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The Premier Clostridium diffwile toxin A enzyme immunoassay (PTA ETA) (Meridian Diagnostics, Inc., Cincinnati, Ohio) for rapid diagnosis of antibiotic-associated colitis (AAC) was evaluated in a multicenter study. Stool samples from 421 patients suspected of having AAC were tested for toxin A by the PTA EIA and for toxin B by three tissue culture assays (TCA) employing WI-38 cells (New England Deaconess Hospital) in conventional tubes or foreskin fibroblasts (Children's Hospital) or Vero cells (Beth Israel Hospital) in microwells. The tubes and plates were examined at 24 and 48 h for cytotoxicity. Clinical criteria, repeat testing at another site, and culture of frozen stool samples for C. diJficik were used to evaluate discrepant results. Of 504 samples, 66 were positive and 409 were negative by both tests. Eight samples had indeterminate PTA EIA results and were excluded from this analysis. Of 21 discrepancies, 9 were PTA EIA positive and TCA negative and 12 were PTA EIA negative TCA positive. Following resolution of the discrepancies, 11 of 12 PTA EIA-negative-TCA-positive and 5 of 9 PTA EIA-positive-TCA-negative samples were considered true positive for AAC. The sensitivity and specificity were, respectively, 86.6 and 99.0% for the PTA EIA and 93.9 and 99.8% for TCA. The predictive values of positive and negative tests were, respectively, 94.7 and 97.4% for the PTA EIA and 98.7 and 98.8% for TCA. We conclude that the PTA EIA is a rapid, simple EIA technique whose accuracy in detecting enterotoxin A approaches that of reference TCA methods for detection of cytotoxin B.

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Besides their role in fighting viral infection and tumor resistance, recent studies have shown that NK cells also participate in the immune response against other infectious diseases. The aim of this study was to characterize the possible role of NK cells in the immune response against Paracoccidioides brasiliensis. Purified NK cells from paracoccidioidomycosis patients and healthy individuals were incubated with P. brasiliensis yeast cells or P. brasiliensis-infected monocytes, with or without the addition of recombinant IL-15. We found that NK cells from paracoccidioidomycosis patients exhibit a lower cytotoxic response compared with healthy individuals. NK cells are able directly to recognize and kill P. brasiliensis yeast cells, and this activity seems to be granule-dependent but perforin-independent, whereas the cytotoxicity against P. brasiliensis-infected monocytes is perforin-dependent. These results indicate that NK cells participate actively in the immune response against the P. brasiliensis infection either by directly destroying yeast cells or by recognizing and killing infected cells. Granulysin is the possible mediator of the cytotoxic effect, as the reduced cytotoxic activity against the yeast cells detected in patients with paracoccidioidomycosis is accompanied by a significantly lower frequency of CD56+granulysin+ cells compared with that in healthy controls. Furthermore, we show that NK cells released granulysin in cultures after being stimulated by P. brasiliensis, and this molecule is able to kill the yeast cells in a dose-dependent manner. Another important finding is that stimulated NK cells are able to produce proinflammatory cytokines (IFN-γ and TNF-α) supporting their immunomodulatory role in the infection.

Besides interleukin (IL)-1β and IL-18, the newly described cytokines of IL-1 family IL-33 and IL-37 can contribute to the differentiation and maintenance of different population of T cells. IL-33 acts as an allarmin and promotes a predominant Th2 inflammatory response, whereas IL-37 plays an important role as an antagonist of inflammation. In paracoccidioidomycosis (PCM), caused by the dimorphic fungi Paracoccidioides brasiliensis and P. lutzii, it has been shown that the acquired immune responses are associated with the diverse clinical manifestations. The severe and disseminated forms (acute form [AF] and multifocal chronic form [CF-MF]) are characterized by high Th2 cytokines and antibody production, impaired cellular immune response, and eosinophilia. In contrast, in the localized form (unifocal chronic form [CF-UF]), the cellular immune response is preserved, with high production of Th1 and Th17 cytokines, and low antibody titers. This study aimed to quantify interleukin-1 family cytokines (IL-1β, IL-18, IL-37, IL-33, and the soluble IL-33 receptor sST2) in sera of patients presenting different clinical forms of PCM before, during, and after antifungal treatment, as well as to analyze the expression of these cytokines in lesions of PCM patients. We found that AF patients presented high serum levels of IL-1β, IL-18, IL-33, sST2, and IL-37, and that these cytokines are strongly expressed in lymph nodes lesions. Furthermore, antifungal therapy resulted in the diminution of circulating cytokines and sST2 levels in all groups of patients. These results indicate that, besides IL-1β and IL-18, IL-33, IL-37, and sST2 can be associated with the disease activity and severity.

We aimed to investigate the effects of ethanol and its metabolites (β-hydroxybutyrate and sodium acetate) in the effector functions of macrophages in response to Paracoccidioides brasiliensis yeast cells and to determine their influence in the development of the adaptive response. Purified peripheral blood monocytes were differentiated into macrophages and were treated with ethanol, β-hydroxybutyrate, and sodium acetate, and stimulated with P. brasiliensis yeast cells and evaluated for their phenotypic characteristics, functional activity, and capability to induce T cells activation/differentiation. We found that the ethanol treatment diminished the expression of HLA-AB, HLA-DR, CD80, and CD86, modulating the expression of dectin-1, as well as Syk phosphorylation. The ethanol treatment increased the phagocytic activity, expression of CD206, and IL-10 production; however, reduced ROS production, fungicidal activity, caspase-1 cleavage, and IL-1β and IL-6 production. Our data also showed that the presence of ethanol reduced the differentiation of Th1 and Th17 cells and increased the frequency of Th2 cells. Our results indicated that ethanol exposure could suppress effector function of macrophages, possibly leading to the polarization of M2 macrophages. The ethanol modulates the expression of costimulatory and antigen-presentation molecules and interferes with the NLRP3 inflammasome. Altogether, these alterations affect the development of the adaptive response, decreasing the frequency of IL-17, IL-22, and IFN- γ producing cells, and increasing the frequency of IL-4 producing cells. Therefore, exposure to ethanol can impair the capability of macrophages to exert their effector functions and activate the acquired response related to resistance to P. brasiliensis infection.

Patients who undergo lung transplantation are prone to develop lower respiratory tract infections, leading to severe acute respiratory failure (ARF). Endotracheal intubation may not be indicated in these patients in light of a higher rate of mortality due to infections. The application of non-invasive ventilation could play a role in bridging these patients through the episode of ARF waiting for medical treatment to have effect. We report the evidence of morphological and physiological effects of the application of non-invasive continuous positive airway pressure during ARF sustained by pneumonia in a patient who underwent left lung transplantation because of idiopathic pulmonary fibrosis (IPF). We studied the effects of the application of positive end-expiratory pressure on both the right native lung affected by IPF and the transplanted lung affected by pneumonia.

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