Consensus guidelines for interventional cardiology services delivery during covid-19 pandemic in Australia and new Zealand

The global coronavirus disease (COVID-19) pandemic poses an unprecedented stress on healthcare systems internationally. These Health system-wide demands call for efficient utilisation of resources at this time in a fair, consistent, ethical and efficient manner would improve our ability to treat patients. Excellent co-operation between hospital units (especially intensive care unit [ICU], emergency department [ED] and cardiology) is critical in ensuring optimal patient outcomes. The purpose of this document is to provide practical guidelines for the effective use of interventional cardiology services in Australia and New Zealand. The document will be updated regularly as new evidence and knowledge is gained with time. Goals Considerations.

Induction of glucocorticoid receptor-beta expression in epithelial cells of asthmatic airways by T-helper type 17 cytokines

BACKGROUND

Corticosteroid insensitivity in asthmatics is associated with an increased expression of glucocorticoid receptor-beta (GR-beta) in many cell types. T-helper type 17 (Th17) cytokine (IL-17A and F) expressions increase in mild and in difficult-to-treat asthma. We hypothesize that IL-17A and F cytokines alone or in combination, induce the expression of GR-beta in bronchial epithelial cells.

OBJECTIVES

To confirm the expression of the GR-beta and IL-17 cytokines in the airways of normal subjects and mild asthmatics and to examine the effect of cytokines IL-17A and F on the expression of GR-beta in bronchial epithelial cells obtained from normal subjects and asthmatic patients.

METHODS

The expression of IL-17A and F, GR-alpha and GR-beta was analysed in bronchial biopsies from mild asthmatics and normal subjects by Q-RT-PCR. Immunohistochemistry for IL-17 and GR-beta was performed in bronchial biopsies from normal and asthmatic subjects. The expression of IL-6 in response to IL-17A and F and dexamethasone was determined by Q-RT-PCR using primary airway epithelial cells from normal and asthmatic subjects.

RESULTS

We detected significantly higher levels of IL-17A mRNA expression in the bronchial biopsies from mild asthmatics, compared with normal. GR-alpha expression was significantly lower in the biopsies from asthmatics compared with controls. The expression of IL-17F and GR-beta in biopsies from asthmatics was not significantly different from that of controls. Using primary epithelial cells isolated from normal subjects and asthmatics, we found an increased expression of GR-beta in response to IL-17A and F in the cells from asthmatics (P< or =0.05). This effect was only partially significant in the normal cells. Dexamethasone significantly decreased the IL-17-induced IL-6 expression in cells from normal individuals but not in those from asthmatics (P< or =0.05).

CONCLUSION

Evidence of an increased GR-beta expression in epithelial cells following IL-17 stimulation suggests a possible role for Th17-associated cytokines in the mechanism of steroid hypo-responsiveness in asthmatic subjects.

Advanced applications of 3-dimensional echocardiography

Over the last few decades, advancements in ultrasound, electronic and computing technologies have permitted current second generation 3-dimensional (3D) echocardiography to display on-line 3D rendered images of the heart. Since various studies demonstrated its superiority over 2-dimensional echocardiography, there is growing enthusiasm to embrace this new 3D echocardiographic technology. With its increasing widespread clinical availability, 3D echocardiography is getting closer to routine clinical use. However, as with any new emerging technologies, clinical applications of 3D echocardiography should be based on current evidence. This review will focus on the evidence from clinical studies that form the scientific basis for the advanced applications of 3D echocardiography, from cardiac chamber volume assessments, left ventricular dyssynchrony assessments, quantifications of valvular abnormalities, to the role of 3D echocardiography during cardiac interventions.

How compliant are we with guidelines for coronary angiography in clinical practice?

BACKGROUND

The American College of Cardiology and American Heart Association have published guidelines for coronary angiography. We evaluated the compliance rate with these guidelines in clinical practice, its correlation to results of angiography and aimed to identify problem areas of non-compliance.

METHODS

We prospectively evaluated 802 consecutive referrals for coronary angiography over 5 months in 2002 in a tertiary referral hospital. These referrals were assessed by two independent reviewers blinded to the results of angiography.

RESULTS

Patient age was 62 +/- 11 years (522 men, 433 inpatients, 369 day-only patients). Referrals were outside published guidelines in 34.3 and 36.2% as evaluated by the two reviewers (concordance rate 88.2%, kappa = 0.74, p < 0.001). Intraobserver agreement was 97.5%. The rate of angiography showing either normal arteries or only minor diseases (<50%) was higher for referrals outside guidelines (68.4 vs 22.6%, P < 0.001). Compliance rate was high with indications of non-ST-elevation myocardial infarction (99.2%) and ST-elevation myocardial infarction (95.8%), valvular disease (80%) and arrhythmia (80%). Compliance rate was lower with assessment of dyspnoea or heart failure (74.3%) and before non-cardiac surgery (72.7%) and was particularly low with assessment of chest pain (53.2%). Younger age (odds ratio (OR) 1.04, P < 0.001), female sex (OR 2.67, P < 0.001), day-only procedure (OR 2.27, P < 0.001) and non-invasive cardiologist referrer (OR 1.41, P = 0.046) were independent predictors of non-compliance.

CONCLUSION

Referrals for coronary angiography were outside guidelines in a significant proportion of patients. Rate of negative angiography was higher when the referrals were outside guidelines. Problematic areas of non-compliance could be identified. Measures specifically targeting these areas may be more effective in improving the overall guideline compliance in clinical practice.

End points in clinical trials: are they moving the goalposts?

In selecting and defining composite end points in clinical trials, are we trading off clinical significance for statistical significance?

Functional and prognostic implications of left ventricular contractile reserve in patients with asymptomatic severe mitral regurgitation

OBJECTIVE

To evaluate contractile reserve (CR) determined by exercise echocardiography in predicting clinical outcome and left ventricular (LV) function in asymptomatic severe mitral regurgitation (MR).

DESIGN

Cohort study.

SETTING

Regional cardiac centre.

PATIENTS AND OUTCOME MEASURES

LV volumes and ejection fraction (EF) were measured at rest and after stress in 71 patients with isolated MR. During follow up (mean (SD) 3 (1) years), EF and functional capacity were serially assessed and cardiac events (cardiac death, heart failure, and new atrial fibrillation) were documented.

RESULTS

CR was present in 45 patients (CR+) and absent in 26 patients (CR-). Age, resting LV dimensions, EF, and MR severity were similar in both groups. Mitral surgery was performed in 19 of 45 (42%) CR+ patients and 22 of 26 (85%) CR- patients. In patients undergoing surgery, CR was an independent predictor of follow up EF (p = 0.006) and postoperative LV dysfunction (EF < 50%) persisted in five patients, all in the CR- group. Event-free survival was lower in surgically treated patients without CR (p = 0.03). In medically treated patients, follow up EF was preserved in those with intact CR but progressively deteriorated in patients without CR, in whom functional capacity also deteriorated.

CONCLUSIONS

Evaluation of CR by exercise echocardiography may be useful for risk stratification and may help to optimise the timing of surgery in asymptomatic severe MR.

