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

Role of SPI-1 secreted effectors in acute bovine response to Salmonella enterica Serovar Typhimurium: a systems biology analysis approach

Salmonella enterica Serovar Typhimurium (S. Typhimurium) causes enterocolitis with diarrhea and polymorphonuclear cell (PMN) influx into the intestinal mucosa in humans and calves. The Salmonella Type III Secretion System (T3SS) encoded at Pathogenicity Island I translocates Salmonella effector proteins SipA, SopA, SopB, SopD, and SopE2 into epithelial cells and is required for induction of diarrhea. These effector proteins act together to induce intestinal fluid secretion and transcription of C-X-C chemokines, recruiting PMNs to the infection site. While individual molecular interactions of the effectors with cultured host cells have been characterized, their combined role in intestinal fluid secretion and inflammation is less understood. We hypothesized that comparison of the bovine intestinal mucosal response to wild type Salmonella and a SipA, SopABDE2 effector mutant relative to uninfected bovine ileum would reveal heretofore unidentified diarrhea-associated host cellular pathways. To determine the coordinated effects of these virulence factors, a bovine ligated ileal loop model was used to measure responses to wild type S. Typhimurium (WT) and a ΔsipA, sopABDE2 mutant (MUT) across 12 hours of infection using a bovine microarray. Data were analyzed using standard microarray analysis and a dynamic bayesian network modeling approach (DBN). Both analytical methods confirmed increased expression of immune response genes to Salmonella infection and novel gene expression. Gene expression changes mapped to 219 molecular interaction pathways and 1620 gene ontology groups. Bayesian network modeling identified effects of infection on several interrelated signaling pathways including MAPK, Phosphatidylinositol, mTOR, Calcium, Toll-like Receptor, CCR3, Wnt, TGF-β, and Regulation of Actin Cytoskeleton and Apoptosis that were used to model of host-pathogen interactions. Comparison of WT and MUT demonstrated significantly different patterns of host response at early time points of infection (15 minutes, 30 minutes and one hour) within phosphatidylinositol, CCR3, Wnt, and TGF-β signaling pathways and the regulation of actin cytoskeleton pathway.

Human natural killer cell deficiencies and susceptibility to infection

There are a surprisingly large number of human natural killer (NK) cell deficiency states that provide insight into the role of NK cells in defense against human infectious disease. Many disorders associated with NK cell defects are caused by single gene mutations and, thus, give additional understanding concerning the function of specific molecules in NK cell development and activities. A resounding theme of NK cell deficiencies is susceptibility to herpesviruses, suggesting that unexplained severe herpesviral infection should raise the possibility of an NK cell deficit.

Wiskott-Aldrich syndrome protein is required for NK cell cytotoxicity and colocalizes with actin to NK cell-activating immunologic synapses

The Wiskott-Aldrich syndrome (WAS) is a primary immunodeficiency disorder caused by a mutation in WAS protein (WASp) that results in defective actin polymerization. Although the function of many hematopoietic cells requires WASp, the specific expression and function of this molecule in natural killer (NK) cells is unknown. Here, we report that WAS patients have increased percentages of peripheral blood NK cells and that fresh enriched NK cells from two patients with a WASp mutation have defective cytolytic function. In normal NK cells, WASp was expressed and localized to the activating immunologic synapse (IS) with filamentous actin (F-actin). Perforin also localized to the NK cell-activating IS but at a lesser frequency than F-actin and WASp. The accumulation of F-actin and WASp at the activating IS was decreased significantly in NK cells that had been treated with the inhibitor of actin polymerization, cytochalasin D. NK cells from WAS patients lacked expression of WASp and accumulated F-actin at the activating IS infrequently. Thus, WASp has an important function in NK cells. In patients with WASp mutations, the resulting NK cell defects are likely to contribute to their disease.

Treatment of Familial Hemophagocytic Lymphohistiocytosis With Bone Marrow Transplantation From HLA Genetically Nonidentical Donors

Familial hemophagocytic lymphohistiocytosis (FHL) is a rare genetic disorder associated with the onset early in life of overwhelming activation of T lymphocytes and macrophages invariably leading to death. Allogeneic bone marrow transplantation (BMT) from an HLA-identical related donor is the treatment of choice in patients with this disease. However, fewer than 20% of patients have a disease-free HLA-identical sibling. BMT from HLA-nonidentical related donors has previously met with poor results, with graft rejection a major obstacle in all cases. We describe BMTs from HLA-nonidentical related donors (n = 13) and from a matched unrelated donor (n = 1) performed in two centers in 14 consecutive cases of FHL. Remission of disease was achieved before BMT in 10 patients. Marrow was T-cell–depleted to minimize graft-versus-host disease (GVHD). Antiadhesion antibodies specific for the α chain of the leukocyte function–associated antigen-1 (LFA-1, CD11a) and the CD2 molecules were infused pre-BMT and post-BMT to help prevent graft rejection, in addition to a conditioning regimen of busulfan (BU), cyclophosphamide (CP), and etoposide (VP16) or antithymocyte globulin (ATG). Sustained engraftment was obtained in 11 of 17 transplants (3 patients had 2 transplants) and disease-free survival in 9 patients with a follow-up period of 8 to 69 months (mean, 33). Acute GVHD greater than stage I was not observed, and 1 patient had mild cutaneous chronic GVHD that resolved. Toxicity due to the BMT procedure was low. Results obtained using this protocol are promising in terms of engraftment and event-free survival within the limitations of the small sample. We conclude that an immunologic approach in terms of drugs used to obtain disease remission and a conditioning regimen that includes antiadhesion molecules in T-cell–depleted BMT from HLA genetically nonidentical donors is an alternative treatment that warrants further study in FHL patients who lack a suitable HLA genetically identical donor.

