Lower Natural Killer Cell Cytotoxicity Research Articles

Hemophagocytic Lymphohistiocytosis After Inactivated Influenza Vaccination in a Young Man Complicated by Severe Rhabdomyolysis

Hemophagocytic lymphohistiocytosis (HLH) is an immune response disorder that is usually fatal despite treatment. It is characterized by a dysregulation in natural killer (NK) T-cell function, causing activation of lymphocytes and histiocytes, resulting in a cytokine storm, end-organ damage, and eventually death. In this report, we describe the case of a previously healthy 38-year-old Caucasian man who presented with fever, nausea, vomiting, abdominal pain, myalgias, and weight loss for one week after inactivated influenza vaccination. The initial evaluation showed leukocytosis, lactic acidosis, and a severely elevated creatine kinase level (19,639 IU/L). The presentation was consistent with a diagnosis of sepsis, likely secondary to viral etiology and rhabdomyolysis. Subsequently, he rapidly deteriorated, requiring mechanical ventilation and developed refractory shock requiring pressor support and continuous veno-venous hemofiltration for acute kidney injury due to rhabdomyolysis. Later, he developed bicytopenia, hyperferritinemia, hypertriglyceridemia, and elevated inflammatory markers, raising the possibility of underlying HLH. Further tests showed low NK cell cytotoxicity and elevated sCD25. The H-score, which is a clinical tool to estimate the probability of HLH, showed an 88-93% probability of that potentially fatal disorder.The patient was treated with pulse-dose corticosteroids, intravenous immunoglobulins (IVIGs), and anakinra. He had a prolonged and complicated hospital stay for about two months. However, he was able to slowly recover. We believe that he developed secondary HLH in the setting of vaccination. Although rare, an early suspicion of HLH leads to the early initiation of directed therapy with immunosuppressant that would limit morbidity and mortality.

IFN-\u03bb1 in CHO cells: its expression and biological activity

BackgroundMany studies have investigated the characteristics and biological activities of type III interferon (IFN), finding that it has similar features to type I IFN but also unique actions because it is recognized by a different receptor.ResultsA full-length recombinant human IFN-λ1 (rhIFN-λ1) cDNA was cloned into the pDF expression vector and stably expressed in Flp-In-CHO cells. After four purification steps (ammonium sulfate precipitation, SP Sepharose chromatography, Blue Sepharose 6 fast flow affinity chromatography and molecular sieve chromatography), the rhIFN-λ1 had a purity of about 90% and was found to have the predicted biological activities. The anti-viral activity of rhIFN-λ1 was determined as 106 IU/mg using the vesicular stomatitis virus (WISH-VSV) assay system. The anti-proliferation activity of rhIFN-λ1 was measured using the MTS method and the growth inhibition ratio was 57% higher than that for recombinant human IFN-α2b (rhIFN-α2b) when the rhIFN-λ1 concentration was 1000 IU/ml. rhIFN-λ1 had lower natural killer cell cytotoxicity than rhIFN-α2b.ConclusionThe Flp-In-CHO system is suitable for stably expressing rhIFN-λ1 that possesses the predicted anti-viral, anti-proliferation and natural killer cell cytotoxicity-promoting activities.