Use of a quantitative point-of-care test for the detection of serum cardiac troponin T in patients with suspected acute coronary syndromes

We compared a third generation quantitative cardiac troponin T (cTnT) point-of-care testing (POCT) from Roche Diagnostics with the laboratory assay (Roche Elecsys 2010 immunoassay analyser). Heparin-treated blood and serum were collected simultaneously in 133 unselected patients (mean age 62 +/- 14 years, 38% females) presenting to our hospital with possible cardiac chest pain. Results of the POCT were measured against the laboratory-based assay considered as the gold standard. There were 18 POCT positive versus 24 laboratory assay positive (> or = 0.03 ng/mL) patients. POCT was falsely negative in six patients, with values between 0.03 and 0.1 ng/mL. The POCT had a sensitivity of 75%, specificity of 100%, positive predictive value of 100%, negative predictive value of 95% and a total accuracy of 95%; kappa = 0.831 (P < 0.001). There was good correlation between the values of POCT and the laboratory assay: Y = 1.195X + 0.002, r2 = 0.94 (P < 0.0001). Whereas cTnT levels > 0.1 mg/mL were reliably detected with this current generation of POCT, cTnT levels between 0.03 and 0.10 ng/mL were not. Future generations of devices will need to improve sensitivity to reliably risk stratify patients with suspected acute coronary syndromes.

The keratinocyte as a target for staphylococcal bacterial toxins

Skin infections with Staphylococcus aureus are not only an important cause of morbidity and even mortality, but are thought to serve as initiation and/or persistance factors for numerous inflammatory skin diseases, including psoriasis and atopic dermatitis. One mechanism by which S. aureus can modulate the immune system is through the production of proteins such as superantigenic toxins, Protein A, as well through the cytolytic alpha-toxin. This review serves to discuss the biology of these three types of proteins, with emphasis on their ability to stimulate the production of powerful pro-inflammatory lipid- and protein-derived cytokines in keratinocytes. Characterization of interactions between these proteins and the keratinocyte can provide a better understanding of how bacterial infection modulates inflammatory skin diseases, as well as provide the basis for improved therapies involving antibacterial agents.

Clarithromycin potentiates glucocorticoid responsiveness in patients with asthma: results of a pilot study

BACKGROUND

Selected macrolide antibiotics have steroid-sparing effects in patients with steroid-dependent asthma. In addition to inhibiting methylprednisolone clearance, macrolides may also display anti-inflammatory effects.

OBJECTIVE

To determine whether clarithromycin, by virtue of its anti-inflammatory effects, enhances glucocorticoid sensitivity.

DESIGN

Open-label, pilot study in a paired design (pre- and posttreatment).

PARTICIPANTS

Seven patients, mean age 27 (range 15 to 42 years), with mild to moderate asthma under good control.

METHODS

Clarithromycin (500 mg) was administered twice daily for 10 days with blood drawn for lymphocyte stimulation assays at baseline, and again upon completion of therapy. Lymphocytes were stimulated with phytohemagglutinin in the presence and absence of increasing concentrations of clarithromycin and dexamethasone (DEX).

RESULTS

At baseline, clarithromycin alone did not cause a significant degree of suppression of T-lymphocyte activation, yet clarithromycin significantly enhanced the sensitivity of lymphocytes to suppression by DEX as measured by a shift in the DEX dose-response curve by at least 6-fold (P = 0.04). In addition, a 10-day course of clarithromycin resulted in: 1) a significant decrease in the inhibitory concentration which results in a 50% reduction in proliferation for DEX alone, thereby increasing glucocorticoid sensitivity (P = 0.04); 2) heightened inhibitory effect of clarithromycin alone (P = 0.03); and 3) a sustained suppressive effect with the combination of clarithromycin and DEX on the inhibition of lymphocyte stimulation (P = 0.01).

CONCLUSIONS

Clarithromycin acts synergistically with DEX in suppressing lymphocyte activation. In addition, a 10-day course resulted in a significant treatment effect as evidenced by lower inhibitory concentration which results in a 50% reduction in proliferation value for DEX, a heightened response to clarithromycin alone, and a consistent degree of suppression of lymphocyte stimulation when clarithromycin and DEX were used together.

Pathophysiologic mechanisms in atopic dermatitis

Atopic dermatitis is a common, chronic inflammatory skin disease that frequently predates the development of asthma and/or allergic rhinoconjunctivitis. Recent studies have provided new insights into how the complex interrelationship of genetic, environmental, and immunologic factors may contribute to the development of atopic dermatitis. This article examines some of the factors involved in chronic cutaneous inflammation in this disease. Greater understanding of the mechanisms that underlie the pathophysiology of atopic dermatitis may lead to improved treatment strategies for this increasingly common skin disease.

Onset and persistence of childhood asthma: predictors from infancy

OBJECTIVE

In a prospective study of children with a family history of asthma, asthma onset by 3 years of age was found previously to be positively associated with variables from the first year of life, including elevated total immunoglobulin E (IgE), frequent respiratory infections, and parenting difficulties. We followed this cohort of genetically at-risk children to investigate the relationship between factors assessed in infancy and asthma, allergy, and psychological status at school age.

METHODS

A cohort of 150 children who were at risk for developing asthma were identified prenatally on the basis of the mothers' having asthma. For 28 children, the father had asthma as well, putting them at bilateral genetic risk. Families primarily were middle and upper middle class Caucasians. Parents came to the clinic during the third trimester of pregnancy for assessments of medical and psychosocial functioning. A home visit took place when the infant was 3 weeks old, when parenting risk was assessed before the onset of any asthma symptoms. Parenting difficulties included problems with infant caregiving as well as components of maternal functioning, such as postpartum depression and inadequate marital support. Blood was drawn for serum IgE at 6 months of age. Parents and offspring subsequently came to the clinic multiple times, with the last clinic visit during the child's sixth year. Follow-up at age 6 involved a clinic visit for allergy and psychosocial evaluations, consisting of interviews and a behavior questionnaire. Seventy-seven children received the allergy and psychosocial evaluation, 26 received the psychosocial evaluation in the clinic, and 30 families received telephone interviews and mailed in questionnaires. Additional monitoring of families by telephone and mail was maintained over the next 2 years, until the children were 8, to ensure accurate characterization of the course of illness. Comprehensive medical records were obtained and reviewed for all health care contacts. Children were designated as having asthma when there was documentation in medical records of physician-diagnosed asthma, observed wheezing, and/or prescription of asthma medications during the time period when the child was between 6 and 8 years of age. Parental reports of the occurrence of asthma corroborated the medical record data.

