather low in HIV-infected subjects. HIV was demonstrated in one cell of one AIDS case by in situ techniques and this result was confirmed by a polymerase chain reaction examination using the same amount of tissue as for the in situ techniques.(ABSTRACT TRUNCATED AT 250 WORDS)

In situ immunophenotype of macrophages and lymphocytes in granuloma formation of tuberculous lymphadenitis in HIV-infected and immunocompetent patients.

The phenotype of inflammatory cells in lymph nodes from 16 patients with culture-proven tuberculous lymphadenitis were examined by histological and immunohistochemical techniques. Eight patients were suffering from a symptomatic HIV1 infection and 8 patients were immunocompetent individuals without positive HIV1 serology. In addition, the lymph nodes of 2 AIDS patients with Mycobacterium avium-intracellulare infection were examined using the same techniques. Characteristic granulomas with or without caseation were observed in the 8 immunocompetent and the 4 HIV1-infected patients with less marked lymphopenia of CD4+ peripheral blood lymphocytes (PBL). In lymph nodes from the other HIV1-infected patients with more severe depression of CD4+ PBL, no epithelioid cell formation was present; instead, foamy macrophages were found. The phenotype of the macrophages underwent progressive changes in parallel with the decreasing numbers of CD4+ PBL. Foamy macrophages in M. avium-intracellulare infection exhibited remarkable erythrophagocytotic activity and may represent an end-stage phenotype. They were positive for S100 protein and did not produce lysozyme or alpha-1-antichymotrypsin. They lost the antigen which was detected by monoclonal antibody Mac387 whereas positivity for HLA-DR, CD68 and KI-M8 was preserved. While many lymphocytes expressed CD25 (IL2 receptor) in cases with typical granulomas, there was no such CD25 expression in cases without epithelioid cell formation. Although granulomas have been produced in experimental animals independently of cell-mediated immune mechanisms, our results suggest that T-cell functions are necessary for epithelioid granuloma formation in human tuberculosis.

In situ hybridization analysis of cytomegalovirus lytic infection in Kaposi's sarcoma associated with AIDS. A study of 14 autopsy cases

Cytomegalovirus (CMV) was assayed by in situ hybridization with commercially available biotin-labeled CMV-DNA probes in 45 formalin-fixed paraffin-embedded autopsy specimens with Kaposis sarcoma from 14 cases of the acquired immune deficiency syndrome (AIDS). In seven of the 14 cases, a few scattered hybridizing cells were detected in Kaposis sarcoma, but not all specimens from the same case showed such cells. Most of the positive cells were peculiarly swollen and not typical of Kaposis sarcoma cells. All positive cases had at least some CMV-infected organs with typical cytomegalic cells containing nuclear inclusions while five of the 7 negative cases revealed no CMV-infected tissue by conventional light microscopy. Our results suggest that this in situ hybridization procedure using biotin-labeled DNA probes only reveals generalized CMV infection that is a consequence of impairment of immune mechanisms in AIDS patients.

Immunohistochemical assessment of splenic lymphocyte and macrophage subpopulations in patients with gastric cancer

In order to assess the effects of malignant tumors on the immune system, 25 spleens from patients with gastric carcinoma were studied by in situ immunohistochemical methods for lymphocyte subsets and cells of the mononuclear phagocyte system. Highly significant reductions of CD4+ T cells (P < 0.001), Ki M2+ and Ki M‐3+ MPS cells (P < 0.02 and P < 0.05), and a stage‐dependent reduction of Ki 67+ B cell proliferation activity (P < 0.05) were seen in spleens of patients with gastric cancer. These results, which were obtained by morphologic methods in a noninvolved lymphatic organ, reflect the systemic immunosuppressive and immunodepleting effects of malignant tumors that are probably mediated by tumor‐associated cytokines.

Hodgkin's disease in the spleen: A morphological study of 140 biopsy cases

140 spleens involved by untreated Hodgkins disease were studied utilizing conventional histological methods. Regardless of the sub-type of Hodgkins disease, infiltrates of neoplastic cells were present either in the periarteriolar lymphoid sheath, the marginal zone or in both locations. Initially, infiltrates were confined to the splenic white pulp, later larger nodular foci of Hodgkins disease developed by coalescence of several infiltrates. Neoplastic cells in Hodgkins disease may reach the spleen by both retrograde lymphatic spread or the splenic artery; the presence of neoplastic cells in both T- and B-cell areas of the splenic white pulp implies a preference for Hodgkins disease in the spleen with regard to a suitable microenvironment. This may be provided by certain macrophage subpopulations.

