Suppression of the immune system by oral glucocorticoid therapy in bronchial asthma

The association between three prevalent autoimmune disorders and the likelihood of developing prostate cancer: a Mendelian randomization study

Numerous studies establish a significant correlation between autoimmune disorders (AIDs) and prostate cancer (PCa). Our Mendelian randomization (MR) analysis investigates the potential connection between rheumatoid arthritis (RA) and PCa, aiming to confirm causal links between systemic lupus erythematosus (SLE), hyperthyroidism, and PCa. Summary statistics from genome-wide association studies provided data on PCa and three AIDs. MR analysis, using IVW as the main approach, assessed causal relationships, validated by sensitivity analysis. IVW revealed a correlation between genetically anticipated RA and PCa, notably in Europeans (OR = 1.03; 95% CI 1.01-1.04, p = 2*10-5). Evidence supported a lower PCa risk in individuals with SLE (OR = 0.94; 95% CI 0.91-0.97, p = 2*10-4) and hyperthyroidism (OR = 0.02; 95% CI 0.001-0.2, p = 2*10-3). Weighted mode and median confirmed these findings. No pleiotropic effects were observed, and MR heterogeneity tests indicated dataset homogeneity. Our study establishes a causal link between RA, SLE, hyperthyroidism, and PCa.

Dual activation of estrogen receptor alpha and glucocorticoid receptor upregulate CRTh2-mediated type 2 inflammation; mechanism driving asthma severity in women?

BACKGROUND

Type 2-high asthma is characterized by elevated levels of circulating Th2 cells and eosinophils, cells that express chemoattractant-homologous receptor expressed on Th2 cells (CRTh2). Severe asthma is more common in women than men; however, the underlying mechanism(s) remain elusive. Here we examined whether the relationship between severe asthma and type 2 inflammation differs by sex and if estrogen influences Th2 cell response to glucocorticoid (GC).

METHODS

Type 2 inflammation and the proportion of blood Th2 cells (CD4⁺ CRTh2⁺ ) were assessed in whole blood from subjects with asthma (n = 66). The effects of GC and estrogen receptor alpha (ERα) agonist on in vitro differentiated Th2 cells were examined. Expression of CRTh2, type 2 cytokines and degree of apoptosis (Annexin V⁺ , 7-AAD) were determined by flow cytometry, qRT-PCR, western blot and ELISA.

RESULTS

In severe asthma, the proportion of circulating Th2 cells and hospitalizations were higher in women than men. Women with severe asthma also had more Th2 cells and serum IL-13 than women with mild/moderate asthma. Th2 cells, eosinophils and CRTh2 mRNA correlated with clinical characteristics associated with asthma control in women but not men. In vitro, GC and ERα agonist treated Th2 cells exhibited less apoptosis, more CRTh2 as well as IL-5 and IL-13 following CRTh2 activation than Th2 cells treated with GC alone.

CONCLUSION

Women with severe asthma had higher levels of circulating Th2 cells than men, which may be due to estrogen modifying the effects of GC, enhancing Th2 cell survival and type 2 cytokine production.

Listeria Bacteremia Presenting With Cerebral Abscess and Endocarditis in an Elderly Patient With Chronic Immune Thrombocytopenia

Central nervous system involvement by Listeria monocytogenes usually presents as meningitis, meningoencephalitis or, less frequently, rhombencephalitis. Listerial brain abscesses are rare. Moreover, only 5-8% of listerial bacteremia is complicated by infective endocarditis (IE). A 70-year-old man with chronic immune thrombocytopenia (ITP) presented to our emergency department with acute onset of altered mental status and right-sided weakness. He was afebrile, with no heart murmurs or peripheral IE stigmata. Neurologic examination showed disorientation, expressive aphasia, and right-sided hemiparesis. Laboratory findings were unremarkable except for leukocytosis and hyponatremia. Brain MRI showed an irregular rim-enhancing lesion in the left frontal lobe, suspicious for a high-grade glial neoplasm. The lesion was excised, and he was started empirically on vancomycin, ceftriaxone, and metronidazole. After blood cultures grew Listeria monocytogenes, antibiotics were de-escalated to ampicillin and gentamicin. Echocardiography showed mitral valve vegetation. By Day 6, his mental status had improved. On Day 9, he was discharged to our inpatient rehabilitation center to complete six weeks on IV ampicillin and IV gentamicin. Pathology of the brain mass was subsequently reported as a listerial brain abscess. Chronic treatment with high-dose oral glucocorticoids and pre-existing ITP have been independently implicated as predisposing factors in listerial brain abscess. There is a propensity to misdiagnose listerial brain abscess as an intracranial neoplasm due to similar clinical/imaging findings. In addition, Listeria monocytogenes is an atypical cause of IE. Therefore, a high index of suspicion is necessary for early recognition and successful treatment of listerial brain abscess and listerial endocarditis in high-risk patients.

Parasitological and immunological aspects of oral and subcutaneous prednisolone treatment in rats experimentally infected with Strongyloides venezuelensis

Strongyloides venezuelensis is a model to study human strongyloidiasis, which infects wild rodents and shares common antigenic epitopes with Strongyloides stercoralis. This study aimed to evaluate parasitological and immunological parameters of prednisolone immunosuppression protocols in rats (Rattus novergicus) infected with S. venezuelensis. Rats were divided into six groups (n = 36): untreated and uninfected (-) or infected (+); oral treatment and uninfected (o-) or infected (o+); subcutaneous treatment and uninfected (sc-) or infected (sc+). For oral immunosuppression, 5 mg/mL of water diluted prednisolone were given five days before infection, and in the days 8 and 21 (for 5 days). For subcutaneous immunosuppression, 10 mg/kg of prednisolone were given daily. The infection was established by the subcutaneous injection of approximately 3,000 S. venezuelensis filarioid larvae per animal. All animals from the (+) and (o+) groups survived, while four rats from the (sc+) died prior to necropsy date. Parasitological analysis showed higher egg elimination in (o+) in comparison to (+) and (sc+) on 7, 13 and 26 days post infection (d.p.i.).The recovery of parasitic females at day 30 was significantly higher in (o+), compared to (+). The (+) and (o+) groups showed a clear increase in anti-S. venezuelensis IgG, IgG1 and IgG2 from 13th d.p.i. Oral immunosuppression led to a higher number of adult females and increased egg output while maintaining IgG and subclasses antibody levels comparable to the positive control.

Chronic inflammatory diseases, anti-inflammatory medications and risk of prostate cancer: a population-based case-control study

Background

Whether chronic inflammation increases prostate cancer risk remains unclear. This study investigated whether chronic inflammatory diseases (CID) or anti-inflammatory medication use (AIM) were associated with prostate cancer risk.

Methods

Fifty-five thousand nine hundred thirty-seven cases (all prostate cancer, 2007–2012) and 279,618 age-matched controls were selected from the Prostate Cancer Database Sweden. CIDs and AIMs was determined from national patient and drug registers. Associations were investigated using conditional logistic regression, including for disease/drug subtypes and exposure length/dose.

Results

Men with a history of any CID had slightly increased risk of any prostate cancer diagnosis (OR: 1.08; 95%CI: 1.04–1.12) but not ‘unfavourable’ (high-risk or advanced) prostate cancer. Generally, risk of prostate cancer was highest for shorter exposure times. However, a positive association was observed for asthma > 5 years before prostate cancer diagnosis (OR: 1.21; 95%CI: 1.05–1.40). Risk of prostate cancer was increased with prior use of any AIMs (OR: 1.26; 95%CI: 1.24–1.29). A positive trend with increasing cumulative dose was only observed for inhaled glucocorticoids (p < 0.011).