RESULTS

Data regarding asthma status were available for 145 children through 8 years of age. Forty (28%) of the children manifested asthma between 6 and 8 years of age. Among variables previously reported to predict asthma onset by age 3, 3 proved to have significant univariate relationships with asthma between ages 6 and 8: elevated IgE levels measured when the children were 6 months of age, global ratings of parenting difficulties measured when infants were 3 weeks old, and higher numbers of respiratory infections in the first year of life. Among these offspring of mothers with asthma, paternal asthma showed a significant association with asthma between ages 6 and 8. Eczema in the first year was not significantly related to later asthma. Multiple logistic regression showed that the model that best predicted asthma at ages 6 to 8 from infancy variables included 2 main effects. The adjusted odds ratio for 6-month IgE was 2.15 (1.51, 3.05) and for parenting difficulties was 2.07 (1.15, 3.71). Although socioeconomic status (SES) was not associated with asthma at ages 6 to 8, families of lower SES were more likely to be rated as having parenting difficulties early in the child's life. The mothers of lower SES breastfed for a shorter period of time and were more likely to smoke during their infant's first year. There were more respiratory infections during the first year of life among infants whose mother was rated as having more parenting difficulties. Mothers who reported smoking breastfed their infants for a shorter length of time. Male gender was significantly associated with higher IgE levels when infants were 6 months of age. Laboratory testing was completed for 77 children at age 6. Total serum IgE levels were significantly higher for the children with asthma between ages 6 and 8. Skin-prick testing showed that the children with asthma had significantly more positive skin test reactions than did the children without asthma. Psychosocial interview data at 6 years of age were available for 103 families, and behavioral questionnaires were available for 133 families. On the basis of 6-year interviews, children with asthma were rated as being at greater psychological risk than were the children without asthma. Mothers' Child Behavior Checklist (CBCL) ratings of their children's behavior indicated higher internalizing scores for the children with asthma as compared with the children without asthma. Like the 6-month IgE, 6-year IgE was higher for boys. IgE levels measured at 6 months of age were significantly correlated with 6-year IgE levels. Parenting difficulties measured at 3 weeks were significantly correlated with 6-year measures of maternal depression, CBCL Internalizing score, and Child Psychological Risk (CPR) score. There also were significant correlations among the psychosocial variables assessed when the children were 6 years of age; maternal depression was significantly associated with child CBCL Internalizing score and CPR score, and the last 2 also were significantly correlated. Multiple logistic regression showed that 2 concurrently measured variables entered the model showing the strongest associations with asthma at ages 6 to 8. The adjusted odds ratio for CPR score was 3.21 (1.29-7.96) and for 6-year IgE was 1.71 (1.04-2.80).

CONCLUSIONS

This study of the natural history of childhood asthma focused on the development of asthma into the school-age years in a genetically at-risk group of children. The relationships between biological and psychosocial variables in the first year and school-age asthma support the formulation of asthma as beginning early in life, with the developing immune system interacting with environmental influences. The data provide support for the possible contribution of psychosocial factors to asthma onset and persistence into childhood.

Fibronectin and fibrinogen contribute to the enhanced binding of Staphylococcus aureus to atopic skin

BACKGROUND

Staphylococcus aureus colonizes the skin lesions of more than 90% of patients with atopic dermatitis (AD). The mechanism for increased S aureus colonization in AD is unknown. However, the initial event in colonization requires adherence of S aureus to the skin.

OBJECTIVE

The purpose of this study was to examine the roles of various bacterial adhesins on S aureus binding to AD skin.

METHODS

In an attempt to delineate the mechanism behind this adherence process, an in vitro bacterial binding assay was developed to quantitate the adherence of various S aureus strains to AD, psoriatic, and normal skin sections. S aureus strains used in this study were obtained either from cultures of AD skin lesions or from genetically manipulated strains of S aureus that lacked specific microbial surface components recognizing adhesive matrix molecules (MSCRAMMs)--namely, fibronectin-binding protein (Fnbp), fibrinogen-binding protein (Clf), collagen-binding protein (Cna), and their parent strains. In addition, S aureus strains from patients with AD were pretreated with fibronectin or fibrinogen to block MSCRAMM receptors and interfere with binding.

RESULTS

Under all experimental conditions, binding of S aureus was localized primarily to the stratum corneum. Immunocytochemical staining of AD skin sections showed a redistribution of fibronectin to the cornified layer, an observation not seen in normal skin. S aureus binding to uninvolved AD skin was significantly greater than the binding to uninvolved psoriatic skin (P <.0001) and normal skin (P <.0005). The Fnbp-negative S aureus showed a significant reduction in binding to the AD skin (P <.0001) but not to the psoriatic and normal skin. In the AD skin, a significant reduction in the binding of S aureus was also observed in the Clf-negative strain (P <.0001) but not in the Cna-negative S aureus. Preincubation of S aureus with either fibronectin or fibrinogen also inhibited bacterial binding to AD skin (P <.0001).

CONCLUSION

These data suggest that fibronectin and fibrinogen--but not collagen--play a major role in the enhanced binding of S aureus to the skin of patients with AD.

Preferential binding of Staphylococcus aureus to skin sites of Th2-mediated inflammation in a murine model

Staphylococcus aureus is found on over 90% of atopic dermatitis skin lesions and is thought to contribute to skin inflammation via the production of potent exotoxins. In contrast, less than 5% of normal subjects harbor S. aureus. This suggests that an atopic immune response itself may play a role in preferential binding of S. aureus to the skin. To examine this issue more directly, we analyzed the S. aureus binding characteristics of skin in mice undergoing different T helper type 1 cell versus T helper type 2 cell inflammatory responses using a novel in vitro bacterial binding assay. BALB/C female mice were first sensitized to ovalbumin with alum or ovalbumin with complete Freund's adjuvant to induce T helper type 2 or T helper type 1 responses, respectively. Mice were then challenged intradermally with either saline (control) or ovalbumin. Forty-eight hours later, skin specimens were obtained from the challenge sites, and the number of S. aureus binding to each skin section was quantitated. Bacterial binding was found to be significantly greater at skin sites of BALB/C mice that had been ovalbumin/alum sensitized compared with ovalbumin/complete Freund's adjuvant sensitized (p < or = 0.01). When compared to the ovalbumin sensitized/challenged skin of wild type BALB/C mice or interferon-gamma gene knockout mice, interleukin-4, but not interferon-gamma, gene knockout mice had significantly less S. aureus binding at their ovalbumin sensitized/challenged skin sites. Mutant S. aureus strains that lacked either fibronectin- or fibrinogen-binding protein expression showed significantly reduced S. aureus binding compared with the parent wild type strain (p < 0.005). Moreover, preincubation of the wild type bacteria with fibronectin or fibrinogen, but not collagen, resulted in significantly less skin binding of S. aureus (p < 0.01). Incubation of skin with interleukin-4, and less so with interferon-gamma, led to more binding of wild type S. aureus but not of an S. aureus mutant deficient in fibronectin binding protein expression. After interleukin-4 incubation, but not interferon-gamma, epidermal immunoreactivity for fibronectin was observed in murine skin explants. These results show that a T helper type 2 inflammatory environment can promote skin binding by S. aureus and that this binding is mediated by fibronectin and fibrinogen.

GRbeta expression in nasal polyp inflammatory cells and its relationship to the anti-inflammatory effects of intranasal fluticasone

BACKGROUND

Nasal polyposis disease is an inflammatory disorder with intense eosinophilic infiltration of respiratory mucosa that is often difficult to control with topical steroids. Recent evidence suggests that overexpression of the glucocorticoid receptor splice variant GRbeta in inflammatory cells might contribute to steroid insensitivity in diseases such as asthma.

OBJECTIVE

The purposes of this investigation were to determine whether nasal polyp (NP) inflammatory cells overexpress GRbeta and to examine whether GRbeta overexpression is associated with insensitivity to the potent topical steroid fluticasone propionate (FP).

