Studies of human natural killer cells. III. Neutropenia associated with unusual characteristics of antibody-dependent and natural killer cell-mediated cytotoxicity

[Natural killer cell activity in mice infected with free-living amoeba with reference to their pathogenicity]

The purpose of this observation was to investigate the natural killer cell activities in mice infected with pathogenic free-living amoeba, Naegleria fowleri and Acanthamoeba culbertsoni according to the infection doses, and infected with non-pathogenic free-living amoeba, Naegleria gruberi. The natural killer cell activity was examined by means of target binding capacity, active NK cell and maximum recycling capacity of the mice after inoculating free-living amoebae with low and high doses. The mice infected with 1,103, 1,105 A. culbertsoni trophozoites showed mortality rates of 6.9% and 65.5%, respectively. The mice infected with 1,104, 1,105 N. fowleri trophozoites showed mortality rates of 5.9% and 72.2%, respectively. The NK cell activities in all experimental groups increased significantly on day 1 after infection as compared with control group, and then remarkably declined thereafter, there was no difference of the cytotoxic activity of the NK cells in mice among inoculation doses of pathogenic free-living amoebae. The target binding capacities of NK cells and percentages of activated NK cells in mice infected with pathogenic free-living amoebae were significantly increased a day after infection, as compared with control group. There was no difference of the maximal recycling capacities of NK cells in all experimental groups as compared with control group. There was significant difference in the cytotoxic activity and single cell cytotoxicity of NK cells between the experimental groups infected with pathogenic free-living amoebae and that infected with non-pathogenic free-living amoebae.

Lymphoproliferative disease of "LAK cell" precursor large granular lymphocytes in association with celiac disease

We have investigated a case of lymphoproliferative disease of large granular lymphocytes (LDGL) occurring in association with celiac disease, anemia, neutropenia, and carcinomas of the endometrium, breast, and skin. The large granular lymphocyte (LGL) proliferation was monoclonal, T cell in origin, with T cell receptor beta-chain gene rearrangement, and a CD3+, CD8+, CD16+/- phenotype. In spite of the high frequency of LGL, natural killer (NK) cell activity was absent. Stimulation with interleukin-2 in vitro, however, resulted in high lymphokine-activated killer (LAK) cell activity against NK-resistant targets. The T-cell nature of the LAK precursor cells is in contrast to the majority seen in normal peripheral blood. Therapeutic trials of cyclosporin A, low-dose cyclophosphamide, and levamisole were unsuccessful in reducing transfusion requirements. This case is unique in the association of LDGL with celiac disease. It is also unique in that the patient had been followed for several years prior to the onset of the LDGL. The case extends the list of lymphoproliferative disorders documented to be associated with celiac disease and, conversely, adds to our knowledge of lymphoproliferative disorder of LGL and its "dysimmune" manifestations.

[Natural killer cell activity in mice infected with Acanthamoeba culbertsoni]

The natural killer cell activity of splenocytes and TBC, active NK cells, recycling capacity of natural killer cells were observed by means of both the 51Cr-release cytotoxicity assay and single cell cytotoxicity assay against YAC-1. C3H/HeJ mice were infected intranasally with 1 x 10(4) or 1 x 10(5) trophozoites of pathogenic Acanthamoeba culbertsoni. The infected mice showed mortality rate of 34% in 1 x 10(4) group and 65% in 1 x 10(5) group, and mean survival time was 16.40 +/- 3.50 and 13.20 +/- 4.09 days respectively. The cytotoxic activity of natural killer cells of the 2 groups was significantly higher than that of non-infected mice from the 12th hour to the 2nd day after infection, showing the highest on the first day. On the 10th day after infection, the cytotoxic activity of natural killer cells was significantly suppressed as compared with that of the control. There was no significant difference in NK cell cytotoxicity between two infected groups. The target-binding capacity and active NK cells of natural killer cells in 1 x 10(5) trophozoite infected mice was significantly increased on the 12th hour and the first day after infection as compared with the control group. Maximal recycling capacity (MRC) was not changed during the observation period. The present results indicated that the elevation of natural killer cell activity in the mice infected with A. culbertsoni was due to elevation of target-binding capacity and increased active NK cells of natural killer cells, and not due to the maximal recycling capacity of the individual NK cell, and there was no difference between two experimental dose groups.

The pathology of large granular lymphocyte leukemia

The authors conducted a histopathologic study on tissues from 11 patients with the recently described syndrome of large granular lymphocyte (LGL) leukemia. Distinctive pathologic findings were found most often in the bone marrow, liver, and spleen. The bone marrow biopsies contained nonparatrabecular lymphoid infiltrates that were nodular or diffuse and interstitial. Plasmacytosis was found and in two cases there was myeloid maturation arrest. The liver biopsies contained sinusoidal and portal infiltrates and the spleen had red pulp cord and sinus infiltrates, plasmacytosis, and follicular hyperplasia. Lymph node involvement was nondiagnostic, consistent with the usual absence of lymphadenopathy. The morphologic findings were sometimes indistinguishable from other reactive or low-grade lymphoproliferative disorders, especially chronic lymphocytic leukemia/well-differentiated lymphocytic lymphoma (CLL/WDLL) and hairy cell leukemia. These results suggest the need to correlate peripheral blood cell counts and morphology as well as immunophenotypic studies with tissue histology to distinguish LGL leukemia from other disorders. Establishing a correct diagnosis of LGL leukemia may help clarify the etiology of unexplained peripheral blood cytopenias, arthritis, and other autoimmune manifestations in individual patients.