Conclusion

Detection bias most likely explains the elevated risk of prostate cancer with prior history of CIDs or use of AIMs, given the higher risk immediately after first CID event and lack of dose response. However, findings for length of time with asthma and dose of inhaled glucocorticoids suggest that asthma may increase risk of prostate cancer through other pathways.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5846-3) contains supplementary material, which is available to authorized users.

Will Attention by Vaccine Developers to the Host's Nuclear Hormone Levels and Immunocompetence Improve Vaccine Success?

Despite extraordinary advances in fields of immunology and infectious diseases, vaccine development remains a challenge. The development of a respiratory syncytial virus vaccine, for example, has spanned more than 50 years of research with studies of more than 100 vaccine candidates. Dozens of attractive vaccine products have entered clinical trials, but none have completed the path to licensing. Human immunodeficiency virus vaccine development has proven equally difficult, as there is no licensed product after more than 30 years of pre-clinical and clinical research. Here, we examine vaccine development with attention to the host. We discuss how nuclear hormones, including vitamins and sex hormones, can influence responses to vaccines. We show how nuclear hormones interact with regulatory elements of immunoglobulin gene loci and how the deletion of estrogen response elements from gene enhancers will alter patterns of antibody isotype expression. Based on these findings, and findings that nuclear hormone levels are often insufficient or deficient among individuals in both developed and developing countries, we suggest that failed vaccine studies may in some cases reflect weaknesses of the host rather than the product. We encourage analyses of nuclear hormone levels and immunocompetence among study participants in clinical trials to ensure the success of future vaccine programs.

The effects of prednisolone treatment on serological responses and lipid profiles in Ethiopian leprosy patients with Erythema Nodosum Leprosum reactions

BACKGROUND

Erythema nodosum leprosum (ENL) is a systemic inflammatory complication occurring mainly in patients with lepromatous leprosy (LL) and borderline lepromatous leprosy (BL). Prednisolone is widely used for treatment of ENL reactions. However, it has been reported that prolonged treatment with prednisolone increases the risk for prednisolone-induced complications such as osteoporosis, diabetes, cataract and arteriosclerosis. It has been speculated that perhaps these complications result from lipid profile alterations by prednisolone. The effects of extended prednisolone treatment on lipid profiles in ENL patients have not been studied in leprosy patients with ENL reactions. Therefore, in this study we conducted a case-control study to investigate the changes in lipid profiles and serological responses in Ethiopian patients with ENL reaction after prednisolone treatment.

METHODS

A prospective matched case-control study was employed to recruit 30 patients with ENL and 30 non-reactional LL patient controls at ALERT Hospital, Ethiopia. Blood samples were obtained from each patient with ENL reaction before and after prednisolone treatment as well as from LL controls. The serological host responses to PGL-1, LAM and Ag85 M. leprae antigens were measured by ELISA. Total cholesterol (TC), triglyceride (TG), high density lipoprotein (HDL) and low density lipoprotein (LDL) were measured by spectrophotometric method.

RESULTS

The host antibody response to M. leprae PGL-1, LAM and Ag85 antigens were significantly reduced in patients with ENL reactions compared to LL controls after treatment. Comparison between patients with acute and chronic ENL showed that host-response to PGL-1 was significantly reduced in chronic ENL after prednisolone treatment. Untreated patients with ENL reactions had low lipid concentration compared to LL controls. However, after treatment, both groups had comparable lipid profiles except for LDL, which was significantly higher in patients with ENL reaction. Comparison within the ENL group before and after treatment showed that prednisolone significantly increased LDL and HDL levels in ENL patients and this was more prominent in chronic ENL than in acute patients with ENL.

CONCLUSION

The significantly increased prednisolone-induced LDL and TG levels, particularly in patients with chronic ENL reactions, is a concern in the use of prednisolone for extended periods in ENL patients. The findings highlight the importance of monitoring lipid profiles during treatment of patients to minimize the long-term risk of prednisolone-induced complications.

A la Pêche aux Moules

In a recent manuscript, Goff and collaborators (Metzger et al. 2016) reported data arguing for the spread of contagious cancer cells among different species of shellfish. Although horizontal transmission of cancer cells has been observed in a few cases in higher organisms, it appears to be rather frequent among molluscs. Recent evidence supports the concept of inter-species horizontal infectious transmission of cancer cells both in molluscs but also in mammals, including humans.

Corticosteroids in the management of prostate cancer: a critical review

Corticosteroids have been used in the management of prostate cancer for over 30 years. Although daily oral corticosteroids have frequently used in conjunction with chemotherapy for metastatic castration-resistant prostate cancer, their independent impact on survival is unclear. However, corticosteroids confer palliative benefits and are associated with objective responses and circulating tumor cell (CTC) and PSA declines in a small minority of patients, although toxicities such as osteoporosis and immunosuppression complicate long-term use. Following the demonstration of a palliative benefit for mitoxantrone combined with corticosteroids compared with corticosteroids alone, subsequent trials that demonstrated a benefit for first-line docetaxel over mitoxantrone, and second-line cabazitaxel over mitoxantrone, administered concurrent daily oral corticosteroids with all of these agents to maintain uniformity. Conversely, improved outcomes were demonstrated with docetaxel without corticosteroids for metastatic castration-sensitive prostate cancer. Daily oral corticosteroids are routinely combined with abiraterone to mitigate symptoms of mineralocorticoid excess. In contrast daily corticosteroids are not essential when administering enzalutamide or radium-223, and there is a concern of deleterious immune effects concurrently with sipuleucel-T. Given emerging evidence for promotion of resistance mechanisms, routine administration of daily oral corticosteroids in settings other than abiraterone administration and palliation of symptoms is probably not required.

IFN-γ-induced JAK/STAT, but not NF-κB, signaling pathway is insensitive to glucocorticoid in airway epithelial cells

Although the majority of patients with asthma are well controlled by inhaled glucocorticoids (GCs), patients with severe asthma are poorly responsive to GCs. This latter group is responsible for a disproportionate share of health care costs associated with asthma. Recent studies in immune cells have incriminated interferon-γ (IFN-γ) as a possible trigger of GC insensitivity in severe asthma; however, little is known about the role of IFN-γ in modulating GC effects in other clinically relevant nonimmune cells, such as airway epithelial cells. We hypothesized that IFN-γ-induced JAK/STAT-associated signaling pathways in airway epithelial cells are insensitive to GCs and that strategies aimed at inhibiting JAK/STAT pathways can restore steroid responsiveness. Using Western blot analysis we found that all steps of the IFN-γ-induced JAK/STAT signaling pathway were indeed GC insensitive. Transfection of cells with reporter plasmid showed IFN-γ-induced STAT1-dependent gene transcription to be also GC insensitive. Interestingly, real-time PCR analysis showed that IFN-γ-inducible genes (IIGs) were differentially affected by GC, with CXCL10 being GC sensitive and CXCL11 and IFIT2 being GC insensitive. Further investigation showed that the differential sensitivity of IIGs to GC was due to their variable dependency to JAK/STAT vs. NF-κB signaling pathways with GC-sensitive IIGs being more NF-κB dependent and GC-insensitive IIGs being more JAK/STAT dependent. Importantly, transfection of cells with siRNA-STAT1 was able to restore steroid responsiveness of GC-insensitive IIGs. Taken together, our results show the insensitivity of IFN-γ-induced JAK/STAT signaling pathways to GC effects in epithelial cells and also suggest that targeting STAT1 could restore GC responsiveness in patients with severe asthma.