METHODS

Biopsies were obtained from 10 subjects with NPs before and 4 weeks after treatment with intranasal FP. Middle turbinates biopsies from 6 healthy, nonallergic subjects served as normal controls. Biopsies were immunostained for inflammatory cell markers as well as GRbeta and probed for various cytokine mRNA. The anti-inflammatory response to FP was examined in relation to pretreatment levels of GRbeta expression.

RESULTS

The total numbers of inflammatory cells were increased in NPs. The percentage of inflammatory cells expressing GRbeta was also increased (40.5% +/- 19.2% vs 16.1% +/- 4.0%, P =.009). GRbeta expression in NPs was almost exclusive to T lymphocytes, eosinophils, and macrophages. An inverse correlation was observed between the baseline inflammatory cell GRbeta expression and the reduction after FP treatment in EG2-positive eosinophils, CD4-positive T lymphocytes, endothelial VCAM-1 expression, and IL-4 mRNA-positive cells. NPs that were "FP-insensitive" in terms of suppression of eosinophil numbers (major basic protein-positive) had a significantly greater percentage of GRbeta-positive inflammatory cells, a higher ratio of GRbeta-positive/GRalpha-positive cells, and increased numbers of GRbeta-positive eosinophils and macrophages in comparison with those that were "FP-sensitive." "FP-insensitive" NPs also demonstrated a higher percentage of IL-5-positive inflammatory cells expressing GRbeta before and after FP treatment.

CONCLUSION

GRbeta expression appears to be a marker of steroid insensitivity in NPs. Expression of GRbeta by NP inflammatory cells, particularly T cells and eosinophils, might render them resistant to suppression by topical steroids and thereby contribute to persistent NP inflammation.

Metropolitan home living conditions associated with indoor endotoxin levels

BACKGROUND

Household endotoxin exposure in allergy and asthma has been gaining attention for its dual potential to exacerbate these conditions in individuals with established disease and to abrogate atopy before disease onset.

OBJECTIVE

We sought to better understand the home environmental and lifestyle factors influencing house dust endotoxin levels.

METHODS

From the homes of 86 infants with wheeze in metropolitan Denver, Colorado, house dust endotoxin (detected with a standardized Limulus Amebocyte Lysate assay) and common indoor allergen (Fel d 1, Can f 1, Der p 1, Der f 1, and Bla g 1) contents were quantified. Comprehensive home environment and lifestyle questionnaires were completed during home visits by trained study staff and parents.

RESULTS

House dust endotoxin levels were associated with only 2 home environmental features: animals in the home and the presence of central air conditioning. The strongest positive associations were found with animals in the home. Interestingly, the homes without cats or other animals revealed a negative correlation between house dust Fel d 1 and endotoxin (P =.03). Central air conditioning, especially during months of typical use, was associated with lower house dust endotoxin levels. No significant associations between house dust endotoxin levels and home dampness, number of household inhabitants or young children, cleaning frequency, or presence of tobacco smokers in the home were found.

CONCLUSIONS

Indoor endotoxin exposure can be increased by the presence of animals in the home and decreased with central air conditioning. In some homes without animals, where allergen exposure adequate for sensitization still occurs, there are lower levels of house dust endotoxin. Therefore in homes without animals, factors that influence allergen and endotoxin levels in house dust probably differ. Households with detectable allergen levels but low endotoxin levels may provide a predisposing environment for animal allergen sensitization.

Decreased steroid responsiveness at night in nocturnal asthma. Is the macrophage responsible?

As peripheral blood mononuclear cells from patients with nocturnal asthma (NA) exhibit reduced steroid responsiveness at 4:00 A.M. as compared with 4:00 P.M., we hypothesized that NA is associated with increased nocturnal airway cell expression of GRbeta, an endogenous inhibitor of steroid action. Ten subjects with NA and seven subjects with nonnocturnal asthma (NNA) underwent bronchoscopy with bronchoalveolar lavage (BAL) at 4:00 P.M. and 4:00 A.M. BAL lymphocytes and macrophages were incubated with dexamethasone (DEX) at 10(-5) to 10(-8) M. DEX suppressed proliferation of BAL lymphocytes similarly at 4:00 P.M. and 4:00 A.M. in both groups. However, BAL macrophages from NA exhibited less suppression of IL-8 and TNF-alpha production by DEX at 4:00 A.M. as compared with 4:00 P.M. (p = 0.0001), whereas in the NNA group DEX suppressed IL-8 and TNF-alpha production equally at both time points. GRbeta expression was increased at night only in NA, primarily due to significantly increased expression by BAL macrophages (p = 0.008). IL-13 mRNA expression was increased at night, but only in the NA group and addition of neutralizing antibodies to IL-13 reduced GRbeta expression by BAL macrophages. We conclude that the airway macrophage may be the airway inflammatory cell driving the reduction in steroid responsiveness at night in NA, and this function is modulated by IL-13.

The revised two-factor Study Process Questionnaire: R-SPQ-2F

AIM

To produce a revised two-factor version of the Study Process Questionnaire (R-SPQ-2F) suitable for use by teachers in evaluating the learning approaches of their students. The revised instrument assesses deep and surface approaches only, using fewer items.

METHOD

A set of 43 items was drawn up for the initial tests. These were derived from: the original version of the SPQ, modified items from the SPQ, and new items. A process of testing and refinement eventuated in deep and surface motive and strategy scales each with 5 items, 10 items per approach score. The final version was tested using reliability procedures and confirmatory factor analysis.

SAMPLE

The sample for the testing and refinement process consisted of 229 students from the health sciences faculty of a university in Hong Kong. A fresh sample of 495 undergraduate students from a variety of departments of the same university was used for the test of the final version.

RESULTS

The final version of the questionnaire had acceptable Cronbach alpha values for scale reliability. Confirmatory factor analysis indicated a good fit to the intended two-factor structure. Both deep and surface approach scales had well identified motive and strategy subscales.

CONCLUSION

The revision process has resulted in a simple questionnaire which teachers can use to evaluate their own teaching and the learning approaches of their students.

Functional characterization of streptococcal pyrogenic exotoxin J, a novel superantigen

Streptococcal toxic shock syndrome (STSS) is a highly lethal, acute-onset illness that is a subset of invasive streptococcal disease. The majority of clinical STSS cases have been associated with the pyrogenic toxin superantigens (PTSAgs) streptococcal pyrogenic exotoxin A or C (SPE A or C), although cases have been reported that are not associated with either of these exotoxins. Recent genome sequencing projects have revealed a number of open reading frames that potentially encode proteins with similarity to SPEs A and C and to other PTSAgs. Here, we describe the cloning, expression, purification, and functional characterization of a novel exotoxin termed streptococcal pyrogenic exotoxin J (SPE J). Purified recombinant SPE J (rSPE J) expressed from Escherichia coli stimulated the expansion of both rabbit splenocytes and human peripheral blood lymphocytes, preferentially expanded human T cells displaying Vbeta2, -3, -12, -14, and -17 on their T-cell receptors, and was active at concentrations as low as 5 x 10(-6) microg/ml. Furthermore, rSPE J induced fevers in rabbits and was lethal in two models of STSS. Biochemically, SPE J had a predicted molecular weight of 24,444 and an isoelectric point of 7.7 and lacked the ability to form the cystine loop structure characteristic of many PTSAgs. SPE J shared 19.6, 47.1, 38.8, 18.1, 19.6, and 24.4% identity with SPEs A, C, G, and H, streptococcal superantigen, and streptococcal mitogenic exotoxin Z-2, respectively, and was immunologically cross-reactive with SPE C. The characterization of a seventh functional streptococcal PTSAg raises important questions relating to the evolution of the streptococcal superantigens.

