Lymphokine-activated killer cells, natural killer cells and cytokines

In the past year, natural killer cells have been the subject of much active investigation. The analysis of the effect of cytokines on the generation, proliferation and function of natural killer cells, and the definition of the lymphokines that they produce, have been particularly important areas of research in view of their possible application in adaptive immunotherapy, combined with biological response modifiers.     

Natural killer cell function in patients with acquired immunodeficiency syndrome and related diseases

This review describes current knowledge of changes in natural killer (NK) cell function in acquired immunodeficiency syndrome (AIDS)-related disorders, vis-à-vis associated abnormalities in NK cytolytic function, NK cell subset distribution, NK cytopathology, and lymphokine regulation. NK cells, which are closely associated with large granular lymphocytes, are spontaneously cytotoxic to tumor and virally infected targets. As such, they may play a role in natural resistance to human immunodeficiency virus type 1 (HIV-1)-associated disorders and other opportunistic infections. Yet, peripheral blood NK activity is frequently reduced in patients with HIV-1-induced disease. NK cells are heterogeneous both with respect to their expression of serologically defined membrane antigens and functional activity. In AIDS-related syndromes, there appears to be a diminution of the NK pool (CD16+ cells) involved in cytolytic function, while there is an elevation of the NK pool that coexpresses NK (Leu 7+) and T (CD8+) cell markers, which show little or no involvement in cytolytic function. The impairment of in vitro NK function is not associated with a reduced frequency of lytic conjugates of effectors and target cells nor with the recycling capacity of these effector cells but rather is associated with defects in the NK cell lytic machinery following formation of such conjugates. NK cells in AIDS patients show an impairment in effector cell microtubule rearrangement following target cell interaction. The causes of NK cell dysfunction in AIDS-related disorders remain unknown. NK cells do not appear to express the CD4 epitope of the HIV receptor, nor have they been demonstrated to be susceptible to infection by HIV-1. There appears to be a preponderance of immature NK cells and a lymphokine imbalance in patients with HIV-1 associated disease. Interleukin-2 can partially restore diminished in vitro NK function. Elucidation of the involvement of the NK compartment in natural resistance to HIV-1 merits further investigation.     

Lymphokine-activated killer cytotoxicity against leukaemic blast cells.

While the sensitivity of cell lines and solid tumours to lymphokine-activated killer (LAK) cell cytotoxicity is extensively reported, the ability of these generated cytotoxic cells to lyse leukaemic blast cells is controversial. This study reports the successful generation of LAK cells with specificity for leukaemic blast cells. Control donors, patients in remission and patients with active leukaemia were capable of lysing allogeneic leukaemic blast cells. One patient was also capable of lysing autologous leukaemic blast cells. Successful LAK generation was achieved by the use of high dose recombinant interleukin-2 (rIL-2) while combinations of lymphokines did not improve LAK specificity or efficacy. These findings suggest that LAK immunotherapy may be considered for the treatment of patients with acute leukaemia.     

Botryomycosis in acquired immunodeficiency syndrome

The first case, to our knowledge, of an integumentary form of botryomycosis is reported in a homosexual man with acquired immunodeficiency syndrome. Anal fistula and ischiorectal and gluteal abscesses developed following severe cryptosporidial diarrhea. Grains composed of gram-positive cocci were identified in the suppurative exudate. The grains had attached to multinucleated macrophages, many of which contained clusters of cocci in their cytoplasm. It is postulated that the cocci were able to survive and probably replicate in the cytoplasm of multinucleated macrophages, and were subsequently extruded as grains. These observations suggest a defect in intracellular killing of cocci by the monocyte-macrophage system. This may relate to failure in induction of control of macrophage activity by T4-inducer subsets.     

Myositis and acquired immunodeficiency syndrome

Clinical and pathologic observations made in a patient with inflammatory myopathy associated with the acquired immunodeficiency syndrome (AIDS) are presented. Multinucleated giant cells were a prominent histopathologic feature in the muscle biopsy samples. The findings indicate that in some patients with AIDS myositis, inflammatory myopathy may be the direct result of infection with the human immunodeficiency virus.     