Treatment of Familial Hemophagocytic Lymphohistiocytosis With Bone Marrow Transplantation From HLA Genetically Nonidentical Donors

Familial hemophagocytic lymphohistiocytosis (FHL) is a rare genetic disorder associated with the onset early in life of overwhelming activation of T lymphocytes and macrophages invariably leading to death. Allogeneic bone marrow transplantation (BMT) from an HLA-identical related donor is the treatment of choice in patients with this disease. However, fewer than 20% of patients have a disease-free HLA-identical sibling. BMT from HLA-nonidentical related donors has previously met with poor results, with graft rejection a major obstacle in all cases. We describe BMTs from HLA-nonidentical related donors (n = 13) and from a matched unrelated donor (n = 1) performed in two centers in 14 consecutive cases of FHL. Remission of disease was achieved before BMT in 10 patients. Marrow was T-cell–depleted to minimize graft-versus-host disease (GVHD). Antiadhesion antibodies specific for the α chain of the leukocyte function–associated antigen-1 (LFA-1, CD11a) and the CD2 molecules were infused pre-BMT and post-BMT to help prevent graft rejection, in addition to a conditioning regimen of busulfan (BU), cyclophosphamide (CP), and etoposide (VP16) or antithymocyte globulin (ATG). Sustained engraftment was obtained in 11 of 17 transplants (3 patients had 2 transplants) and disease-free survival in 9 patients with a follow-up period of 8 to 69 months (mean, 33). Acute GVHD greater than stage I was not observed, and 1 patient had mild cutaneous chronic GVHD that resolved. Toxicity due to the BMT procedure was low. Results obtained using this protocol are promising in terms of engraftment and event-free survival within the limitations of the small sample. We conclude that an immunologic approach in terms of drugs used to obtain disease remission and a conditioning regimen that includes antiadhesion molecules in T-cell–depleted BMT from HLA genetically nonidentical donors is an alternative treatment that warrants further study in FHL patients who lack a suitable HLA genetically identical donor.

Thymosin alpha 1 effects, in vitro, on lymphokine-activated killer cells from patients with primary immunodeficiencies: preliminary results

In patients with primary immunodeficiencies the role of natural killer (NK)- and lymphokine (IL-2)-activated killer (LAK)-cells is not yet satisfactorily established. Using a clonogenic assay with K562 leukemia target cells, we studied their NK- and LAK-cell activity in vitro. Moreover, the effect of thymosin alpha 1 (T alpha 1) on LAK-cell activity was studied in 11 patients with different immunodeficiencies. The results were compared with data of healthy controls (n = 11) and cord blood samples (n = 6). Common variable immunodeficiency patients demonstrated a mean LAK-cell activity of about 65% of normal controls and cord blood samples. The moderately reduced LAK-cell activity was not affected by T alpha 1. In the immunodeficient other patients, low levels of LAK-cell activity with a mean value of 10% of normal controls were seen. The mean LAK-cell activity could be improved by T alpha 1: three patients showed an improvement of their LAK-cell activity up to 25-30% after T alpha 1 administration in vitro, but in one case T alpha 1 was without any effect. Analysis of the expression of the surface markers CD8, CD16, CD57 and CD8/CD57 revealed that only CD16 positive lymphocytes were significantly less in immunodeficient patients. We found a linear correlation between LAK-cell activity and CD8/CD57 double positive lymphocytes in all patients. Our results demonstrate that suppressed LAK-cell activity from immunodeficient patients can be individually improved by T alpha 1. Further in vivo studies should evaluate thymic peptide immunotherapy for individual immunodeficient patients.

Partial albinism with immunodeficiency (Griscelli syndrome)

Partial albinism with immunodeficiency is a rare and fatal immunologic disorder characterized by pigmentary dilution and variable cellular immunodeficiency. To define the phenotype, therapy, and outcome, we retrospectively analyzed seven consecutive patients. Primary abnormalities included a silvery-grayish sheen to the hair, large pigment agglomerations in hair shafts, and an abundance of mature melanosomes in melanocytes, with reduced pigmentation of adjacent keratinocytes. Clinical onset occurred between the ages of 4 months and 4 years and was characterized by accelerated phases (lymphohistiocytic infiltration of multiple organs, including the brain and the meninges), triggered by viral and bacterial infections. Characteristic laboratory features included pancytopenia, hypofibrinogenemia, hypertriglyceridemia, and hypoproteinemia. Consistent immunologic abnormalities were characterized by absent delayed-type cutaneous hypersensitivity and impaired natural killer cell function. Some patients had secondary hypogammaglobulinemia, impaired major histocompatibility complex-mediated cytotoxic effects, a decreased capacity of lymphocytes to trigger a mixed lymphocyte reaction, or various functional granulocytic abnormalities. The disease seems to be invariably lethal without bone marrow transplantation; the mean age at the time of death was 5 years. Bone marrow transplantation has been performed in three cases; two patients died in the immediate posttransplantation period of infectious complications, but one patient is cured after a follow-up of 5 years. We conclude that partial albinism with immunodeficiency (Griscelli syndrome) can be differentiated from Chédiak-Higashi syndrome by pathognomonic histologic features. One of the underlying immunologic defects may be a defective function of natural killer cells, predisposing the patient to virus-associated hemophagocytic syndrome or accelerated phases. The prognosis is very poor unless early bone marrow transplantation is carried out.