Lymphovascular invasion enhances the prediction of non-sentinel node metastases in breast cancer patients with positive sentinel nodes

BACKGROUND

Fifty percent of patients with sentinel lymph node (SLN) metastases have no metastatic disease in non-SLNs on axillary lymph node dissection (ALND). The goal of this study is to determine which patients have metastatic disease limited to the SLN, and, therefore, may not require completion ALND.

METHODS

Of the first 1000 patients undergoing SLN biopsy at Memorial Sloan-Kettering Cancer Center, using a combined blue dye and isotope technique, 231 (26%) had positive SLN. Of these, 206 underwent completion ALND. They are the study group for this report.

RESULTS

The likelihood of non-SLN metastasis was inversely related to three clinicopathologic variables: tumor size < or = 1.0 cm; absence of lymphovascular invasion (LVI); and SLN micrometastases (< or = 2 mm). None of 24 patients with all three predictive factors had non-SLN metastases, whereas 58% of patients with none of the factors had disease in the non-SLN.

CONCLUSION

Patients with small breast cancers, no LVI, and SLN micrometastases have a low risk of non-SLN metastases, and may not require completion ALND.

Cellular and immunologic mechanisms in atopic dermatitis

Atopic dermatitis is a chronic inflammatory skin disease that is frequently associated with respiratory allergies. Atopic dermatitis develops as a result of a complex interrelationship of environmental, immunologic, genetic, and pharmacologic factors. Efforts to understand the relative contributions of these factors have led to research seeking to identify the relevant effector cells and mediators involved in the pathogenesis of atopic dermatitis. These factors include the pattern of local cytokine release, the differentiation of helper T cells, multiple roles of IgE, skin-directed cell responses, infectious agents, and superantigens. This article reviews these cellular and immunologic mechanisms underlying atopic dermatitis and discusses how an understanding of their role in the inflammatory process may lead to improved treatments for atopic dermatitis.

Characteristics of urban ozone level in Hong Kong

The long term trend of ozone level in Hong Kong has been investigated. One of the characteristics of ozone level in Hong Kong is the existence of autumn maximum and summer minimum. Observations of the diurnal variation of ozone level have been made in different area categories. There are early morning peak and afternoon peak occurred in the diurnal variation, which are different from some metropolitans where only an afternoon peak is observed. A negative correlation coefficient was found between monthly ozone level with nitric oxide level. On the contrary, there is a positive correlation between ozone and nitrogen dioxide. The positive correlation coefficient between nitric oxide and nitrogen dioxide shows that the total amount of nitric oxide emitted from a series of moving and fixed sources greatly exceeded the stoichiometric amount of ozone formed from chemical reactions of precursors and long distance transportation.

A 12-week study of tacrolimus ointment for the treatment of atopic dermatitis in pediatric patients

The safety and efficacy of 0.03% and 0.1% tacrolimus ointment for the treatment of atopic dermatitis were evaluated in a 12-week, randomized, double-blind, vehicle-controlled study of 351 children 2 to 15 years of age with moderate to severe atopic dermatitis. The mean age of patients was 6.1 years. A total of 61.5% of patients had severe atopic dermatitis at baseline. The mean percentage of body surface area affected was 47.7%, and 83.5% of patients were affected on the head and/or neck. Significantly more patients (P<.001) achieved clinical improvement of 90% or better with 0.03% or 0.1% tacrolimus ointment compared with vehicle. Significant improvements in the signs and symptoms of atopic dermatitis, percent body surface area affected, and the patient's assessment of pruritus were also observed early in treatment and were maintained throughout the study. Adverse events with a statistically significantly greater incidence in the 0.03% tacrolimus ointment treatment group compared with vehicle were limited to the sensation of skin burning, pruritus, varicella, and vesiculobullous rash ("blisters"). Varicella and vesiculobullous rash occurred at a low incidence (<5%). No adverse event occurred at a statistically higher incidence in the 0.1% tacrolimus ointment-treated group compared with vehicle. Tacrolimus ointment was equally safe for younger (2-6 years) and older (7-15 years) children. Both tacrolimus ointment concentrations (0.03% and 0.1%) were safe and significantly more effective than vehicle for the treatment of atopic dermatitis in children.

Biochemical and biological properties of Staphylococcal enterotoxin K

Staphylococcus aureus is an important human pathogen which is implicated in a wide variety of diseases. Major determinants of the virulence of this organism include extracellular virulence factors. Staphylococcal enterotoxins (SEs) are important causative agents in staphylococcal toxic shock syndrome and food poisoning. Our study identified a novel enterotoxin, SEK, and examined its biochemical and biological properties. SEK had a molecular weight of 26,000 and an experimentally determined pI of between 7.0 and 7.5. SEK was secreted by clinical isolates of S. aureus. We demonstrated that SEK had many of the biological activities associated with the SEs, including superantigenicity, pyrogenicity, the ability to enhance the lethal effect of endotoxin, and lethality in a rabbit model when administered by subcutaneous miniosmotic pump. Recombinant SEK was shown to stimulate human CD4(+) and CD8(+) T cells in a Vbeta-specific manner; T-cells bearing Vbeta 5.1, 5.2, and 6.7 were significantly stimulated to proliferate.

Allergen sensitization through the skin induces systemic allergic responses

The skin is a unique immunologic organ that acts as an interface between the external environment and the systemic immune response. As such, it may react directly with allergens that are applied epicutaneously, thereby influencing the systemic allergic response. It is well known that atopic dermatitis (frequently in association with food allergy) predates the development of asthma and allergic rhinitis by several years. The possibility that atopic dermatitis may influence the course of asthma is suggested by several interesting observations. First, children with atopic dermatitis and positive skin tests to allergens frequently have more severe asthma than asthmatic children without atopic dermatitis. Second, because total serum IgE is strongly associated with the prevalence of asthma, it raises the interesting question of whether allergen sensitization through the skin predisposes to more severe and persistent respiratory disease because of its effects on the systemic allergic response. Indeed, epicutaneous sensitization of mice to a protein antigen induces both a localized allergic dermatitis and hyperresponsiveness to methacholine, which suggests that epicutaneous exposure to antigen in atopic dermatitis may enhance the development of asthma. Finally, systemic immune activation in atopic dermatitis is supported by the observation that these patients have increased numbers of circulating activated T(H)2 cells, eosinophils, macrophages, and IgE. Many of the markers of leukocyte activation have been shown to correlate with the severity of atopic dermatitis disease. This systemic activation might facilitate local infiltration of primed T cells, eosinophils, and macrophages into the respiratory mucosa after inhalation of allergen in genetically predisposed hosts. The systemic aspects of atopic dermatitis, with an emphasis on respiratory effects, are summarized.

