Cerebral aspergillosis within new tumour site presents as incidental new brain lesion in patient receiving temozolomide for glioblastoma multiforme.

Glioblastoma multiforme (GBM) is an aggressive tumour that can lead to lymphopaenia. Its standard treatment involves temozolomide (TMZ) chemotherapy with radiation, often with addition of corticosteroids for symptomatic management. Although TMZ is also immunosuppressive, patients receiving TMZ rarely develop disseminated opportunistic infections. Here, we report the case of a patient with GBM receiving TMZ, radiotherapy and corticosteroids, who develops an incidental new brain lesion that is found to be disseminated Aspergillus within a new GBM tumour site. The patient received successful early treatment of her central nervous system aspergillosis. This case illustrates the profound immunosuppressive potential of GBM in conjunction with TMZ and corticosteroids, which can lead to high-morbidity opportunistic infections concurrently with tumour progression. Future research is needed to elucidate GBM, TMZ and corticosteroids' compound immune effects and guide management that strikes a balance between treating high-morbidity infections and continuing with immunosuppressive chemotherapy.

Fabry disease in mice protects against lethal disease caused by Shiga toxin-expressing enterohemorrhagic Escherichia coli.

Fabry disease is an X-linked recessive disorder in which affected persons lack alpha-galactosidase A (alpha -GalA), which leads to excess glycosphingolipids in tissues, mainly globotriaosylceramide (Gb3). Gb3 is the cellular receptor for Shiga toxin (Stx), the primary virulence factor of enterohemorrhagic Escherichia coli. alpha-GalA-knockout mice were significantly protected against lethal intraperitoneal doses of Stx2 or oral doses of Stx2-expressing bacteria, compared with wild-type (wt) control mice. Kidneys of moribund wt mice revealed tubular necrosis, but no histopathologic changes were observed in Gb3-overexpressing mice. Reducing Gb3 levels in alpha-GalA-knockout mice by the intravenous injection of recombinant human alpha-GalA restored the susceptibility of knockout mice to lethal doses of Stx2. These results suggest that excess amounts of Gb3 in alpha-GalA-deficient mice may impair toxin delivery to susceptible tissues.

Identification of genes encoding arabinosyltransferases (SCA) mediating developmental modifications of lipophosphoglycan required for sand fly transmission of leishmania major.

At key steps in the infectious cycle pathogens must adhere to target cells, but at other times detachment is required for transmission. During sand fly infections by the protozoan parasite Leishmania major, binding of replicating promastigotes is mediated by galactosyl side chain (scGal) modifications of phosphoglycan repeats of the major surface adhesin, lipophosphoglycan (LPG). Release is mediated by arabinosyl (Ara) capping of LPG scbetaGal residues upon differentiation to the infective metacyclic stage. We used intraspecific polymorphisms of LPG structure to develop a genetic strategy leading to the identification of two genes (SCA1/2) mediating scAra capping. These LPG side chain beta1,2-arabinosyltransferases (scbetaAraTs) exhibit canonical glycosyltransferase motifs, and their overexpression leads to elevated microsomal scbetaAraT activity. Although the level of scAra caps is maximal in metacyclic parasites, scbetaAraT activity is maximal in log phase cells. Because quantitative immunolocalization studies suggest this is not mediated by sequestration of SCA scbetaAraTs away from the Golgi apparatus during log phase, regulation of activated Ara precursors may control LPG arabinosylation in vivo. The SCA genes define a new family of eukaryotic betaAraTs and represent novel developmentally regulated LPG-modifying activities identified in Leishmania.

Functional identification of galactosyltransferases (SCGs) required for species-specific modifications of the lipophosphoglycan adhesin controlling Leishmania major-sand fly interactions.

Lipophosphoglycan (LPG) is an abundant surface molecule that plays key roles in the infectious cycle of Leishmania major. The dominant feature of LPG is a polymer of phosphoglycan (PG) (6Galbeta1,4Manalpha1-PO(4)) repeating units. In L. major these are extensively substituted with Gal(beta1,3) side chains, which are required for binding to midgut lectins and survival. We utilized evolutionary polymorphisms in LPG structure and cross-species transfections to recover genes encoding the LPG side chain beta1,3-galactosyltransferases (betaGalTs). A dispersed family of six SCG genes was recovered, whose predicted proteins exhibited characteristics of eukaryotic GalTs. At least four of these proteins showed significant LPG side chain betaGalT activity; SCG3 exhibited initiating GalT activity whereas SCG2 showed both initiating and elongating GalT activity. However, the activity of SCG2 was context-dependent, being largely silent in its normal genomic milieu, and different strains show considerable variation in the extent of LPG galactosylation. Thus the L. major genome encodes a family of SCGs with varying specificity and activity, and we propose that strain-specific LPG galactosylation patterns reflect differences in their expression.