Tuberculosis and acquired immunodeficiency syndrome

India has the largest HIV-infected population in the world with over 4 million infected. The current evidence indicates that the doubling time of the epidemic in India is less than 2 years. Those infected with Mycobacterium tuberculosis add to the gravity of the situation enhancing both morbidity and mortality in these dually infected patients. With the incomprehensive diagnostic facilities available, it is wise to exploit the situation with utilization of tuberculin test with a different cut off criterion for the early diagnosis of mycobacterial infection amongst HIV positive population, especially when there are financial constraints and lack of diagnostic facilities to get CD4 cell count.     

Natural killer cell function and interferon generation in patients with primary immunodeficiencies

Patients with primary immunodeficiency disorders were evaluated for three aspects of natural defense: natural killer (NK) cells which lyse HSV-infected fibroblasts [NK(HSV-FS)], NK cells which lyse K562 tumor targets [NK(K562)], and interferon-alpha generation. In addition, capacity to make interferon upon challenge with other commonly used inducers was also evaluated. Most patients with severe combined immunodeficiency disease (SCID) and deficits of both T- and B-cell function demonstrated normal NK function with one or both targets. Six of eight SCID patients generated interferon-alpha at or below the lower limit of normal while only two made clearly normal levels. Six of 10 patients with Wiskott-Aldrich syndrome (WAS) had normal NK(K562) and five of 10 generated normal levels of interferon-alpha but all had severely deficient NK(HSV-FS). Patients with Bruton's agammaglobulinemia demonstrated normal NK and interferon generation, as did patients with common variable immunodeficiency, even when subdivided into patients with T-cell proliferative deficiencies and those with only hypogammaglobulinemia. Natural defense parameters may help categorize patients with SCID and WAS and help define these heterogeneous diseases.     

Natural killer and killer cell activities in patients with primary immunodeficiencies or defects in immune interferon production

Natural cell-mediated cytotoxicity (NCMC) against K-562 target cells was explored in patients with various primary immunodeficiencies. (a) NCMC was present in 2 patients lacking detectable B cells. Conversely, NCMC was depressed in 2 patients with severe combined immunodeficiency presenting a normal number of circulating B cells. These data exclude a major role for B cells in NCMC. (b) NCMC was depressed mainly in patients with severe combined immunodeficiency or with defects affecting cellular immunity, which suggests a major role in NCMC for cells of T lineage. (c) Four patients with various clinical features associated with a lack of immune interferon production exhibited a strikingly depressed NCMC. Interferon thus appears as a major in vivo activator of natural killer (NK) cell activity. (d) Eight patients exhibiting a depressed NK cell activity had a normal killer (K) cell activity against L1210 cells in the presence of rabbit anti-L1210 antiserum. These data are consistent with the assumption that NK and K cell activity are mediated through two distinct cellular mechanisms.     

Evaluation of natural killer cell activity in patients with persistent generalized lymphadenopathy and acquired immunodeficiency syndrome

Natural killer (NK) cell activity was quantitated using 51Cr release from the human erythroleukemia cell line K562 in 39 heterosexual males, 60 asymptomatic homosexuals, 39 patients with persistent generalized lymphadenopathy (PGL), and 16 patients with acquired immunodeficiency syndrome (AIDS). PGL and AIDS patients showed a slight decrease in NK cell activity compared to control groups. Absolute numbers of Leu 11a-positive cells were decreased in PGL and AIDS patients, and this decrease correlated with a decrease in absolute number of both the T4+ and T8+ cell subsets. Autologous plasma inhibited NK cell activity in 48% of asymptomatic homosexuals, 63% of PGL patients, and 63% of AIDS patients, but in none of the heterosexual controls. NK cell responses in fetal calf serum, normal human plasma, or autologous plasma showed no correlation with absolute numbers of T4+ cells, or with T4/T8 ratio. We conclude that NK cell responses are not of prime importance in the pathogenesis of PGL and AIDS.     

Pituitary pathology in acquired immunodeficiency syndrome

Pituitary morphology was studied in 49 autopsied patients with acquired immunodeficiency syndrome. Direct infectious involvement was noted in six adenohypophyses (12%), including five cases by cytomegalovirus and one by Pneumocystis carinii. Two cases with neurohypophysial lesions presumably caused by cytomegalovirus and one questionable case of Toxoplasma gondii were also observed. In all instances these changes were associated with generalized and/or cerebral infection by these same agents. Neither Kaposi's sarcoma nor malignant lymphoma was encountered in the pituitary glands. Acute necrotic foci, presumably due to infarction, were noted in four cases. Four pituitary microadenomas (8%) and four hyperplastic nodules were identified. The incidence of such noninfectious lesions, as well as the prevalence and distribution of the various immunoreactive adenohypophysial cell types, were similar to those seen in the pituitary glands of age-matched male control patients.     