Evidence for the involvement of bacterial superantigens in psoriasis, atopic dermatitis, and Kawasaki syndrome

A growing body of evidence implicates streptococcal and staphylococcal superantigens in the development of psoriasis, atopic dermatitis and Kawasaki syndrome. In each of these illnesses, an abnormal state of immunologic activity is observed. Superantigens, which have a unique ability to activate large numbers of lymphocytes, are likely to contribute to these disorders in a number of ways. The demonstrated activities of bacterial superantigens include increasing the number of circulating lymphocytes, with activation of autoreactive subsets, upregulation of tissue homing receptors on circulating lymphocytes, and local activation of immune cells within affected tissues. Through these and other mechanisms, superantigens have a proven ability to induce high levels of inflammatory cytokines and/or initiate autoimmune responses that contribute to the development of skin and vascular disorders. Though development of the illnesses discussed in this review are highly complex processes, superantigens may well play a critical role in their onset or maintenance. Understanding superantigen function may elucidate potential therapeutic strategies for these disorders.

Additive immunosuppressive effects of 1,25-dihydroxyvitamin D3 and corticosteroids on TH1, but not TH2, responses

BACKGROUND

The biologic role of the vitamin D analogue 1, 25-dihydroxyvitamin D(3), such as antiinflammatory functions, reduction of cytokine production by T cells, and immunoglobulin production by B cells, has been reported. Such immunomodulatory effects may be potentially useful in dealing with autoimmunity and transplantation. However, whether this hormone has an additive immunosuppressive effect when it is used with corticosteroids has not been investigated, although these agents are commonly used together.

OBJECTIVE

Our purpose was to investigate the additive immunomodulatory effects of 1,25-dihydroxyvitamin D(3) on lymphocyte proliferation and cytokine production when used with corticosteroids.

METHODS

To investigate the additive effects of 1, 25-dihydroxyvitamin D(3) and dexamethasone on suppression of lymphocyte proliferation, normal PBMCs were cultured in anti-CD3 with or without different concentrations of dexamethasone (0-10(-7) mol/L) plus or minus different concentrations of 1, 25-dihydroxyvitamin D(3) (0-10(-6) mol/L). After 3 days, lymphocyte proliferation was assessed by [(3)H]-thymidine incorporation. To investigate the additive effects of 1,25-dihydroxyvitamin D(3) and dexamethasone on cytokine production, PBMCs were cultured for 3 days in the presence of anti-CD3 with or without 10(-6) mol/L dexamethasone plus or minus 10(-6) mol/L 1,25-dihydroxyvitamin D(3). IFN-gamma, IL-5, and IL-13 production in supernatants were measured by ELISA.

RESULTS

Our study demonstrated that, at concentrations of 10(-8), 10(-7), and 10(-6) mol/L, 1,25-dihydroxyvitamin D(3) significantly decreased lymphocyte proliferation compared with an ethanol control (P <.05). The IC(50) for dexamethasone was 4 x 10(-9) mol/L in culture without 1,25-dihydroxyvitamin D(3.) When 10(-9) mol/L of 1,25-dihydroxyvitamin D(3) was added to cultures with dexamethasone, IC(50) became 2 x 10(-9) mol/L. Moreover, when 10(-6), 10(-7), and 10(-8) mol/L of 1,25-dihydroxyvitamin D(3) were added in culture with dexamethasone, IC(50) became less than 1 x 10(-9) mol/L. IFN-gamma production in culture with either dexamethasone or 1,25-dihydroxyvitamin D(3) was significantly decreased compared with media or ethanol control (P <.0001). Moreover, when both agents were added in the same culture, IFN-gamma production was further decreased compared with either agent alone (P <.05). In contrast, 1,25-dihydroxyvitamin D(3) significantly (P <. 0001) increased IL-5 and IL-13, whereas dexamethasone significantly decreased these 2 cytokines (P <.0005). When 1,25-dihydroxyvitamin D(3) was combined with dexamethasone, IL-5 and IL-13 production was increased compared with dexamethasone alone (P <.001).

CONCLUSIONS

Our results demonstrate that 1,25-dihydroxyvitamin D(3) has significant additive effects on dexamethasone-mediated inhibition of lymphocyte proliferation. This hormone also has additive effects on inhibition of T(H)1 cytokine production when combined with dexamethasone. However, this hormone upregulates T(H)2 cytokines and inhibits steroid-mediated suppression of cytokines. These findings demonstrate the potential use of 1,25-dihydroxyvitamin D(3) as an immunosuppressive agent when combined with corticosteroids in T(H)1, but not T(H)2, immune responses.

Risk factors associated with glucocorticoid-induced adverse effects in children with severe asthma

BACKGROUND

Although high-dose inhaled glucocorticoids (GCs) with or without chronically administered oral GCs are often used in children with severe persistent asthma, the adverse effects associated with their use have not been well-described in this patient population.

OBJECTIVE

We sought to determine the GC-induced adverse effects profile of older children with severe persistent asthma.

METHODS

A chart review of 163 consecutive children 9 years of age or older admitted to National Jewish for difficult to control asthma was done.

RESULTS

The population studied consisted mostly of adolescents (mean +/- SD age, 14.4 +/- 2.1 years) with severe asthma receiving high-dose inhaled GC therapy (1675 +/- 94 microg/d) and averaging 6 systemic GC bursts per year. 50% required chronic oral GC therapy. GC-associated adverse effects were common and included hypertension (88%), cushingoid features (66%), adrenal suppression (56%), myopathy (50%), osteopenia (46%), growth suppression (39%), obesity and hypercholesterolemia (30%), and cataracts (14%). Height standard deviation scores of -0.44, -1.22, and -0.93 for those receiving intermittent, alternate day, and daily oral GCs, respectively, were smaller (less suppressed) than published values from the same institution before inhaled GC therapy (standard deviation scores of -1.26, -1.91, and -1.95, respectively). Osteopenia was strongly associated with growth suppression (odds ratio, 5.6; confidence interval, 2.7-11.8; P <.0001) and was found to be more common in female than male subjects, even after correcting for short stature (42% vs 18%, P <.006).

CONCLUSIONS

GC-associated adverse effects are still unacceptably common among children with severe asthma, even in those not receiving chronically administered oral GC therapy yet receiving high-dose inhaled GCs. Therefore close monitoring and proper intervention are warranted, especially in female subjects, who appear to be at greater risk for osteopenia. There is clearly a need to consider alternative therapy or earlier intervention. The magnitude of growth suppression, while still a problem, appeared to be less severe with the addition of inhaled GC therapy. This observation suggests that high-dose inhaled GC therapy, by affording better asthma control and allowing less use of systemic therapy, has attenuated the growth-suppressive effects of poorly controlled asthma.

Increased number of glucocorticoid receptor-beta-expressing cells in the airways in fatal asthma

BACKGROUND

We have recently demonstrated an increased number of glucocorticoid receptor-beta (GRbeta)-positive cells in steroid-insensitive subjects with severe asthma. Insensitivity to steroids may be a major contributing factor in fatal asthma; however, no such direct evidence has been report previously.

