HPV load and anal cytological abnormalities.

OBJECTIVES: The objective of this study was to evaluate the association between estimated human papillomavirus (HPV) viral load and abnormal cytology on anal samples. METHODS: Anal cytological samples of 42 HIV-positive patients were analysed by conventional cytology and Hybrid Capture II. RESULTS: On cytology, 30.95% (13 of 42) anal samples were positive for cytological abnormalities, 47.61% (20 of 42) were negative and 21.42% (nine of 42) were unsatisfactory. High-risk HPV infection was more frequent in anal samples with cytological abnormalities than in negative samples (P = 0.0002, Fisher's exact test), it was detected in all samples with cytological abnormalities and in 35% (seven of 20) of the negative samples. On samples with cytological abnormalities, the median of the relative light unit/cutoff (RLU/CO) value (viral load estimate) was 10.39 (1.02-572.6) and in negative samples it was 0.51 (0.26-51.70). The median of the RLU/CO value was higher in samples with cytological abnormalities when compared with the median in negative samples (P = 0.0001, Mann-Whitney U-test) and only samples with cytological abnormalities showed RLU/CO values > 100. CONCLUSIONS: The estimated high-risk HPV viral load is significantly higher in samples with cytological abnormalities than in negative anal samples and may be useful as an adjunct to anal cytology for triage of patients to high-resolution anoscopy and biopsy.

Morphological changes in eosinophils are reliable markers of the severity of an acute asthma exacerbation in children.

BACKGROUND: Early identification of the severity of asthma exacerbation would be helpful for the management of patients. We aimed to evaluate the correlation of morphological change in activated eosinophils and the severity of an asthma exacerbation. METHODS: Blood was collected from 55 asthmatic children: 40 of whom were having an exacerbation, 15 symptom-free, and 15 healthy controls. The percentage of eosinophils with morphological changes (emission of single or multiple pseudopods, presence of cytoplasmic vacuoles, releasing a small, moderate, or large quantity of granules, spreading, eosinophil death, and presence of cluster of free eosinophil granules) was quantified after the adherence to a slide and compared using the Mann-Whitney test. The correlation between the severity of the asthma exacerbation and the percentage changed eosinophils was tested with Spearman's correlation. RESULTS: The proportion of activated eosinophils was higher in asthmatic symptom-free children than in the control group, and acute asthma exacerbation produced an additional increase in eosinophil activation (P < 0.01). More significantly increased morphological changes were emissions of multiple pseudopods, presence of cytoplasmic vacuoles, spreading, and presence of a cluster of free eosinophil granules (P < 0.001). The following were correlated with the severity of an asthma exacerbation: ≥14% of eosinophils emitting single pseudopod, 8% emitting multiple pseudopods, 17% with vacuoles, 28% eosinophils releasing a large quantity of granules, and 66% of spread eosinophils. CONCLUSIONS: Quantifying the morphological changes in eosinophils is a feasible, easy, and reliable manner to identify the severity of an asthma exacerbation and therefore might improve the clinical management of asthmatic children.

Foxp3 expression in lesions of the different clinical forms of American tegumentary leishmaniasis.

As the diversity in clinical presentation of American tegumentary leishmaniasis (ATL) is determined mainly by the immune response of host, our aim was to evaluate the in situ expression of Foxp3 [marker of regulatory T (Treg) cell] in lesions of the different clinical forms of ATL. Foxp3(+) cells were observed in 39.5% (32/81) of the samples and the number of positive cells was low in all the clinical forms. Even presenting a significantly lower number of CD4(+) T cells, diffuse cutaneous leishmaniasis (DCL) showed a higher expression of Foxp3 when compared with localized cutaneous leishmaniasis (LCL) and mucocutaneous leishmaniasis (MCL). In LCL and MCL, the number of Foxp3(+) cells correlated positively with the number of apoptotic cells (active caspase-3(+) cells). A positive correlation was also observed between the expression of active caspase-3 and FasL in these clinical forms. Our data suggest that increased number of Treg cells may be associated to the hyporesponsiveness observed in DCL and also indicate that the apoptosis may be a possible mechanism of action of Foxp3(+) Treg cell in LCL and MCL. However, further studies are required to better understand the mechanism of action of Treg cell.

Influence of tumor necrosis factor-alpha on the ability of monocytes and lymphocytes to destroy intraerythrocytic Plasmodium falciparum in vitro.

It has been shown that administration of TNF-alpha causes an increase of survival of plasmodium-infected mice. However, this anti-parasitic effect cannot be reproduced in vitro upon direct incubation of the cytokine with the parasite. This suggests that TNF-alpha may act through modulation of some plasmodicidal mechanism not yet clarified. We evaluated the effect of exogenous TNF-alpha on the phagocytosis of Plasmodium falciparum-infected erythrocytes by monocytes and its influence on the ability of monocytes and lymphocytes to inhibit parasite growth. The capacity of endogenous TNF-alpha to influence the ability of monocytes to inhibit the parasite was also verified. We found that addition of 33 ng TNF-alpha/mL to cultures of human monocytes and P. falciparum-infected erythrocytes increased the phagocytic index from 3.8 to 7.8 in the presence of serum containing P. falciparum antibody. TNF-alpha increased the capacity of monocyte plus lymphocyte to inhibit parasite growth by about 3 times at 0.5 and 5 ng/mL. Sera from severely ill P. falciparum-infected individuals inhibited the parasite growth, but addition of anti-TNF-alpha antibody was unable to modify this inhibition. These data show that TNF-alpha can increase the phagocytic capacity. This was probably due to an increased expression of Fc receptors on monocytes or to the modulation of Fc receptor signaling pathways by signals originating from the binding of TNF-alpha to its receptors. TNF-alpha also acted on lymphocytes plus monocytes by increasing the inhibition of P. falciparum by a mechanism not related to phagocytosis. These findings suggest that TNF-alpha has a pleiotropic anti-malaria effect and that this protective effect depends on the interplay of different factors, such as monocytes/macrophages, lymphocytes, and antibodies, in addition to other cells and molecules.

