Lora G. Bankova

Allergy to monoclonal antibodies: cutting-edge desensitization methods for cutting-edge therapies

Monoclonal antibodies are important therapeutic tools, but their usefulness is limited in patients who experience acute infusion reactions, most of which are consistent with type I hypersensitivity reactions including anaphylaxis. Patients who experience acute infusion reactions face the prospect of stopping treatment or switching to an alternative, and potentially more toxic or inferior treatment. Another option that overcomes the treatment hurdle of these reactions is rapid desensitization, a procedure in which the offending agent is re-administered in a step-wise, highly controlled fashion. While the risk of reactions is not completely eliminated, desensitization has proven to be a highly effective re-administration strategy for most patients who otherwise would not be able to tolerate their monoclonal antibody therapy owing to drug-induced anaphylaxis. This article reviews the current literature on desensitization and other readministration protocols to monoclonal antibodies with an emphasis on four agents: rituximab, infliximab, cetuximab and trastuzumab.

Safety, Costs, and Efficacy of Rapid Drug Desensitizations to Chemotherapy and Monoclonal Antibodies

BACKGROUND Rapid drug desensitization (RDD) is used to address hypersensitivity reactions to chemotherapeutics and monoclonal antibodies, allowing patients to be treated with optimal pharmacological agents. RDD protocols are tailored to each individual patients reaction and needs, and protect against anaphylaxis, but overall risks, costs, and benefits have not been determined. OBJECTIVE We investigated the safety, efficacy, costs, and life expectancy of patients in a large population undergoing RDD. METHODS We analyzed 2177 RDD procedures performed in 370 patients with cancer, vasculitis, and hematological and connective tissue diseases who presented 402 reactions. A subgroup of carboplatin allergic patients with ovarian cancer treated with RDD was analyzed for costs and life expectancy and compared with a nonallergic control group. RESULTS RDD allowed all patients to receive safely the full dose of the medication to which they were reactive. A gradual increase in the fraction of outpatient desensitizations from 81% to 98% was achieved through risk stratification. Of the 2177 desensitizations, 93% had no or mild reactions whereas 7% had moderate to severe reactions, which did not preclude the completion of the treatment, and there were no deaths. Overall health costs in the carboplatin allergic group were not higher than those in the nonallergic group treated with standard of care. Administration of carboplatin through RDD was as effective as standard administration with a nonsignificant increase in life expectancy in desensitized patients as compared with nonallergic, nondesensitized controls. CONCLUSIONS RDD is cost effective and safe for allergic patients with cancer and chronic disease to remain on first line therapy.

Leukotriene E4 elicits respiratory epithelial cell mucin release through the G-protein–coupled receptor, GPR99

Significance Leukotriene E4 (LTE4), a lipid mediator detected in asthma exacerbations triggered by allergen, viruses, and aspirin, elicits airflow obstruction and lung inflammation in asthmatics. GPR99 is the recently identified high-affinity receptor for LTE4 and is resistant to blockade by commercially available cysteinyl leukotriene (cysLT) receptor antagonists. Here we find that GPR99 is expressed in respiratory epithelial cells and mediates mucin release and submucosal swelling in response to LTE4 or to cysLTs elicited by Alternaria, a common airborne fungus. Furthermore, among cysLT receptors, only GPR99 regulates baseline numbers of mucin-containing goblet cells. These studies demonstrate a unique role for GPR99 in epithelial cell homeostasis and activation and indicate that epithelial cells may be a dominant site of LTE4 action in the lung. Cysteinyl leukotrienes (cysLTs), leukotriene C4 (LTC4), LTD4, and LTE4 are proinflammatory lipid mediators with pathobiologic function in asthma. LTE4, the stable cysLT, is a weak agonist for the type 1 and type 2 cysLT receptors (CysLTRs), which constrict airway smooth muscle, but elicits airflow obstruction and pulmonary inflammation in patients with asthma. We recently identified GPR99 as a high-affinity receptor for LTE4 that mediates cutaneous vascular permeability. Here we demonstrate that a single intranasal exposure to extract from the respiratory pathogen Alternaria alternata elicits profound epithelial cell (EpC) mucin release and submucosal swelling in the nasal mucosa of mice that depends on cysLTs, as it is absent in mice deficient in the terminal enzyme for cysLT biosynthesis, LTC4 synthase (LTC4S). These mucosal changes are associated with mast cell (MC) activation and absent in MC-deficient mice, suggesting a role for MCs in control of EpC function. Of the three CysLTRs, only GPR99-deficient mice are fully protected from EpC mucin release and swelling elicited by Alternaria or by intranasal LTE4. GPR99 expression is detected on lung and nasal EpCs, which release mucin to doses of LTE4 one log lower than that required to elicit submucosal swelling. Finally, mice deficient in MCs, LTC4S, or GPR99 have reduced baseline numbers of goblet cells, indicating an additional function in regulating EpC homeostasis. These results demonstrate a novel role for GPR99 among CysLTRs in control of respiratory EpC function and suggest that inhibition of LTE4 and of GPR99 may have therapeutic benefits in asthma.