High folic acid intake reduces natural killer cell cytotoxicity in aged mice

Presence of unmetabolized folic acid in plasma, which is indicative of folic acid intake beyond the metabolic capacity of the body, is associated with reduced natural killer (NK) cell cytotoxicity in postmenopausal women ≥50years. NK cells are cytotoxic lymphocytes that are part of the innate immune system critical for surveillance and defense against virus-infected and cancer cells. We determined if a high folic acid diet can result in reduced NK cell cytotoxicity in an aged mouse model. Female C57BL/6 mice (16-month-old) were fed an AIN-93M diet with the recommended daily allowance (1× RDA, control) or 20× RDA (high) folic acid for 3months. NK cytotoxicity was lower in splenocytes from mice fed a high folic acid diet when compared to mice on control diet (P<.04). The lower NK cell cytotoxicity in high folic acid fed mice could be due to their lower mature cytotoxic/naïve NK cell ratio (P=.03) when compared to the control mice. Splenocytes from mice on high folic acid diet produced less interleukin (IL)-10 when stimulated with lipopolysaccharide (P<.05). The difference in NK cell cytotoxicity between dietary groups was abolished when the splenocytes were supplemented with exogenous IL-10 prior to assessment of the NK cytotoxicity, suggesting that the reduced NK cell cytotoxicity of the high folic acid group was at least partially due to reduced IL-10 production. This study demonstrates a causal relationship between high folic acid intake and reduced NK cell cytotoxicity and provides some insights into the potential mechanisms behind this relationship.

Low NK Cell Activity in Chronic Fatigue Syndrome (CFS) and Relationship to Symptom Severity

Background: Natural killer (NK) cells act as an immune surveillance against invading pathogens and tumors. NK cell cytotoxicity (NKCC) has been reported to be decreased in patients with CFS.Methods: The objective of this review was to conduct an analysis of available publications that reported NKCC data in CFS in order to evaluate any relationships to case definitions used to define CFS and symptom severity.Results: Of 17 studies that evaluated NKCC in patients with CFS, defined using the CDC 1988 and/or 1994 case definition (CD), 88% (15/17) concluded that NKCC was decreased in CFS patients compared to normal controls. The NKCC decrease was seen using two established methods, 51Cr release (11/13) and flow cytometry (4/4). The mean percent decrease in NKCC using the CDC 1988 CD (66.3%) was significantly greater than that using the CDC 1994 CD (49.7%) (p 0.5). Finally, seven studies investigating the ability of various agents to augment NKCC in patients with CFS showed increases of NKCC with both in vitro exposure (4/5) and in vivo exposure using randomized trials (2/2).Conclusions: Low NKCC is commonly seen in CFS and is associated with increase symptom severity.

Lower natural killer cell cytotoxicity in smokers may be mediated by epithelial cells

Cigarette smoking is a risk factor for viral infections, yet the mechanisms underlying this susceptibility remain unknown. Natural killer (NK) cells play an important role in fighting influenza and signals from epithelial cells (EC) likely regulate NK cell activity. We have previously shown that markers of cytotoxicity are reduced in nasal NK cells from smokers after influenza infection. This study investigated if human EC from smokers and nonsmokers differentially affect NK cell activity in the context of influenza infection.EC were infected with influenza and subsequently co‐cultured with NK cells. NK cells were also incubated with apical washes and basolateral supernatants of EC to identify the role of soluble mediators.At baseline, co‐culturing NK cells either directly with smoker EC or stimulating with basolateral supernatants from these cells reduced markers of cytotoxicity. Similarly, after influenza infection markers of cytotoxicity as well as levels of IFN‐γ, IL‐4 and granzyme B were decreased in NK cells incubated with basolateral supernatants of smoker EC.Co‐culturing NK cells with EC from smokers reduced markers of cytotoxicity in NK cells through a potential mechanism involving EC‐derived soluble mediators. Thus, EC‐mediated modification of NK cell activity may contribute to the higher susceptibility to influenza infections seen in smokers.The work was supported by NIH, EPA and FAMRI.

Frequent intentional weight loss is associated with lower natural killer cell cytotoxicity in postmenopausal women: possible long-term immune effects