Partial engraftment of donor bone marrow cells associated with long-term remission of haemophagocytic lymphohistiocytosis

We used polymerase chain reaction amplification of minisatellite sequences or of a Y chromosome-specific sequence and Southern blotting to analyse long-term engraftment (12-82 months) after bone marrow transplantation (BMT) for familial haemophagocytic lymphohistiocytosis (FHL). Six children aged from 1 to 18 months were transplanted with bone marrow from an HLA-identical sibling in five cases and from an HLA-nonidentical related donor (one mismatched HLA antigen) in one. The conditioning regiment included VP 16-213 (900 mg/m2), busulfan (16 mg/kg), cyclophosphamide (200 mg/kg) and, in one case, aracytine (2 g/m2). Four patients are alive without therapy more than 3 years after BMT; the other two relapsed 1 year after BMT. DNA was extracted from separated polymorphonuclear cells and mononuclear cells, as well as from separated E+ and E- cells in one case and CD16+ (natural killer) and CD16- cells in two cases. Engraftment was partial in the four long-term survivors. Recipient cells were largely predominant in three of them as well as in one of the patients who relapsed (the donor also developed FHL 18 months after BMT). E+, E-, CD16+ and CD16- cells presented the same pattern of chimaerism. Engraftment failed to occur in the patient who received an HLA-nonidentical bone marrow. These results indicate that partial engraftment is compatible with long-term remission of FHL and that the presence of a small proportion of cells of donor origin can prevent FHL-related lymphocyte and macrophage activation.

Immunodeficiency with low expression of the T cell receptor/CD3 complex. Effect on T lymphocyte activation

We report the consequences of low expression of the T cell receptor (TcR)/CD3 complex by T lymphocytes from a 4-year-old boy with a mild immunodeficiency. TcR/CD3 expression was found to be deficient on both resting and activated T cells, using both anti-CD3 and anti-TcR alpha/beta monoclonal antibodies. As shown by immunofluorescence and immunoprecipitation studies, residual expression (corresponding to about 10% of normal) was detectable on resting and activated TcR alpha/beta+ T cells. Other T cell membrane receptors were normally expressed. The functional consequences of this TcR/CD3 expression deficiency included an absence of T cell proliferation, interleukin 2 receptor expression and calcium flux following anti-CD3 and anti-CD2 antibody-triggered T cell activation. Antigen (tetanus toxoid, Candida and allogeneic cell)-induced proliferation was detectable. In contrast, cytotoxic T cell activity towards allogeneic cells was deficient. These findings shed light on the function of the TcR/CD3 complex and indicate that the expression of a limited number of TcR/CD3 receptors may be sufficient to trigger antigen-specific T cell activation (and, possibly, differentiation) and that anti-CD3 antibody-induced T cell activation differs somewhat from antigen/major histocompatibility complex molecule-induced activation. These results also confirm that the CD2 pathway of T cell activation is CD3 dependent.

Lymphokine-activated killer cells in primary immunodeficiencies and acquired immunodeficiency syndrome

Cytotoxic mechanisms (e.g., natural killer (NK) lysis, antibody-dependent cellular cytotoxicity, and cytotoxic T lymphocyte lysis) play an important role in host defense against various infections and neoplasms. Lymphokine-activated killer (LAK) cytotoxicity, induced in vitro by incubating mononuclear cells with interleukin 2 (IL-2) for 2-5 days, may also represent an important component of the body's cytotoxic repertoire. In 10 patients with congenital cellular immunodeficiencies, including 5 with severe combined immunodeficiency, the mean LAK activity in a 3-hr chromium release assay against Raji target cells was 44 +/- 8.1%, which is equivalent to that observed in normal adults and neonates. In only one case, a patient with reticular dysgenesis, was there absent LAK cell generation. Haploidentical T cell-depleted bone marrow transplantation (BMT) restored LAK activity in this patient. LAK activity was first observed in this patient and two others 3-6 weeks following BMT, prior to other evidence of immunologic engraftment such as lymphocyte proliferation to mitogens, NK activity, or interferon-gamma production. One patient with adenosine deaminase deficiency showed normal levels of LAK activity despite absent NK activity. Three patients with chronic granulomatous disease also had normal LAK activity (57 +/- 14% specific lysis). In 9 patients with acquired immunodeficiency syndrome (AIDS), IL-2 activation resulted in a mean cytotoxic activity of 56 +/- 8.7% toward Raji targets. In addition, 9 patients with pre-AIDS complex also showed normal levels of cytotoxicity (37 +/- 3.3% toward Raji targets), equivalent to that of 8 normal controls, including two healthy homosexual males (mean lysis 38 +/- 3.9%). These results indicate that LAK cells appear early in immunologic ontogeny. Further, the mechanism of lysis is not oxygen dependent since LAK activity was present in the 3 patients with chronic granulomatous disease. The ability to generate LAK in a wide spectrum of immunodeficiencies may indicate that IL-2 could be used in therapy of such disorders.

The DiGeorge sequence. II. Immunologic findings in partial and complete forms of the disorder

We present immunological in vitro data on a group of 16 patients with the DiGeorge sequence (DGS). Detailed tests gave evidence that the decrease in number and function of mature T-cells is closely correlated with phenotypic expression and represents a wide immunological spectrum ranging from normal function to severe combined immunodeficiency with B-cells. Careful immunological testing in DGS may help to plan therapeutic procedures (i.e. thymic factor therapy or bone marrow transplantation), may also have prognostic significance and help to gain insight into mechanisms operative in disturbances of T-cell regulation.

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.

