Immunological system and Schistosoma mansoni: co-evolutionary immunobiology. What is the eosinophil role in parasite-host relationship?

Schistosomes, ancestors and recent species, have pervaded many hosts and several phylogenetic levels of immunity, causing an evolutionary pressure to eosinophil lineage expression and response. Schistosoma mansoni adult worms have capitalized on the apparent adversity of living within the mesenteric veins, using the dispersion of eggs and antigens to other tissues besides intestines to set a systemic activation of several haematopoietic lineages, specially eosinophils and monocytes/macrophages. This activation occurs in bone marrow, spleen, liver, lymph nodes, omental and mesenteric milky spots (activation of the old or primordial and recent or new lymphomyeloid tissue), increasing and making easy the migration of eosinophils, monocytes and other cells to the intestinal periovular granulomas. The exudative perigranulomatous stage of the periovular reaction, which present hystolitic characteristics, is then exploited by the parasites, to release the eggs into the intestinal lumen. The authors hypothesize here that eosinophils, which have a long phylogenic story, could participate in the parasite - host co-evolution, specially with S. mansoni, operating together with monocytes/ macrophages, upon parasite transmission.

Chagas' Disease and HIV Co-infection: Genotypic Characterization of the Trypanosoma cruzi Strain

In the past few years, new aspects of the immunopathology of Chagas' disease have been described in immunosuppressed patients, such as fatal central nervous system lesions related to the reactivation of the parasite. This article is the first description of the genotypic characterization, at the strain level, of Trypanosoma cruzi isolated from a patient with Chagas` disease/AIDS co-infection. The presence of four hypodense lesions was observed in the cranial compute tomographic scan. The diagnosis of AIDS was assessed by the detection of anti-HIV antibodies using enzyme-linked immunosorbent assay (ELISA) and Western blot techniques. The CD4+ lymphocyte counts were maintained under 200 cells/mm3 during one year demonstrating the severity of the state of immunosuppression. Chagas' disease was confirmed by serological and parasitological methods. Trypomastigote forms were visualized in a thick blood smear. The parasite isolated is genotypically similar to the CL strain. The paper reinforces that cerebral Chagas' disease can be considered as another potential opportunistic infection in AIDS resulting from the reactivation of a dormant T. cruzi infection acquired years earlier.

Adhesion and Co-stimulatory Molecules in the Pathogenesis of Hepatic and Intestinal Schistosomiasis Mansoni

Infection of a susceptible host with the blood fluke Schistosoma mansoni results in the formation of periovular granulomas and subsequent fibrosis in the target organs. Granulomogenesis and fibrogenesis are mediated by immunological events which require cell-cell and cell-matrix interactions. In this review, the role of adhesion and co-stimulatory molecules in the genesis of the schistosomal pathology (granulomogenesis and fibrogenesis) is outlined. These molecules provide essential immunological interactions not only for the initiation of granuloma formation but also for the maintenance and modulation of the schistosomal granuloma during chronic infection. Furthermore, the role of secreted soluble adhesion molecules in the different clinical forms and in the modulation of the schistosomal granuloma is discussed. Recent new insights into the role of adhesion molecules for the induction of pathology by other developmental stages of the parasite (other than eggs) will be presented.

Plasmodium/intestinal helminth co-infections among pregnant Nigerian women

Hospital based studies were conducted to investigate the occurrence of Plasmodium/intestinal helminth co-infections among pregnant Nigerian women, and their effects on birthweights, anaemia and spleen size. From 2,104 near-term pregnant women examined, 816 (38.8%) were found to be infected with malaria parasites. Among the 816 parasitaemic subjects, 394 (48.3%) were also infected with intestinal helminths, 102 (12.5%) having mixed helminth infections. The prevalence of the helminth species found in stool samples of parasitaemic subjects examined was, Ascaris lumbricoides (19.1%), hookworm (14.2%), Trichuris trichiura (7%) Schistosoma mansoni (3.4%), Enterobius vermicularis (2%), Hymenolepis sp. (1.6%) and Taenia sp. (1%). Mothers with Plasmodium infection but without intestinal helminth infection had neonates of higher mean birthweights than those presenting both Plasmodium and intestinal helminth infections and this effect was more pronounced in primigravids. The mean haemoglobin values of malarial mothers with intestinal helminth infections were lower than those with Plasmodium infection but without intestinal helminth infections but these were not statistically significant. Severe splenomegaly was predominant among parasitaemic gravidae who also harboured S. mansoni infection in two of the hospitals studied.