Abnormal chemokine receptor profile on circulating T lymphocytes from nonallergic asthma patients

BACKGROUND

T lymphocytes are involved in the pathogenesis of nonallergic asthma. The objective of this study was to characterize the subset distribution and pattern of chemokine receptor expression in circulating T lymphocyte subsets from nonallergic asthma patients.

METHODS

Forty stable nonallergic asthma patients and 16 sex- and age-matched healthy donors were studied. Twelve patients did not receive inhaled steroids (untreated patients), 16 received 50-500 μg b.i.d. of inhaled fluticasone propionate (FP) (standard-dose patients), and 12 received over 500 μg b.i.d. of inhaled FP (high-dose patients) for at least 12 months prior to the beginning of this study and were clinically well controlled. Flow cytometry was performed using a panel of monoclonal antibodies (4 colors).

RESULTS

Nonallergic asthma patients treated with high doses of inhaled FP showed a significant reduction in the percentages of CD3+ T lymphocytes compared to healthy controls. Untreated patients showed a significant increase in CCR6 expression in CD8+CD25+ and CD8+CD25+bright T cells compared to healthy controls. The results were similar for CXCR3 and CCR5 expression. In patients treated with standard doses of FP, CCR5 expression was significantly increased in CD3+ T lymphocytes relative to healthy controls.

CONCLUSIONS

The different groups of clinically stable nonallergic asthmatic patients showed distinct patterns of alterations in subset distribution as well as CCR6, CXCR3, and CCR5 expression on circulating T lymphocytes. .

Asthma combined with Hodgkin's lymphoma: a case report and review of the literature

Both asthma and hematological malignancies are influenced by genetic and environmental factors. The previous studies have revealed lymphoma were found among atopic men and women. However, the relationship between asthma and Hodgkin's lymphoma has not been well recognized. We present here, a case of a 53-year-old male patient suffered asthma and then Hodgkin's lymphoma.

Surgery and stress promote cancer metastasis: new outlooks on perioperative mediating mechanisms and immune involvement

Surgery for the removal of a primary tumor presents an opportunity to eradicate cancer or arrest its progression, but is also believed to promote the outbreak of pre-existing micrometastases and the initiation of new metastases. These deleterious effects of surgery are mediated through various mechanisms, including psychological and physiological neuroendocrine and paracrine stress responses elicited by surgery. In this review we (i) describe the many risk factors that arise during the perioperative period, acting synergistically to make this short timeframe critical for determining long-term cancer recurrence, (ii) present newly identified potent immunocyte populations that can destroy autologous tumor cells that were traditionally considered immune-resistant, thus invigorating the notion of immune-surveillance against cancer metastasis, (iii) describe in vivo evidence in cancer patients that support a role for anti-cancer immunity, (iv) indicate neuroendocrine and paracrine mediating mechanisms of stress- and surgery-induced promotion of cancer progression, focusing on the prominent role of catecholamines and prostaglandins through their impact on anti-cancer immunity, and through direct effects on the malignant tissue and its surrounding, (v) discuss the impact of different anesthetic approaches and other intra-operative procedures on immunity and cancer progression, and (vi) suggest prophylactic measures against the immunosuppressive and cancer promoting effects of surgery.

Bacteria in sputum of stable severe asthma and increased airway wall thickness

BACKGROUND

Patients with chronic asthma have thicker intrapulmonary airways measured on high resolution computed tomography (HRCT). We determined whether the presence of lower airway bacteria was associated with increased airway wall thickness.

METHODS

In 56 patients with stable severe asthma, sputum specimens obtained either spontaneously or after induction with hypertonic saline were cultured for bacteria and thoracic HRCT scans obtained. Wall thickness (WT) and area (WA) expressed as a ratio of airway diameter (D) and total area, respectively, were measured at five levels.

RESULTS

Positive bacterial cultures were obtained in 29 patients, with H. influenzae, P. aeruginosa and S. aureus being the commonest strains. Logistic regression analysis showed that this was associated with the duration of asthma and the exacerbations during the past year. In airways > 2 mm, there was no significant difference in WA (67.5 ± 5.4 vs 66.4 ± 5.4) and WT/D (21.6 ± 2.7 vs 21.3 ± 2.4) between the culture negative versus positive groups. Similarly, in airways (≤ 2 mm), there were no significant differences in these parameters. The ratio of √wall area to Pi was negatively correlated with FEV1% predicted (p < 0.05).

CONCLUSIONS

Bacterial colonization of the lower airways is common in patients with chronic severe asthma and is linked to the duration of asthma and having had exacerbations in the past year, but not with an increase in airway wall thickness.

Prednisone affects inflammation, glucose tolerance, and bone turnover within hours of treatment in healthy individuals

OBJECTIVE

Use of glucocorticoids for anti-inflammatory efficacy is limited by their side effects. This study examined, in the same individuals, prednisone's acute, dose-dependent effects on inflammation as well as biomarkers of glucose regulation and bone homeostasis.

DESIGN

In this randomized, double-blind, parallel-design trial of healthy adults demonstrating cutaneous allergen-induced hypersensitivity, patients received placebo or prednisone 10, 25 or 60 mg daily for 7 days.

METHODS

Effects on peripheral white blood cell (WBC) count, ex vivo whole blood lipopolysaccharide (LPS)-stimulated TNF-α release and response to cutaneous allergen challenge were assessed concurrently with biomarkers for glucose tolerance and bone turnover.

RESULTS

Differential peripheral WBC counts changed significantly within hours of prednisone administration. Ex vivo, LPS-stimulated TNF-α was significantly reduced by all prednisone doses on days 1 and 7. The late phase cutaneous allergen reaction was significantly reduced with prednisone 60 mg vs placebo on days 1 and 7. Oral glucose tolerance tests revealed significant increases in glycaemic excursion on days 1 and 7, whereas increases in insulin and C-peptide excursions were more notable on day 7 with all doses of prednisone. The bone formation markers osteocalcin, and procollagen I N- and C-terminal peptides decreased significantly on days 1 and 7 vs placebo.

CONCLUSIONS

In healthy young adults after single doses as low as 10 mg, prednisone treatment has significant effects on glucose tolerance and bone formation markers within hours of treatment, in parallel with anti-inflammatory effects.

Dexamethasone effects in the Strongyloides venezuelensis infection in a murine model

The aim of this study was to investigate the immunomodulatory effects of glucocorticoids on the immune response to Strongyloides venezuelensis in mice. Balb/c mice were infected with S. venezuelensis and treated with Dexamethasone (Dexa) or vehicle. Dexa treatment increased circulating blood neutrophil numbers and inhibited eosinophil and mononuclear cell accumulation in the blood, bronchoalveolar, and peritoneal fluid compared with control animals. Moreover, Dexa decreased tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), interleukin-3 (IL-3), IL-4, IL-5, IL-10, and IL-12 production in the lungs and circulating immunoglobulin G1 (IgG1), IgG2a, and IgE antibody levels while increasing the overall parasite burden in the feces and intestine. Dexa treatment enhanced the fertility of female nematodes relative to untreated and infected mice. In summary, the alterations in the immune response induced by Dexa resulted in a blunted, aberrant immune response associated with increased parasite burden. This phenomenon is similar to that observed in S. stercoralis-infected humans who are taking immunosuppressive or antiinflammatory drugs, including corticosteroids.