OBJECTIVE

Our aims were to investigate the expression of GRbeta immunoreactivity, an endogenous inhibitor of steroid action previously associated with steroid insensitivity, within the airways of patients who died of slow-onset fatal asthma and to compare its expression in patients with emphysema and in nonasthmatic subjects who died of unrelated causes. Sections from airways, both large and small, were obtained from 7 patients who died of asthma, 6 who died from emphysema, and 8 who died from nonpulmonary diseases. Sections from lungs of 6 patients with mild asthma whose lungs were resected for carcinoma were also included as controls.

METHODS

Tissue samples were processed for immunocytochemistry with a polyclonal antibody to GRbeta with use of the avidin-biotin technique and with monoclonal CD3, major basic protein, CD68, and elastase antibodies with the alkaline phosphatase-anti-alkaline phosphatase technique. Sequential immunocytochemistry was performed to phenotype the GRbeta immunoreactive cells. Tissue sections from both large (>2 mm) and small (<2 mm) airways were examined.

RESULTS

There was a significantly greater number of GRbeta immunoreactive cells in fatal asthma compared with emphysema and controls (P <.001 and P <.05, respectively). There was no difference in the expression of GRbeta in emphysema compared with controls. GRbeta immunoreactivity was also significantly higher in fatal asthma compared with mild asthma. The expression of GRbeta in the small airways of patients with severe asthma did not differ significantly from that in the large airways. The majority of GRbeta-positive cells were T cells and to a lesser extent eosinophils, macrophages, and neutrophils.

CONCLUSION

The results of this study support the association of GRbeta expression with fatal asthma and suggest that alternative anti-inflammatory agents need to be considered in the acute setting for patients who are not responding to steroid therapy.

Relation between house-dust endotoxin exposure, type 1 T-cell development, and allergen sensitisation in infants at high risk of asthma

BACKGROUND

Bacterial endotoxin is known to induce interferon gamma and interleukin 12 production, and therefore has the potential to decrease allergen sensitisation. To find out the role of early chronic endotoxin exposure in the development of allergen sensitisation and asthma, we compared concentrations of endotoxin in house dust with allergen sensitisation in infants at high risk for developing asthma.

METHODS

61 infants 9-24 months old with at least three physician-documented episodes of wheezing were studied. Concentrations of house-dust endotoxin and allergens were measured in the infants' homes. Allergen sensitisation was measured by skin-prick testing with a panel of common inhalant and food allergens. In a subset of these infants, proportions of T lymphocytes producing interferon gamma, and interleukins 4, 5, and 13 were calculated by cell-surface and intracellular cytokine staining, with flow cytometry.

FINDINGS

House-dust endotoxin concentrations ranged from 104 to 10,000 endotoxin units (EU) per mL (geometric mean 912 EU/mL). Concentrations did not vary significantly over a 6-month interval. Ten infants (16%) were sensitised to at least one allergen. The homes of allergen-sensitised infants contained significantly lower concentrations of house-dust endotoxin than those of non-sensitised infants (mean 468 vs 1035 EU/mL, respectively; p=0.01). Increased house-dust endotoxin concentrations correlated with increased proportions of interferon-gamma-producing CD4 T cells (p=0.01). Such concentrations did not correlate with proportions of cells that produced interleukins 4, 5, or 13.

INTERPRETATION

This study may provide the first direct in-vivo evidence that indoor endotoxin exposure early in life may protect against allergen sensitisation by enhancing type 1 immunity.

Evidence for increased expression of eotaxin and monocyte chemotactic protein-4 in atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is a chronic inflammatory skin disease associated with tissue eosinophilia and the activation of T lymphocytes. The novel eosinophil chemoattractants, eotaxin and monocyte chemotactic protein (MCP)-4, are up-regulated at sites of allergic inflammation, yet their contribution to the pathophysiologic mechanisms of AD remains to be determined.

OBJECTIVE

We sought to investigate the expression of eotaxin and MCP-4 in acute and chronic lesions from patients with AD and to determine their relationship to the numbers of resident inflammatory cells.

METHODS

With use of in situ hybridization, the expression of eotaxin and MCP-4 messenger RNA (mRNA) in skin biopsy specimens from patients with acute and chronic AD skin lesions was compared with that of uninvolved skin from these patients and skin from healthy volunteers.

RESULTS

There was a constitutive expression of eotaxin and MCP-4 mRNA in skin biopsy specimens from healthy subjects. Positive signal for chemokine mRNA was observed both within the epidermis and inflammatory cells (macrophages, eosinophils, and T cells) of the subepidermis in AD skin lesions. Within the subepithelium acute and chronic skin lesions exhibited a significant increase in the numbers of eotaxin and MCP-4 mRNA-positive cells compared with uninvolved skin (P <.01), whereas the numbers of eotaxin and MCP-4 mRNA-positive cells were significantly higher in chronic AD compared with acute AD skin lesions (P <.005, P <.001, respectively). Correlations were observed between the expression of eotaxin and MCP-4 mRNA and the presence of eosinophils and macrophages, respectively, in AD lesions (r(2) = 0.84, r(2) = 0.94).

CONCLUSION

There is an increased expression of eotaxin and MCP-4 in acute and chronic lesions, suggesting that these chemotactic factors play a major role in the pathophysiologic mechanisms of AD.

Atopic dermatitis: new insights and opportunities for therapeutic intervention

Atopic dermatitis (AD) is a chronic inflammatory skin disease that frequently predates the development of allergic rhinitis or asthma. It is an important skin condition with significant costs and morbidity to patients and their families; the disease affects more than 10% of children. Recent studies have demonstrated the complex interrelationship of genetic, environmental, skin barrier, pharmacologic, psychologic, and immunologic factors that contribute to the development and severity of AD. The current review will examine the cellular and molecular mechanisms that contribute to AD as well as the immunologic triggers involved in its pathogenesis. These insights provide new opportunities for therapeutic intervention in this common skin condition.

Induction of corticosteroid insensitivity in human PBMCs by microbial superantigens

BACKGROUND

Microbial superantigens have been described to contribute to the pathogenesis of chronic inflammatory diseases often complicated by insensitivity to glucocorticoid therapy. In bronchial asthma glucocorticoid insensitivity has been associated with increased expression of glucocorticoid receptor beta, an endogenous inhibitor of the classic glucocorticoid receptor alpha.

OBJECTIVE

To study a potential mechanism by which superantigens could contribute to poor disease control, we examined their capacity to alter steroid sensitivity and expression of glucocorticoid receptor beta.

METHODS

The capacity of dexamethasone to inhibit stimulation of PBMCs from 7 healthy subjects with the prototypic superantigens, staphylococcal enterotoxin (SE) B, toxic shock syndrome toxin (TSST)-1 and SEE, versus PHA, was tested. The expression of glucocorticoid receptor beta in normal PBMCs after stimulation with SEB, versus PHA, was assessed by immunocytochemistry.

RESULTS

Dexamethasone 10(-6) mol/L caused a 99% inhibition of PHA-induced PBMC proliferation but only a 19% inhibition of the SEB-induced, 26% inhibition of the TSST-1, and 29% inhibition of the SEE-induced PBMC proliferation (P <.01 for all superantigens versus PHA) demonstrating that superantigens can induce steroid insensitivity. Stimulation of normal PBMCs with SEB induced a significant increase of glucocorticoid receptor beta compared with PHA and unstimulated cells (P <.01).

