Antibodies against enteroviruses in intravenous Ig preparations: great variation in titres and poor correlation with the incidence of circulating serotypes.

Antibody titres in immunoglobulin preparations for intravenous use were tested against 24 different enterovirus serotypes and varied between 1:100 and 1:10,000 within a single batch. Differences up to 8-fold were found for homologous titres between two different batches that were prepared 6 years apart. The lowest titre obtained was 1:40. The observed differences within and between the two batches could not be explained by different incidence of serotypes of enteroviruses circulating at the time blood was collected. Differences in titres of up to 18-fold were observed when several strains of the same serotype were tested suggesting that intratypic variation influences antibody titres. It is concluded that immunoglobulin preparations contain antibodies against many enteroviruses, but that titres can be low and cannot be predicted from the incidence of any particular serotype circulating in the community. Because of intratypic variation, selection of a batch for specific treatment should be based on results obtained with the patient's own isolate, and not with a reference strain.

Cutaneous infection due to Mycobacterium abscessus. A case report.

Erythematous nodular and ulcerating skin lesions occurred in a 56-year-old woman treated with chemotherapy and glucocorticosteroids for metastatic breast cancer. Subsequent culture yielded Mycobacterium abscessus, a facultative pathogen which exists as a saprophyte in the environment and rarely produces clinical disease in humans. This organism is usually relatively resistant to antituberculous as well as a number of other antimicrobial agents. On the basis of in vitro susceptibility results, treatment with clarithromycin and clofazimine was installed and resolution of the lesions initiated. This report emphasizes once again that one should investigate any new or unusual skin lesions in immunocompromised patients by histology and culture of biopsies, including cultures for acidfast organisms.

Inflammatory cytokines in an experimental model for the multiple organ dysfunction syndrome.

OBJECTIVE: To investigate the alterations in circulating pro-inflammatory cytokines and cytokine production by peritoneal macrophages during the development of multiple organ dysfunction syndrome. DESIGN: Prospective, controlled laboratory study on zymosan-induced generalized inflammation in mice. Single intraperitoneal administration of zymosan induces, over a 12-day period, a triphasic illness in mice; the third phase, from day 6 onward, resembles multiple organ dysfunction syndrome. SETTING: Animal research laboratory. SUBJECTS: C57BL/6CRW mice received a single intraperitoneal dose of zymosan on day 0, and standard numbers of animals were killed at different time points up until day 12. MEASUREMENTS AND MAIN RESULTS: Plasma concentrations of interleukin (IL)-1 alpha and IL-1 beta, IL-6, and tumor necrosis factor (TNF)-alpha were measured from 3 hrs to 12 days after administration of zymosan. At the same time points, both lipopolysaccharide-stimulated and unstimulated production of these cytokines by peritoneal macrophages were measured in vitro. Plasma TNF and IL-6 concentrations transiently increased during the first 24 hrs after administration of zymosan. After 8 days, a prominent peak of biologically inactive TNF was observed. Both unstimulated and lipopolysaccharide-stimulated cytokine production by peritoneal cells showed profound changes during the experimental period. CONCLUSIONS: These findings seem to confirm our hypothesis that the macrophages are in a continuously activated state and altered in their function, when the animals develop multiple organ dysfunction syndrome. Further studies are needed to elucidate what happens with these cytokines at the tissue level, to better understand the pathophysiology of multiple organ dysfunction syndrome.

Interleukin-1 (IL-1)-induced resistance to bacterial infection: role of the type I IL-1 receptor.

Pretreatment with a low dose of recombinant human interleukin-1 beta (IL-1) (3 to 30 micrograms/kg) 24 h before a lethal Pseudomonas aeruginosa infection prolongs survival in neutropenic mice. We investigated the role of the type I IL-1 receptor (IL-1RI) and IL-1RII in this IL-1-induced protection by using a specific IL-1 receptor antagonist (IL-1-Ra), which blocks effects mainly via IL-1RI. Pretreatment with IL-1Ra before IL-1 partially blocked the IL-1-induced enhanced survival, whereas pretreatment with a specific neutralizing monoclonal antibody to IL-1RI (35F5) eliminated the IL-1 induced protection. The nonapeptide fragment 163-171 of recombinant human IL-1 beta, which possesses the immunoadjuvant but not the inflammatory effect of the entire molecule via a non-receptor-mediated signal transduction process, did not reproduce the IL-1-induced protection. IL-1-induced protection was associated with reduced serum aspartate aminotransferase and alanine aminotransferase concentrations in conjunction with ameliorated histopathology of the liver. These findings may be due to reduced cytokine production and cytokine sensitivity of target cells after infection. We conclude that the IL-1-induced nonspecific resistance to infection is mediated by cells bearing IL-1RI and is associated with a reduction of liver damage.

