Maria Heloisa Souza Lima Blotta

Cytokines and lymphocyte proliferation in juvenile and adult forms of paracoccidioidomycosis: comparison with infected and non-infected controls.

Cellular immune response to Paracoccidiodes brasiliensis antigens (PbAg) was evaluated in patients with the juvenile (JF) and adult (AF) forms of paracoccidioidomycosis as well as in a group of infected individuals living in the endemic area but without any clinical manifestation of the disease. The immune profile of this group of paracoccidioidomycosis-infected individuals was characterized by: 1) a positive skin test to P. brasiliensis antigen; 2) absence of specific antibodies; 3) a vigorous lymphoproliferative response to PbAg; and 4) a typical Th1 pattern of cytokines, with production of IFN-gamma and basal levels of IL-4, IL-5 and IL-10. At the opposite end of the spectrum were the JF patients whose proliferative response to PbAg was significantly impaired and whose cytokine pattern was characteristically Th2, i.e. lower IFN-gamma secretion and significantly higher levels of IL-4, IL-5 and IL-10. These profiles are compatible with forms of higher and lower resistance, respectively. Intermediate immune responses were observed in AF patients, whose specific lymphoproliferative response was lower than in the paracoccidioidomycosis-infected group but higher than in the JF patients. The secretion of IFN-gamma and IL-10 did not differ from the JF group, although IL-4 and IL-5 levels were significantly lower. Since AF patients are able to control fungal dissemination for decades, they can be considered more resistant than JF patients, who manifest the disease soon after infection.

TLR-2, TLR-4 and dectin-1 expression in human monocytes and neutrophils stimulated by Paracoccidioides brasiliensis

Paracoccidioidomycosis (PCM) is an endemic mycosis in Latin America caused by the dimorphic fungus Paracoccidioides brasiliensis. The pattern of the immune responses to P. brasiliensis determines the disease progression and clinical outcome. Innate immune response is mediated by phagocytic cells, such as macrophage and neutrophils, which ingest and kill invading pathogens and then trigger the adaptive immune system through the secretion of cytokines and chemokines. The C-type like lectin receptors (CLR) and Toll-like receptors (TLRs) are the two main pattern recognition receptors in phagocytic cells that recognize fungal components. Therefore, the purpose of the present study was to evaluate the expression of TLR-1, TLR-2, TLR-4 and dectin-1 (CLR) in monocytes and neutrophils from healthy individuals after stimulation with Pb18 (high virulence) and Pb265 (low virulence) yeasts of P. brasiliensis. As positive controls we used specific ligands to TLR-4 (LPS), TLR-2 and dectin-1 (zymosan). Our results demonstrated a decreased of TLRs and dectin-1 expression mainly on monocytes as opposes on neutrophils, as soon as 30 minutes after yeast cells stimulation. This decrease was similar to the one caused by zymosan stimulation and indicates that up binding the complexes are rapidly internalized. There was a tendency towards an increased TLR2 and dectin-1 mRNA expression in response to fungal cells, mainly to Pb265. P. brasiliensis yeast cells induced the production of pro-inflammatory and anti-inflammatory cytokines, but the low ratio between TNF-alpha and IL-10 in response to zymosan and Pb265 indicates a balanced production of IL-10 and TNF-alpha, while Pb18 predominantly induced TNF-alpha secretion. Fungal cells also induced an elevated production of PGE(2) by monocytes and neutrophils showing their potential to provoke an intense inflammatory response. Altogether our results suggest the participation of TLR2, TLR-4 and dectin-1 in P. brasiliensis recognition, internalization and consequent activation of the immune response against the fungus. Moreover, the preferential recognition of zymosan and Pb265 by TLR-2 and dectin-1 would result in the production of adequate concentration of IL-10, which would be able to counterbalance the excessive inflammatory response mediated by TNF-alpha and PGE2. With these attributes the low virulence strain of P. brasiliensis would induce a controlled immune response beneficial to the host.