Cytomegalovirus adrenalitis in acquired immunodeficiency syndrome

Seventy-three adrenal glands of 44 patients with acquired immunodeficiency syndrome (AIDS) were examined and graded histologically to reveal cytomegaloviral (CMV) adrenalitis. The number of CMV inclusion bodies (IB) were evaluated and compared with 3 methods in 58 adrenal glands of 40 patients: histological sections, immunocytochemistry for early antigens of CMV, and in situ hybridization with biotinylated probes for CMV DNA All 73 adrenal glands contained foci of lymphocytic infiltrate. Forty (55%) showed CMV adrenalitis and necrosis, which were more extensive in the medulla than in the cortex. The number of CMV IB increased with the severity of necrosis and fibrosis (grades I, 1.0; II, 3.6; III, 27.8 IB/ thousand cells counted in 20 fields). More than 85 percent of both glands were necrotic in0 only I patient (2.3%). For the 3 methods, the means of the number of CMV IB were as follows: in situ hybridization with biotinylated probe, 17.7; immunocytochemistry, 12.9; and H&E, 8.1. However, using multivariant analysis, there was no statistically significant difference. Thirty-three (45%) adrenal glands contained no CMV IB by any of the 3 methods. We conclude that CMV adrenalitis is a common finding in patients with AIDS. Destruction of adrenal tissue is usually not widespread enough to result in adrenocortical insufficiency.     

Intestinal leishmaniasis in acquired immunodeficiency syndrome

In endemic regions, visceral leishmaniasis is one of the most common opportunistic infections in HIV positive patients. Simultaneous infection with Leishmania and HIV has been reported in some countries but this is the first report of such a case in Iran. Our patient was a 27 years old man with intermittent night fever, abdominal pain, loss of appetite, vomiting, watery diarrhea and severe weight loss for 6 months. He had low socio-economic status with an imprisonment history. The patient was quite cachectic and had low grade fever. Physical exam and upper GI endoscopy revealed oropharyngeal candidiasis. Microscopic evaluation of duodenal biopsy material showed Leishmania amastigotes in macrophages of lamina propria. Leishman bodies were also observed in bone marrow aspiration specimen. Serologic tests were positive for Leishmania infantum. HIV antibody was also positive with a CD4+cell count of 80/μl. The diagnosis was acquired immunodeficiency syndrome with simultaneous visceral leishmaniasis involving intestinal mucosa.     

Lymphokine-activated killer cytotoxicity against pancreas adenocarcinoma cell lines and vascular endothelial cells

Eight pancreas carcinoma cell lines of duct cell origin (PCI-6, 10, 19, 24, 35, 43, 55, and 64) were established. Using one of these lines, PCI-24, human umbilical vein endothelial cells (HUVEC), and several recombinant cytokines, conditions and specificity of antl-PCI LAK induction were Investigated, with the focus on a search for lymphokine-activated killer (LAK) activity that differentiates neoplastic (PCI) from non-neoplastic (HUVEC) cells. Interferon-γ (IFN-γ), IFN-α, IL-4, 11–6, and IL-7, but not tumor necrosis factor-α (TNF-α) or IL-1β, induced a weak LAK activity against PCI-24, whereas IL-2-induced (1000U/mL) LAK exhibited a far more potent cytotoxicity. When these cytokines were added at the suboptimal dose IL-2 (100U/mL), no significant augmentation in LAK activity was induced. Staphylococcal protein A (SpA) induced LAK activity as potent as that seen with IL-2 (1000 U/mL). Both IL-2-induced and SpA-induced LAK had a potent, dose-dependent cytotoxicity against HUVEC. HUVEC inhibited both IL-2– and SpA-induced LAK cytotoxicity against PCI-24 to almost the same extent as seen with PCI-24. Thus, two potent LAK-inducers did not generate LAK activity that differentiates neoplastic from non-neoplastic cells. Thus, in vitro cytotoxicity of LAK agalnst non-neoplastic endothelial cells is unavoidable when handling cytokines in LAK induction.