Anna M. Feldweg

Tumor-specific cell surface expression of the -KDEL containing endoplasmic reticular heat shock protein gp96

Heat shock protein (HSP) gp96/grp94 contains a signal peptide at the amino terminus and a ‐KDEL sequence at the carboxy terminus and is a major component of the lumen of the mammalian endoplasmic reticulum (ER). We show, by a number of immunolocalization methods using light and electron microscopy, that a significant proportion of intact gp96 molecules is also expressed on the cell surface. Surface gp96 molecules truly represent surface expression and do not result from adventitious deposition of gp96 released by dead cells on to the live cells in culture. Cell surface expression of gp96 is enhanced by heat shock and exposure to reducing agents. Gp96 molecules are not released from plasma membranes by repeated salt washes, and gp96 is not an integral membrane protein. Our observations suggest that gp96 and perhaps other HSPs are anchored to the cell surface as part of larger molecular complexes, which also transport them to the cell surface.

Prevention of Lipopolysaccharide-induced Microangiopathy by gp49B1 Evidence for an Important Role for gp49B1 Expression on Neutrophils

gp49B1 is expressed on mast cells and inhibits immunoglobulin E–dependent activation and inflammation in vivo. We now show that gp49B1 is expressed on neutrophils and prevents neutrophil-dependent vascular injury in response to lipopolysaccharide (LPS). The intradermal (i.d.) injection of LPS into gp49B1-null (gp49B − / −) but not gp49B1-sufficient (gp49B + / +) mice elicited macroscopic hemorrhages by 24 h, which were preceded on microscopic analyses by significantly more intravascular thrombi (consisting of neutrophils, platelets, and fibrin) that occluded venules and by more tissue neutrophils than in gp49B + / + mice. However, there were no differences in the number of intact (nondegranulating) mast cells or the tissue levels of mediators that promote neutrophil recruitment. Hemorrhage was prevented by depleting neutrophils, blocking β2 integrin–intercellular adhesion molecule 1 interactions, or inhibiting coagulation. These characteristics indicate that gp49B − / − mice are exquisitely sensitive to a local Shwartzman reaction (LSR) after a single i.d. injection of LPS, whereas in the classic LSR, a second exposure is required for increased β2 integrin function, intravascular neutrophil aggregation, formation of occlusive thrombi, and hemorrhage. Moreover, LPS increased gp49B1 expression on neutrophils in vivo. The results suggest that gp49B1 suppresses the LPS-induced increase in intravascular neutrophil adhesion, thereby providing critical innate protection against a pathologic response to a bacterial component.

gp49B1 suppresses stem cell factor-induced mast cell activation-secretion and attendant inflammation in vivo

We report that gp49B1, a mast cell membrane receptor with two immunoreceptor tyrosine‐based inhibitory motifs (ITIM), constitutively inhibits mast cell activation‐secretion induced by stem cell factor (SCF), a tissue‐derived cytokine that also regulates mast cell development. The intradermal injection of SCF into the ears of gp49B1 null (gp49B–/–) mice elicited∼4‐ and 2.5‐fold more degranulating mast cells and tissue swelling caused by edema, respectively, than in gp49B+/+ mice. SCF did not induce tissue swelling in mast cell‐deficient mice, and the responsiveness of gp49B–/– mice to mast cell‐associated amine and lipid mediators was unaltered. When gp49B+/+ and gp49B–/– mice were pretreated with antagonists of the amines, SCF‐induced tissue swelling was reduced by >90% and 60%, respectively, and it was reduced by >90% in both genotypes when a cysteinyl leukotriene receptor antagonist was also provided. Hence, the dominant contribution of secretory granule amines to SCF‐induced tissue swelling is the result of gp49B1‐mediated inhibition of the production of cysteinyl leukotrienes by mast cells. Our findings also provide the first example of an ITIM‐bearing receptor that constitutively suppresses inflammation generated in vivo independently of the adaptive immune response by a receptor that signals through intrinsic tyrosine kinase activity rather than immunoreceptor tyrosine‐based activation motifs.

Alcohol-induced Respiratory Symptoms Are Common in Patients With Aspirin Exacerbated Respiratory Disease

BACKGROUND A large percentage of patients with aspirin exacerbated respiratory disease (AERD) report the development of alcohol-induced respiratory reactions, but the true prevalence of respiratory reactions caused by alcoholic beverages in these patients was not known. OBJECTIVE We sought to evaluate the incidence and characteristics of alcohol-induced respiratory reactions in patients with AERD. METHODS A questionnaire designed to assess alcohol-induced respiratory symptoms was administered to patients at Brigham and Womens Hospital and Scripps Clinic. At least 50 patients were recruited into each of 4 clinical groups: (1) patients with aspirin challenge-confirmed AERD, (2) patients with aspirin-tolerant asthma (ATA), (3) patients with aspirin tolerance and with chronic rhinosinusitis, and (4) healthy controls. Two-tailed Fisher exact tests with Bonferroni corrections were used to compare the prevalence of respiratory symptoms among AERD and other groups, with P ≤ .017 considered significant. RESULTS The prevalence of alcohol-induced upper (rhinorrhea and/or nasal congestion) respiratory reactions in patients with AERD was 75% compared with 33% with aspirin-tolerant asthma, 30% with chronic rhinosinusitis, and 14% with healthy controls (P < .001 for all comparisons). The prevalence of alcohol-induced lower (wheezing and/or dyspnea) respiratory reactions in AERD was 51% compared with 20% in aspirin-tolerant asthma and with 0% in both chronic rhinosinusitis and healthy controls (P < .001 for all comparisons). These reactions were generally not specific to one type of alcohol and often occurred after ingestion of only a few sips of alcohol. CONCLUSION Alcohol ingestion causes respiratory reactions in the majority of patients with AERD, and clinicians should be aware that these alcohol-induced reactions are significantly more common in AERD than in controls who are aspirin tolerant.