Detection of circulating gp43 antigen in serum, cerebrospinal fluid, and bronchoalveolar lavage fluid of patients with paracoccidioidomycosis

ABSTRACT Paracoccidioidomycosis (PCM) is an important systemic fungal disease, particularly among individuals living and working in rural areas of endemicity in Latin America, who, without antifungal therapy, may develop fatal acute or chronic infection. For such patients, the detection of antibody responses by immunodiffusion is of limited value due to false-negative results. In contrast, the detection of Paracoccidioides brasiliensis gp43 circulating antigen may represent a more practical approach to the rapid diagnosis of the disease. Accordingly, an inhibition enzyme-linked immunosorbent assay (inh-ELISA) was developed for the detection of a 43-kDa P. brasiliensis-specific epitope incorporating a species-specific murine monoclonal antibody. With sera from patients with acute and chronic forms of the disease (n = 81), the overall sensitivity of the test was found to be 95.1%, while specificity was found to be 97.5% compared to that with normal human sera from blood donors (n = 93) and sera from patients with other chronic fungal infections (histoplasmosis [n = 33] and cryptococcosis [n = 20]). The inh-ELISA detected circulating antigen in 100% of patients with the acute form of PCM and in 95.31 and 100% of patients with the chronic multifocal and unifocal forms of PCM according to the patients clinical presentation. Cerebrospinal fluid from 14 patients with neuroparacoccidioidomycosis and 13 samples of bronchoalveolar lavage fluid from patients with pulmonary unifocal PCM were also tested for gp43 detection, with the test showing 100% sensitivity and specificity. This novel, highly specific inh-ELISA represents a significant addition to the existing tests for the diagnosis of PCM.

Impaired Humoral Response to Vaccines among HIV-Exposed Uninfected Infants

ABSTRACT Little is known about the vaccine protective response for infants born from HIV-infected mothers. We evaluated the antibody response to hepatitis B, tetanus, and diphtheria vaccine in vertically HIV-exposed uninfected infants and compared them to those of control infants not exposed to the virus. The quantitative determination of specific neutralizing antibodies against hepatitis B, diphtheria, and tetanus were performed blindly on serum samples. The results showed that 6.7% of the HIV-exposed uninfected individuals were nonresponders to hepatitis B vaccine (anti-HBs titer, <10 mIU/ml), and 64.4% were very good responders (anti-HBs titer, ≥1,000 mIU/ml), whereas only 3.6% of the nonexposed infants were nonresponders (χ2=10.93; 1 df). The HIV-exposed uninfected infants showed protective titers for diphtheria and tetanus but lower geometric mean anti-tetanus titers compared to those of the HIV-unexposed infants. Our data point to the necessity of evaluating vaccine immune responses in these children and reinforced that alterations in lymphocyte numbers and functions reported for newborns from HIV-infected mothers interfere with the vaccine response.

Detection of Paracoccidioides brasiliensis gp70 Circulating Antigen and Follow-Up of Patients Undergoing Antimycotic Therapy

ABSTRACT Paracoccidioidomycosis (PCM), one of the most important systemic mycoses in Central and South America, is caused by the dimorphic fungus Paracoccidioides brasiliensis and has a high prevalence in Brazil. Glycoproteins of 43 and 70 kDa are the main antigenic compounds of P. brasiliensis and are recognized by Western blotting by 100 and 96% of PCM patient sera, respectively. In the present study, an inhibition enzyme-linked immunosorbent assay (ELISA) was used to detect gp70 in different biological samples from patients with PCM. gp70 was detected in 98.76% of 81 serum samples, with an average concentration of 8.19 μg/ml. The test was positive for 100% of the patients with the acute and chronic unifocal forms of PCM and 98.43% of the patients with the multifocal chronic form, with average concentrations of 11.86, 4.83, and 7.87 μg/ml, respectively. Bronchoalveolar lavage fluid from 23 patients with pulmonary unifocal PCM and 14 samples of cerebrospinal fluid from patients with neurological PCM were also tested for gp70 detection, with the test showing 100% sensitivity and 100% specificity, with mean gp70 concentrations of 7.5 and 6.78 μg/ml, respectively. To investigate the potential of gp70 detection by inhibition ELISA for the follow-up of PCM patients during antimycotic therapy with itraconazole (ITZ), the sera of 23 patients presenting with the chronic multifocal form of PCM were monitored at regular intervals of 1 month for 12 months. The results showed a decrease in circulating gp70 levels during treatment which paralleled the reduction in anti-P. brasiliensis antibody levels. The detection of P. brasiliensis gp70 from the biological fluids of patients suspected of having PCM proved to be a promising method for diagnosing infection and evaluating the efficacy of ITZ treatment.