Mast Cells Recruited to Mesenteric Lymph Nodes during Helminth Infection Remain Hypogranular and Produce IL-4 and IL-6

Mast cells (MC) and basophils share expression of the high-affinity receptor for IgE (FcεRI) but can be distinguished by their divergent expression of KIT and CD49b. In BALB/c mice, MC lineage cells expressing high levels of FcεRI by flow cytometry were seen only in bone marrow whereas those expressing intermediate levels of FcεRI were present in bone marrow and spleen of naive mice and in mesenteric lymph nodes (mLN) of Trichinella spiralis–infected mice. These FcεRI+KIT+CD49b− cells had a membrane phenotype similar to i.p. connective tissue-type MC, but were smaller and hypogranular by flow cytometry forward and side scatter profiles, respectively. Consistent with this, they lacked the prominent secretory granules identified by histochemistry and immunodetection for the MC-specific granule proteases that are readily seen in mature jejunal mucosal MC that also are induced by the infection and present at the same time. The concentration of these MC lineage cells in mLN determined by flow cytometry was comparable to that of MC progenitors (MCp) measured by limiting dilution and clonal expansion with maturation. We observed upregulation of IL-4 transcription by MCp in mLN and spleens of helminth-infected 4get mice, and we demonstrated by intracellular cytokine staining production of IL-4 and IL-6 by the mLN MCp in helminth-infected mice. Furthermore, treatment of helminth-infected mice with anti-FcεRI mAb, a protocol known to deplete basophils, also depleted mLN MCp. Thus, this study identifies a hypogranular subset of MCp recruited to mLN by helminth infection that may be an important unrecognized source of cytokines.

Fruit acids and sodium hydroxide in the food industry and their combined effect with sodium lauryl sulphate: controlled in vivo tandem irritation study.

Background  Cutaneous exposure to a variety of irritants has been extensively studied in recent years. Nevertheless, knowledge of the induction of irritant dermatitis, especially by mild irritants at low doses and for a short duration of exposure, is still incomplete.

Maturation of mast cell progenitors to mucosal mast cells during allergic pulmonary inflammation in mice

In contrast to resident constitutive mast cells (CMCs), mucosal MCs (MMCs) appear in the lung and trachea of sensitized mice only following inhalation challenge. We monitored the influx and maturation of MCs by their expression of Kit, FcɛRI, β7-integrin and side scatter (SSC) by flow cytometry. Influx of MC progenitors (MCps) (FcɛRIlo, Kitint, β7hi, and SSClo) peaks 1 day after challenges and subsides to baseline by day 7 after challenge. The mature MMCs appear as a distinct population on day 7 and peak at day 14 with higher SSC and FcɛRI expression, but lower β7 and Kit expression. A distinct transitional population is present between 1 and 7 days after challenge. Maturation occurs more rapidly in the trachea. The resident tracheal CMCs had higher SSC, FcɛRI, and Kit and lower β7-integrin expression than the MMCs. By histology, the MMCs follow similar kinetics to the flow cytometry-identified mature MMCs and are notably persistent for >42 days. Steroid treatment reduced inflammation and MCp influx but had no effect on established MMCs. Thus, changes in SSC, FcɛRI, and Kit together with the expression of αE/α4:β7-integrins characterizes the development of induced MMCs from MCps and distinguishes them from resident CMCs in the trachea and large airways.

