BAFF Mediates Splenic B Cell Response and Antibody Production in Experimental Chagas Disease

Chagas disease, caused by the protozoan Trypanosoma cruzi, is endemic in Central and South America. It affects 20 million people and about 100 million people are at risk of infection in endemic areas. Some cases have been identified in non-endemic countries as a consequence of blood transfusion and organ transplantation. Chagas disease presents three stages of infection. The acute phase appears one to two weeks after infection and includes fever, swelling around the bite site, enlarged lymph glands and spleen, and fatigue. This stage is characterized by circulating parasites and many immunological disturbances including a massive B cell response. In general, the acute episode self-resolves in about 2 months and is followed by a clinically silent indeterminate phase characterized by absence of circulating parasites. In about one-third of the cases, the indeterminate phase evolves into a chronic phase with clinically defined cardiac or digestive disturbances. Current knowledge suggests that the persistence of parasites coupled with an unbalanced immune response sustain inflammatory response in the chronic stage. We believe that an effective treatment for chronic Chagas disease should combine antiparasitic drugs with immunomodulators aimed at reducing inflammation and autoreactive response. Our findings enlighten a new role of BAFF-BAFF-R signaling in parasite infection that partially controls polyclonal B cell response but not parasitespecific class-switched primary effectors B cells

HISTOCHEMICAL-DEMONSTRATION OF PHOSPHOLIPID CONTAINING CHOLINE IN THE CYTOPLASM OF MURINE DECIDUAL CELLS

The localization of lipids in the endometrium of virgin and 6- to 9-day-pregnant mice was detected by histochemical methods. Total lipids (as shown by staining with Sudan black) and phospholipids containing choline (PCC) were detected. Sections subjected to reactions that have been proposed for the demonstration of vitamins E and D and cholesterol gave negative results. In the virgin animals, lipids were found in epithelial cells but not in the endometrial stroma. On the other hand in the pregnant animals, the endometrial stroma contained both Sudan-black-stained lipids and PCC. Maximal staining was reached on day 8 of pregnancy. The staining was more conspicuous in the more differentiated decidual cells adjacent to the embryos than in the less differentiated predecidual cells. The nondecidualized stroma, situated peripherally near the myometrium did not stain for lipids. In the cytoplasm of decidual cells the reaction for PCC was observed in the form of granules, which were often arranged in groups surrounding the nuclei. We suggest that decidual cells store PCC to be mobilized as a precursor for mediators of decidualization, such as prostaglandins, that would act as paracrine inducers of the decidual reaction.150211912