Clinical and immunological consequences of human T cell leukemia virus type-I and Schistosoma mansoni co-infection

Human T cell leukemia virus type-I (HTLV-I) infection is associated with spontaneous T cell activation and uncontrolled lymphocyte proliferation. An exacerbated type-1 immune response with production of pro-inflammatory cytokines (interferon-gamma and tumor necrosis factor-alpha) is significantly higher in patients with myelopathy associated to HTLV-I than in HTLV-I asymptomatic carriers. In contrast with HTLV-I, a chronic Schistosoma mansoni infection is associated with a type-2 immune response with high levels of interleukin (IL-4, IL-5, and IL-10) and low levels of IFN-gamma. In this study, clinical and immunological consequences of the HTLV-I and S. mansoni infection were evaluated. The immune response in patients with schistosomiasis co-infected with HTLV-I showed low levels of IL-5 (p < 0.05) in peripheral blood mononuclear cells cultures stimulated with S. mansoni antigen (SWAP) and decreased SWAP-specific IgE levels when compared with patients with only schistosomiasis (p < 0.05). Liver fibrosis was mild in all HTLV-I co-infected patients. Immunological response was also compared in individuals who had only HTLV-I infection with those who were co-infected with HTLV-I and helminths (S. mansoni and Strongyloides stercoralis). In patients HTLV-I positive co-infected with helminths the IFN-gamma levels were lower than in individuals who had only HTLV-I. Moreover, there were fewer cells expressing IFN-gamma and more cells expressing IL-10 in individuals co-infected with HTLV-I and helminths. These dates indicate that HTLV-I infection decrease type 2-response and IgE synthesis and are inversely associated with the development of liver fibrosis. Moreover, helminths may protect HTLV-I infected patients to produce large quantities of pro-inflammatory cytokines such as IFN-gamma.

Immune response in cervical dysplasia induced by human papillomavirus: the influence of human immunodeficiency virus-1 co-infection - review

Human immunodeficiency virus (HIV-1) has become an important risk factor for human papillomavirus (HPV) infection and the development of HPV associated lesions in the female genital tract. HIV-1 may also increase the oncogenicity of high risk HPV types and the activation of low risk types. The Center for Disease Control and Prevention declared invasive cervical cancer an acquired immunodeficience virus (AIDS) defining illness in HIV positive women. Furthermore, cervical cancer happens to be the second most common female cancer worldwide. The host's local immune response plays a critical factor in controlling these conditions, as well as in changes in the number of professional antigen-presenting cells, cytokine, and MHC molecules expression. Also, the production of cytokines may determine which arm of the immune response will be stimulated and may influence the magnitude of immune protection. Although there are many studies describing the inflammatory response in HPV infection, few data are available to demonstrate the influence of the HIV infection and several questions regarding the cervical immune response are still unknown. In this review we present a brief account of the current understanding of HIV/HPV co-infection, emphasizing cervical immune response.

Effects of antifolates - co-trimoxazole and pyrimethamine-sulfadoxine - on gametocytes in children with acute, symptomatic, uncomplicated, Plasmodium falciparum malaria

Antimalarial drugs including the antifolate, pyrimethamine-sulfadoxine (PS), can modulate the prevalence and intensities of gametocytaemia following treatment of acute malaria infections. They may also directly influence the transmission and spread of drug insensitivity. Little is known of the effects of co-trimoxazole (Co-T), another antifolate antimalarial, on gametocytes in children with acute malaria infections. We compared the effects of Co-T and PS on the prevalence and intensities of gametocytaemia and gametocyte sex ratios in 102 children aged 0.5-12 years presenting with acute and uncomplicated falciparum malaria. Compared to pre-treatment, both drugs significantly increased gametocyte carriage post-initiation of treatment. However, gametocyte carriage was significantly lower on day 14 in those treated with Co-T than PS. Significant increase in gametocytaemia with time occurred in PS - but not Co-T-treated children. Kaplan-Meier survival curve of the cumulative probability of remaining gametocyte-free in children who were agametocytaemic at enrolment showed that by day 7 of follow up, children treated with PS had a significantly higher propensity to have developed gametocytes than in Co-T-treated children (Log-rank statistic 5.35, df = 1, P = 0.02). Gametocyte sex ratio changes were similar following treatment with both drugs. PS and Co-T treatment of acute malaria infections in children from this endemic area is associated with significant increases in prevalence and intensities of gametocytaemia but these effects are more marked in those treated with PS than Co-T.

Ocurrence of co-infection by Leishmania (Leishmania) chagasi and Trypanosoma (Trypanozoon) evansi in a dog in the state of Mato Grosso do Sul, Brazil

A natural case of co-infection by Leishmania and Trypanosoma is reported in a dog (Canis familiaris) in south- western state of Mato Grosso do Sul, Brazil. Both amastigote and trypomastigote forms were observed after Giemsa staining of cytological preparations of the dog's bone marrow aspirate. No parasite was detected using medium culture inoculation of the sample. DNA obtained from the bone marrow aspirate sample and from the blood buffy coat was submitted to polymerase chain reaction (PCR) with a set of rDNA-based primers S4/S12. The nucleotide sequence of the PCR product was identical to that of Trypanosoma (Trypanozoon) evansi. The S4/S12 PCR was then used as template in a nested-PCR using a specific Leishmania set S17/S18 as primers, to explain the amastigote forms. The nucleotide sequence of the new PCR product was identical to that of Leishmania (Leishmania) chagasi. This case, as far as we know, is the first report of a dog co-infected with these parasites, suggesting that besides L. (L.) chagasi, the natural transmission of T. (T.) evansi occurs in the area under study.

