Immunoregulation of human natural killer cells (NK) by corticosteroids: inhibitory effect of culture supernatants

Effect of cortisol and ACTH on corticosteroid-suppressed peripheral blood natural killer cells from healthy volunteers and patients with Crohn's disease

Recently, we have shown that administration of adrenocorticotropic hormone (ACTH) to corticosteroid-treated Crohn's disease (CD) patients increased the peripheral blood natural killer (NK) cell activity which was suppressed by the corticosteroids. To elucidate this observation we analysed the in vitro effect of budesonide, prednisolone, cortisol, and ACTH on NK cells of healthy volunteers and corticosteroid-treated CD patients. Incubation of peripheral blood mononuclear cells (PBMNC) from healthy volunteers during the cytotoxicity assay caused a dose-dependent inhibition of NK cell activity by the three corticosteroids, while ACTH had hardly any effect. Pre-incubation for 18 h with high and low inhibiting concentrations also showed a significant inhibiting effect on NK cell activity of the corticosteroids. The percentage of CD56+ NK cells tended to increase after pre-incubation with a high inhibiting concentration of budesonide, prednisolone, and cortisol. Incubation of budesonide- or prednisolone-suppressed PBMNC from healthy volunteers and CD patients, with ACTH and/or cortisol, to mimic the in vivo situation, did not restore the corticosteroid-induced suppression of NK cell activity. The increase of the budesonide- or prednisolone-suppressed NK cell activity after in vivo administration of ACTH to the CD patients is therefore probably not a direct effect of cortisol or ACTH. Presumably other factors like cytokines and/or neurohormones must be involved in the in vivo interaction between corticosteroids, ACTH, and NK cells.

Awake epidural anesthesia is associated with improved natural killer cell cytotoxicity and a reduced stress response

BACKGROUND

Laparotomy under general anesthesia is associated with depressed natural killer cell cytotoxicity (NKCC) and compromised clearance of tumor cells. We tested the hypothesis that awake epidural anesthesia (AEA) improves NKCC compared to conventional general endotracheal anesthesia (GEA).

PATIENTS AND METHODS

Preoperative, perioperative, and postoperative (day 3) NKCC, plasma epinephrine, norepinephrine, cortisol levels, and 24-hour urinary cortisol levels were measured in 20 patients undergoing open colectomy under either AEA or GEA.

RESULTS

Preoperative and postoperative measurements were not significantly different in the two groups. Patients receiving GEA had a significant reduction in NKCC from 36% +/- 4% preoperatively to 22% +/- 4% perioperatively (P = 0.02). Patients receiving AEA had no significant change in NKCC. Perioperative plasma epinephrine and cortisol levels were higher with GEA than AEA. The perioperative 24-hour urinary cortisol excretion values were significantly higher in the group receiving GEA, suggesting a greater stress hormone response in this group compared to AEA patients.

CONCLUSIONS

Compared to GEA, AEA appears to preserve perioperative NKCC. This effect may be related to an attenuated stress hormone response associated with AEA. Cancer patients may have improved killing of embolized tumor cells during surgery performed under AEA.

Budesonide and prednisolone suppress peripheral blood natural killer cells in Crohn's disease

AIM

To study the effect of oral budesonide and prednisolone on peripheral blood natural killer (NK) cell activity in patients with active ileocaecal Crohn's disease (Crohn's disease activity index, CDAI > or = 200).

METHODS

One group of patients was treated for 10 weeks with oral budesonide (n = 9; 9 mg/day), and another group of patients for the same period with prednisolone (n = 9; 40 mg/day). Budesonide was tapered to 6 mg/day after 8 weeks and prednisolone after 2 weeks to 5 mg/day in the last week. Before treatment, and at 2, 4 and 10 weeks of treatment, natural killer cell activity was determined with a 51Cr release assay, and the number of CD16+ NK cells by Fluorescence activated cell sorter (FACS) analysis.

RESULTS

Budesonide, as well as prednisolone treatment, significantly decreased natural killer cell activity at weeks 2 and 4. This decrease was found to be accompanied by a similar decrease in the number of CD16+ NK cells. At 10 weeks, natural killer cell activity had almost returned to pre-treatment levels in the budesonide group and was significantly higher than pre-treatment levels in the prednisolone group. Disease activity was significantly decreased in all patients at week 2 until the end of the trial period.

CONCLUSION

Both budesonide and prednisolone treatment suppress peripheral blood natural killer cell activity of patients with active ileocaecal Crohn's disease by decreasing the numbers of CD16+ NK cells in the circulation.

