Got a Pen for Allergen Immunotherapy? Lessons from Near-Fatal Anaphylaxis with Pulmonary Edema.

On our pediatric intensive care unit, we successfully treated a 10-year-old boy with severe pulmonary edema due to anaphylaxis after his last injection of a 3-year course of allergen immunotherapy (AIT). In view of the severity of the adverse event, we initiated a case analysis with all involved medical professionals. The evaluation revealed delayed administration of epinephrine due to dosing uncertainty and underestimation of severity. Consequently, all involved institutions established epinephrine auto-injectors (EAIs) in their emergency equipment. We suggest providing EAIs in every practice conducting AIT, as well as in pediatric emergency rooms and ambulances. We would like to remind readers of the risk of anaphylaxis, even on the last day of AIT.

Molecular and functional analysis of the antigen receptor of Art v 1-specific helper T lymphocytes.

BACKGROUND: Ninety-five percent of patients with mugwort allergy are sensitized to Art v 1, the sole major allergen in mugwort (Artemisia vulgaris) pollen. Sixty-nine percent of patients recognizing the single immunodominant T-cell epitope Art v 1(25-36) have an HLA-DRB1*01 phenotype. OBJECTIVE: We studied cloning and functional expression of a human alphabeta T-cell receptor (TCR) specific for Art v 1(25-36). METHODS: TCR chains were RT-PCR amplified from an Art v 1(25-36)-specific T-cell clone, retrovirally transferred, and functionally tested in Jurkat T cells or alternatively in peripheral blood T lymphocytes of nonallergic individuals. RESULTS: The alpha-chain of the TCR is composed of TRAV17 and TRAJ45 segments, and the beta-chain uses TRBV18, TRBD1, and TRBJ2-7. Analyses of 23 other Art v 1-specific T-cell clones did not reveal preferential usage of the TRAV17, TRBV18, or other TCR gene families. Efficient TCR transfer into Jurkat T cells was shown by binding of TCR Vbeta18-specific mAb and DRB1*0101/Art v 1 tetramers. Transgenic Jurkat T cells specifically recognized syngeneic EBV B cells pulsed with Art v 1(25-36) peptide and artificial antigen-presenting cells expressing invariant chain::Art v 1 fusion proteins. Moreover, transfer of the TCR into peripheral blood lymphocytes generated T cells that were Art v 1 reactive. Activation of transgenic T cells by artificial antigen-presenting cells was strictly dependent on costimulation. CONCLUSION: For the first time, a detailed molecular and functional analysis of a human allergen-specific TCR is presented.

Cytochemical demonstration of expression and distribution of non-glycosylated human lysosomal cathepsin S in HEK 293 cells.

The lysosomal cysteine protease cathepsin S is synthesized as inactive precursor at the rough endoplasmic reticulum (ER), further processed in the Golgi compartment and finally targeted to the lysosomes where it becomes activated by the proteolytic cleavage of the inhibitory propeptide. Biochemical studies with a non-glycosylated mutant of procathepsin S (plasma membrane binding at 2 degrees C, reuptake of secreted enzyme at 37 degrees C) led to the suggestion of an additional sorting motif in procathepsin S besides the classical Man-6-P recognition signal. In order to further confirm this suggestion on a morphological basis we performed a series of laser scanning confocal microscopy (CLSM) and electron microscopical analyses with HEK 293 cells expressing the mutant non-glycosylated procathepsin S. Immunolocalization with CLSM documented clearly a fine granular fluorescence in the paranuclear region of mutant expressing cells. Electron microscopy demonstrated the presence of cathepsin S immunoreactive deposits within cytosolic vacuoles (lysosomes), at the plasma membrane and in ER buds. These buds were also visible in the cytosol as well as in form of concentrated patches at the plasma membrane indicating the direct transport of (pro)cathepsin S from the ER to the cell surface.