CONCLUSION

We have demonstrated the capacity of microbial superantigens to induce glucocorticoid insensitivity, which should be considered in the diagnosis and treatment of patients with superantigen-triggered diseases. These data suggest that superantigens may contribute to glucocorticoid insensitivity through induction of glucocorticoid receptor beta.

Application of Staphylococcal enterotoxin B on normal and atopic skin induces up-regulation of T cells by a superantigen-mediated mechanism

BACKGROUND

The skin of patients with inflammatory skin diseases such as atopic dermatitis is frequently colonized with Staphylococcus aureus. Colonization with S aureus has been reported to exacerbate atopic dermatitis. Recent studies have demonstrated that S aureus isolated from the skin of patients with atopic dermatitis releases bacterial toxins that act as superantigens. We have previously applied the staphylococcal superantigen staphylococcal enterotoxin B (SEB) on intact human skin and found that the application led to induction of dermatitis.

OBJECTIVE

The purpose of the study was to determine whether superantigen-induced dermatitis is primarily due to a T cell-superantigen-mediated reaction or represents nonspecific cytokine-driven inflammation.

METHODS

We applied SEB, vehicle, and sodium lauryl sulfate on normal skin in healthy (n = 6) and atopic subjects (n = 6) and biopsy specimens were taken from all treated areas. The biopsy specimens from all subjects and peripheral blood from the atopic subjects were analyzed for the T-cell receptor (TCR) Vbeta repertoire with mAbs against TCR Vbeta 2, 3, 8.1, 12, 14, and 17.

RESULTS

From all subjects, both healthy and patients with atopic dermatitis, skin biopsy specimens from SEB-treated areas demonstrated selective accumulation of T cells expressing SEB-reactive TCR Vbeta 12 and 17 (P <.05). This selective up-regulation was not found in the sodium lauryl sulfate-treated areas.

CONCLUSION

Our data strongly support that superantigen-induced T-cell activation is involved in the dermatitis seen after experimental application of SEB on intact skin.

The many faces of Kawasaki syndrome

The clinical challenge lies in recognizing cases not fully meeting the syndrome's diagnostic criteria and those that strongly resemble a variety of infectious and reactive disorders. Prompt treatment with high-dose intravenous immune globulin in combination with aspirin can significantly reduce the frequency and severity of cardiovascular complications.

The modulation of cytokine and IgE production by tumor necrosis factor-beta in atopic dermatitis

Atopic dermatitis (AD) is associated with increased IL-4, IL-5, and IL-13 but decreased IFN-gamma production. This cytokine profile may account for the atopic features of this illness, including IgE upregulation. Recent studies have demonstrated that tumor necrosis factor (TNF)-beta is produced by Th1-like cells, but the cytokine modulation by TNF-beta and the clinical significance of this cytokine in AD is not known. Therefore, this study was carried out to determine the potential role of TNF-beta in AD. In this study, we cultured peripheral blood mononuclear cells from patients with AD and normal subjects with anti-CD3 monoclonal antibodies and investigated the production of TNF-beta by ELISA. The mean +/- SEM of TNF-beta production in AD was significantly lower than normal subjects (p = 0.03). The effect of TNF-beta on cytokine production was investigated by culturing peripheral blood mononuclear cells with anti-CD3 monoclonal antibodies in the presence or absence of TNF-beta. Compared with medium control, TNF-beta significantly decreased IL-5 (p = 0.0004) and IL-13 (p = 0.008) but increased IFN-gamma (p = 0.001) production. The effect of TNF-beta on IgE production was determined by culturing peripheral blood mononuclear cells in the IL-4- and anti-CD40-induced IgE production system. Interestingly, TNF-beta significantly decreased IgE (p = 0.02), but not IgG production compared with medium control. Our study demonstrates that TNF-beta production is downregulated in AD. This cytokine increases IFN-gamma production but decreases IL-5, IL-13, as well as IgE production. These findings suggest a potential role for TNF-beta in the pathogenesis of AD.

Epidermal HLA-DR and the enhancement of cutaneous reactivity to superantigenic toxins in psoriasis

Streptococcal and staphylococcal superantigens (SAg's) have been implicated in the pathogenesis of inflammatory skin diseases, but the mechanisms by which these toxins act are unknown. The present study assessed the ability of nanogram quantities of topically applied purified toxic shock syndrome toxin-1 (TSST-1), staphylococcal enterotoxin type B, and streptococcal pyrogenic enterotoxin types A and C to induce inflammatory reactions in clinically uninvolved skin of normal controls and subjects with psoriasis, atopic dermatitis, and lichen planus. These SAg's triggered a significantly greater inflammatory skin response in psoriatics than in normal control subjects or in subjects with atopic dermatitis or lichen planus. Surprisingly, skin biopsies did not exhibit the T-cell receptor Vbeta stimulatory properties predicted for SAg-induced skin reactions. By 6 hours after patch testing with SAg's, TNF-alpha mRNA had increased in the epidermis (but not the dermis) in biopsies from psoriatics, compared with controls. Immunohistochemical studies revealed significantly higher HLA-DR expression in keratinocytes from psoriatics than from controls. However, a mutant TSST-1 protein that fails to bind HLA-DR did not elicit an inflammatory skin reaction. These results indicate that keratinocyte expression of HLA-DR enhances inflammatory skin responses to SAg's. They may also account for previous studies failing to demonstrate selective expansion of T-cell receptor Vbetas in psoriatics colonized with SAg-producing Staphylococcus aureus, and they identify a novel T cell-independent mechanism by which SAg's contribute to the pathogenesis of inflammatory skin diseases.

The modulation of B7.2 and B7.1 on B cells by immunosuppressive agents

Several recent studies demonstrate that B7.2, but not B7.1, play an important role in allergic inflammation and IgE production. Agents that down-regulate B7.2 may therefore be of benefit for the treatment of Th2-driven allergic diseases. Our current study was carried out to investigate the effect of immunosuppressive agents, cyclosporin A (CsA) and dexamethasone, on B7.2 and B7.1 expression on B cells stimulated with the superantigen, toxic shock syndrome toxin-1 (TSST-1). The analysis of B7.2 and B7.1 on the same cells by flow cytometry demonstrated that TSST-1 up-regulated B7.2+B7.1- but not B7.1+B7.2- on B cells in a dose-dependent fashion. CsA and dexamethasone significantly down-regulated B7.2+B7.1- but up-regulated B7.2-B7.1+ B cells in the presence or absence of TSST-1 (100 ng/ml). Interestingly, the combination of CsA and dexamethasone was much more potent in the inhibition of B7.2 expression than either of these agents alone. As CD40 is known to up-regulate B7.2 expression on B cells, the mechanism of B7.2 down-regulation by CsA and dexamethasone was further studied by investigating the effect of these agents on CD40 expression on B cells. TSST-1 significantly increased CD40 expression on B cells. However, the addition of CsA or dexamethasone significantly down-regulated CD40 expression. Anti-CD40 MoAb significantly reversed the effects of CsA or dexamethasone on B7.2 and B7.1 expression, suggesting that T cell engagement of CD40 plays a role in the mechanisms by which CsA and dexamethasone acts on B cells. These data demonstrate the modulatory effect of CsA and dexamethasone on B7.2 and B7.1 expression on B cells and the potential role of CD40 in mediating this effect.