Autoimmune progesterone dermatitis: clinical presentation and management with progesterone desensitization for successful in vitro fertilization

OBJECTIVE To report clinical cases of autoimmune progesterone (P) dermatitis, its relationship to IVF, and the potential for P desensitization to treat these cases to achieve viable pregnancies. DESIGN Clinical description. SETTING Institutional hospitalary practice. Allergy Division. PATIENT(S) Six patients from the Allergy Clinic consulting for cyclic rashes or anaphylaxis related to the luteal phase of the menstrual cycle. Three of the conditions were related to IVF. INTERVENTION(S) Skin tests were performed with P. For IVF, rapid 8- and 10-step P desensitization protocols were performed, with increasing doses administered every 20 minutes via intravaginal suppositories. A rapid oral desensitization protocol was performed in one patient who required an oral contraceptive for uterine bleeding. MAIN OUTCOME MEASURE(S) Progesterone skin test results. Tolerance to P desensitization. Achievement of viable pregnancies. RESULT(S) Skin tests were positive in all patients and negative in 10 controls. Desensitization was successful in four patients: three patients for IVF, resulting in viable pregnancies. Another patient achieved tolerance to oral contraceptives. CONCLUSION(S) Women with autoimmune P dermatitis can be desensitized successfully to P. We provide the first evidence of successful P desensitization in patients requiring IVF culminating in successful pregnancies.

Food-Dependent, Exercise-Induced Anaphylaxis: Diagnosis and Management in the Outpatient Setting

Food-dependent, exercise-induced anaphylaxis is a disorder in which anaphylaxis develops most predictably during exercise, when exercise takes place within a few hours of ingesting a specific food. IgE to that food should be demonstrable. It is the combination of the food and exercise that precipitates attacks, whereas the food and exercise are each tolerated independently. Recently, it was demonstrated that exercise is not essential for the development of symptoms, and that if enough of the culprit food is ingested, often with additional augmentation factors, such as alcohol or acetylsalicylic acid, symptoms can be induced at rest in the challenge setting. Thus, food-dependent, exercise-induced anaphylaxis appears to be more correctly characterized as a food allergy syndrome in which symptoms develop only in the presence of various augmentation factors, with exercise being the primary one. However, additional factors are not usually present when the patient exercises normally, so ongoing investigation is needed into the physiologic and cellular changes that occur during exercise to facilitate food-induced anaphylaxis.

Exercise-induced anaphylaxis.

Exercise-induced anaphylaxis is an uncommon disorder in which anaphylaxis occurs in response to physical exertion. Food-dependent exercise-induced anaphylaxis is a disorder with similar symptoms, although symptoms develop only if exercise takes place within a few hours of eating and, in most cases, only if a specific food is eaten. Management includes education about safe conditions for exercise, the importance of ceasing exercise immediately if symptoms develop, appropriate use of epinephrine, and, for patients with food-dependent exercise-induced anaphylaxis, avoidance of the culprit food for at least 4 hours before exercise.

Drug Interactions Affecting the Efficacy of Corticosteroid Therapy A Brief Review with An Illustrative Case

A drug interaction that seemed to contribute to sudden worsening of corticosteroid-stabilized vasculitis stimulated this review. A large number of drugs share with corticosteroids critical phase I metabolic steps mediated by hepatic cytochrome P450 (CYP) enzymes, particularly the individual enzyme CYP3A4. In their metabolic interaction with CYP3A4 as substrates, a growing number of these drugs have the potential to induce (upregulate) hepatic CYP3A4 levels, resulting in accelerated clearance (and reduced efficacy) of concomitantly administered glucocorticoids, which are also CYP3A4 substrates. Many other drugs can have the opposite effect, that is, they can inhibit CYP3A4 function by tight binding to its active site. This can result in reduced clearance (and augmented efficacy) of concurrently administered glucocorticoids. Current knowledge of this type of drug interaction, the drugs to watch out for, and multiple clinical reports of altered corticosteroid efficacy, are reviewed after presentation of the case illustrating potential relevance to the management of rheumatic diseases.

An integrated clinical program and crowdsourcing strategy for genomic sequencing and Mendelian disease gene discovery

Despite major progress in defining the genetic basis of Mendelian disorders, the molecular etiology of many cases remains unknown. Patients with these undiagnosed disorders often have complex presentations and require treatment by multiple health care specialists. Here, we describe an integrated clinical diagnostic and research program using whole-exome and whole-genome sequencing (WES/WGS) for Mendelian disease gene discovery. This program employs specific case ascertainment parameters, a WES/WGS computational analysis pipeline that is optimized for Mendelian disease gene discovery with variant callers tuned to specific inheritance modes, an interdisciplinary crowdsourcing strategy for genomic sequence analysis, matchmaking for additional cases, and integration of the findings regarding gene causality with the clinical management plan. The interdisciplinary gene discovery team includes clinical, computational, and experimental biomedical specialists who interact to identify the genetic etiology of the disease, and when so warranted, to devise improved or novel treatments for affected patients. This program effectively integrates the clinical and research missions of an academic medical center and affords both diagnostic and therapeutic options for patients suffering from genetic disease. It may therefore be germane to other academic medical institutions engaged in implementing genomic medicine programs.