Airway epithelial indoleamine 2,3-dioxygenase inhibits CD4+ T cells during Aspergillus fumigatus antigen exposure

Indoleamine 2,3-dioxygenase (IDO) suppresses the functions of CD4(+) T cells through its ability to metabolize the essential amino acid tryptophan. Although the activity of IDO is required for the immunosuppression of allergic airway disease by the Toll-Like-Receptor 9 (TLR9) agonist, oligonucleotides comprised of cytosine and guanine nucleotides linked by phosphodiester bonds (CpG) DNA, it is unclear whether IDO expression by resident lung epithelial cells is sufficient to elicit these effects. Therefore, we created a transgenic mouse inducibly overexpressing IDO within nonciliated airway epithelial cells. Upon inhalation of formalin-fixed Aspergillus fumigatus hyphal antigens, the overexpression of IDO from airway epithelial cells of these mice reduced the number of CD4(+) T cells within the inflamed lung and impaired the capacity of antigen-specific splenic CD4(+) effector T cells to secrete the cytokines IL-4, IL-5, IL-13, and IFN-γ. Despite these effects, allergic airway disease pathology was largely unaffected in mice expressing IDO in airway epithelium. In support of the concept that dendritic cells are the major cell type contributing to the IDO-inducing effects of CpG DNA, mice expressing TLR9 only in the airway epithelium did not augment IDO expression subsequent to the administration of CpG DNA. Furthermore, the systemic depletion of CD11c(+) cells rendered mice incapable of CpG DNA-induced IDO expression. Our results demonstrate that an overexpression of IDO within the airway epithelium represents a novel mechanism by which the number of CD4(+) T cells recruited to the lung and their capacity to produce cytokines can be diminished in a model of allergic airway disease, and these results also highlight the critical role of dendritic cells in the antiasthmatic effects of IDO induction by CpG DNA.

[Pneumocystis jiroveci pneumonia during prolonged corticosteroid therapy in an immunocompetent infant]

INTRODUCTION

Pneumocystis jiroveci (PJ) infection is rare in infants and is suggestive of primary or secondary immunodeficiency. We report on a case of severe PJ pneumonia in an immunocompetent infant after prolonged corticosteroid treatment.

CASE REPORT

A 5 1/2 month-old girl presented with hypoxemic respiratory distress. Her medical record was remarkable only for a bulky parotid haemangioma, which was treated with prolonged oral corticosteroid therapy. The chest X-ray showed a mixed alveolar-interstitial pattern, and bronchoalveolar lavage revealed the presence of PJ. A favourable outcome was obtained after three weeks of intravenous trimethoprim-sulfamethoxazole treatment.

CONCLUSION

PJ infection should be suspected in infants presenting with progressive respiratory distress associated with a mixed alveolar-interstitial pattern. Its potential seriousness justifies prophylactic therapy during prolonged immunosuppressive treatment (chemotherapy, corticosteroid treatment).

Natural glucocorticoids induce expansion of all developmental stages of murine bone marrow granulocytes without inhibiting function

Natural glucocorticoids (Gc) produced during stress have profound effects on the immune system. It is well known that Gc induce apoptosis in precursor T and B cells, markedly altering lymphopoiesis. However, it has been noted that marrow myeloid cells expanded both in proportion and absolute numbers in the mouse after Gc exposure. Mice were implanted with a corticosterone (CS) tablet that increased serum Gc and caused atrophied thymuses, both classic signs of activation of the stress axis. Blood neutrophil counts were elevated (4.8x), whereas lymphocyte counts declined. Flow cytometric analysis of the marrow revealed that the phenotypic distribution of the various major classes of cells was shifted by Gc exposure. As expected, marrow lymphocyte numbers declined >40% after 3 days of exposure to Gc. Conversely, in the myeloid compartment, both monocytes and granulocytes increased in number by >40%. Further, all granulocyte developmental stages showed large increases in both total number and percentage of cells. To investigate the functional capacity of mature granulocytes from Gc-treated mice, an improved granulocyte isolation method was developed. Gc exposure had little effect on the ability of granulocytes to produce superoxide or undergo chemotaxis or phagocytose bacteria. These results indicate that Gc treatment shifts bone marrow composition and provides evidence that granulocytes and their progenitors are selectively preserved under stressful conditions without losing function.

The threat of avian influenza A (H5N1). Part III: Antiviral therapy

Among emerging and re-emerging infectious diseases, influenza constitutes one of the major threats to mankind. In this review series epidemiologic, virologic and pathologic concerns raised by infections of humans with avian influenza virus A/H5N1 as well as treatment options are discussed. The third part discusses therapeutic options. Neuraminidase (NA) inhibitors are the most promising agents despite uncertainty about efficacy. Dosage increase, prolonged treatment or combination therapies may increase treatment efficacy and/or inhibit resistance formation. Immune system dysregulation contributes to H5N1 disease. Although current evidence does not support the use of anti-inflammatory drugs beneficial effects cannot be excluded at later disease stages.

Corticothérapie systémique et risque infectieux

PURPOSE

It was shown that corticosteroids alter the inflammatory and immune responses. Many publications report on serious infections occurring in patients receiving corticosteroids or presenting with Cushing's syndrome. This information is synthesized in this article.

CURRENT KNOWLEDGE AND KEY POINTS

The demonstration of the infectious risk associated with corticosteroids relies on observational data and on biological plausibility. However, this risk remains difficult to quantify, because of many confusing factors such as the patients' associated conditions and immunosuppressive treatments, and the highly variable dose and duration of the corticosteroid treatment. Taking into account the published data, the screening for a chronic infection seems licit among patients receiving a systemic corticosteroid treatment, in particular for those who will receive more than 10 mg of prednisone per day.

FUTURE PROSPECTS

Although no clinical trials of prevention of infections in corticosteroid treated patients has been published, a strategy aiming at minimizing the infectious risk of corticosteroid treated patients is proposed, based on the analysis of the literature presented in this article.

Pneumocystis jiroveci (carinii) pneumonia after infliximab therapy: a review of 84 cases

Anti-tumor necrosis factor-alpha therapy, infliximab, has become an established effective therapy for Crohn's disease and rheumatoid arthritis. However, infliximab has been associated with various opportunistic pathogens such as tuberculosis, histoplasmosis, listeriosis, aspergillosis, and Pneumocystis jiroveci (carinii) pneumonia. We reviewed the FDA Adverse Event Reporting System for cases of Pneumocystis associated with infliximab use from January 1998 through December 2003. The database revealed 84 cases of PCP following infliximab therapy. Concomitant immunosuppressive medications included methotrexate, prednisone, azathioprine, 6-mercaptopurine, and cyclosporine. Mean time between infliximab infusion and onset of symptoms of pneumonia, when reported, was 21 days (+/-18 days; n=40). Twenty-three of the 84 (27%) patients died. The use of infliximab is associated with PCP infection. Further, the mortality rate for Pneumocystis following the use of infliximab is significant. The potential for severe disease, mortality, and often subtle presentation of these infections warrant close follow-up and careful monitoring after therapy.

Asthma history, occupational exposure to pesticides and the risk of non-Hodgkin's lymphoma

We previously reported that, although asthma did not increase the risk of non-Hodgkin's lymphoma (NHL), the risk from pesticide exposures was higher among asthmatics than that among nonasthmatics. To further evaluate this finding, we analyzed data from a population-based case-control study of NHL conducted in Iowa, Detroit, Los Angeles and Seattle. Cases (n = 668) diagnosed with NHL from 1998 to 2000 and controls (n = 543) randomly selected from the same geographical areas as that of the cases were included in this analysis. Odds ratios (OR) for the risk of NHL from potential occupational exposure to pesticides tended to be higher among asthmatics (OR = 1.7; 95% CI 0.3-9.1) when compared with that among nonasthmatics (OR = 0.9; 95% CI 0.6-1.5). The risks of NHL associated with pesticide exposure were also higher among asthmatics who had history of hospitalization (OR = 2.1; 95% CI 0.2-29.0) or daily medication for asthma (OR = infinite) than those among asthmatics who did not have such histories. Our results support the previous finding that the risk of NHL from pesticide exposure may be greater among asthmatics.

