Functional diversity of T-cell subpopulations in subacute and chronic hypersensitivity pneumonitis.

RATIONALE: Hypersensitivity pneumonitis (HP) exhibits a diverse outcome. Patients with acute/subacute HP usually improve, whereas patients with chronic disease often progress to fibrosis. However, the mechanisms underlying this difference are unknown. OBJECTIVES: To examine the T-cell profile from patients with subacute HP and chronic HP. METHODS: T cells were obtained by bronchoalveolar lavage from 25 patients with subacute HP, 30 patients with chronic HP, and 8 control subjects. T-cell phenotype and functional profile were evaluated by flow cytometry, cytometric bead array, and immunohistochemistry. MEASUREMENTS AND MAIN RESULTS: Patients with chronic HP showed higher CD4+:CD8+ ratio (median, 3.05; range, 0.3-15; subacute HP: median, 1.3; range, 0.1-10; control: median, 1.3; range, 0.7-2.0; P < 0.01), and a decrease of gammadeltaT cells (median, 2.0; range, 0.5-3.4; subacute HP: median, 10; range, 4.8-17; control: median, 15; range, 5-19; P < 0.01). Patients with chronic HP exhibited an increase in the terminally differentiated memory CD4+ and CD8+ T-cell subsets compared with patients with subacute HP (P < 0.05). However, memory cells from chronic HP showed lower IFN-gamma production and decreased cytotoxic activity by CD8+ T lymphocytes. Chronic HP displayed a Th2-like phenotype with increased CXCR4 expression (median, 6%; range, 1.7-36, vs. control subjects: median, 0.7%; range, 0.2-1.4; and subacute HP: median, 2.2%; range, 0.1-5.3; P < 0.01), and decreased CXCR3 expression (median, 4.3%; range, 1.4-25%, vs. subacute HP: median, 37%; range, 4.9-78%; P < 0.01). Likewise, supernatants from antigen-specific-stimulated cells from chronic HP produced higher levels of IL-4 (80 +/- 63 pg/ml vs. 25 +/- 7 pg/ml; P < 0.01), and lower levels of IFN-gamma (3,818 +/- 1671 pg/ml vs. 100 +/- 61 pg/ml; P < 0.01) compared with subacute HP. CONCLUSIONS: Our findings indicate that patients with chronic HP lose effector T-cell function and exhibit skewing toward Th2 activity, which may be implicated in the fibrotic response that characterizes this clinical form.

Infection by human immunodeficiency virus-1 is not a risk factor for amebiasis.

The purpose of this study was to determine whether HIV-1 infected patients in our community were more susceptible to Entamoeba histolytica and Entamoeba dispar infection than non-HIV-infected individuals. The prevalence and frequency of invasive amebiasis was determined in 203 HIV+/AIDS subjects and 140 close relatives or sexual partners, all of whom were HIV-. Anti-E. histolytica antibodies (IgG, IgA) were assessed as indicators of E. histolytica invasive infection. Polymerase chain reaction (PCR) was used for the characterization of the Entamoeba species. The prevalence estimated with PCR data showed that E. histolytica infection was more common in the HIV+/AIDS group (25.32%), than in HIV- contacts (18.46%). E. histolytica + E. dispar infection was more frequent in HIV+/AIDS patients (13.3%), than in HIV- contacts (0.7%). E. histolytica and/or E. dispar infection was highly prevalent in HIV+/AIDS patients (34.1%) without evidence of recent or current invasive disease. Contacts of HIV+/AIDS patients who were infected with E. histolytica were asymptomatic cyst passers. Our results suggest that E. histolytica strains prevalent in the studied community appear to be of low pathogenic potential.

High prevalence rate of Entamoeba histolytica asymptomatic infection in a rural Mexican community.

The frequency of Entamoeba histolytica and Entamoeba dispar infection was analyzed in a rural community in the state of Morelos, Mexico, using polymerase chain reaction (PCR). Sociodemographic variables as risk factors for the infection were assessed. Results highlighted the number of individuals with intestinal parasites (43.1%) in the community, indicating extensive fecalism. A high frequency of E. histolytica asymptomatic infection, higher than E. dispar infection (13.8% versus 9.6%), was detected by PCR. Anti-amebic antibody levels (IgG) in serum and saliva (IgA) samples were not associated with E. histolytica intestinal infection. These findings suggest a predominant distribution of E. histolytica strains of low invasive potential in this community.