Biology of natural killer cells

Studies of cytotoxicity by human lymphocytes revealed not only that both allogeneic and syngeneic tumor cells were lysed in a non-MHC-restricted fashion, but also that lymphocytes from normal donors were often cytotoxic. Lymphocytes from any healthy donor, as well as peripheral blood and spleen lymphocytes from several experimental animals, in the absence of known or deliberate sensitization, were found to be spontaneously cytotoxic in vitro for some normal fresh cells, most cultured cell lines, immature hematopoietic cells, and tumor cells. This type of nonadaptive, non-MHC-restricted cellmediated cytotoxicity was defined as “natural” cytotoxicity, and the effector cells mediating natural cytotoxicity were functionally defined as natural killer (NK) cells. The existence of NK cells has prompted a reinterpretation of both the studies of specific cytotoxicity against spontaneous human tumors and the theory of immune surveillance, at least in its most restrictive interpretation. Unlike cytotoxic T cells, NK cells cannot be demonstrated to have clonally distributed specificity, restriction for MHC products at the target cell surface, or immunological memory. NK cells cannot yet be formally assigned to a single lineage based on the definitive identification of a stem cell, a distinct anatomical location of maturation, or unique genotypic rearrangements.

A T cell- and natural killer cell-specific, trypsin-like serine protease. Implications of a cytolytic cascade

A new trypsin-like serine protease was cloned from both a murine cytotoxic T lymphocyte and a human PHA-stimulated peripheral blood lymphocyte cDNA library. In both the mouse and human system, this transcript had a T cell- and NK-specific distribution, being detected in cytotoxic T lymphocytes (CTL), some T-helper clones, and NK, but not in a variety of normal tissues. T-cell activation with Con A plus IL-2 induced mouse spleen cells to express this gene with kinetics correlating with the acquisition of cytolytic capacity. Both the mouse and human nucleotide sequences of this gene encoded an amino acid sequence with 25-40% identity to members of the serine protease family. The active-site "charge-relay" residues (His-57, Asp-102, and Ser-195 of the chymotrypsin numbering system) are conserved, as well as the trypsin-specific Asp (position 189 in trypsin). We reviewed the evidence of this serine protease's role in lymphocyte lysis and proposed a "lytic cascade." We discussed the biological and clinical implications of a cascade, proposing these enzymes as markers for cytolytic cells and as targets for rational drug therapy. Genetic and acquired deficits in the lethal hit-delivery system are considered as a basis for approaching some immunodeficiency states, including severe EBV infections, T-gamma leukemias, and T8+ lymphocytosis syndromes.

Immunoferon (AM3) enhances the activities of early-type interferon inducers and natural killer cells

The "in vivo" effect of Immunoferon (AM3) on the production of interferon (IFN) and natural killer (NK) activity in young and old mice was studied. Although AM3 is not an IFN inducer by itself, enhancements in the serum IFN levels were produced when drug was associated to Newcastle disease virus or bacterial lipopolysaccharides as IFN inducers. This effect appeared to be dependent on the time lapsed between the inducer agent and drug. In addition, a significant stimulating effect on NK cell activity was also produced by AM3 treatments. This effect could be a consequence of a marked IFN induction and/or a modifying effect in prostaglandin synthesis.

Correlation of circulating natural killer cell count with prognosis in large cell lymphoma

A monoclonal antibody recognizing a natural killer (NK) cell-associated antigen was used to sequentially quantify numbers of peripheral blood NK cells in a small group of patients with large cell lymphoma. Patients with active disease had low numbers (less than 100/mm3) of NK cells. Patients in complete remission after therapy had normal numbers of NK cells, but those patients who relapsed had a fall of NK cell number to less than 100/mm3 preceding or concurrent with clinical relapse. A role for NK cells in the surveillance and control of abnormal lymphoproliferation is suggested, as is the possible prognostic utility of sequential peripheral blood NK cell quantification in patients with large cell lymphoma.

Correlation of circulating natural killer cell count with prognosis in large cell lymphoma

A monoclonal antibody recognizing a natural killer (NK) cell-associated antigen was used to sequentially quantify numbers of peripheral blood NK cells in a small group of patients with large cell lymphoma. Patients with active disease had low numbers (less than 100/mm3) of NK cells. Patients in complete remission after therapy had normal numbers of NK cells, but those patients who relapsed had a fall of NK cell number to less than 100/mm3 preceding or concurrent with clinical relapse. A role for NK cells in the surveillance and control of abnormal lymphoproliferation is suggested, as is the possible prognostic utility of sequential peripheral blood NK cell quantification in patients with large cell lymphoma.

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.

Metabolic defects in severe combined immunodeficiency in man and animals

Severe combined immunodeficiency (SCID) was originally thought to be one disease. Accumulating evidence indicates that SCID is a heterogeneous group of diseases that are clinically similar but are caused by quite different biochemical abnormalities. The best-studied form of SCID is that associated with an autosomal recessive inheritance pattern of adenosine deaminase (ADA) deficiency. Several biochemical mechanisms have been postulated to explain how a deficiency of ADA causes immune dysfunction. In forms of SCID not associated with ADA deficiency, other biochemical abnormalities have been detected. These abnormalities include deficiency in biotin-dependent carboxylases, alteration in lymphocyte surface membranes and irregularities in cytokine production. Two animal models for SCID now exist. Neither of these models is associated with ADA deficiency. Evidence for a possible defect in purine metabolism in one model has been demonstrated.

