Asunto(s)

RESUMEN

BACKGROUND: Cutaneous acanthamebiasis is a rare infection and few patients have been reported worldwide. METHODS: Observational and descriptive study carried out from March 1996 to February 2006 in patients with diagnosis of cutaneous free-living amebic infection caused by Acanthamoeba spp. The patients were diagnosed at the Dos de Mayo National Hospital (Lima-Peru) where skin biopsies, histopathologic studies and cultures were performed. The clinical and epidemiologic characteristics, diagnosis, treatment and evolution were recorded in a survey. RESULTS: Five patients with cutaneous free-living amebic infection caused by Acanthamoeba spp. were identified. Skin lesions were ulceronecrotic (four patients), an infiltrative bluish plaque (one patient), and a periorbital tumor (one patient). Three patients were positive for human immunodeficiency virus (HIV), had only cutaneous involvement, and died of opportunistic infections. The two immunocompetent patients developed Acanthamoeba granulomatous encephalitis and meningoencephalitis that progressed to intracranial hypertension and death. CONCLUSION: The clinical manifestations of cutaneous free-living amebic infection caused by Acanthamoeba spp. appear to vary according to the underlying immunologic status.

Asunto(s)

RESUMEN

Tecidual reaction at the inoculation site of L. (L.)chagasi promastigotes in hamsters depleted and non-depleted of complement was studied within 2, 6, 12, 24, 48 and 72 hours of infection. The inflammatory reaction was characterized by early predominance of polymorphonuclear cells (PMN) at 2, 6 and 12 hours of infection, mixed infiltrate of PMN and mononuclear cells (MN) at 24 hours, followed by predominance of MN at 48 and 72 hours after infection. The group depleted of complement showed a higher number of PMN at 2 hours and lower numbers of MN at 72 hours after infection (P < 0.0001). In the depleted group the phagocytosis by PMN was lower at 2 and 24 hours and by MN was lower at 24, 48 and 72 hours after infection. Electron microscopy showed extracellular intact and degenerated parasites, and lysed intracellular parasites, in PMN; and, rarely, preserved intracellular parasites in MN at 2, 6 and 12 hours after infection. The groups examined at 24, 48 and 72 hours of infection showed only cellular and parasite debris in mononuclear inflammatory cells. C3b deposits were detected by immunofluorescence in the interstitium and in the cytoplasm of inflammatory cells in non-depleted group at 2, 6 and 12 hours of infection. No immunoglobulin was detected in either group. Visceralization was detected 240 days after infection. The complement system has an important role in the inflammatory reaction and phagocytosis. The ultrastructural findings showed that the escape of the parasite probably occurs soon after inoculation.

Asunto(s)

RESUMEN

We examined the immunogenicity of various connective tissue proteins in patients with chronic onchocercal dermatitis and the effect of filarial proteases on this host-parasite interaction. Sera from patients with onchocerciasis reacted strongly with cuticular collagens from filarial parasites and with mammalian laminin. Some sera also contained antibodies to elastin and collagen type IV, but none reacted with collagen types I-III or fibronectin. This pattern of reactivity was characteristic for onchocerciasis: sera from patients with mansonellosis reacted strongly with collagen type IV but only weakly with laminin. Reactivity with mammalian laminin or collagen could not be absorbed with cuticular proteins from filarial worms and vice versa. Digestion fragments of laminin treated with filarial proteases retain antigenic determinants recognized by sera from patients with onchocerciasis. In contrast, proteases from Onchocerca volvulus adults and microfilariae drastically decreased the reactivity of the same sera with collagen type IV. These results indicate that filarial proteases may contribute to the pathogenesis of chronic onchocercal dermatitis, directly, by enzymatically destroying connective tissue of the skin, and indirectly, by triggering autoimmune responses to self-determinants on connective tissue proteins that are normally hidden within the supramolecular structure of the extracellular matrix complex.

Asunto(s)

RESUMEN

Mice were immunized with whole membranes of cultured epimastigotes and then inoculated with cultured trypomastigotes. The blood parasite count was lower than in the control. No changes could be detected however, in the length of the prepatent period nor in the extent and duration of the tissue damage observed in the chronic phase of the infection. Damage was evident in the tissues of both immunized and naive animals up to 171 days post inoculum. Blood parasites could be demonstrated neither by direct observation nor by culture, as soon as 117 days after infection. The presence of mast cells a few hours after infection and throughout the study suggests a role of these cells in both the specific and nonspecific components of host response.

Asunto(s)

RESUMEN

Mice were immunized with whole membranes of cultured epimastigotes and then inoculated with cultured trypomastigotes. The blood parasite count was lower than in the control. No changes could be detected however, in the length of the prepatent period nor in the extent and duration of the tissue damage observed in the chronic phase of the infection. Damage was evident in the tissues of both immunized and naive animals up to 171 days post inoculum. Blood parasites could be demonstrated neither by direct observation nor by culture, as soon as 117 days after infection. The presence of mast cells a few hours after infection and throughout the study suggests a role of these cells in both the specific and nonspecific components of host response

Asunto(s)

RESUMEN

Congenitally athymic nude Balb/c (nu/nu) and their phenotypically normal adult and neonate littermates (nu/+), the C3H/HeN as well, were intraperitoneally infected with two strains (Y or CL) or Trypanosoma cruzi. The nude mice and the neonates developed a severe parasitaemia, the susceptible C3H/HeN also presented high level and adult Balb/c mice presented parasitaemia similar to that observed in outbred mice. Erythematous skin lesions were observed initially in infected athymic nude and neonates, being characterized by nests of amastigotes in the dermis; in C3H/HeN infected mice no nest of parasite was observed but a low-grade inflammatory reaction was seen. In adult Balb/c or OF1 outbred mice nest was found but discreet inflammatory reaction was observed in severe infections.

Asunto(s)

Asunto(s)

RESUMEN

This study documents the immunohistologic and ultrastructural morphometric features of a case of cutaneous myiasis due to Dermatobia hominis. The mixed host inflammatory response surrounding the larvae included lymphoblasts, eosinophils, activated fibroblasts, mature histiocytes, mast cells, plasma cells, and Langerhans cells, indicating a complex interactive immunologic response to the botfly parasite. Immunotyping revealed that the dominant dermal cells were activated (Ia+) T-helper cells. Although the strikingly elevated T-helper/T-suppressor cell ratio might suggest a monoclonal infiltrate, a mixture of Leu 8+ and Leu 8- T-cells indicates both immunoregulatory subsets of T-helper cells as found in a reactive process. Furthermore, our ultrastructural histogram found the lymphoid nuclear shapes were oval with few nuclear invaginations as found in inflammatory infiltrates. As indicated by electron microscopy, there were abundant activated fibroblasts elaborating collagen which may relate to larval containment.

Asunto(s)