Clinical and immunological aspects and outcome of a Brazilian cohort of 414 patients with systemic lupus erythematosus (SLE): comparison between childhood-onset, adult-onset, and late-onset SLE.

The clinical expression of systemic lupus erythematosus (SLE) is influenced by genetic and environmental factors and therefore varies between ethnicities. Information on the epidemiology of SLE in Brazil is scarce and practically limited to studies conducted in socioeconomically developed regions (South and Southeast). The objective of this study was to describe the clinical and immunological aspects and outcome of a cohort of patients with SLE treated at a university hospital in northeastern Brazil and compare patterns related to age at onset: childhood (cSLE), adult (aSLE), and late (lSLE). A random sample of 414 records (women: 93.5%) were reviewed. The mean age at SLE onset and the mean disease duration were 28.9 ± 10.9 years and 10.2 ± 6.6 years, respectively. Most patients had aSLE (n = 338; 81.6%), followed by cSLE (n = 60; 14.5%) and lSLE (n = 16; 3.9%). The female/male ratio was 6.5:1 in cSLE and 16.8:1 in aSLE; in lSLE, all patients were female (p = 0.05). During follow-up, the cSLE group presented higher rates of nephritis (70% vs. 52.9% vs. 12.5%; p = 0.0001) and leuko/lymphopenia (61.7% vs. 43.8% vs. 56.2%; p = 0.02). No significant differences were found for anti-dsDNA, anti-Sm, and antiphospholipid antibodies. Treatment with immunosuppressants was significantly more common, and higher doses of prednisone were used, in cSLE. The prevalence of cardiovascular diseases were more frequent in lSLE (p = 0.03). No significant differences were found between the three groups with regard to mean damage accrual (SDI), remission, and mortality. Although cSLE presented higher rates of nephritis and leuko/lymphopenia, more frequent use of immunosuppressants and higher prednisone doses than aSLE and lSLE, the three groups did not differ significantly with regard to damage accrual, remission, and mortality.

The peripheral vesicles of trophozoites of the primitive protozoan Giardia lamblia may correspond to early and late endosomes and to lysosomes.

Giardia lamblia, a primitive eukaryotic cell, lacks organelles such as mitochondria, peroxisomes, and a typical Golgi complex and presents a system of vesicles located below the plasma membrane. We used fluorescence and electron microscopy to better characterize the peripheral vesicles. Incubation of living cells with acridine orange showed that the peripheral vesicles correspond to an acidic compartment. Incubation with lucifer yellow, and with horseradish peroxidase, showed labeling of the peripheral vesicles even after several hours. Acid phosphatase was localized in the endoplasmic reticulum and in most of the peripheral vesicles. On the other hand, glucose 6-phosphatase, an endoplasmic reticulum marker, was observed in the endoplasmic reticulum cisternae and in some peripheral vesicles. A similar labeling pattern was observed using the zinc iodide technique, which reveals SH-containing proteins. Three-dimensional reconstruction and electron microscopy tomography of cells stained for acid phosphatase and glucose-6-phosphatase revealed the connection between some vesicles and profiles of the endoplasmic reticulum. Taken together, our observations suggest that trophozoites of G. lamblia present an endosomal-lysosomal system concentrated in a single system, the peripheral vesicles, which may represent an ancient organellar system that later on subdivided into compartments such as early and late endosomes and lysosomes.

Early events related with the behaviour of Trypanosoma cruzi within an endocytic vacuole in mouse peritoneal macrophages.

Transmission electron microscopy was used to analyse the process of interaction of Trypanosoma cruzi with resident and activated mouse peritoneal macrophages. Initially, the parasites are located within a membrane-bounded endocytic vacuole. Lysosomes from the host cell fuse and discharge their content into the parasite-containing vacuole, as visualized by localization of horseradish peroxidase and acid phosphatase activity. Acridine orange was used to label secondary lysosomes in order to quantify the process of lysosome-phagosome fusion by fluorescence microscopy. The fusion index was higher for amastigote than for epimastigote and trypomastigote forms. Images were obtained showing that a few hours after ingestion of trypomastigote forms by the macrophages there is progressive disruption of the membrane lining the vacuole, until its complete disappearance.