Reduced expression of systemic proinflammatory and myocardial biomarkers after off-pump versus on-pump coronary artery bypass surgery: A prospective randomized study

BACKGROUND The effects of off-pump (OffPCABG) and on-pump (OnPCABG) coronary artery bypass grafting (CABG) on myocardium and inflammation are unclear. OBJECTIVE Compare the inflammatory response and myocardial injury from patients (pts) submitted to OffPCABG with those that undergo OnPCABG. METHODS Patients with normal left ventricular function were assigned to OffPCABG (n = 40) and OnPCABG (n = 41). Blood samples were collected before and 24 hours after surgery for determination of creatine kinase (CK)-MB (CK-MB), troponin I (cTnI), interleukin (IL)-6, IL-8, P-selectin, intercellular adhesion molecule (ICAM)-1 and C-reactive protein (CRP). Mortalities were registered at 12 months. RESULTS Preoperative CK-MB and cTnI levels were 3.1 +/- 0.6 IU and 1.2 +/- 0.5 ng/mL for OffPCABG and 3.0 +/- 0.5 IU and 1.0 +/- 0.2 ng/mL for OnPCABG pts. Postoperative CK-MB and cTnI levels were 13.9 +/- 6.5 IU and 19.0 +/- 9.0 ng/mL for OffPCABG vs 29.5 +/- 11.0 IU and 31.5 +/- 10.1 ng/mL for OnPCABG (P < .01). OffPCABG and OnPCABG pts had similar preoperative IL-6 (10 +/- 7 and 9 +/- 13 pg/mL), IL-8 (19 +/- 7 and 17 +/- 7 pg/mL), soluble P-selectin (70 +/- 21 and 76 +/- 23 pg/mL), soluble ICAM-1 (117 +/- 50 and 127 +/- 52 ng/mL), and CRP (0.09 +/- 0.05 and 0.11 +/- 0.07 mg/L). At 24 hours, for OffPCABG and OnPCABG: IL-6 was 37 +/- 38 and 42 +/- 41 g/mL; IL-8, 33 +/- 31 and 60 +/- 15 pg/mL; soluble P-selectin, 99 +/- 26 and 172 +/- 30 pg/mL; soluble ICAM-1, 227 +/- 47 and 236 +/- 87 ng/mL; and CRP, 10 +/- 11 and 14 +/- 13 mg/L (P < .01 vs preoperation; P < .01 vs OffPCABG). Increased 24-hour postoperative CRP levels was the only marker to have significant positive correlations with events and occurred just for the OnPCABG pts. In-hospital and 1-year mortalities for the OnPCABG and OffPCABG pts were 2.0% and 2.2% (P = .1) and 2.7% and 4.7% (P = .06), respectively. CONCLUSIONS Thus, the absence of CPB during CABG preserves better the myocardium and attenuates inflammation-however, without improving survival.

Involvement of Regulatory T Cells in the Immunosuppression Characteristic of Patients with Paracoccidioidomycosis

ABSTRACT Patients with paracoccidioidomycosis (PCM) exhibit a suppression of the cellular immune response characterized by negative delayed-type hypersensitivity (DTH) to Paracoccidioides brasiliensis antigens, the apoptosis of lymphocytes, and high levels of expression of cytotoxic-T-lymphocyte-associated antigen 4 (CTLA-4), interleukin-10 (IL-10), and transforming growth factor β (TGF-β). The aim of this study was to investigate whether and how regulatory T cells (Treg cells) are involved in this immunosuppression by analyzing the number, phenotype, and activity of these cells in patients with active disease (AD group) and patients who had received treatment (TD group). Our results showed that the AD patients had more Treg cells than the TD patients or controls (C group) and also had elevated levels of expression of regulatory markers (glucocorticoid-induced tumor necrosis factor [TNF] receptor-related protein [GITR], CTLA-4, CD95L, LAP-1, and CD38). An analysis of regulatory activity showed that Treg cells from the AD group had greater activity than did cells from the other groups and that cell-cell contact is mandatory for this activity in the C group but was only partially involved in the regulatory activity of cells from AD patients. The addition of anti-IL-10 and anti-TGF-β neutralizing antibodies to the cultures showed that the production of cytokines may be another mechanism used by Treg cells. In conclusion, the elevated numbers of these cells with an increased regulatory phenotype and strong suppressive activity suggest a potential role for them in the immunosuppression characteristic of paracoccidioidomycosis. In addition, our results indicate that while Treg cells act by cell-cell contact, cytokine production also plays an important role.