Subtle immunodeficiency in severe asthma: IgA and IgG2 correlate with lung function and symptoms

BACKGROUND

Atopy, increased serum IgE and eosinophilic airway inflammation are common in asthma and may indicate aberrant immune responses, but the cause(s) are unknown. It was hypothesized that differences in serum immunoglobulins, immunoglobulin free light chains (FLC) and secretory IgA (sIgA) would exist between subjects with asthma of varying severity and normal subjects, and the levels would correlate with lung function, symptoms and airway inflammation.

METHODS

Serum IgG, IgA, IgE and IgM, IgG subclasses and FLC, and bronchoalveolar lavage sIgA were evaluated from 15 normal subjects, 9 mild and 22 severe asthmatics with similar atopic status. Asthma symptoms were obtained by questionnaire, and airway inflammation was assessed by immunostaining for five inflammatory cell types.

RESULTS

Immunoglobulin levels in all groups were generally within the normal range. However, IgA and IgG were lower in severe asthmatics than normal subjects (overall p = 0.006 and 0.02, respectively). IgA, but not IgG, correlated with lung function and asthma symptoms (r-values >0.58; p-values <0.009). Although similar among the groups, higher sIgA and IgG(2) also positively correlated with lung function and negatively with asthma symptoms (r-values >0.63; p-values <0.009). IgA and IgG/IgG(1) positively correlated with tissue mast cells.

CONCLUSIONS

Subtle alterations in IgA- and IgG(2)-mediated responses in asthma may be disease-related. As their levels are generally normal, it is possible that the quality/repertoire of immune protection provided by these isotypes, perhaps against carbohydrate epitopes, may be altered in asthma.

Naturally occurring parainfluenza virus 3 infection in adults induces mild exacerbation of asthma associated with increased sputum concentrations of cysteinyl leukotrienes

BACKGROUND

Viral respiratory tract infections represent the most frequent cause of asthma exacerbation in both children and adults, but the precise mechanism of such exacerbation remains unknown.

OBJECTIVES

To determine the critical mediator of naturally occurring parainfluenza virus (PIV) 3-induced mild asthma exacerbations in adults.

METHODS

The study subjects were 19 adult asthmatics with mild asthma exacerbation (peak expiratory flow = 60-80% of predicted before bronchodilator use and >80% of predicted after initial bronchodilator treatment). Differential cell counts and concentrations of inflammatory markers including eosinophil cationic protein (ECP), cysteinyl leukotrienes (cysLTs), interleukin (IL)-5, IL-10 and IL-12 were measured in the induced sputum obtained from adults with PIV3- (n = 9) and non-cold-induced (n = 10) exacerbation of asthma during both acute and convalescent phases.

RESULTS

PIV3 infection was confirmed by the presence of viral RNA in nasopharyngeal aspirates. Mild exacerbation of asthma was not associated with significant changes in sputum differential cell counts. Concentrations of sputum ECP and cytokines were comparable between PIV3 and non-cold-induced patients. In contrast, PIV3 infection was associated with a significant increase in sputum cysLTs during the acute phase of mild asthma exacerbation.

CONCLUSIONS

Our results identified cysLTs as a critical mediator of PIV3-induced acute asthma exacerbation.

Lipopolysaccharide (LPS) induced activation of the immune system in control rats and rats chronically exposed to a low level of the organothiophosphate insecticide, acephate

Lipopolysaccharide (LPS), a key inflammatory component of gram-negative bacteria, induces a distinctive pattern of cytokine release that regulates inflammation. An alteration in the LPS response may play a fundamental role in the pathogenesis of a number of inflammatory diseases. Therefore, this study was conducted to determine whether chronic exposure to a low level of acephate (Ace), a commonly used organophosphate insecticide, impaired the LPS response in rats. This study showed that LPS injection in control rats caused (1) a time-dependent increase in blood lymphocyte enumeration and differentiation, and (2) a sequential increase the pro-inflammatory (interleukin-1beta (IL1beta), tumor necrosis factor-alpha (TNFalpha), interferon-gamma (INTgamma), and inducible nitric oxide synthase (iNOS)) and anti-inflammatory (interleukin-4 (IL-4), corticotropin-releasing factor (CRF), and blood corticosterone (Cort)) cytokines. The pro-inflammatory cytokines increased after 30 min, while the anti-inflammatory cytokines increased 3 h after LPS injection. An increase in proinflammatory cytokines increased lymphocyte enumeration and differentiation, while the increase in anti-inflammatory cytokines re-established homeostasis. In comparison to the control rats, the Ace-exposed rats exhibited (1) lower levels of IL1beta, TNFalpha and iNOS, (2) higher levels of CRF and Cort, and (3) lower levels of IL-4 in blood and/or brain samples. The abnormal cytokine production may be associated with abnormal phenotypic distribution of B and T cells. Blood IgMhi IgDhi, IgMlo IgDlo and CD8+ CD45RA- CCR7+ cells were elevated, while IgMlo IgDhi, IgMhi IgDlo, IgMin IgDlo, CD8+ CD45RA+ CCR7+ and CD8+ CD45RA- CCR7 cells were depressed in Ace-exposed rats. Thus, chronic low-level Ace exposure may impair the lineage commitment in lymphocytes, possibly by altering cytokine signaling in the brain.

Pharmacokinetics and pharmacodynamics of systemically administered glucocorticoids

Glucocorticoids have pleiotropic effects that are used to treat diverse diseases such as asthma, rheumatoid arthritis, systemic lupus erythematosus and acute kidney transplant rejection. The most commonly used systemic glucocorticoids are hydrocortisone, prednisolone, methylprednisolone and dexamethasone. These glucocorticoids have good oral bioavailability and are eliminated mainly by hepatic metabolism and renal excretion of the metabolites. Plasma concentrations follow a biexponential pattern. Two-compartment models are used after intravenous administration, but one-compartment models are sufficient after oral administration.The effects of glucocorticoids are mediated by genomic and possibly nongenomic mechanisms. Genomic mechanisms include activation of the cytosolic glucocorticoid receptor that leads to activation or repression of protein synthesis, including cytokines, chemokines, inflammatory enzymes and adhesion molecules. Thus, inflammation and immune response mechanisms may be modified. Nongenomic mechanisms might play an additional role in glucocorticoid pulse therapy. Clinical efficacy depends on glucocorticoid pharmacokinetics and pharmacodynamics. Pharmacokinetic parameters such as the elimination half-life, and pharmacodynamic parameters such as the concentration producing the half-maximal effect, determine the duration and intensity of glucocorticoid effects. The special contribution of either of these can be distinguished with pharmacokinetic/pharmacodynamic analysis. We performed simulations with a pharmacokinetic/pharmacodynamic model using T helper cell counts and endogenous cortisol as biomarkers for the effects of methylprednisolone. These simulations suggest that the clinical efficacy of low-dose glucocorticoid regimens might be increased with twice-daily glucocorticoid administration.