Contribution of plasma cortisol to corticosteroid-suppressed peripheral blood natural killer cell activity in Crohn's disease

We recently showed that patients with active ileocecal Crohn's disease (CD) have a temporarily suppressed peripheral blood natural killer (NK) cell activity during treatment with oral budesonide or prednisolone. This suppression was caused by a decrease in the number of CD16+ NK cells in the circulation. In the present study we evaluated the contribution of cortisol in plasma to this suppressed NK cell activity. The CD patients took part in a controlled study where they received either oral budesonide or prednisolone for 10 weeks. Before treatment, and at 4 and 10 weeks of treatment, peripheral blood NK cell activity, numbers of circulating CD16+ NK cells, and plasma cortisol levels were analysed. These parameters were determined both before and 30 min after administration of adrenocorticotropic hormone (ACTH). The ACTH-induced plasma cortisol increase was accompanied by a stimulated NK cell activity, when both are suppressed by corticosteroid treatment, without changing the number of CD16+ NK cells. Therefore, a low plasma cortisol level contributes to the corticosteroid mediated NK cell suppression in active ileocecal CD.

Selective inhibition by alcohol and cortisol of natural killer cell activity of lymphocytes from cord blood

1. The immunosuppressive effects of drugs such as alcohol or hormones such as cortisol may be age-related. To test this hypothesis, the authors investigated the in vitro effects of ethanol (EtOH) and cortisol on Natural Killer (NK) cell activity of lymphocytes from normal cord blood in comparison with that of lymphocytes from normal adult peripheral blood. 2. K562, an erythroleukemia cell line, was used as a target in a 4 hr 51Cr release assay. 3. Ethanol at 0.3% (V/V) and cortisol at 0.05, 0.1 and 0.2 microgram/ml concentrations, added directly to a mixture of effector and target cells significantly suppressed the NK activity of cord blood lymphocytes in a dose dependent fashion, whereas similar concentrations of either EtOH or cortisol did not manifest significant immunoregulatory effects on NK cell activity of normal adult lymphocytes. 4. Pre-treatment of the target with either EtOH or cortisol for 4 hours did not affect cytotoxicity. Inhibition of cytotoxicity was also not due to direct toxicity of effector cells because lymphocytes treated with either EtOH or cortisol showed normal 51Cr release and their viability was comparable to that of untreated control cells. 5. This suggests a selective inhibitory effect of EtOH and cortisol on NK activity of neonatal lymphocytes that may be of clinical significance.

Perioperative immunomodulation in cancer surgery

Despite undergoing a curative resection, many patients with colorectal cancer will develop and die of metastatic disease. It has been shown clinically and experimentally that surgery causes a transient period of immunosuppression, and it is postulated that this may encourage both the implantation of surgically disseminated tumor cells and the growth of existing micrometastases. The present study used natural killer cell cytotoxicity (NKCC) and tumor burden to evaluate perioperative modulation of immunocompetence in a murine model. We measured NKCC and tumor burden responses to a standardized surgical stress (SSS) alone, and to either morphine sulfate (MS) (15 mg/kg subcutaneously x 4 doses), ketorolac (a prostaglandin synthetase--prostaglandin E2--inhibitor) (2.5 mg/kg subcutaneously x 4 doses), or interleukin 2 (2,000 units intraperitoneally x 3 doses) administration with the SSS. In this model, we found that both low-dose interleukin-2 (IL-2) and ketorolac reversed the NKCC suppression associated with surgery, whereas morphine resulted in further depression of NKCC. In addition, IL-2 significantly decreased tumor incidence, whereas continuous MS exposure markedly increased tumor burden after surgery. These data suggest that IL-2 and ketorolac may be effective agents for the restoration of perioperative immune competence, whereas the use of continuous morphine might have significant deleterious effects.

Glucocorticoid effects on natural and humoral immunity in mallards

Two studies were conducted to determine the effects of dexamethasone (DEX) on immune function in mallard ducks. Each day ducks were injected intramuscularly with DEX at doses ranging from 0.2-4.0 mg/kg for 28-30 days. Physiologic effects consistent with high dose glucocorticoid (GC) treatment were observed at the 4 mg/kg dose, and included significant body weight loss, lowered hematocrit, and elevated alanine aminotransferase (ALT) activity. At all doses, effects of DEX on the immune system were observed. When DEX was given at 0.2 mg/kg/day, significant suppression of primary IgG antibody titers to sheep erythrocytes (SRBC) was observed. At 1 mg/kg/day, primary IgM and secondary IgM and IgG titers were suppressed as well. These doses of DEX also produced significant elevation in natural killer cell (NKC) activity of peripheral blood mononuclear cells (PBMNC). Removal of adherent cells from the PBMNC prior to NKC assay eliminated the enhancement in NKC activity. Based on these results, it was postulated that the elevation in NKC activity may be due to suppression by DEX of monocyte production of prostaglandin-E2 (PGE-2) resulting in the release of NKC activity from the inhibitory effects of PGE-2. This hypothesis was supported by a measured decrease in PGE-2 production during the NKC assay by cells from DEX-treated birds. Furthermore, an enhanced NKC activity could be reproduced in vitro with the addition of indomethacin or DEX to NKC cultures containing adherent cells from PBMNC. Direct effects of DEX on nonadherent cell NKC activity and lymphocyte viability were only observed at high concentrations (10(-4) M) of DEX, while the phagocytic activity of adhered blood monocytes was inhibited at 10(-6) M DEX. The suppressed phagocytic activity may contribute to the suppressed antibody responses observed in DEX-treated birds. Together, these results support an indirect immunomodulatory effect of DEX on NKC activity and perhaps antibody responses in vivo via altered monocyte function in mallard ducks.

