Persistent skin colonization with Staphylococcus aureus in atopic dermatitis: relationship to clinical and immunological parameters.

BACKGROUND: Staphylococcus aureus has important implications for the pathogenesis of atopic dermatitis (AD). In some patients S. aureus can be eradicated from the skin during anti-inflammatory treatment, while in others bacterial colonization is persistent. Potential mechanisms and features of these two distinct groups of patients are not known. OBJECTIVE: Accordingly, we studied relationships between the ability to eliminate S. aureus during an anti-inflammatory treatment and selected clinical and immunological features. METHODS: Quantitative assessment of S. aureus on the skin, in nasal vestibule and throat, serum IgE levels, CD4/CD8 T-cell ratio, lymphocyte proliferation and phagocyte oxidative burst were determined during the exacerbation and after 4 and 12 weeks of the treatment using topical steroid and oral antihistamine in 34 patients with AD. RESULTS: S. aureus was found on the skin of all 34 patients during exacerbation. Disease severity scoring of atopic dermatitis (SCORAD) correlated with the density of bacteria. Treatment with oral antihistamine and topical steroid resulted in a significant alleviation of symptoms, which correlated with the elimination of S. aureus from the skin in 70% of patients. In the remaining 30% of patients, dense (more than 10(10)/cm2) S. aureus skin colonization, persisted despite the treatment. Patients with persistent S. aureus presented with higher serum IgE levels, lower lymphocyte proliferation in response to staphylococcal enterotoxin B, phytohaemagluttinin and anti-CD3. Persistence of S. aureus was more common in men. CONCLUSIONS: Patients with AD differ in the ability to clear S. aureus from the skin during anti-inflammatory treatment, which appears to be related to the abnormalities in immunological parameters. Local antibiotic therapy should be considered only in patients with persistent S. aureus colonization.

[Selected parameters of the cellular and humoral immunity in atopic dermatitis. Relationship to the severity of the disease]. / Charakterystyka wybranych parametrów odpornosci komórkowej i humoralnej u chorych na atopowe zapalenie skóry. Zwiazek z zaawansowaniem klinicznym choroby.

UNLABELLED: Despite the great progress, our understanding of the pathogenesis of atopic dermatitis (AD) is still incomplete. In particular, the clinical importance of various changes of the immune system parameters is unclear. Accordingly we have undertaken the study to compare selected parameters of cellular and humoral immunity between AD subjects (n = 26) and healthy controls (n = 10). These parameters included immunoglobulin levels (IgE in particular), neutrophil respiratory, oxygen burst, peripheral blood lymphocyte phenotype and response to mitogens. We also analysed the relationship between these parameters and clinical severity of skin lesions. RESULTS: Mean total immunoglobulin E levels were very significantly increased in the AD group (1563 +/- 459 vs 35.5 +/- 12.1 IU/ml; p = 0.001). Simultaneously total serum IgE levels varied extensively between individual subjects with AD and were significantly correlated to clinical severity of the disease (Rs = 0.44; p = 0.02). Atopic dermatitis was also associated with the increase in the number of CD4+ and simultaneous decrease in the CD8+ lymphocytes causing statistically significant difference in CD4:CD8 ratio compared to the control group. We also observed changes of proliferation indices to phytohaemagglutinin (decrease) and increase of responses to anti CD3 mAb (OKT-3) and staphylococcal enterotoxin B. None of these immune parameters however, appeared to be statistically correlated to clinical status. CONCLUSIONS: We find that atopic dermatitis is associated with significant changes of several important indices of cellular and humoral immunity including increased IgE levels and altered peripheral lymphocyte proliferation capacity and phenotype. Change of total IgE levels appears to be the most important from clinical point of view.

[Evaluation of interactions between strains of S. aureus isolated from different clinical specimens with peripheral blood phagocytic cells]. / Ocena interakcji zachodzacych pomiedzy szczepami S. aureus a komórkami fagocytujacymi krwi obwodowej.

