Alpha 2,3-sialyltransferase-IV is essential for L-selectin ligand function in inflammation.

L-selectin belongs to the C-type lectin family of glycoproteins and is constitutively expressed on most leukocytes. L-selectin mediates leukocyte rolling in inflamed microvessels and high endothelial venules (HEV) via binding to specific carbohydrate structures on selectin ligands. Previous studies using sialidase treatment suggested a role of sialic acid residues in L-selectin-dependent rolling. To investigate the role of the alpha2,3-sialyltransferase (ST3Gal)-IV on L-selectin ligand activity in vivo, we studied leukocyte rolling in inflamed venules of the cremaster muscle and in Peyer's patch HEV of ST3Gal-IV-deficient mice and littermate control mice. In cremaster muscle venules with or without TNF-alpha treatment, L-selectin-dependent rolling was almost completely abolished in ST3Gal-IV(-/-) mice. In both models, L-selectin interacts with P-selectin glycoprotein ligand-1 (PSGL-1) presented by adherent leukocytes and leukocyte fragments, but not with endothelial L-selectin ligands. In contrast, L-selectin-dependent rolling in Peyer's patch HEV, which is mediated by unknown endothelial L-selectin ligands, was not impaired in the absence of ST3Gal-IV. Our in vivo data show that PSGL-1, the molecule responsible for L-selectin-mediated leukocyte interactions in inflammation, is dependent on ST3Gal-IV, while alpha2,3-sialylation by ST3Gal-IV is not necessary for L-selectin ligand activity on high endothelial cells of Peyer's patch HEV.

Naive regulatory T cells: a novel subpopulation defined by resistance toward CD95L-mediated cell death.

Most CD4(+)CD25(hi)FOXP3(+) regulatory T cells (T(regs)) from adult peripheral blood express high levels of CD45RO and CD95 and are prone to CD95L-mediated apoptosis in contrast to conventional T cells (T(convs)). However, a T(reg) subpopulation remained consistently apoptosis resistant. Gene microarray and 6-color flow cytometry analysis including FOXP3 revealed an increase in naive T-cell markers on the CD95L-resistant T(regs) compared with most T(regs). In contrast to T(regs) found in adult humans, most CD4(+)CD25(+)FOXP3(+) T cells found in cord blood are naive and exhibit low CD95 expression. Furthermore, most of these newborn T(regs) are not sensitive toward CD95L similar to naive T(regs) from adult individuals. After short stimulation with anti-CD3/CD28 monoclonal antibodies (mAbs), cord blood T(regs) strongly up-regulated CD95 and were sensitized toward CD95L. This functional change was paralleled by a rapid up-regulation of memory T-cell markers on cord blood T(regs) that are frequently found on adult memory T(regs). In summary, we show a clear functional difference between naive and memory T(regs) that could result in different survival rates of those 2 cell populations in vivo. This new observation could be crucial for the planning of therapeutic application of T(regs).

Incontinentia pigmenti in combination with decreased IgG subclass concentrations in a female newborn.

Incontinentia pigmenti (IP) is a rare neurocutaneous disorder caused by mutations in the NEMO (NF-kappaB essential modulator) gene. Skin lesions are typically the first manifestation of IP though they may be accompanied by multiple malformations. This report presents the case of a female newborn with early onset of IP lesions within the 1st day of life. After the age of 1 month she developed frequent episodes of severe gastroenteritis. Examination of the immune system revealed low concentrations of IgG subclasses. This study suggests that, contrary to previous belief, IP is associated with immune deficiency.

Buprenorphine and norbuprenorphine concentrations in human breast milk samples determined by liquid chromatography-tandem mass spectrometry.

Buprenorphine (BUP) is considered to be safe during pregnancy. However, the extent of BUP transfer into breast milk has not been investigated thoroughly. Because the drug concentration in the milk is 1 of the determinants in the assessment of the exposure risk, a rapid and sensitive LC-MS/MS method has been developed and evaluated to measure BUP and norbuprenorphine (norBUP) concentrations in milk. A solid-phase and 2 liquid-liquid extraction procedures have been compared. The lower limits of detection and quantification were 0.05 ng/mL and 0.18 ng/mL for BUP and 0.05 ng/mL and 0.20 ng/mL for norBUP, respectively, using a sample volume of 0.5 mL milk. BUP and norBUP concentrations determined from 10 random breast milk samples collected over 4 successive days from a lactating woman during buprenorphine maintenance therapy ranged from 1.0 to 14.7 and 0.6 to 6.3 ng/mL, respectively. Drug exposure of the infant may be considered to be low. Further investigations may seek to extend these preliminary findings to evaluate an infant's level of BUP exposure through breast milk.