Persistently high antibody titers and deficient specific cellular immunity to varicella-zoster virus in a retarded patient after varicella infection

We report on a 19 month old female who has been retarded developmentally after a severe varicella infection contracted from her mother 4 months after delivery. Her titer of varicella-zoster virus (VZV) IgG antibody has been remarkably high for 4 years after the infection. Natural killer activity and the specific cellular immunity to VZV, as tested by delayed type hypersensitivity skin test and lymphocyte-proliferation assay, were impaired. She had an improvement of ataxia and then progressed developmentally after administration of an anti-viral agent. Administration of oral corticosteroids and methylprednisolone transiently decreased titers of VZV antibody and, contrary to previous reports, returned natural killer activity to normal levels. We suggest that this case may be a persistent VZV infection similar to congenital cytomegalovirus infection due to selective defects in cellular immunity including NK cells. Whether this specific deficient cellular immunity is genetically determined or secondary to the viral infection is speculative. This is the first known report of such a case.

NK cell activity in treated prostate cancer patients as a probe for circulating tumor cells: hormone regulatory effects in vivo

Natural killer (NK) cell activity was studied together with tumor marker serotests (PSA, PAP) and blood testosterone, estradiol, cortisol, and prolactin concentrations in treated prostate cancer patients. NK cell activity data were correlated with tumor stage (stage D0 + D1 versus stage D2) and showed statistically insignificant differences. Both tumor progression and stabilization of metastatic disease, triggered by the application of more appropriate therapy in progressive subjects, yielded low NK activity data. By contrast, normal NK activity was found during both partial remission of stage D2 tumor and stabilization of the same disease, after an initial period of tumor remission. Differences between NK activity data from the aforementioned two groups are statistically significant (P less than 0.01). In subjects examined, the application of NK activity assay to those with advanced disease reflected changes in the outcome of the treatment more closely than it did routine tumor marker assessment. The activity of NK cells seems unaffected by changes in basal blood estradiol, cortisol, testosterone, and prolactin concentrations that occur during therapy with pharmacological agents (estradiol, cyproterone acetate, diethylstilbestrol, and flutamide) and during surgical castration. The reported NK activity recordings in treated prostate cancer patients might be indicative of the presence of tumor cells in the circulation. If this holds true, the measurement of NK activity would appear to furnish urological oncology with a new tool for early, rapid recognition of progressive metastatic tumors.

Neurochemical, endocrine and immunological responses to stress in young and old Fischer 344 male rats

Two experiments were performed. In the first, a 20 min conditioned emotional response (CER) paradigm was used to compare the neurochemical, endocrine and immunological responses to stress of 7- and 22-month-old Fischer 344 (F344) male rats. In the second, corticosterone levels 20 min following ether stress, and regional brain type I and II corticosterone receptor densities were examined using 7- and 17.5-month-old F344 male rats. Dopamine (DA) metabolism in old nonstressed rats was significantly reduced in the medial frontal cortex, neostriatum, nucleus accumbens and hypothalamus, but not in the amygdala. The CER procedure, nevertheless, increased medial frontal cortical, nucleus accumbens and amygdaloid DA turnover in both the young and old rats. The young and old nonstressed rats did not evidence differences in norepinephrine (NE) and serotonin (5-HT) concentrations. However, stress resulted in a decrease in medial frontal cortical 5-hydroxyindoleacetic acid (5-HIAA) and hypothalamic 5-HT levels in old but not in young animals. These observations suggest age-related differences in the response of central NE and 5-HT systems to stress. Ether and the CER procedure led to exaggerated corticosterone responses in the old rats (17.5 and 22 month, respectively). Hippocampal type I but not type II corticosterone receptors were decreased by 47% in the 17.5-month-old rats. Thus, age-related changes in hippocampal corticosterone receptor types do not occur in unison, and the exacerbated corticosterone response to stress precedes the reported down-regulation of hippocampal type II corticosterone receptors in aged rats. Age-related changes were not observed in the concentrations of corticosterone receptors in other brain regions, or in the prolactin response to stress. The old rats, however, evidenced a reduction in the availability of the renin substrate, angiotensinogen, and in stress-induced renin secretion. Immune function was impaired in the old nonstressed rats, and further compromised by exposure to the CER procedure. In comparison to the young control rats, the old nonstressed rats showed an increased percentage of splenic large granular lymphocytes, reduced splenic natural killer cytotoxicity, and impaired Con-A-stimulated splenic T lymphocyte proliferation. Reductions in T splenic cell proliferation and natural killer cytotoxicity were observed in the young rats subjected to the CER paradigm, but not to the same extent as in the old rats. These observations indicate that aging male F344 rats evidence major alterations in basal central monoamine, endocrine and immune functions, and an increased sensitivity of these systems to stress.