Factors influencing phagocytosis of Salmonella typhimurium by macrophages in murine schistosomiasis.

Macrophages from Schistosoma mansoni-infected mice showed depressed capacity to increase the phagocytosis in the presence of a high bacterial load, due to a reduced involvement of these cells in phagocytosis and to a deficient ability to increase the number of phagocytosed bacteria. Normal and Salmonella-infected mice increased their phagocytic capacity when exposed to a high bacterial load. Antibody to Salmonella increased the phagocytic capacity of macrophages from Schistosoma-infected mice due to an increase in the number of bacteria phagocytosed but caused no modification in the number of macrophages engaged in phagocytosis. Our data indicate that macrophages from Schistosoma-infected mice work close to their functional limit, since no increase in phagocytosis was observed after increasing the bacterial load. Specific antibodies can improve their phagocytic capacity and, therefore, could help clearing concurrent infection.

Antibody response to Salmonella typhi in human schistosomiasis mansoni.

Antibody response to Salmonella typhi O and H antigens was evaluated in 24 individuals with either hepatointestinal or hepatosplenic schistosomiasis mansoni before and after typhoid vaccination, and compared with that of non-infected controls. Before vaccination, Schistosoma-infected patients showed a higher frequency of positive antibody to O antigen and the same frequency to H antigen when compared with that of healthy individuals. However, those with hepatosplenic schistosomiasis showed higher titres of antibody to H antigen than those with hepatointestinal disease or healthy individuals. Infected subjects, particularly those with hepatointestinal disease, showed a decreased response after typhoid vaccine. This diminished ability to mount an immune response towards typhoid antigens during schistosomiasis may interfere with the clearance of the bacteria from blood stream and, therefore, play a role in the prolonged survival of salmonella as observed in some patients with chronic salmonellosis associated with schistosomiasis.

Reduction of spleen size in a child with hyperreactive malarious splenomegaly (HMS) treated outside the Brazilian endemic area of malaria with only one course of quinine.

We report the clinical picture, treatment and evolution of a child with hyperreactive malarious splenomegaly treated outside the endemic area of malaria. The patient presented gross splenomegaly, proceeded from an area where malaria is endemic, showed increased immunoglobulins levels, high antimalarial antibody titres and hepatic sinusoidal lymphocytosis. The child did not return to an area where malaria is endemic and showed a favorable response to only one course of quinine. The response of this patient to limited antimalarial therapy suggests the importance of reinfection with malaria in the development and maintenance of this syndrome.

Phagocytic and bactericidal function of mouse macrophages to Salmonella typhimurium in schistosomiasis mansoni.

Patients infected with schistosomes may develop a clinical picture of chronic salmonellosis. We have investigated the altered function of macrophages capable of playing a role in the development of chronic salmonellosis associated with Schistosoma mansoni in an experimental model. The capacity of mouse peritoneal macrophages to ingest and kill Salmonella was assessed in mice infected with S. mansoni with or without concurrent Salmonella typhimurium infection. Schistosomiasis was associated with a significant decrease in the phagocytic index of macrophages, due to the reduced number of cells engaged in phagocytosis. However, the number of bacteria ingested by these cells was comparable to that of the control group. The bactericidal capacity of macrophages from S. mansoni-infected mice was also significantly lower than that of cells from normal mice. Macrophages from animals infected only with Salmonella typhimurium showed an increased phagocytic capacity. It was concluded that S. mansoni infection alters phagocytosis and intracellular destruction of salmonellae. This demonstration of a novel mechanism of survival of salmonellae represents a step forward in understanding the pathogenesis and management of chronic septicemic salmonellosis.

Specific treatment of hepatosplenic schistosomiasis can increase T-lymphocyte reactivity.

It has been recognized that Schistosoma mansoni infection causes depression of T-cell responsiveness. In this study we have evaluated whether immunodepression associated to schistosomiasis could be reverted by specific treatment. T-cell immune response was assessed by means of intradermal tests using recall antigens in a group of 22 patients with hepatosplenic schistosomiasis, one year after treatment with oxamniquine and compared with a group of untreated hepatosplenic patients. Only 27% of treated patients presented complete anergy to all tested antigens, in marked contrast to 80% unresponsiveness showed by hepatosplenic patients without treatment. Although most of the treated individuals showed some response to the tested antigens, in some individuals this unresponsiveness still persisted after treatment. Anergy was not found in any normal individual of the control group. It was concluded that Schistosoma mansoni infected patients may recover their normal immune responsiveness after the elimination of the worm by treatment.

T cell-dependent immunodepression in vivo in Schistosoma mansoni infected patients.

T-cell function was evaluated in 29 patients with either hepatointestinal or hepatosplenic schistosomiasis by intradermal tests to recall antigens. Immunodepression was detected in 26% of the subjects with hepatointestinal schistosomiasis and in 50% of those with the hepatosplenic form. Cellular immunodepression was related to worm load and spleen size. This non specific T-cell immunodepression may represent a serious constraint to the elimination of intracellular pathogens both in hepatosplenic or hepatointestinal schistosomiasis.