The aim of this study was to investigate the interactions occurring between peripheral blood phagocytes and strains of S. aureus isolated from different clinical specimens (blood, respiratory tract, pus). To evaluate the sensitivity of microorganisms to bactericidal activity of phagocytes, monocytes and granulocytes separated from peripheral blood by standard density gradient and by counter-current centrifugal elutriation were incubated with suspensions of opsonized bacteria. In parallel, the viability of phagocytes was examined by flow cytometry, and the ability of bacteria to trigger reactive oxygen intermediates (ROI) production was evaluated by chemiluminescence measurement. To investigate efficiency of phagocytosis, bacteria were labelled with fluorescein isothiocyanate (FITC) and the percentage of cells containing FITC-labelled bacteria was analysed by flow cytometry. The data obtained show that strains of S. aureus originated from different clinical specimens, differ in their sensitivity to bactericidal activity of phagocytes--strains isolated from the blood show the highest, but strains isolated from respiratory tract show the lowest sensitivity for killing. These strains differ too in their ability to trigger monocyte CL response. Contrary, there was no difference in toxicity of bacteria against phagocytes. Strains isolated from peripheral blood showed significant negative correlation between the ability to trigger CL response and toxicity against phagocytes.

[Evaluation of the interactions between strains of S. aureus and peripheral blood phagocytic cells]. / Ocena interakcji zachodzacych pomiedzy szczepami S. aureus a komórkami fagocytujacymi krwi obwodowej.

The aim of this study was to investigate the interactions occurring between peripheral blood phagocytes and strains of S. aureus isolated from different clinical specimens (blood, respiratory tract, pus). To evaluate the sensitivity of microorganisms to bactericidal activity of phagocytes, monocytes and granulocytes separated from peripheral blood by standard density gradient and by counter-current centrifugal evaluation these cells were incubated with suspensions of opsonized bacteria. In parallel, the viability of phagocytes was examined by flow cytometry, and the ability of bacteria to trigger reactive oxygen intermediates (ROI) production was evaluated by chemiluminescence measurement. To investigate the efficiency of phagocytosis, bacteria were labelled with fluorescein isothiocynate (FITC) and the percentage of cells containing FITC-labelled bacteria were analysed by flow cytometry. The data obtained show the strains of S. aureus derived from different clinical specimens, differ in their sensitivity to bactericidal activity of phagocytes--strains isolated from the blood show the highest, but strains isolated from the respiratory tract have the lowest sensitivity to killing. These strains differ too in their ability to trigger monocyte CL response. On the contrary, there was no difference in toxicity of bacteria against phagocytes. Strains isolated from peripheral blood showed a significant negative correlation between the ability to trigger CL response and toxicity against phagocytes.

Experimental studies of Rio Grande virus in rodent hosts.

Rio Grande (RG) virus, a new member of the Phlebotomus fever serogroup, was inoculated into wild wood rats (Neotoma micropus) and laboratory-reared cotton rats (Sigmodon hispidus) to determine if these potential hosts could be experimentally infected. Nine of 14 (64%) wood rats became viremic, with titers of circulating virus ranging from 10(2.3) to 10(5.3) plaque-forming units (PFU)/ml and a geometric mean titer of 10(3.7) PFU/ml. Virus was not detected in urine specimens from inoculated wood rats but was found in a single saliva specimen. RG virus was detected in the blood of 1 of 12 (8%) cotton rats. Neutralizing (N) antibody developed in 8 of 9 inoculated wood rats which survived for 30 days postinoculation and in 11 of 12 cotton rats. N antibody was still detectable in 4 of 7 wood rats which survived for 1 year, and all 7 were resistant to rechallenge with the virus, as were 3 wood rats with naturally-acquired antibody. High mortality (36%) occurred in inoculated wood rats; whereas low mortality (8%) occurred in cotton rats. The specific cause of death of the rats was not determined. Modes of transmission of the virus in nature are discussed.

Rio Grande--a new phlebotomus fever group virus from south Texas.

Three strains of a new Phlebotomus fever group virus were isolated from pack rats (Neotoma micropus) collected in south Texas during 1973--1974; the name Rio Grande was proposed for this virus. The virus is pH 3.0 labile, sensitive to the action of sodium deoxycholate and heat (56 degrees C) labile. The results of a serosurvey indicated that pack rats are probably the principal vertebrate host for Rio Grande virus and that year-round transmission of the virus may occur. Because no isolations of this virus were made from hematophagous insects, the vector, if any, remains undetermined.