Natural cytotoxicity in immunodeficiency diseases: preservation of natural killer activity and the in vivo appearance of radioresistant killing

We studied spontaneous natural killer (NK) cell activity and radiation-resistant NK mediated cytotoxicity in four patients with clinically documented severe combined immune deficiency disease (SCID), and in one subject each with intestinal lymphangiectasia and cartilage-hair hypoplasia. We observed the preservation of spontaneous NK activity in all patients despite the presence of profound B- and T-lymphocytopenia and clinical immunodeficiency. NK activity was associated with relatively normal circulating numbers of OKM1+ lymphocytes, a population known to contain NK effectors. Spontaneous NK activity resistant to 3000 rad was increased in all patients, indicating the presence of activated natural killer cells in vivo. The concept of a chronically activated immune system in these patients was further supported by the presence of increased Ia positive T cells in all subjects tested, suggesting that radioresistant NK activity may be a useful parameter to measure when assessing in vivo immune activation. Our data, as well as that of others, supports the hypothesis that at least one population of NK cells is a distinct lineage arising at the differentiation level of myeloid and lymphoid stem cells in the bone marrow.

Natural killer activity in two cases of ataxia telangiectasia

We report two cases of ataxia telangiectasia in which a small number of T cells and a slightly diminished response to phytohaemagglutinin or concanavalin A were observed. In one case, serum IgA was undetectable. In spite of T and/or B cell involvement, natural killer activity and the percentage of natural killer cells determined by monoclonal antibodies Leu 7 were normal in both cases.

The role of the thymus in the maintenance of natural killer cells in vivo

This report describes a model for investigating the role of the thymus in regulating natural killer (NK) cell activity in vivo. Evidence is presented that the thymus can regulate NK cells, and that at least some NK cells can develop without thymic help. Marrow from thymectomized rats depleted of circulating T cells by thoracic duct cannulation was transplanted into rats without a thymus (1 degree ATX.BM). These 1 degree ATX.BM rats had NK cell levels above controls 3 months after reconstitution but markedly depressed NK cell levels by 9 months. When 1 degree ATX.BM marrow was used to reconstitute rats with or without a thymus, those without a thymus (2 degrees ATX.BM) exhibited low NK cell levels after 3 months, and a similar result was obtained when 2 degrees ATX.BM marrow was used to reconstitute 3 degrees ATX.BM rats. The low NK cell levels in 2 degrees and 3 degrees ATX.BM rats were due to a deficiency in spontaneously cytotoxic NK cells, as they had normal numbers of interferon-responsive pre-NK cells. Spleen cells from 2 degrees and 3 degrees ATX.BM rats produced less interferon than control spleen cells when cultured with P815 tumor cells in vitro. However, 2 degrees and 3 degrees ATX.BM rats had higher numbers of large granular lymphocytes than controls despite their low NK cell levels. In marked contrast to 2 degrees and 3 degrees ATX.BM rats, spleen cells from 4 degrees ATX.BM rats had higher levels of cytotoxicity and a higher frequency of both spontaneously cytotoxic and pre-NK cells than controls. The 4 degrees ATX.BM rats also had the highest frequency of large granular lymphocytes in the spleen.

Intraepithelial lymphocytes of human gut: isolation, characterisation and study of natural killer activity

A method using a mechanical procedure for isolation of lymphocytes from the epithelium of human intestinal mucosa allows the study of some of their characteristics and functions. Most of the isolated cells are of the T lineage (E+ and T3+) and express the phenotype associated with cytotoxic-suppressor T cells (T8). A large number contain intracytoplasmic granules. Granules are stained with alcian blue (pH 2.2), are metachromatic with Toluidine blue (pH 4) and some are shown to incorporate 35sulphate, suggesting that they contain sulphated mucopolysaccharides. As these cells are similar in many respects to the large granular lymphocytes that mediate natural killer activity in the peripheral blood, their natural cytotoxicity was tested against K 562 target cells. No activity was detected among the human intraepithelial lymphocytes and treatments with known potentiators of natural killer activity, ie, interferon or PHA-depleted conditioned medium containing Il-2, failed to reveal any cytotoxic activity.

Natural killer cells

It is proposed that this article will encompass a review of primarily the human natural killer cell. The following parameters of the human natural killer (NK) cell will be reviewed: its ontogeny; surface membrane characteristics including monoclonal antibody reactivity, cell lineage, the natural killer sensitive targets, and the proposed mechanism of action of natural killer cells cytotoxicity against these NK sensitive targets; the status of natural killer cell in relationship to clinical disease; the alteration of natural killer cells both in vitro and in vivo; and finally postulate relevance of the natural killer cell in context of the evolution or pathophysiology of human disease. There will be an attempt through this review to encompass the more recent publications that pertain to the various sections.

Allogeneic bone marrow transplantation in man: in vitro activity of FTS-Zn on T-cell markers and functions

Thymulin (FTS-Zn) is a synthetic metallo-nonapeptide similar to the serum factor of thymic origin FTS, which induces the maturation of lymphoid cells. The activity of this compound on peripheral blood mononuclear cells from 12 bone marrow recipients was studied in vitro. It was demonstrated that thymulin was able to induce or modulate the expression of T-cell membrane markers, to enhance the proliferative responsiveness of lymphocytes to mitogens or allogeneic cells, and to increase mononuclear cells' natural killer activity. This in vitro responsiveness was contemporary to a transient decrease of FTS levels in the patients' serum, documented by sequential assays. These results suggest that thymulin could be of interest as a prophylactic therapy to speed up the immunological reconstitution of bone marrow recipients.