Mouse Mast Cell Proteases 4 and 5 Mediate Epidermal Injury through Disruption of Tight Junctions

We previously established a mast cell (MC)–dependent thermal injury model in mice with ulceration and scar formation that depended on nonredundant functions of mouse MC protease (mMCP)4 and mMCP5. We hypothesized that MC activation is an early event and now find by histology that exocytosis of granule contents occurred by 2 min after thermal injury in wild-type (WT) C57BL/6 mice and in the mMCP4- or mMCP5-deficient mice. The degranulation was equivalent for MCs in the dermis and hypodermis of all three strains, but only the WT mice showed an appreciable increase in epidermal thickness. There was no loss of total MCs, partially degranulated plus intact, during the 4 h of observation. By electron microscopy, MCs in all strains showed early zonal degranulation at 30 s with marked progression in magnitude by 120 s and no mitochondrial injury or cellular necrosis. Concomitantly there was an increase in intercellular spaces indicative of tight junction (TJ) disruption in WT mice but not in the mMCP4- or mMCP5-deficient strains. The desmosomes were intact in all strains. Immunodetection of the TJ protein claudin 4 in WT and mMCP5-deficient mice indicated a significant reduction after scald injury whereas mMCP4−/− mice showed no significant changes. Taken together, these findings reveal that a second-degree burn injury can initiate an immediate novel zonal degranulation of MCs throughout all skin layers and a disruption of the epidermal TJs dependent on the nonredundant presence of mMCP4 and mMCP5.

Generalized Bullous Eruption after Routine Vaccination in a Child with Diffuse Cutaneous Mastocytosis

Division of Rheumatology, Immunology and Allergy, Brigham and Women’s Hospital, Harvard Medical School Division of Allergy, Immunology and Pulmonology, MassGeneral Hospital for Children, Harvard Medical School Department of Dermatology, Massachusetts General Hospital, Harvard Medical School Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School Conflicts of interest: M.C.C. has received consultancy fees from Merck and Sanofi and has received research support from the National Institutes of Health. The rest of the authors declare that they have no relevant conflicts of interest. Received for publication August 16, 2012; accepted for publication August 28, 2012. Available online November 6, 2012. Cite this article as: Bankova LG, Walter JE, Iyengar SR, Lorenzo ME, Hornick JL, Castells MC. Generalized bullous eruption after foutine vaccination in a child with diffuse cutaneous mastocytosis. J Allergy Clin Immunol: In Practice 2013;1:94-6. http://dx.doi.org/10.1016/j.jaip.2012.08.008. Corresponding author: Mariana C. Castells, MD, PhD, One Jimmy Fund Way, Smith Building, Rm 626 D, Boston, MA 02115. E-mail: mcastells@partners.org. J Allergy Clin Immunol: In Practice 2013;1:94-6. 2213-2198/

Mouse Mast Cell Protease-6 and MHC Are Involved in the Development of Experimental Asthma

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The quality of human skin xenografts on SCID mice: a noninvasive bioengineering approach

Allergic asthma is a complex disease with a strong genetic component where mast cells play a major role by the release of proinflammatory mediators. In the mouse, mast cell protease-6 (mMCP-6) closely resembles the human version of mast cell tryptase, β-tryptase. The gene that encodes mMCP-6, Tpsb2, resides close by the H-2 complex (MHC gene) on chromosome 17. Thus, when the original mMCP-6 knockout mice were backcrossed to the BALB/c strain, these mice were carrying the 129/Sv haplotype of MHC (mMCP-6−/−/H-2bc). Further backcrossing yielded mMCP-6−/− mice with the BALB/c MHC locus. BALB/c mice were compared with mMCP-6−/− and mMCP-6−/−/H-2bc mice in a mouse model of experimental asthma. Although OVA-sensitized and challenged wild type mice displayed a striking airway hyperresponsiveness (AHR), mMCP-6−/− mice had less AHR that was comparable with that of mMCP-6−/−/H-2bc mice, suggesting that mMCP-6 is required for a full-blown AHR. The mMCP-6−/−/H-2bc mice had strikingly reduced lung inflammation, IgE responses, and Th2 cell responses upon sensitization and challenge, whereas the mMCP-6−/− mice responded similarly to the wild type mice but with a minor decrease in bronchoalveolar lavage eosinophils. These findings suggest that inflammatory Th2 responses are highly dependent on the MHC-haplotype and that they can develop essentially independently of mMCP-6, whereas mMCP-6 plays a key role in the development of AHR.