Phenotypical and functional heterogeneity of the large granular lymphocytes increased after various treatments in a patient with combined immunodeficiency

A boy with combined immunodeficiency having low natural killer (NK)-cell activity received thymopoietin pentapeptide (TP-5) treatment, transplanted with T cell-depleted HLA-haploidentical bone marrow (BMT) cells from his father and with thymus tissue from an infant at different times during the first year of life. He showed a marked increase in large granular lymphocytes (LGL) both during the treatment with TP-5 and after BMT. The LGL generated following TP-5 injection had a T3+Leu11- surface phenotype and low NK activity. In contrast, the LGL appearing after BMT showed T3-, Leu7+, and/or Leu11+ surface phenotypes, had high NK- and K-cell activities, and were lymphokine-activated killer (LAK)-cell precursors. These killer activities were assigned to the Leu7-Leu11+ subset and proved to be of recipient origin. LGL proliferation following BMT was accompanied by neutropenia, which was improved in association with a reduction in the number of LGL and the appearance of T cells of BMT donor origin following thymus transplantation. This suggested the inhibition of granulopoiesis by the LGL and an in vitro study revealed that the Leu7+Leu11- subset of LGL suppressed the growth of granulocyte/macrophage colony-forming units. These results indicated that phenotypically different LGL could be generated by different treatments and that the LGL showing NK activity were distinct from those regulating granulopoiesis. It was also suggested that the generation of LGL was controlled by T cells.

K-cell lymphocytosis/neutropenia syndrome: the neutropenia is not caused by autoimmunity

The role of humoral immune mechanisms in the pathogenesis of the neutropenia in five patients with chronic killer (K)-cell lymphocytosis was studied. For the detection of neutrophil antibodies in the patient's blood, immunofluorescence, cytotoxicity and agglutination tests and a sensitive antibody-dependent cellular cytotoxicity (ADCC) assay were applied. An assay for bone-marrow colony growth (CFU-GM, BFU-E) inhibition was applied as well. A C1q-binding test was used to detect immune complexes. The lymphocytes of all five patients had the capacity to lyse alloantibody sensitized neutrophils. Neutrophil-bound IgG was found only in one patient. Two patients had neutrophil-reactive antibodies in their serum; in one patient these antibodies were only detectable in the ADCC using the patient's serum to sensitize target cells. However, these antibodies reacted also with lymphocytes, were absorbable with platelets and thus probably were HLA antibodies. The serum of one of these two patients showed complement-dependent CFU-GM and BFU-E inhibition, but the observed inhibition was probably also due to the anti-HLA antibodies present in his serum, as the inhibiting effect disappeared after absorption of the serum with platelets. The serum of only one patient contained low amounts of immune complexes, as measured in the C1q-binding test. Our data suggest that humoral autoimmune mechanisms, such as autoantibodies against neutrophils or neutrophil precursors or circulating immune complexes, do not seem to play an important role in the K-cell lymphocytosis/neutropenia syndrome. The possible role of the expanded K-cell population, and its humoral products (tumour necrosis factor, interferons), in the syndrome is discussed.

Large granular lymphocyte (LGL) lymphoproliferative diseases: naturally cytotoxic tumors in man and experimental animals

It has recently become clear that in the spleen and blood of both rodents and man that a unique subpopulation of lymphocyte is the mediator of virtually all of the inherent natural killer (NK) and antibody-dependent cell-mediated cytotoxic (ADCC) activity. Because of their large size, eccentric kidney-shaped nucleus and prominent cytoplasmic granules, these cytotoxic cells, termed large granular lymphocytes (LGL), can be readily identified in Geimsa stained cytocentrafuge preparations. Unfortunately, the relatively low numbers of these cells in normal lymphoid tissues has made the detailed analysis of LGL quite difficult. Recently however, a number of investigators have reported both rodent and human leukemias or leukocytosis in which there was an abnormally high number of circulating lymphocytes with either the appearance and/or function of LGL. The present manuscript reviews this literature with an emphasis on the biological and clinical characteristics of this lymphoproliferative disease. Emphasis is also placed on the usefulness of these cells for the detailed analysis of LGL morphology and function.

The biology of the human natural killer cell

Natural killer (NK) cells in the human are a population of large granular lymphocytes (LGL) with at least one unique surface antigen not expressed on cells of other lineages. NK-target-cell interaction appears to involve carbohydrate recognition and, following binding, the NK cells are induced to generate O2-, transmethylate membrane phospholipids, and activate phospholipase A2. Some or all of these activities trigger a cascade of events which ultimately leads to the secretion of a substance toxic to the target cell. A variety of genes controls various steps in this cytolytic pathway. There is a good deal of evidence in the mouse, and some in the human, that NK cells play a role in host surveillance against tumor development, resistance to viral infections, and, possibly, hematopoietic regulation.