Severe combined immunodeficiency with natural killer-cell predominance: abrogation of graft-versus-host disease and immunologic reconstitution with HLA-identical bone marrow cells

A 3 1/2-month-old infant with severe combined immunodeficiency was found to have an unusual blood lymphocyte phenotype. Thirty percent of her cells formed rosettes with sheep erythrocytes, but only 7.9% reacted with the pan T monoclonal antibody OKT3, and 5% reacted with an antibody (OKT4)-recognizing T-helper cells. Surprisingly 19.4% of her cells reacted with an antibody (OKT8)-recognizing T-suppressor cells and 94% reacted with OKT10 . Few reacted with other monoclonal antibodies detecting cellular activation antigens. Despite absence of T or B cell function, her monocyte-depleted blood lymphocytes caused a high degree of specific lysis of 51Cr-labeled K562 erythromyeloid cells in a natural killer-cell assay. Most of her lymphocytes were large and had azurophilic granules and a monocytoid nucleus. Because she had received a nonirradiated, unrelated red-cell transfusion 3 days earlier, 4.8 X 10(9) nucleated bone-marrow cells from her HLA-identical brother were given shortly after admission. Two days later a graft-versus-host reaction began but subsided completely within 3 days. On day 15 posttransplantation, a profuse secretory diarrhea began, accompanied by a rise in her serum IgE from 4 to 3000 IU. With engraftment, the number of T10+ cells and natural killer-cell function fell to normal, and full immunologic reconstitution was achieved.

Changes in natural killer activities in experimental secondary amyloidosis

Natural killer (NK) cell activity in experimental murine amyloidosis was studied. In CBA/J mice, which show a high incidence of amyloidosis, NK activity was significantly decreased after 1 week of casein treatment. In C3H mice, which show a low incidence of amyloidosis, NK activity was not changed by casein treatment. Pretreatment with lipopolysaccharide in vivo enhanced the NK activities in CBA/J and C3H mice. These increases were not observed after casein treatment. The lowered NK activity of cells from CBA/J mice after casein treatment was restored to the normal range by indomethacine in vitro. Depletion of adherent cells from the spleen cells treated with casein had no effect on NK activity. Single-cell assay showed that casein treatment impaired the killing but not the binding of NK cells to target cells. After casein treatment, the splenic serum amyloid A (SAA) level gradually increased in CBA/J mice but remained low in C3H mice. NK activity was suppressed by the addition of serum obtained from CBA/J mice treated with casein but not by normal control serum. And partially purified AA protein obtained from the spleen of CBA/J mice treated with casein also suppressed NK activity in vitro.

Isolation of new lymphotropic retrovirus from two siblings with haemophilia B, one with AIDS

A human T-lymphotropic retrovirus was isolated from cultured T lymphocytes from two siblings with haemophilia B. Patient 2 was healthy, but patient 1 had acquired immunodeficiency syndrome. The retrovirus differed from human T-cell leukaemia virus (HTLV) but it was similar to the lymphadenopathy-associated retrovirus (LAV) in its morphology and its major core protein (P25). Both patients had antibodies against LAV and patient 1's retrovirus, detected by an enzyme-linked immunosorbent assay or a radioimmunoprecipitation assay. Seroepidemiological data indicated the transmission of this retrovirus by plasma products.

Impaired natural killer activity in lymphohistiocytosis syndrome

In six patients with well-documented lymphohistiocytosis syndrome, natural killer activity was found to be profoundly impaired and could not be increased by incubation in vitro with interferon. This abnormality was not found in parents of the affected children. A clear correlation with the activity of the disease was observed, although a delay of a few weeks (possibly reflecting the life span of NK cells in blood) was seen in the disappearance of NK activity after the onset of the disease and its reappearance after remission. No absolute correlation was observed between NK activity and percentage of leukocytes detected by the Leu-7 monoclonal antibody. Our findings indicate that testing NK activity is useful for the diagnosis of lymphohistiocytosis syndrome and can be used as an index of activity of the disease, among other major clinical and biologic signs of this syndrome. Reversal of the NK activity defect (rather than detection of Leu-7 positive cells) appears to be a good criterion of complete remission.

Interferon production in children with undue susceptibility to infections

The interferon-producing ability of peripheral blood mononuclear leukocytes obtained from children with undue susceptibility to infections was investigated. Patients were grouped according to three clinical patterns, i.e. children with mainly upper respiratory tract infections, with lower respiratory tract infections and with frequent middle ear infections. There was no evidence of impaired mean interferon-alpha responses to the inducers Sendai virus and beta-hemolytic Group G streptococci in patients compared with control children, and there were no differences in this respect between the patient subgroups. A tendency to increased Concanavalin A-induced interferon-gamma production was seen in patients, particularly those with middle ear infections. Leukocytes from patients displayed a higher proliferative response to the T cell mitogens Concanavalin A and Lens culinaris lectin. In a minority of patients (5/28) reproducibly low interferon responses to Sendai virus were found but only one of these patients showed a response below the -2 SD limit for the control group. The results therefore indicate no major defects in the interferon responses of infection-prone children, and at the most suggest that a minority of such patients may be low responders to a viral interferon inducer.

Growth pattern of intrauterine growth retarded (IUGR) babies in first nine months of life

Forty-one full term intrauterine growth retarded (IUGR) babies of different maternal etiologies viz. maternal undernutrition (12), small maternal size (12), toxaemia of pregnancy (9) and idiopathic (8) were studied for growth pattern during first 9 months of life. Eighteen fullterm and 11 preterm who were appropriate for gestational age served as controls. These mothers were comparable for age, parity, socioeconomic status, weight and height (except in small size mothers), haemoglobin and plasma albumin (except in undernourished group). The various anthropometric parameters studied were weight, crown-heel length, head circumference, their velocities and ponderal index. The IUGR babies of undernourished mothers had lowest means for weight, crown-heel length and skull circumference. The babies of small sized mothers suffered most in crown-heel length followed by weight. The head growth was not affected in these babies. The IUGR babies of mothers with toxaemia of pregnancy demonstrated a catch up growth for all three parameters. The IUGR babies of idiopathic group showed a spurt in weight gain around 3 to 6 months and a similar spurt for crown heel length and head circumference was observed between 6 to 9 months of age. These babies were close to IUGR babies of mothers with toxaemia of pregnancy at 9 months. The preterm AGA babies also demonstrated a catch up growth for the weight, crown heel length and circumference.