Entamoeba histolytica and Entamoeba dispar: prevalence infection in a rural Mexican community.

The frequency of Entamoeba histolytica and Entamoeba dispar infection was analyzed in a rural community in the state of Morelos, Mexico, through PCR technique by using specie specific primer. The E. histolytica specie was detected in 33 of 290 analyzed stool samples (11.4%), E. dispar specie was observed in 21 samples (7.2%) and both species of Entamoeba were detected in seven samples (2.4%). So a higher E. histolytica than E. dispar frequency infection was detected (13.8 versus 9.6%). Even though in our design we did not considered the follow-up of included individuals, the absence of invasive amebiasis cases in the studied population during our stay in town was unexpected.

Entamoeba histolytica and/or Entamoeba dispar: infection frequency in HIV+/AIDS patients in Mexico city.

The objective of this work was to evaluate the frequency of Entamoeba histolytica/Entamoeba dispar intestinal infection in HIV+/AIDS subjects and their HIV- close relatives or sexual partners. Enteric parasites were investigated in stool samples by microscopic examination and E. histolytica and E. dispar were identified by PCR. We found by microscopic analysis in HIV+/AIDS group that the E. histolytica/E. dispar complex was present in 5.9% of the members, while in the HIV- group was 2.9%. With PCR we found that the E. histolytica prevalence was 25.3% in the HIV+/AIDS group and 18.5% in the HIV-group. The difference in the results obtained with the microscopic and PCR is due to the different sensibility of the procedures. Besides, we found patients who were infected with E. histolytica in both groups were asymptomatic cyst passers. Our results suggest that E. histolytica strains prevalent in the studied community appear to be of low pathogenic potential.

E. dispar strain: analysis of polymorphism as a tool for study of geographic distribution.

The intra-species polymorphism of E. histolytica and E. dispar species in endemic area is an important tool for geographic distribution and spread mechanism studies. Since E. dispar and E. histolytica shears ecological niche, cell cycle, and transmission mechanism for human host, we studied the intra-specie variation and distribution of E. dispar strains obtained from cyst passers, in two neighbor rural communities in Morelos Mexico. We analyzed the polymorphic region of the quitinase protein gene in isolates of E. dispar. In 45 isolates from one community we identified 12 different CHI patterns while in 15 isolates from the other community we identified 5 different patterns. However both communities share 4 patterns. This finding suggests the presence of strains with different geographic mobility.

Defective production of reactive oxygen intermediates (ROI) in a patient with recurrent amebic liver abscess.

Previously, we reported the case of a man in the fourth decade of life afflicted with three independent episodes of amebic liver abscesses over a period of 4 years. Previous evidence has indicated that the cellular immune response is involved in protection against recurrent invasive amebic infection, and macrophage-mediated effector mechanisms appear important for host resistance to Entamoeba histolytica infection. The aim of the present work was to investigate locomotor activity and oxidative burst function of peripheral mononuclear cells of this individual after healing of the third amebic liver abscess. A locomotion assay using Boyden chemotaxis chambers and the respiratory burst evaluated by chemiluminescence were performed in both mononuclear phagocytes (MPs) and polymorphonuclear (PMN) leukocytes. Levels of salivary IgA and serum IgG anti-amebic antibodies were followed during 48 months after the second amebic liver abscess. Results obtained showed a deficiency in MP but not in PMN leukocyte respiratory burst. Respiratory burst is a major microbicidal mechanism in MP leukocytes; this also has been considered as a host resistance strategy against E. histolytica. It may be at least one risk factor in our patient that was responsible for recurrence of amebic liver abscess.

Calreticulin-like molecule in trophozoites of Entamoeba histolytica HM1:IMSS (Swissprot: accession P83003).

In this work, we report the partial sequence of a 51 kDa protein of Entamoeba histolytica that is highly immunogenic in humans. Partial sequencing of the N-terminal end showed that 18 of the first 20 amino acid residues of the protein were identified uniquely, indicating that the final product was a homogeneous protein preparation. The N-terminal sequence that was found was: KVYFEETFENGWKXIWSKW. Comparing the 19-amino acid sequence of the protein in automated databases shows significant similarity with amino acid sequences of the calreticulin-like protein of spinach leaves (77%) and of the calreticulin precursor of Dictyostelium discoideum (60%).