Systemic envenomation caused by the wandering spider Phoneutria nigriventer, with quantification of circulating venom

Introduction. Bites by Phoneutria spp. spiders are common in Brazil, although only 0.5–1% result in severe envenomation, with most of these occurring in children. Cases of systemic envenomation in adults are very unusual, and no serum venom levels have been previously quantified in these cases. Case report. A 52-year-old man was bitten on the neck by an adult female Phoneutria nigriventer. Immediately after the bite, there was intense local pain followed by blurred vision, profuse sweating, tremors, and an episode of vomiting; 1–2 h post bite the patient showed agitation and a blood pressure of 200/130 mmHg, and was given captopril and meperidine. Upon admission to our service 4 h post bite (time zero – T0), his blood pressure was 130/80 mmHg with a heart rate of 150 beats/min, mild tachypnea, agitation, cold extremities, profuse sweating, generalized tremors, and priapism. The patient was treated with antivenom, local anesthetic, and fluid replacement. Most of the systemic manifestations disappeared within 1 h after antivenom. Laboratory blood analyses at T0, T1, T6, T24, and T48 detected circulating venom by ELISA only at T0, before antivenom infusion (47.5 ng/mL; cut-off, 17.1 ng/mL); his serum blood sugar was 163 mg/dL at T0. The patient was discharged on the second day with a normal arterial blood pressure and a follow-up evaluation revealed no sequelae. Conclusion. This is the first report of confirmed moderate/severe envenoming in an adult caused by P. nigriventer with the quantification of circulating venom.

Immunocytochemical localization of cytokines and inducible nitric oxide synthase (iNOS) in oral mucosa and lymph nodes of patients with paracoccidioidomycosis

Paracoccidioidomycosis (PCM) is a deep mycosis caused by Paracoccidioides brasiliensis, with high incidence in Brazil. In order to examine the immune response in lesional tissue from patients with PCM, we analyzed cytokines as well as the phenotype of the cell infiltrate. Paraffin-embedded tissue from the oral mucosa of eight patients with the localized adult form (AF) of PCM and from the lymph nodes of 10 patients with the juvenile form (JF) of PCM was analyzed by immunohistochemistry to detect tumor necrosis factor-alpha (TNF-alpha), inducible nitric oxide synthase (iNOS), transforming growth factor-beta (TGF-beta) and interleukin-10 (IL-10). Most of the inflammatory cells in the lymph nodes were CD68+ (macrophages, epithelioid and giant cells), while a mixed infiltrate with macrophages, plasma cells and neutrophils was detected in the oral mucosa. TNF-alpha as well as iNOS expression was similar in lymph nodes and oral mucosa, whereas TGF-beta and IL-10 were observed in a larger number of macrophages, epithelioid and giant cells in the lymph nodes, where numerous yeast cells were visualized. The higher expression of anti-inflammatory cytokines (IL-10 and TGF-beta) in lesions of patients with the JF of PCM (lymph nodes) may represent a mechanism by which the fungus evades the host immune response, contributing to a more severe and disseminated form of the disease.

Characterization of CD4+CD28null T cells in patients with coronary artery disease and individuals with risk factors for atherosclerosis

Risk factors for atherosclerosis may contribute to chronic low-grade inflammation. A highly cytotoxic and inflammatory CD4(+) cell subset (CD4(+)CD28(null) cells) has been associated with inflammatory diseases, including acute coronary syndromes (ACS). The aim of this study was to quantify and characterize CD4(+)CD28(null) cells in individuals with risk factors for atherosclerosis and patients with coronary artery disease (CAD). In order to achieve this goal, peripheral blood mononuclear cells (PBMCs) from individuals with risk factors for atherosclerosis and patients with CAD were analyzed using flow cytometry to detect cytotoxic molecules and evaluate the expression of homing receptors and inflammatory cytokines in CD4(+) cell subsets. The cells were evaluated ex vivo and after stimulation in culture. We found no differences in the proportions of CD4(+)CD28(null) cells among the groups. Compared with the CD4(+)CD28(+) population, the ex vivo CD4(+)CD28(null) subset from all groups expressed higher levels of granzymes A and B, perforin, granulysin and interferon-γ (IFN-γ). Individuals with risk factors and patients with ACS showed the highest levels of cytotoxic molecules. After stimulation, tumor necrosis factor-α (TNF-α) expression in the CD4(+)CD28(null) subset from these groups increased more than in the other groups. Stimulation with LPS decreased the expression of cytotoxic molecules by CD4(+)CD28(null) cells in all groups. In conclusion, our results show that risk factors for atherosclerosis may alter the CD4(+)CD28(null) cells phenotype, increasing their cytotoxic potential. Our findings also suggest that CD4(+)CD28(null) cells may participate in the early phases of atherosclerosis.