Antibody-dependent cellular cytotoxicity and natural killing in nude rats: quantitative study according to age and sex

Rats bearing the rnu mutation were used to study the influence of the thymus on killer (K) and natural killer (NK) cytotoxic activities. Both functions developed to a comparable level in 3-month old homozygote rnu/rnu athymic rats and their normal rnu/+ littermates. In old rats, cytotoxic activities did not decrease, except in the case of female rnu/rnu rats. K and NK cytotoxic activities are thus able to develop normally in the absence of thymic influence. Moreover, nude rats will be useful as a source of potent effector cells for studying both the cellular functions themselves and the antibodies involved in K-cell activity.

Severe combined immunodeficiencies, primary T-cell defects and DiGeorge syndrome in humans: characterization by monoclonal antibodies and natural killer cell activity

Peripheral blood mononuclear cells from three patients with severe combined immunodeficiency (SCID), three with SCID whether B cell positive or with pure T-cell defect, and two with DiGeorge syndrome were analyzed with a panel of monoclonal antibodies against immature and mature T-cell subsets. Natural killer (NK) cells were enumerated by the use of the HNK-1 monoclonal antibody. NK activity against the K562 and MOLT 4 cell lines was also investigated. According to the monoclonal antibodies profile and the NK activity, patients could be divided into three groups. Patients with classical SCID had no detectable circulating T cells as well as NK cells and activity, probably due to an early block in stem cell differentiation. Patients affected by SCID with B cells or pure T cell defect showed a decrease in lymphocytes with mature phenotypes but prothymocytes or immature thymocytes circulated in peripheral blood. Children with DiGeorge syndrome had a decrease in mature thymocytes and, in this study, NK cells were normal. These data help to clarify both the preeminent immunologic features of SCID and related syndromes and the character of NK cells.

Long lasting lymphadenopathy in childhood as an expression of a severe hyperimmune B lymphocyte disorder

On the basis of the 6 cases reported here and scattered published cases, the existence of a childhood chronic immunoblastic lymphadenopathy syndrome is proposed. It is characterized by the following features: A systemic immunoblastic proliferation with varying degrees of maturation resembling the B lymphocyte hyperimmune disorder observed in angioimmunoblastic lymphadenopathy but with no deposits of interstitial amorphous material or vascular proliferation. Disseminated superficial and deep lymphadenopathy. Chronic, pronounced splenomegaly. A constant thrombocytopenia. A polyclonal hypergammaglobulinemia, with markedly elevated antibody titers to various agents. An early onset and a course of several years (up to 20), interrupted in half the cases by the occurrence of a virus-associated (EBV, Papova) neoplastic process or a fatal viral infection. Low natural killer (NK) cell activity in 2 cases.

Comparison of ADCC and NK activities of peripheral blood mononuclear cells from patients at risk for acquired immune deficiency syndrome (AIDS)

Numerous cellular immune defects have been described in patients with acquired immune deficiency syndrome (AIDS). These include anergy, reduced numbers of helper T cells, and decreased effectiveness of natural killer (NK) cells. In this study, we have measured the lytic activity of antibody-dependent cellular cytotoxic (K) cells using a recently described 51Cr release assay in patients clinically displaying lymphadenopathy syndrome (LAD). We then compared ADCC activity with NK activity, T helper/T suppressor ratios and NK cell number in these same patients. Our results indicate that a reduction of ADCC activity can occur in patients with LAD. In our study, patients that showed reduced ADCC activity also showed reduced NK cell function. Other individuals in this study had reduced NK function while ADCC values remained within the normal range. The degree of reversal of the T helper/T suppressor cell ratio was not a useful indicator of cellular immune function as measured by these assays in that individuals with very low ratios often had normal cytotoxic cell function while some patients with ratios in the normal range had decreased cytotoxicity. The percentage of NK cells as determined by HNK-1 monoclonal antibody also did not prove useful in defining potential cytotoxic activities.

Natural killer (NK) and antibody-dependent cellular cytotoxicity (ADCC) activities can be differentiated by their different sensitivities to interferon and prostaglandin E1

Though purported to be identical cells (or in identical populations of cells), the natural killer (NK) cell mediating spontaneous natural cytotoxicity and the killer (K) cell mediating antibody-dependent cellular cytotoxicity (ADCC) may not be totally identical, at least in susceptibility to regulation by the immunomodulators prostaglandin E1 (PGE1) and interferon (IFN). We demonstrate here that NK cells are always enhanced by IFN, while K cells are inhibited from binding targets, resulting in fewer effectors at optimal concentrations of antibody. Only at 10- to 100-fold suboptimal concentrations of antibody is ADCC activity enhanced. As measured by magnitude of inhibition and dose-response titration, ADCC activity is less sensitive to the effects of PGE1 than is NK activity in the 51Cr release assay and single-cell assay. After overnight incubation with or without PGE1, whatever sensitivity ADCC activity had to PGE1 is lost. However, NK cells incubated in the presence of PGE1 overnight are still sensitive to inhibition. Indomethacin boosts NK activity without having any effect on ADCC activity. Finally, NK activity is substantially reduced by overnight incubation of cells at room temperature, which has no effect on K cells.