In situ immunophenotyping of lymphocytes/macrophages: Grading of lymphadenopathy, staging and pathophysiology of HIV infection☆

Histological changes in lymph nodes in HIV1-related lymphadenopathy were analysed in 106 lymph node biopsies and in lymph nodes of 140 autopsy cases. A classification system of five stages was established on the basis of histological and immunohistochemical studies. The analysis confirmed a close correlation between the progression of HIV1-related disease and our staging system. Although the classification is chiefly based on histological and immunohistochemical changes of the follicles, other frequently seen findings are included. Alterations in the interfollicular tissue, e.g. vascular proliferation and lymphocyte depletion, correspond to an increasing concentration of macrophages within this tissue. In HIV1 infection, the macrophages appear to produce high concentrations of angiogenic factors responsible for the frequent and sometimes extreme lymph node vascularization. Since the vascular proliferation can be subject to regression and sclerosis as seen in autopsy cases, the macrophages may lose the ability to produce large amounts of angiogenic factors in the final stage of the disease.

The spleen in Hodgkin's disease. An immunohistochemical study of lymphocyte subpopulations and macrophages

Lymphocyte subpopulations and macrophages in 16 spleens from patients with Hodgkins disease were analysed immunohistochemically using monoclonal antibodies of the Leu and the Ki M series. In non‐involved splenic tissue there is an increase of T‐lymphocytes with an increased T‐helper/T‐suppressor cell ratio, while Ki M‐1, ‐2, ‐3 and ‐5‐positive, i.e. phenotypically different macrophages, are reduced. These results indicate that involvement of the spleen in Hodgkins disease is accompanied by changes with respect not only to lymphocyte subpopulations but also to cells of the mononuclear phagocyte system. The immunodeficiency associated with Hodgkins disease is probably not solely due to lymphocyte dysfunction, since the disease may lead, at least in the spleen, to alterations in macrophages and accessory cells and this may contribute to the impairment of cell‐mediated immunity.

Splenic haematopoiesis in patients with cirrhosis of the liver

Hitherto it has generally been assumed that splenic haematopoiesis in adult humans occurs very infrequently and is predominantly associated with haematological disorders. In the present study of patients with cirrhosis of the liver, a marked splenic haematopoiesis was a constant finding. Moreover, low-level splenic erythro- and granulopoiesis was highly prevalent even in haematologically normal controls, while splenic thrombopoiesis was conspicuously absent in both groups. We suggest that splenic haematopoiesis results from entrapment and proliferation of circulating haematopoietic precursor cells in the splenic red pulp. This would account for the presence of splenic haematopoiesis in normal controls as well as in patients with cirrhosis of the liver. In the latter, stimulation of bone marrow haematopoiesis and increased splenic pooling of haematopoietic precursor cells may contribute to the marked increase of splenic haematopoiesis observed.

Growth patterns, inflammatory cells and prognosis in AIDS-associated Kaposi's sarcoma

AIDS-associated cutaneous Kaposis sarcomas (KS) in 35 patients were the subject of a histopathological and immunohistochemical study. Histologically, the tumours were classified as granulation-tissue-like (GR, n = 10), angioma-like (A, n = 11), angiosarcoma-like (AS, n = 9) and as spindle cell type (SP, n = 5). There was a distinct relationship between the main growth patterns of KS and the CD4+ peripheral blood lymphocyte (PBL) count. A decrease in numbers of CD4+ PBL was correlated with an increase in the frequency of AS and SP growth patterns. There were no correlations between growth pattern and concentrations of protein S100+, MT1+, CD45+ and MAK387+ tumour-associated inflammatory cells. When the GR type was grouped together with the A type, and the AS type with the SP type, statistically significant differences emerged for CD45+ and MT1+ tumour-associated cells, and for survival time, respectively. In all these instances, the GR/A group values were higher than those of the AS/SP group. Additionally, linear correlation analysis revealed an inverse relationship between the concentrations of CD4+ PBL and of protein S100+ tumour-associated inflammatory cells within the GR/A group. In contrast to what is observed with certain tumours of HIV-negative patients, this suggests that a high concentration of protein S100+ tumour-associated cells may indicate a worse prognosis in the GR/A group. The concentration of MAK387+ tumour-associated macrophages did not vary as a function of the growth patterns, even when they were grouped together as described above.(ABSTRACT TRUNCATED AT 250 WORDS)