Objective Weight-loss attempts are likely to become more frequent as the prevalence of obesity rises. Repeated cycles of loss and gain are a common consequence of failed weight-loss attempts. The question of whether this pattern has negative health effects is unresolved. The objective of this research was to investigate associations between weight-loss history and current measures of immune function. Design The study design was a cross-sectional study. Subjects One hundred fourteen healthy, overweight, sedentary, postmenopausal women were recruited for an exercise intervention study and were currently weight stable. Methods History of intentional weight loss was assessed by questionnaire. Flow cytometry was used to measure natural killer cell (NK) cytotoxicity at four effector-to-target (E:T) ratios and for enumerating and phenotyping lymphocytes. Multiple linear regression analysis was used to investigate associations between weight loss within the past 20 years and current immune function. Results Women who reported ever intentionally losing ≥10 pounds had lower measured NK cytotoxicity than those who did not (24.7%±12.1% vs 31.1%±14.7%, respectively, at E:T 25:1; P=.01). Increasing frequency of previous intentional weight loss was associated with lower NK cytotoxicity ( P=.003, trend). As an independent predictor, longer duration of recent weight stability was associated with higher NK cytotoxicity (21.6%±11.9%, 24.4%±11.0%, and 31.9%±14.4% for ≤2, >2 to ≤5, and >5 years of weight stability, respectively; P=.0002, trend). The frequency of weight loss episodes was also associated with differences in the number and proportion of NK cells. Conclusions This study provides evidence that frequent intentional weight loss may have long-term effects on immune function.

Natural killer (NK) cell function is a strong prognostic factor in colorectal carcinoma patients treated with the monoclonal antibody 17-1A.

Tumor cells might be susceptible to different effector functions of the immune system. This cytotoxic capacity has been utilized to analyze the prognostic significance of peripheral blood mononuclear cells (PBMC) in patients with metastatic colorectal carcinoma (CRC) treated with the monoclonal antibody (MAb)17-1A. Such analysis might form the basis for future patient selection and may lead to improvements in therapeutic strategies. Between 1986 and 1998, 73 patients were treated with regimens containing MAb17-1A. Prior to therapy, the lytic capability of PBMC was assayed against: K562 (4 hr assay), the CRC cell line SW948 (4 hr and 18 hr assays) and antibody-dependent cellular cytotoxicity (ADCC, 18 hr assay). Since the study was performed over 13 years, the assays were checked for time-related bias. Reproducibility over time was satisfactory. Patients exhibited a significantly higher cytotoxic capability in all 4 assays compared to healthy control donors. No correlation to clinical outcome was noted for 18 hr ADCC and 18 hr spontaneous cytotoxicity. Pretreatment natural killer (NK) cell cytotoxicity (K562) was significantly related to overall survival (OS), progression-free survival (PFS), and response rate. OS for patients with high and low NK cell cytotoxicity was 71 vs. 30 weeks, respectively (p = 0.007). NK cell cytotoxicity (K562) was an independent prognostic factor for OS (p = 0.016). Pretreatment NK cell activity is a strong prognostic factor for patients with metastatic CRC receiving MAb17-1A therapy and is a predictor for OS, PFS and response. These results should be considered when designing antibody-based therapeutic protocols.

Cytokines and chronic fatigue syndrome.

Chronic fatigue syndrome (CFS) patients show evidence of immune activation, as demonstrated by increased numbers of activated T lymphocytes, including cytotoxic T cells, as well as elevated levels of circulating cytokines. Nevertheless, immune cell function of CFS patients is poor, with low natural killer cell cytotoxicity (NKCC), poor lymphocyte response to mitogens in culture, and frequent immunoglobulin deficiencies, most often IgG1 and IgG3. Immune dysfunction in CFS, with predominance of so-called T-helper type 2 and proinflammatory cytokines, can be episodic and associated with either cause or effect of the physiological and psychological function derangement and/or activation of latent viruses or other pathogens. The interplay of these factors can account for the perpetuation of disease with remission/exacerbation cycles. A T-helper type 2 predominance has been seen among Gulf War syndrome patients and this feature may also be present in other related disorders, such as multiple chemical sensitivity. Therapeutic intervention aimed at induction of a more favorable cytokine expression pattern and immune status appears promising.