Pharmacologic inhibitors of tumor necrosis factor production exert differential effects in lethal endotoxemia and in infection with live microorganisms in mice.

Tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta) are principal mediators of septic shock; inhibition of TNF-alpha production may ameliorate outcome in severe infections. Pentoxifylline, chlorpromazine, and thalidomide inhibit TNF-alpha production. Their effects were tested in lethal endotoxemia in sensitized mice. Only chlorpromazine significantly improved survival. Chlorpromazine and pentoxifylline significantly reduced postendotoxin circulating TNF-alpha, by 89% and 76%, respectively. Chlorpromazine also significantly reduced IL-1 beta and soluble TNF receptor-P75. No drug improved survival in Klebsiella pneumoniae-infected mice despite significantly lower circulating TNF-alpha concentrations in chlorpromazine- or pentoxifylline-treated animals. The three compounds decreased circulating TNF-alpha in Candida albicans-infected mice, but survival was not influenced. In neutropenic mice, chlorpromazine had no influence on candida in organs, but in normal mice, Candida counts in kidneys were higher in chlorpromazine-treated mice. Thus, inhibition of TNF-alpha production was of no benefit in K. pneumoniae infection and worsened outcome in C. albicans infection.

Differential gene expression for IL-1 receptor antagonist, IL-1, and TNF receptors and IL-1 and TNF synthesis may explain IL-1-induced resistance to infection.

IL-1 pretreatment prolongs survival in lethal infection in normal and in neutropenic mice. We investigated whether this protection occurs by interference with deleterious cytokine effects. The effect of IL-1 pretreatment on concentrations of IL-1 alpha, IL-1 beta, IL-6, and TNF-alpha circulating in vivo and the ex vivo cytokine production capacity of macrophages was assessed in uninfected, non-neutropenic and neutropenic Swiss mice, in Swiss mice infected with Klebsiella pneumoniae (non-neutropenic mice) or Pseudomonas aeruginosa (neutropenic mice), and in neutropenic C3H/HeN and C3H/HeJ mice infected with P. aeruginosa. In Swiss and C3H/HeN mice, IL-1 pretreatment enhanced survival and reduced circulating TNF-alpha and IL-6 as well as LPS-stimulated production of IL-1 alpha and TNF-alpha. In C3H/HeJ mice, a lack of IL-1-induced protection was associated with low cytokine concentrations and production. In contrast, up-regulation of mRNA for the IL-1 receptor antagonist (IL-1Ra) was observed in several organs of IL-1-pretreated mice, suggesting that IL-1Ra could attenuate deleterious IL-1 effects. In addition, IL-1 pretreatment down-regulated steady state mRNA for the type I IL-1R and the type I TNFR in several organs at the time of infection, suggesting desensitization of target cells as an additional mechanism of IL-1-induced protection. We conclude that the IL-1-induced protection is at least partially mediated by down-regulating cytokine production, and that the induction of IL-1Ra and the desensitization of target cells by receptor down-modulation may also contribute to this phenomenon.

Roles of tumor necrosis factor alpha, granulocyte-macrophage colony-stimulating factor, platelet-activating factor, and arachidonic acid metabolites in interleukin-1-induced resistance to infection in neutropenic mice.

