Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0751295 (memory loss)
 3,619 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Whipple's disease (WD) is a rare chronic infectious disorder caused by the rod- shaped bacterium Tropheryma whipplei. The disorder is characterized clinically by arthralgia, abdominal pain, diarrhea, malabsorbtion and progressive weight loss. Other important sites of infection include the heart (resulting in the clinical picture of endocarditis and heart failure) and the central nervous system (CNS) (manifestations include confusion, memory loss, focal cranial nerve signs, nystagmus and ophtalmoplegia). The bacterium is presumed to be ubiquitously present. A defect in cellular immune response may predispose patients for an infection with T. whipplei and this might explain the rarity of the disorder despite the ubiquitous bacterial presence. The presumed immunological defect is likely to be quite specific for T. whipplei, since patients are not generally affected by other infections. Decreased production of Interleukin(IL)-12, IL-2 and Interferon (IFN)-g accompanied by an increased secretion of IL-4 are the main features of this defective immunological response. The finding of periodic acid-Schiff (PAS)-positive macrophages in the lamina propria of tissue samples obtained by duodenal biopsy usually establishes the diagnosis. The PAS-positive inclusions represent the remnants of the bacteria. Attempts to isolate the causative agent were unsuccessful for nearby 100 years after the first recognition of the disease. In the year 2000, the bacterium was finally successfully grown on a human fibroblast cell line. Untreated WD patients suffer from a chronic progressive disorder which possibly leads to death. Most patients show a fast clinical improvement to antibiotic therapy, but clinical relapses are described frequently. There is a number of patients, unable to eradicate the bacterium even after several antibiotic treatments and patients with CNS disease, in both of whom alternative therapy strategies are necessary.
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PMID:Current concepts of immunopathogenesis, diagnosis and therapy in Whipple's disease. 1707 38

CCR6, a homeostatic chemokine receptor, is shown here to characterize subsets of both central and effector memory T cells that secrete high levels of IL-2 and TNF-alpha in response to polyclonal and antigen-specific stimulation. CCR6(+) T lymphocytes disappeared dramatically from the peripheral blood of HIV-infected patients as HIV disease progressed. The capacity of CD4(+)CCR6(+) to secrete multiple cytokines remained intact among HIV-infected long-term nonprogressors but was partially lost from subjects with standard disease progression. CCR6(+) T lymphocytes, regardless of their CCR7 expression, accumulated in the spleen of HIV-infected patients, where they died by apoptosis. Assessment of CCR6 expression allowed us to describe novel memory T-cell subpopulations capable of high cytokine production and provided evidence of a pathologic CCR6-dependent pathway of memory T-cell homing that may participate in the loss of memory response against infections.
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PMID:Trapping and apoptosis of novel subsets of memory T lymphocytes expressing CCR6 in the spleen of HIV-infected patients. 1719 36

Loss of memory B cells occurs from the onset of HIV-1 infection and persists into the chronic stages of infection. Lack of survival of these cells, even in subjects being treated, could primarily be the consequence of an altered local microenvironment induced by HIV infection. In this study we showed that memory B cell survival was significantly decreased in aviremic successfully treated (ST) subjects compared with subjects who control viral load as a result of natural immunity (elite controller [EC]) or with uninfected control (HIV-) subjects. The lower survival levels observed in memory B cells from ST subjects were the result of disrupted IL-2 signaling that led to increased transcriptional activity of Foxo3a and increased expression of its proapoptotic target TRAIL. Notably, memory B cell survival in ST subjects was significantly enhanced by the addition of exogenous IL-2 in a Foxo3a-dependent manner. We further showed that Foxo3a silencing by siRNA resulted in decreased expression of TRAIL and apoptosis levels in memory B cells from ST subjects. Our results thus establish a direct role for Foxo3a/TRAIL signaling in the persistence of memory B cells and provide a mechanism for the reduced survival of memory B cells during HIV infection. This knowledge could be exploited for the development of therapeutic and preventative HIV vaccines.
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PMID:Loss of memory B cells during chronic HIV infection is driven by Foxo3a- and TRAIL-mediated apoptosis. 2192 63