Immunology of Chronic Fatigue Syndrome

SUMMARYA review of the literature on the immunology of CFS reveals that people who have Chronic Fatigue Syndrome (CFS) have two basic problems with immune function that have been documented by most research groups: 1. immune activation, as demonstrated by elevation of activated T lymphocytes, including cytotoxic T cells, as well as elevations of circulating cytokines; and 2. poor cellular function, with low natural killer cell cytotoxicity (NKCC), poor lymphocyte response to mitogens in culture, and frequent immunoglobulin deficiencies, most often IgGl and IgG3. These findings have a waxing and waning temporal pattern which is consistent with episodic immune dysfunction (with predominance of so called T-helper type 2 and proinflammatory cytokines and low NKCC and lymphoproliferation) that can be associated as cause or effect of the physiological and psychological function derangement and/or activation of latent viruses or other pathogens. The interplay of these factors can account for the perpetuation of ...

Stressful events, pessimism, natural killer cell cytotoxicity, and cytotoxic/suppressor T cells in HIV+ black women at risk for cervical cancer.

This study examines whether stressful negative life events and pessimism were associated with lower natural killer cell cytotoxicity (NKCC) and T cytotoxic/suppressor cell (CD8+CD3+) percentage in black women co-infected with human immunodeficiency virus Type 1 (HIV-1) and human papillomavirus (HPV), a viral initiator of cervical cancer. Psychosocial interviews, immunological evaluations, and cervical swabs for HPV detection and subtyping were conducted on 36 HIV+ African-American, Haitian, and Caribbean women. Greater pessimism was related to lower NKCC and cytotoxic/suppressor cells after controlling for presence/absence of HPV Types 16 or 18, behavioral/lifestyle factors, and subjective impact of negative life events. A pessimistic attitude may be associated with immune decrements, and possibly poorer control over HPV infection and increased risk for future promotion of cervical dysplasia to invasive cervical cancer in HIV+ minority women co-infected with HPV.

Dietary Nucleotides: Cellular Immune, Intestinal and Hepatic System Effects

AbstractInvestigations with animals demonstrate that dietary nucleotides influence immune function. Restriction of dietary nucleotides in mice decreases several indices of cell-mediated immunity as well as resistance to challenge with Staphylococcus aureus or Candida albicans. Spleen cells of mice maintained on nucleotide-free diet produce less interleukin-2 and have lower natural killer cell cytotoxicity and macrophage activation than those of animals fed nucleotide-supplemented diets. In vivo lymphoproliferative response, macrophage phagocytic activity and expression of interleukin-2 receptor and lyt1 surface marker are also lower in animals fed nucleotide-free diets. At 2 mo of age, infants fed breast milk or nucleotide-supplemented infant formula exhibit increased natural killer cell activity compared with infants fed unsupplemented formula. Dietary nucleotide restriction in animals may also result in hepatic lipid accumulation and decreased mucosal height and gut wall thickness. Adenosine monophosphate, a mediator of hepatic and small bowel blood flow, may play a unique role among the nucleotides studied. In conclusion, de novo synthesis and salvage of nucleotides is a metabolically costly process. An exogenous source of nucleotides from the diet may optimize the function of rapidly dividing tissues, particularly when growth is rapid and the diet is low in nucleotides.

Natural Killer Cell cytotoxicity and Alpha-interferon in Early Rheumatoid Arthritis

Natural killer (NK) cell number, cytotoxicity, and serum alpha-interferon (alpha-IFN) was measured in a group of early synovitis patients and compared to that of established rheumatoid arthritis patients and normal controls. No significant differences in NK cell number or serum alpha-IFN were found. NK cell cytotoxicity (NKCC) in the early synovitis group was significantly (p < 0.05) reduced compared to that of the normal controls and not significantly different from the established rheumatoid controls. There was a trend for those early synovitis patients with a good outcome to have higher NKCC. Low NKCC is evident very early in the course of rheumatoid arthritis and is thus unlikely to be secondary to chronic inflammation. There is no relationship between NKCC and alpha-IFN levels and the cause of the reduced NKCC is unknown. Alpha-IFN levels are not raised early in the course of RA.