Treatment with a single low dose (80 to 800 ng) of interleukin-1 (IL-1) 24 h before a lethal bacterial challenge in granulocytopenic and in normal mice enhances nonspecific resistance. The mechanism behind this protection has only partially been elucidated. Since IL-1 induces production of tumor necrosis factor alpha (TNF-alpha), granulocyte-macrophage colony-stimulating factor (GM-CSF), platelet-activating factor (PAF), and arachidonic acid metabolites, we investigated the potential role of these substances in IL-1-induced protection. Low doses of murine TNF-alpha but not of human TNF-alpha enhanced survival, suggesting an effect via the type II TNF receptor rather than the type I TNF receptor, which has little species specificity. In line with this TNF-alpha-induced protection from infection, pretreatment with a low dose of a rat anti-murine TNF-alpha monoclonal antibody tended to inhibit IL-1-induced protection, suggesting a role of TNF-alpha as a mediator of IL-1-induced enhanced resistance to infection. Pretreatment with higher doses of anti-TNF-alpha, however, showed a dose-related protective effect per se, which could be further enhanced by a suboptimal dose of IL-1. A combination of optimal doses of anti-TNF-alpha and IL-1 produced an increase in survival similar to that produced by separate pretreatments. This lack of further enhancement of survival by combined optimal pretreatments suggests a similar mechanism of protection, most likely attenuation of deleterious effects of overproduced proinflammatory cytokines like TNF-alpha during lethal infection. Pretreatment with different doses of GM-CSF before a lethal Pseudomonas aeruginosa challenge in neutropenic mice did not enhance survival. Different doses of WEB 2170, a selective PAF receptor antagonist, of MK-886, a selective inhibitor of leukotriene biosynthesis, or of several cyclooxygenase inhibitors did not reduce the protective effect of IL-1 pretreatment. We conclude that IL-1-induced nonspecific resistance is partially mediated by induction of TNF-alpha and not by GM-CSF, PAF, and arachidonic acid metabolites. The mechanism of action of IL-1 seems to be similar to that of anti-TNF-alpha.

Interleukin-1 and related pro-inflammatory cytokines in the treatment of bacterial infections in neutropenic and non-neutropenic animals.

Bacterial infections in the immunocompromized host cause considerable mortality, and even the recently developed antimicrobial strategies often fail to cure these infections, especially in granulocytopenic patients. Cytokines and hematopoietic growth factors have been shown to stimulate host defense mechanisms in vitro and in vivo. We discuss the possible role of the pro-inflammatory cytokines interleukin-1, tumor necrosis factor-alpha, interleukin-6 and interleukin-8 as modulators of host resistance to bacterial infections. Interleukin-1 has been shown effective in various animal models of potentially lethal bacterial infection, even during severe granulocytopenia. The protective mechanism of interleukin-1 may be mediated via downregulation of cytokine receptors and cytokine production, and via induction of acute phase proteins. Moreover, in subacute and chronic infections interleukin-1 interferes with microbial outgrowth, via mechanisms that have only been partially elucidated.

Role of acute-phase proteins in interleukin-1-induced nonspecific resistance to bacterial infections in mice.

Treatment with a single low dose (80 to 800 ng) of interleukin-1 (IL-1) 24 h before a lethal bacterial challenge of granulocytopenic and normal mice enhances nonspecific resistance. Since IL-1 induces secretion of acute-phase proteins, liver proteins which possess several detoxifying effects, we investigated the role of these proteins in the IL-1-induced protection. Inhibition of liver protein synthesis with D-galactosamine (GALN) completely inhibited the IL-1-induced synthesis of acute-phase proteins. GALN pretreatment abolished the protective effect of IL-1 on survival completely (neutropenic mice infected with Pseudomonas aeruginosa) or partially (nonneutropenic mice infected with Klebsiella pneumoniae). Pretreatment with IL-6, a cytokine induced by IL-1, did not reproduce the protection offered after IL-1 pretreatment, nor did it enhance or deteriorate the IL-1-enhanced resistance to infection. A protective effect of IL-1 via effects on glucose homeostasis during the acute-phase response was investigated by comparing plasma glucose levels in IL-1-treated mice and control mice before and during infection. Although glucose levels in IL-1-pretreated mice were somewhat higher in the later stages of infection, no significant differences from levels in control mice were present, and the glucose levels in control-treated animals never fell to hypoglycemic values. We conclude that the IL-1-induced nonspecific resistance is mediated neither by the induction of IL-6 nor by the effects of IL-1 on glucose homeostasis. Acute-phase proteins generated after IL-1 pretreatment, however, seem to play a critical role in the IL-1-induced protection to infection.

Effects of interleukin-8 on nonspecific resistance to infection in neutropenic and normal mice.