Effect of a synthetic thymic factor (facteur thymique serique) on natural killer cell activity in humans

The effect of the serum thymic factor, FTS, on human NK cells was studied. NK cell activity was measured in a 51Chromium-release assay in which effector cells were peripheral blood lymphocytes (PBL) or bone marrow (BM) lymphocytes from healthy individuals and patients, and targets were K562 cells. When added in vitro in this assay, FTS modulated NK cell activity of normal PBL. Low concentrations of FTS (10(-2) ng/ml) increased NK activity (P less than 0.001) whereas higher concentrations decreased it (P less than 0.01) for 10 and 10(2) ng/ml. FTS exhibited no effect on NK cell activity of BM lymphocytes. When administered in vivo to 4 cancer patients (10 micrograms/kg i.v. every 3 days), FTS progressively increased peripheral NK activity in two patients with low pre-treatment NK values, whereas it decreased NK activity in two patients with previously normal or high NK values. The mechanism by which FTS modulates NK cell activity is still unknown but such modulation suggests that NK cells belong in part to the T-lineage.

Low natural killer cell activity in patients with malignant lymphoma

Natural killer (NK) cell activity was found decreased (mean value: 27.5%) in peripheral blood lymphocytes from 59 untreated patients with malignant lymphoma, when compared to 112 healthy subjects (46.3%) and to 75 cancer patients with nonlymphoid tumors (43.7%) (P less than 0.001). NK cell values were similar in patients with Hodgkin's disease (25.5%) and with non-Hodgkin's lymphoma (28.2%). Decreased NK cell activity was not correlated with age, lymphoma extension or leukocyte counts. A physiological role for NK cells in the immune surveillance against lymphoid neoplasias is discussed.

Deficiency of monoclonal antibody-defined NK Cells (HNK-1+) in primary immunodeficiency disorders

Natural killer (NK) cells were enumerated in the peripheral blood mononuclears from 13 patients with primary immunodeficiency disease, using recently developed monoclonal antibody, Leu 7 (HNK-1). Eight of 13 patients demonstrated quantitative deficiency of NK cells when compared to simultaneously studied healthy controls, using monoclonal antibody and fluorescence-activated cell sorter (FACS). The quantitative deficiency of NK cells could be one of several factors responsible for increased susceptibility to infections and increased incidence of malignancies in patients with primary immunodeficiencies.

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.

Spontaneous lymphocyte-mediated (NK cell) cytotoxicity in systemic sclerosis: a comparison with antibody-dependent lymphocyte (K cell) cytotoxicity

Spontaneous (NK cell) and antibody-dependent (K cell) cytotoxicity were investigated in 39 patients with systemic sclerosis (SS) and compared with that found in 52 normal controls. Cr-labelled Chang liver cells were used as targets in assays utilising both whole blood (WB) and peripheral blood mononuclear cells (PBM) as effectors. Patients with SS, who were severely affected by extensive visceral disease, were found to have significant impairment of both NK (p less than 0.005; p less than 0.05) and K (p less than 0.001; p less than 0.05) cell cytotoxicity by both effector systems, when compared with normal controls. These findings, which seem to be part of a wider defect in cell-mediated immunity, may provide a possible explanation for the described association of malignancy with systemic sclerosis.

Studies of the function of natural killer-interferon system in patients with Sjögren syndrome

The natural killer (NK)-interferon (IFN) system is shown to be significantly involved in the resistance of host to viral infections and to tumours in numbers of animal models (1-4). The patients with Sjögren syndrome (SS) as well as those with collagen diseases were systematically investigated for the functions of NK-IFN system, including endogenous and augmented NK activity, IFN production, and responsiveness of NK cells to IFN stimulation, using virus persistently infected cells (heLa-measles cells) as target and stimulator cells. Although endogenous NK activity was not reduced, augmented NK activity by HeLa-measles cells in vitro was significantly depressed in patients with SS compared with that in age-matched normal controls. The patients with SS had also impaired capacity to produce IFN, which is shown to be a major factor regulating NK activity (5,6) in response to HeLa-measles cells in vitro. In three patients with SS who showed severely depressed NK activity, the effect of exogenous IFN was examined, and virtually no augmentation of NK activity was observed in all cases. Under the same condition, the normal controls demonstrated a dramatic increase in NK activity. The reduced IFN production was observed in all examined patients with SS, whereas impaired augmentation of NK activity by the stimulation with HeLa-measles cells as well as IFN seemed to be more striking in patients with the systemic manifestations of the disease, such as hypergammaglobulinemia and lymphoid hyperplasia. The possible involvement of dysfunction of NK-IFN system in the systemic manifestations of SS is discussed.

Psychosocial factors and psychophysiological mechanisms in the aetiology and development of cancers

Socio-cultural factors which may play a contributory role in the aetiology of cancer have been extensively investigated and it is well established that the incidence rates of different forms and sites of the disease are not equally distributed throughout the population. Social class, occupational, environmental and 'life-style' differences, amongst others, have been found to be associated with an excess risk of cancer, although the argument concerning the relative importance of these various factors remains a controversial one. It seems increasingly clear however, that there are large behavioural components which govern exposure to potential carcinogens and there is growing interest in the extent to which social and psychological demands may be associated with these agents or may operate as contributory factors in their own right. A number of early studies of psychological approaches to the study of cancer aetiology are reviewed from a methodological perspective. Much of the early work suffered from the problem that psychological characteristics of individuals who already had cancer were used to construct models concerned with aetiological factors. A number of the more recent studies which have attempted to overcome these difficulties are discussed. Tentatively, these later investigations suggest that two main groups of factors are related to an increased risk of cancer. First, the loss of, or lack of closeness or attachment to an important relation (often a parent) early in life, and second, the inability to express hostile feelings or more generally the abnormal release of emotion. Several psychophysiological mechanisms are reviewed which have attempted to account for the relationship between psychological disturbances and the onset of cancer, particularly the growing evidence which implicated a role for the immune system as a link between the central nervous system and disease processes.