Chronic Fatigue Syndrome

To the Editor.— We read with interest the article by Gold et al. 1 We have recently reported the psychosocial attributes 2 and the clinical and immunologic characteristics 3 of a sample of 30 subjects. We noted frequent personality and cognitive abnormalities in the cohort, such as moderate to severe depression (as measured by the Hamilton Depression Rating Scale) seen in 79% of the subjects and frequent pathological personality disorders as defined by the Millon Clinical Multiaxial Inventory II. These subjects showed clear evidence of immunologic deficiency, the most notable being low natural killer-cell cytotoxicity (73%), low phytohemagglutinin and pokeweed mitogen response (63%), normal CD4 numbers but abnormal distribution of CD4 subsets, elevated CD8 and I 2 + CD8 + cells and low production of interferon-γ by mitogen-stimulated lymphocytes. Perhaps the explanation for the difference in our report and that by Gold et al lies in patient selection. All of the subjects

Natural killer cells and metastases from pharyngeal carcinoma

Natural killer cell activity was assessed in 100 previously untreated pharyngeal carcinoma patients. Diminished natural killer cell function in these patients was associated with an increased risk of death from uncontrolled regional and distant metastases. During the assessment, the cell line MDA686-Ln was established from a metastatic pharyngeal carcinoma of a patient with low natural killer cell cytotoxicity. The initially cytotoxicity-resistant cell line could be lysed when natural killer cell cytotoxicity was enhanced in vitro either through enrichment of a Leu 19+ natural killer cell population by fluorescent-activated cell sorting or by interleukin-2 activation. Additionally, increased circulating immune complexes were identified in these patients, subsequently isolated, and found to block natural killer cell reactivity against MDA686-Ln. In light of this negative interaction, 38 patients were randomly evaluated for both circulating immune complex levels and natural killer cell function. Both parameters examined together were complementary in defining the risk of death with disease; four of five deaths occurred in patients with both high circulating immune complex levels and low natural killer cell function. Results support the biologic modification of natural killer cell activity for controlling metastatic pharyngeal carcinoma and point to the potential confounding influence of circulating immune complex.

Natural killer cells in children with malignant solid tumors. Effect of recombinant interferon-alpha and interleukin-2 on natural killer cell function against tumor cell lines.

Natural killer (NK) cells and NK cell activity were determined in three groups (newly diagnosed [n = 21], on therapy [n = 21], and off therapy [n = 18]) of children with various types of malignant solid tumors and in a control group (n = 26) by means of Leu-7 and Leu-11b monoclonal antibodies and a 4-hour 51Cr-release assay, respectively. The erythroleukemia cell line K562 was used as a target cell. The newly diagnosed group included eight patients with localized disease (Stage I-II), ten with bulky but nonmetastatic disease (Stage III), and three with metastases (Stage IV). The mean percent of NK cell activity in the newly diagnosed group was significantly higher than that of the control group. Children with Stage III tumors at diagnosis had higher mean NK cell function than those with Stage I-II and Stage IV. On therapy patients had significantly fewer NK cells and lower NK cell cytotoxicity than those in the other groups studied. We also studied the following: (1) the in vitro effect of recombinant interferon-alpha (rIFN-alpha) and recombinant interleukin-2 (rIL-2) on NK cell function of peripheral blood lymphocytes (PBL) from children with solid malignancies; and (2) the susceptibility of neuroblastoma-derived (CHP-126 and SKNSH) and rhabdomyosarcoma-derived (A-204) cell lines to NK cell lysis. Both rIFN-alpha and rIL-2 enhanced NK cell activity of PBL from children with malignancies and healthy children against K562 and solid tumor cell lines. The enhancing effect or rIL-2 was greater than that of rIFN-alpha. CHP-126 and SKNSH cell lines were susceptible to NK cell lysis mediated by the PBL of children with neuroblastoma and the control group. The A-204 cell line was less sensitive than K562 to NK cell cytotoxicity. Our results suggest a potential therapeutic role for both cytokines in the treatment of malignant solid tumors of childhood.