Studies in a co-infection murine model of Plasmodium chabaudi chabaudi and Leishmania infantum: interferon-g and interleukin-4 mRNA expression

This work aimed to study the T helper type 1/2 (Th1/Th2) cytokine profile in a co-infection murine model of Plasmodium chabaudi chabaudi and Leishmania infantum. Expression of interferon-gamma (IFN-g) and interleukin-4 (IL-4) was analyzed, in spleen and liver of C57BL/6 mice, by reverse transcriptase-polymerase chain reaction. High levels of IFN-g expression did not prevent the progression of Leishmania in co-infected mice and Leishmania infection did not interfere with the Th1/Th2 switch necessary for Plasmodium control. The presence of IL-4 at day 28 in co-infected mice, essential for Plasmodium elimination, was probably a key factor on the exacerbation of the Leishmania infection.

High expression of co-stimulatory and adhesion molecules are observed on eosinophils during human Schistosoma mansoni infection

Herein we have focused attention on major phenotypic features of peripheral blood eosinophils from chronic Schistosoma mansoni-infected patients. For this purpose, detailed immunophenotypic profiles of a range of cell surface markers were performed, including activation markers (CD23/CD69/CD25/HLA-DR), co-stimulatory molecules (CD28/CD80/CD86), chemokine receptors (CXCR1/CXCR2/CCR3/CCR5) besides L-selectin-CD62L and adhesion molecules (CD18/CD54). Our major findings pointed out increased frequency of CD23+-cells, besides decreased percentages of CD69+-eosinophils, suggesting a chronic activation status with low frequency of early activated eosinophils in chronic S. mansoni-infected patients (INT) in comparison to non-infected individuals (NI). Moreover, a dichotomic expression of beta-chemokine receptors was observed during human schistosomiasis mansoni with higher CCR5 and lower levels of CCR3 observed between groups. Enhanced expression of co-stimulatory receptors (CD28/CD86) and adhesion molecules (CD54/CD18), besides striking lower frequency of L-selectin+ were reported for eosinophils from INT group as compared to NI. Interestingly, the frequency of CD62L+-eosinophils and a range of cell activation related molecules pointed out an opposite pattern of association in NI and INT, where only INT patients that display lower frequency of CD62L+-eosinophils (first CD62L tertile) kept the unusual relationship between the expression of L-selectin and the CD23 activation marker. These findings suggest that distinct dynamic of activation markers expressed by eosinophils may occur during chronic S. mansoni infection.

Preliminar evaluation of cytokines in the hepatitis C-schistosomiasis co-infection

Evaluation of hepatic fibrosis is usually performed by histopathological examination of biopsies. However, this is an invasive and potentially dangerous procedure. Several studies have proposed serum biological markers of hepatic fibrosis. This communication evaluates the use of serum cytokines as markers of hepatic fibrosis in hepatitis C, schistosomiasis, and co-infection.

Patterns of co-association of C-reactive protein and nitric oxide in malaria in endemic areas of Iran

In addition to numerous immune factors, C-reactive protein (CRP) and nitric oxide (NO) are believed to be molecules of malaria immunopathology. The objective of this study was to detect CRP and NO inductions by agglutination latex test and Griess microassay respectively in both control and malaria groups from endemic areas of Iran, including Southeastern (SE) (Sistan & Balouchestan, Hormozgan, Kerman) and Northwestern (NW) provinces (Ardabil). The results indicated that CRP and NO are produced in all malaria endemic areas of Iran. In addition, more CRP and NO positive cases were observed amongst malaria patients in comparison with those in control group. A variable co-association of CRP/NO production were detected between control and malaria groups, which depended upon the malaria endemic areas and the type of plasmodia infection. The percentage of CRP/NO positive cases was observed to be lower in NW compare to SE region, which may be due to the different type of plasmodium in the NW (Plasmodium vivax) with SE area (P. vivax, Plasmodium falciparum, mixed infection). The fluctuations in CRP/NO induction may be consistent with genetic background of patients. Although, CRP/NO may play important role in malaria, their actual function and interaction in clinical forms of disease remains unclear.

Evidence for the co-circulation of dengue virus type 3 genotypes III and V in the Northern region of Brazil during the 2002-2004 epidemics

The reintroduction of dengue virus type 3 (DENV-3) in Brazil in 2000 and its subsequent spread throughout the country was associated with genotype III viruses, the only DENV-3 genotype isolated in Brazil prior to 2002. We report here the co-circulation of two different DENV-3 genotypes in patients living in the Northern region of Brazil during the 2002-2004 epidemics. Complete genomic sequences of viral RNA were determined from these epidemics, and viruses belonging to genotypes V (Southeast Asia/South Pacific) and III were identified. This recent co-circulation of different DENV-3 genotypes in South America may have implications for pathological and epidemiological dynamics.