Characterization of a population of small macrophages in induced sputum of patients with chronic obstructive pulmonary disease and healthy volunteers

The inflammatory process in chronic obstructive pulmonary disease (COPD) is active mainly in the airways, but little is known about the properties of the inflammatory cells in this compartment. We have studied leucocytes in induced sputum of COPD patients compared to controls in order to uncover what types of macrophages might be involved in the disease. Sputum induction was performed by inhalation of nebulized sodium chloride solution. Leucocytes were isolated and stained with specific monoclonal antibodies for analysis in flow cytometry. Flow cytometry analysis revealed that a major portion of CD14+ macrophages in COPD has lower forward scatter, i.e. they are small macrophages. While in control donors these small macrophages accounted for 6.9% of all macrophages, the percentage of these cells in COPD was 45.7%. CD14 and HLA-DR expression was high on these small sputum macrophages while the large sputum macrophages expressed only low levels of these surface molecules, both in control donors and COPD patients. Small sputum macrophages of both control donors and COPD patients showed higher levels of constitutive tumour necrosis factor (TNF) compared to the large macrophages. TNF was inducible by lipopolysaccharide (LPS) preferentially in the small sputum macrophages in the control donors but there was no further induction in COPD patients. These data show that the small sputum macrophages are a major macrophage population in COPD and that these cells exhibit features of highly active inflammatory cells and may therefore be instrumental in airway inflammation in COPD.

Eosinophils and atopic dermatitis

In spite of the progress regarding the description of immunological phenomena associated with atopic dermatitis (AD), the pathogenesis of this disease still remains unclear. The presence of eosinophils in the inflammatory infiltrate of AD has long been established. Eosinophil numbers as well as eosinophil granule protein levels in peripheral blood are elevated in most AD patients and appear to correlate with disease activity. Moreover, eosinophil granule proteins, which possess cytotoxic activity, are deposited in the skin lesions. These observations indicate a role of eosinophils in the pathogenesis of AD. Furthermore, AD is associated with increased production of T helper 2 cytokines including interleukin (IL)-5, which specifically acts on eosinophils, resulting in accelerated eosinophilopoiesis, chemotaxis, cell activation, and delayed apoptosis. Therefore, IL-5 is an interesting target for experimental therapy in this inflammatory disorder of the skin. Such studies might result in new insights into the pathogenetic role of eosinophils in AD.

Influence of dexamethasone on some cellular aspects of the immune system in cats

In view of the frequent use of glucocorticoids in the treatment of cats, we studied the effect of dexamethasone on their immunological system. The phagocytic activity and oxidative burst of neutrophils and monocytes were evaluated by cytometric analysis using commercial kits and the subpopulations of lymphocytes were assessed. Neutrophilia and monocytosis reduced phagocytic activity, as shown from the number of phagocytized bacteria, and variations in the intensity of the oxidative burst in activated neutrophils and monocytes were observed. Dexamethasone also caused an increase in the number of B lymphocytes.

Clinical and immunological effects of low-dose IFN-alpha treatment in patients with corticosteroid-resistant asthma

BACKGROUND

Interferon (IFN)-alpha is a cytokine that possesses potent anti-viral and immunoregulatory activities. We aimed to assess clinical and immunological effects of low-dose IFN-alpha in patients with severe corticosteroid-resistant asthma with and without Churg-Strauss syndrome. There is currently no efficient pharmacological treatment available for this group of patients.

METHODS

We studied 10 patients with corticosteroid-resistant asthma, in which 3x10(6) IU/day IFN-alpha were administrated in addition to the prednisone dose given already before introduction of the cytokine therapy. The prednisone dose was gradually reduced dependent on the clinical situation and used as a clinical readout to evaluate the efficacy of the cytokine therapy. To distinguish between IFN-alpha- and prednisone-mediated immunological changes, the corticosteroid dose was kept constant for at least 2 weeks upon introduction of the cytokine therapy in seven patients. The effects of treatment on clinical and immunological parameters were measured at 2-4 weeks and 5-10 months depending on the availability of the patient.

RESULTS

Interferon-alpha treatment rapidly improved the clinical situation as assessed by lung function parameters and required prednisone dose. Important immunological changes included: decreased leukocyte numbers, increased relative numbers of CD4+ T cells, increased differentiation of T helper (Th)1 cells, and increased expression of interleukin (IL)-10 in peripheral blood mononuclear cells.

CONCLUSION

Interferon-alpha treatment was associated with dramatic improvements in the condition of patients with corticosteroid-resistant asthma with and without Churg-Strauss syndrome. Potential mechanisms of action include the establishment of a correct Th1/Th2 balance and the induction of the anti-inflammatory IL-10 gene.

Effect of montelukast on polymorphonuclear leukocyte functions in asthmatic patients

Leukotriene receptor antagonists are being used widely in the treatment of bronchial asthma. They have been shown to possess anti-inflammatory properties, but there is no sufficient data about their effects on polymorphonuclear leukocyte functions. The aim of this study was to investigate the effects of montelukast, a specific cysteinyl leukotriene-1 receptor antagonist, on human polymorphonuclear leukocyte (PMN) functions (phagocytic and intracellular killing activity) in asthmatic patients. Fifteen mild to moderate asthmatic patients were included in the study. They were treated with montelukast (10 mg/day per os) in addition to their previous medications for 2 weeks. Whole blood samples of patients were taken before and after this treatment period. Phagocytic activities and intracellular killing activities of polymorphonuclear leukocytes isolated from whole blood samples were tested by using appropriate technics. Phagocytic and intracellular killing activities of PMNs were significantly increased (p<0.001, p<0.05) by montelukast compared to those before treatment. These results show that montelukast has an enhancing effect on PMN functions in asthmatic patients.

IVIG--mechanisms of action

Intravenous immunoglobulin (IVIG) preparations are fractionated from a plasma pool of several thousand donors. IVIG contain immune antibodies and physiologic autoantibodies. Immune antibodies reflect the immunologic experience of the donor population. This fraction of IVIG preparations is useful for replacement therapy and passive immunisation. Natural autoantibodies are able to react with the immune system of the recipient of IVIG and are suggested to help to correct immune deregulation. Immunomodulatory and anti-inflammatory properties are based on multiple mechanisms of action which are described. These mechanisms are effective concomitantly and synergistically at every occasion of use of IVIG in inflammatory and autoimmune disorders.

Anti-inflammatory activity of an extract of Petasites hybridus in allergic rhinitis

Previous studies have suggested that histamine and leukotrienes (LTs) play an important pathobiological role in IgE-mediated allergic diseases. In vitro studies suggested that an extract of Petasites hybridus (Ze339) blocks LT synthesis in monocytes and granulocytes. Petasins are considered to be the pharmacologically active fraction within Ze339. Patients suffering from allergic rhinitis received three times a day two tablets of Ze339 standardized to 8 mg petasins within a time period of 1 week. After 5 days of treatment, Ze339 significantly improved primary end points, which were day- and nighttime nasal symptoms. Nasal resistance, which was measured by rhinomanometry, gradually decreased as a consequence of Ze339 treatment reaching normal levels after 5 days (rhinomanometry: from 403.5+/-62.0 to 844.8+/-38.8 ml). Levels of inflammatory mediators in nasal fluids and serum were measured 90 min after drug administration every day in the morning. After 5 days of treatment, a significant reduction of histamine (from 153.7+/-32.1 to 53.0+/-8.4 pg/ml) and LT levels (LTB4: from 313.1+/-46.5 to 180.6+/-32.2 pg/ml; cysteinyl-LT: from 137.0+/-42.2 to 70.1+/-16.5 pg/ml) could be observed. Moreover, quality-of-life scores significantly improved. The drug had no effect on the distribution of lymphocyte subpopulations in the blood as well as on the capacity of blood leukocytes to generate cytokines and lipid mediators. These results suggest that Ze339 is effective in treating allergic rhinitis patients by decreasing levels of nasal inflammatory mediators.