The effect of treatment with interleukin-8 (IL-8), a neutrophil-activating cytokine, was investigated in normal and neutropenic mice infected with a lethal dose of Pseudomonas aeruginosa, Klebsiella pneumoniae, or Plasmodium berghei. Intraperitoneal (i.p.) IL-8 treatment was associated with accelerated death when IL-8 was administered shortly before i.p. infection with P. aeruginosa or shortly after i.p. infection with P. aeruginosa and K. pneumoniae. Histopathological analyses demonstrated a tendency to more severe organ lesions in IL-8-treated mice. Only nonneutropenic mice that received IL-8 shortly before the infectious challenge and at the site of infection were protected by IL-8. Whether IL-8 is protective of or detrimental to the survival of infection appeared to depend on the presence of bacteria at the injection site and on the presence of neutropenia. IL-8 may be an important participant in the cascade of interacting cytokines that is induced by the lethal infectious challenge.

Interleukin-1-induced nonspecific resistance to bacterial infection in mice is not mediated by glucocorticosteroids.

Preexposure to a low dose of interleukin-1 (IL-1; 3 to 30 micrograms/kg) 24 h before a lethal gram-negative bacterial infection prolonged survival in normal and granulocytopenic mice. To examine whether this protective effect is mediated by glucocorticosteroids, we first measured corticosterone concentrations in mice after administration of 80 and 800 ng of IL-1. IL-1 induced a dose-dependent increase in corticosterone levels in plasma. Next, the corticosterone peak induced by a protective dose of IL-1 (800 ng) was simulated by administration of synthetic human adrenocorticotropic hormone 1-24 (ACTH) in normal and neutropenic mice. Although corticosterone levels induced by pretreatment with IL-1 or ACTH were virtually identical, the ACTH-induced corticosterone peak was not associated with protection against Klebsiella pneumoniae infection in normal mice and Pseudomonas aeruginosa infection in neutropenic mice. This indicates that the protective effect of IL-1 pretreatment against gram-negative bacterial infection is not mediated by elevated levels of glucocorticosteroids. In addition, we found that plasma corticosterone concentrations during K. pneumoniae infection were significantly lower after pretreatment with IL-1 than after pretreatment with ACTH or vehicle, probably reflecting the better physical condition of IL-1-treated mice.

Dietary fish-oil supplementation in experimental gram-negative infection and in cerebral malaria in mice.

Dietary fish-oil supplementation interferes with eicosanoid production and appears to decrease production of interleukin-1 (IL-1) and tumor necrosis factor (TNF). The effect of fish oil was investigated in an intramuscular Klebsiella pneumoniae infection in Swiss mice and in cerebral malaria induced by Plasmodium berghei in C57B1/6 mice. After a low inoculum of K. pneumoniae, 90% of fish oil-fed mice survived; survival in control mice fed equal amounts of corn or palm oil or normal chow was 30%, 40%, and 0, respectively. Cerebral malaria occurred in only 23% of fish oil-fed mice; in the controls, cerebral malaria developed in 61%, 81%, and 78%, respectively. Contrary to what was expected, lipopolysaccharide-induced ex vivo production of IL-1 alpha and TNF alpha by peritoneal cells was significantly enhanced in fish oil-fed mice compared with controls. Indomethacin treatment did not alter the outcome in these two infections, thus arguing against reduced prostaglandin synthesis as an explanation for the increase in resistance to infection.

Protodyne: an immunostimulatory protein component, prepared from gram-positive Bacillus subtilis.

A protein component derived from bacterial protoplasm, called Protodyne, increases the non-specific resistance to infections by bacteria and viruses. Here we show that Protodyne can be prepared not only from Gram-negative bacteria, but also from Gram-positive bacilli. Several preparations of Protodyne, prepared from Bacillus subtilis by phenol extraction or by ammonium sulfate precipitation, were evaluated for immunomodulatory activities in a variety of assays. Protodyne had a marked mitogenic activity on mouse spleen cells; it was a potent inducer of tumor necrosis factor (TNF) and stimulated production of interleukin-1 (IL-1) in human peripheral blood mononuclear cells; it increased the capacity of activated macrophages to undergo a respiratory burst, to produce intracellular killing of leishmanial parasite and extracellular lysis of mastocytoma cells; it also stimulated phagocytosis of latex particles, and prolonged survival of immunosuppressed mice infected with Pseudomonas aeruginosa. These activities were not inhibited by polymyxin B, indicating that the activity of Protodyne is not the result of contamination with exogenous lipopolysaccharide. It appears that Protodyne exerts its many immunomodulatory actions by inducing the release of soluble mediators, including TNF and IL-1.