Immunopathology of the duodenal mucosa of HIV-positive patients during combined antiretroviral therapy

The objective of the present study was to evaluate the duodenal mucosa of HIV-infected patients during antiretroviral therapy. This was an observational study conducted on HIV-positive patients and a control group. Group 1 comprised 22 HIV-negative individuals while 38 HIV-positive individuals were classified according to the CDC 1993 classification into group 2 (A1 or A2) or group 3 (B2, A3, B3, C2, C3). All subjects were submitted to upper gastrointestinal endoscopy with duodenal biopsies. Qualitative, semi-quantitative and quantitative histological analyses were performed. Results were considered significant when P < 0.05. A higher prevalence of inflammatory infiltrate and eosinophilia was observed in the HIV group, together with a reduction in mucosal CD4+ lymphocyte (L) counts [median (lower-upper quartiles), 12.82 (8.30-20.33), 6.36 (1.75-11.66) and 1.75 (0.87-3.14) in groups 1, 2 and 3, respectively] which was not correlated with disease stage. The extent of CD4+L count reduction was similar in blood and duodenal mucosa. Normal CD8+L and CD45RO+L counts, and normal numbers of macrophages and antigen-presenting cells were also found in the HIV patients. The cytokine pattern did not differ among groups. Tissue HIV, assessed by p24 antigen, correlated with a higher CD45RO+L count (77.0 (61-79.8) and 43.6 (31.7-62.8) in p24+ and p24-, respectively, P = 0.003), and IL-4 positivity (100 and 48.2 percent in p24+ and p24-, respectively, P = 0.005). The duodenal mucosa of HIV+ patients showed a relatively preserved histological architecture. This finding may be characteristic of a population without opportunistic infections and treated with potent antiretroviral therapy, with a better preservation of the immune status.

Lung tissue mechanics in the early stages of induced paracoccidioidomycosis in rats

Pulmonary dysfunction represents the most important cause of death in patients with paracoccidioidomycosis (PBM). In order to investigate the functional changes of the lungs in the early stages of PBM, a model of benign disease was developed by intratracheal challenge of 12-week old isogenic Wistar rats with 1 x 10(6) yeast forms of Paracoccidioides brasiliensis. Animals were studied 30 and 60 days after infection, when fully developed granulomas were demonstrable in the lungs. Measurements of airway reistance, lung elastance and tissue hysteresis were made during sinusoidal deformations (100 breaths/min, tidal volume = 2 ml) with direct measurement of alveolar pressure using the alveolar capsule technique. Infection caused a significant increase in hysteresis (infected: 1.69, N = 13; control: 1.13, N=12,P = 0.024, ANOVA), with no alterations in airway resitance or lung elastance. Histopathological analysis revealed the presence of fully developed granulomas located in the axial compartment of the lung interstitial space. These results suggest that alterations of tissue mechanics represent an early event in experimental PBM.

Comparative and sequential histopathology of plasmodium chabaudi-infected balb/c mice

1. Rodent experimental models have been useful to study severe malaria but few serial and controlled studies have been conducted. In the presente investigation, we describe the histopathology of lethal and non-lethal rodent malaria induced by Plasmodium berghei and P. chabaudi. P. berghei malaria shows a uniformly lethal course, while P. chabaudi malaria produces a non-lethal acute infection with recovery and periodical recurdescences. Sequential histopathological changes were also characterized in P. chabaudi malaria to determine the evolution of the lesions. 2. P. berghei-infected mice have a more severe organ involvement and lower blood regenerative changes than P. chabaudi-infected mice. Two patterns of organ involvement were observed by cimparing the two infections. The first is related to nonspecific parasitized red blood cell clearance by liver and spleen. The second is related to specific changes due to a specific parasite strain interaction with the host, such as those found in the lungs. 3. Sequential changes in P. chabaudi-infected mice were characterized by perihepatocytic reticulin fiber deposition during the recovery from infection, which faded in subsequent stages. Other organs had a similar regressive evolution, except splenic lymphoid tissue which underwent histological restoration or even hypertrophy after depletion in the acute stage. No brain or heart lesions were observed in either model during the acute and subsequent stages. 4. P. chabaudi infection, whose histopathology is described here for the first time, should be useful as a non-lethal experimental model to study the evolution of histological alterations in malaria