Peripheral blood mononuclear cells from IgE- and non-IgE-associated allergic atopic eczema/dermatitis syndrome (AEDS) demonstrate increased capacity of generating interleukin-13 but differ in their potential of synthesizing interferon-gamma

BACKGROUND

A subgroup of patients with allergic atopic eczema/dermatitis syndrome (AEDS) are known to have normal total and specific IgE levels and negative skin prick tests towards common environmental allergens. This form of the disease has been termed non-IgE-associated allergic AEDS. Although allergic mechanisms appear to be important, the pathogenesis of both IgE- and non-IgE-associated forms of the disease is unknown.

METHODS

We have compared the cytokine production pattern of peripheral blood mononuclear cells (PBMC) from IgE-associated AEDS, non-IgE-associated AEDS, and normal control individuals. PBMC were stimulated with anti-CD3 and/or anti-CD28 monoclonal antibodies (mAb) and cytokine production was measured by immunoassays in supernatants of 24-h cultures.

RESULTS

Compared to healthy subjects and non-IgE-associated AEDS patients, stimulated PBMC from IgE-associated AEDS patients produced less interferon (IFN)-gamma. However, stimulated PBMC from both IgE-associated AEDS and non-IgE-associated AEDS patients produced more interleukin (IL)-13 than PBMC from control individuals. Moreover, IL-5 production was significantly increased in non-IgE-associated AEDS but not in IgE-associated AEDS patients.

CONCLUSIONS

The underlying mechanism leading to increased differentiation of T helper (Th) 2 cells may involve a deficient capacity in producing IFN-gamma in IgE-associated AEDS but not in non-IgE-associated AEDS patients. IL-13 may be a key cytokine in the pathogenesis of both allergic forms of AEDS.

Rhinovirus-induced airway inflammation in asthma: effect of treatment with inhaled corticosteroids before and during experimental infection

Asthma exacerbations are frequently linked to rhinovirus infections. However, the associated inflammatory pathways are poorly understood, and treatment of exacerbations is often unsatisfactory. In the present study we investigated whether antiinflammatory treatment with inhaled corticosteroids prevents any rhinovirus-induced worsening of lower airway inflammation. To that end, we selected 25 atopic patients with mild asthma who underwent experimental rhinovirus 16 (RV16) infection, while receiving double-blind, placebo-controlled treatment with the inhaled corticosteroid budesonide (800 microg twice a day) throughout the study period, starting 2 wk before infection. We assessed inflammatory cell numbers in the bronchial mucosa as obtained by bronchial biopsies 2 d before and 6 d after RV16 infection, and analyzed those in relation to cold symptoms, changes in blood leukocyte counts, airway obstruction, and airway hyperresponsiveness. RV16 colds induced an increase in CD3(+) cells in the lamina propria (p = 0.03) and tended to decrease the numbers of epithelial eosinophils (p = 0.06) in both groups analyzed as a whole. The T cell accumulation was positively associated with cold symptoms. Budesonide pretreatment improved airway hyperresponsiveness (p = 0.02) and eosinophilic airways inflammation (p = 0.04). Yet it did not significantly affect the RV16-associated changes in the numbers of any of the inflammatory cell types. We conclude that RV16 infection by itself induces only subtle worsening of airway inflammation in asthma, which is not improved (or worsened) by inhaled corticosteroids. The latter finding is in keeping with the limited protection of inhaled corticosteroids against acute asthma exacerbations.

Effect of oromucosal administration of IFN-alpha on allergic sensitization and the hypersensitive inflammatory response in animals sensitized to ragweed pollen

Oromucosal (o.m.) administration of interferon-alpha (IFN-alpha) during either allergic sensitization (days 0-6) or the hypersensitive response (days 11 and 12) or both periods caused a dose-dependent reduction in allergen-specific IgE production and allergen-induced eosinophil recruitment in mice sensitized to ragweed pollen, a common allergen in humans. Treatment during the hypersensitive response period alone appeared to be most effective. Oromucosal treatment was as effective as intraperitoneal (i.p.) treatment, with maximum inhibition of both allergen-specific IgE production and allergen-induced eosinophil recruitment observed at a dose of a 1000 IU IFN-alpha. Treatment of animals with up to 10(5) IU murine IFN-alpha/beta (MuIFN-alpha/beta) by either the om. or i.p. route did not inhibit significantly allergen-specific IgG production, which may even have been increased at certain doses of IFN. Treatment of animals with up to 10(5) IU MuIFN-alpha/beta by either the o.m. or i.p. route did not affect significantly total serum IgE or IgG levels. Oromucosal administration of IFN-alpha reduced allergen-specific IgE production and allergen-induced eosinophil recruitment in the absence of detectable toxicity, the induction of H(2) antigen expression, and 2',5'-oligoadenylate synthetase activity associated with parenteral administration of IFN-alpha and thus may find application for the treatment of asthma and associated viral infections.

Quantitative analysis of the neuroendocrine-immune axis: linear modeling of the effects of exogenous corticosterone and restraint stress on lymphocyte subpopulations in the spleen and thymus in female B6C3F1 mice

The effects of exogenous corticosterone and restraint stress on the number and percentage of lymphocyte subpopulations in the spleen and thymus were evaluated. The data were used to generate linear models that describe the relationship between these parameters and the area under the corticosterone concentration vs time curve (AUC). Comparison of the models revealed that the number of nucleated cells in the spleen was decreased similarly by exogenous corticosterone and restraint (at equivalent corticosterone AUC values). However, exogenous corticosterone caused a greater decrease in cell number in the thymus than it did in the spleen. Corticosterone preferentially depleted CD4+CD8+ cells in the thymus, whereas the same corticosterone exposure produced by restraint stress did not. In the spleen, cell number for all major cell types was decreased by both treatments, but there were minor differences in the change in percentage of some subpopulations induced by exogenous corticosterone as compared to restraint. The models derived here provide quantitative data that indicate the magnitude of corticosterone and stress-induced effects on lymphocyte populations in the spleen and thymus. These results have mechanistic implications, and they may be useful in future efforts to extrapolate from mouse to human by completing a risk assessment parallelogram.

Active CMV infection before lung transplantation: risk factors and clinical implications

BACKGROUND

Cytomegalovirus (CMV) infection is a major cause of morbidity following lung transplantation, but active CMV infection has not been described before transplantation. Since 1990, we have screened all lung-transplant recipients for CMV infection with viral urine cultures on the day of transplantation. We retrospectively reviewed the medical records of all 102 lung-allograft recipients transplanted between March 1990 and September 1998. Patients with positive urine cultures for CMV were compared to culture negative patients for age, gender, pretransplant diagnosis, time from diagnosis to transplantation, CMV serostatus, use of pretransplant immunosuppression, T-lymphocyte subsets, and presence of fever. Posttransplant outcomes assessed were duration of intubation and hospitalization, acute rejection, frequency of CMV disease, duration of Nashville rabbit antithymocyte serum or globulin (N-RATS/G) and ganciclovir, and survival. Five (5%) of 102 patients had positive urine cultures for CMV; none had symptoms of CMV infection. All 5 had idiopathic pulmonary fibrosis (IPF) (5/5 vs 27/97; p = 0.002). The age, gender, and CMV serostatus of these patients did not differ from the 97 patients in the culture negative group. Four (80%) of the 5 patients with positive cultures were receiving treatment with azathioprine or cyclophosphamide vs only 18 (19%) of the 97 patients with negative cultures (p = 0.007), and all 5 (100%) were receiving steroids compared to 50 (52%) of 97 patients with negative cultures (p = 0.06). Culture-positive IPF patients, when compared with the 27 culture-negative IPF patients, did not differ in any demographic variable or in the use of immunosuppression, but culture-positive patients were more likely to have a CD4/CD8 T-cell subset ratio <1.0 (p = 0.02). Following transplantation, 3 (60%) of 5 IPF patients with positive CMV cultures developed CMV disease compared to 3 (11%) of 27 IPF patients with negative cultures (p = 0.03). Patients with positive cultures also received more days of parenteral antiviral therapy (mean 44 +/- 11 days vs 16 +/- 10 days; p < 0.001). Utilizing pretransplant screening, we have discovered that 16% of patients with IPF had active CMV infection, which was associated with both alterations in their T-cell subsets and a greater risk for CMV disease after transplantation. This occurrence of occult CMV infection in patients with IPF has not been previously recognized, and has important implications.

T cells and T cell-derived cytokines as pathogenic factors in the nonallergic form of atopic dermatitis

A subgroup of patients with atopic dermatitis are known to have normal serum total immunoglobulin E levels, undetectable specific immunoglobulin E, and negative skin prick tests towards allergens. This form of the disease has been termed nonallergic atopic dermatitis. In this study, we found that, among 1151 chronic atopic dermatitis patients, about 10% had normal serum immunoglobulin E levels with no evidence for immunoglobulin E sensitization. We investigated immunologic mechanisms of patients with "allergic" and "nonallergic" atopic dermatitis using peripheral blood and skin biopsy samples. Our data suggest that T cells are likely involved in the pathogenesis of both forms of atopic dermatitis. Skin T cells equally responded to superantigen, staphylococcal enterotoxin B, and produced interleukin-2, interleukin-5, interleukin-13, and interferon-gamma in both forms of the disease. Interleukin-4, however, was not detectable in the skin biopsies of both atopic dermatitis types and was secreted in very low amounts by T cells cultured from the skin biopsies. Moreover, skin T cells from nonallergic atopic dermatitis patients expressed lower interleukin-5 and interleukin-13 levels compared with allergic atopic dermatitis patients. Accordingly, T cells isolated from skin biopsies of atopic dermatitis, but not from the nonallergic atopic dermatitis, induced high immunoglobulin E production in cocultures with normal B cells that was mediated by interleukin-13. In addition, B cell activation with high CD23 expression was observed in the peripheral blood of atopic dermatitis, but not nonallergic atopic dermatitis patients. These data suggest, although high numbers of T cells are present in lesional skin of both types, a lack of interleukin-13-induced B cell activation and consequent immunoglobulin E production in nonallergic atopic dermatitis.

Low HLA-DR expression on peripheral blood monocytes predicts bacterial sepsis after liver transplantation: relation with prednisolone intake

Bacterial sepsis remains a frequent complication after liver transplantation. We previously reported the results of a pilot study that suggested that low expression of HLA-DR on monocytes is a predictive marker for the occurrence of sepsis. We have studied the value of this marker in an additional cohort of patients, and have analyzed the relation of HLA-DR expression with the use of immunosuppressive agents. 20 adult liver transplantation patients were prospectively monitored during the first 4 weeks after transplantation. All were treated according to standard protocols. The percentage of monocytes expressing HLA-DR was measured by flow cytometry. In addition, the effects of incubation of monocytes with prednisolone in vitro on the expression of HLA-DR was determined in 7 healthy volunteers. Seven patients developed bacterial sepsis after a median 15 (range 10-20) days after transplantation. HLA-DR expression was significantly lower in these patients on days 7, 14, 21, and 28 after transplantation compared with non-septic patients. The percentage of HLA-DR positive monocytes was 30% or less, 3 (1-8) days before onset of sepsis. On day 7 after transplantation, HLA-DR expression on 50% or less of monocytes had a positive predictive value for sepsis of 71%, whereas the negative predictive value was 85%. Patients who developed sepsis received significantly more prednisolone. Incubation with prednisolone in vitro lowered the expression of HLA-DR in a dose-dependent manner. We conclude that low HLA-DR expression on monocytes is a marker for a high risk of subsequent sepsis in liver transplantation patients. This high risk may be (at least partly) related to the dose of prednisolone.

Stem cell factor-induced airway hyperreactivity in allergic and normal mice

The induction of airway hyperreactivity during allergic responses involves multiple ill-defined mechanisms. Recently a role for stem cell factor (SCF) in the development of allergic eosinophilic airway inflammation has been identified. In the present study we demonstrate that SCF has a role in both the inflammatory response and airway hyperreactivity. Neutralization of SCF or examination of SCF-mutant mice, which were deficient in SCF and pulmonary mast cells, demonstrated significant alterations in the allergen-induced airway hyperreactive responses. The reduced hyperreactivity response was accompanied by a significant reduction in eosinophil accumulation. To examine the direct role of SCF on airway hyperreactivity, we administered SCF into the airways of normal mice via intratracheal injections and demonstrated a dose dependent increase in airway hyperreactivity at 4 hours that was maintained at 24 hours after administration. Instillation of SCF into SCF-deficient (mast cell deficient) mice demonstrated significantly lower increases in airway hyperreactivity compared with the littermate controls with normal mast cell numbers. These studies demonstrate that locally expressed SCF can induce changes in airway physiology via mast cell activation, verifying the role of SCF in allergic airway inflammation and hyperreactivity.

Glucocorticoids inhibit human antigen-specific and enhance total IgE and IgG4 production due to differential effects on T and B cells in vitro

Although anti-inflammatory properties of glucocorticoids (GC) are well documented, their activity in allergic diseases is still controversial. Recently, it has been reported that GC can increase, both in vivo and in vitro, the polyclonal production of total IgE. In this study we investigated the effects of GC on the antigen (Ag)-specific IgE response in a human in vitro system with peripheral blood mononuclear cells or B cells of bee venom-sensitized individuals that allows the production of bee venom phospholipase A2 (PLA)-specific IgE and IgG4 antibodies (Ab). PLA-specific Ab were induced by simultaneously activating T cells and B cells specifically with allergen and polyclonally with anti-CD2 and soluble CD40 ligand (sCD40L) in the presence of interleukin (IL)-4. Indeed, dexamethasone and prednisolone enhanced the formation of total IgE and IgG4 in PBMC, while the production of PLA-specific IgE and IgG4 Ab was selectively inhibited in a dose-dependent manner. The suppressive effect of GC was mediated during Ag-specific stimulation and T cell-B cell interaction. This was due to GC suppressing specific T cell proliferation and cytokine production, whereas neither allergen-specific nor total IgE and IgG4 production by sCD40L/IL-4-stimulated pure B cells was affected. In contrast to GC, cyclosporine A inhibited both total and PLA-specific IgE and IgG4 secretion in peripheral blood mononuclear cells and B cell cultures. Further experiments showed that increase in nonspecific total isotype response resulted from inhibition of IL-4 uptake by cells other than B cells and sufficient availability of IL-4 to B cells for isotype switch and synthesis. Furthermore, demonstration of opposite regulatory effects of GC on specific and total isotype formation in vitro, including the inhibition of allergy-relevant Ag-specific IgE response, may contribute to a better understanding of apparently controversial observations, and explain why most allergic patients benefit from GC therapy.