Rapid desensitization to antineoplastic drugs in an outpatient immunoallergology clinic: Outcomes and risk factors.

BACKGROUND: Hypersensitivity reactions to antineoplastic agents may lead to discontinuation of first-line treatments. Rapid drug desensitization (RDD) allows for a safe reintroduction in patients who are allergic to them. OBJECTIVE: To evaluate the safety and efficacy of the Brigham and Women's Hospital's 12-step RDD in a Portuguese patient population with cancer and to identify markers associated with breakthrough reactions (BTRs) to platins. METHODS: We conducted a retrospective review of desensitizations undertaken at the Immunoallergology Day-Care Unit of the Santa Maria Hospital in Lisbon, Portugal, from July 2008 to July 2019. Adult patients with cancer and with immediate hypersensitivity reactions were included. Skin testing was performed to platins, trastuzumab, and cetuximab. The 12-step protocol was used for most patients, and a shorter protocol was used in 9 patients who were taxane-reactive to resume regular infusions. RESULTS: A total of 1471 RDDs were performed in 272 patients to 136 platins, 124 taxanes, 13 monoclonal antibodies, and 10 other drugs. Skin test results were positive in 127 of patients who were platin-reactive (95.3%) and negative in patients who were cetuximab- and trastuzumab-reactive. There were 141 BTRs during RDD (9.6% of infusions), 79.4% induced by platins with the majority having mild reactions (68.8%). There were 8 patients who were paclitaxel-reactive, and who completed a shorter protocol and resumed regular infusions successfully. Multiple platin infusions (cutoff: ≥10) and total immunoglobulin E greater than or equal to 100 U/mL were identified as independent risk factors for BTRs in patients who were platin-reactive. CONCLUSION: This large single-center study confirmed the safety and efficacy of the 12-step RDD protocol in a diverse cancer population, providing evidence of its universal applications. Total immunoglobulin E is a potentially useful biomarker to identify high-risk patients who are platin-reactive.

Management of Hypersensitivity Reactions to Taxanes.

Taxanes are an important class of antineoplastic agents used in the treatment of a wide variety of cancers. However, paclitaxel and docetaxel, which are the most commonly used taxanes, elicit immediate hypersensitivity reactions (HSRs) in 5% to 10% of patients. Almost all patients that experience these reactions can be safely re-exposed to taxanes either through desensitization or challenge. This article describes the clinical presentation, diagnosis, and management of HSRs to taxanes and discusses the different options for their safe readministration.

Sensitive Immunoassay for Detection and Quantification of the Neurotoxin, Tetramethylenedisulfotetramine.

Tetramethylenedisulfotetramine (TETS, tetramine) is a formerly used and highly neurotoxic rodenticide. Its lethality, recent history of intentional use for mass poisoning, and the absence of a known antidote raise public health concerns. Therefore, rapid, high throughput, and sensitive methods for detection and quantification of TETS are critical. Instrumental analysis method such as GC/MS is sensitive but not rapid or high throughput. Therefore, an immunoassay selective to TETS was developed. The assay shows an IC50 of 4.5 ± 1.2 ng/mL, with a limit of detection of 0.2 ng/mL, comparable to GC/MS. Performance of the immunoassay was demonstrated by a recovery study using known concentrations of TETS spiked into buffer and human and mouse serum matrices giving recoveries in the range of 80-120%. The assay demonstrated good correlation in TETS recovery with established GC/MS analysis. The immunoassay was then used to quantify TETS concentration in the serum of mice exposed to 2× LD50 dose of TETS and to monitor kinetics of TETS clearance from blood over a short period of time. TETS concentration in the serum reached 150 ng/mL without significant change over 4 h post-treatment. Results obtained with the immunoassay had good correlation with GC/MS analysis. Overall, this immunoassay is an important tool to rapidly detect and quantify levels of TETS from biological samples with high sensitivity. The assay can be adapted to multiple formats including field or hospital use.

Evaluation and management of hypersensitivity reactions to chemotherapy agents.

Hypersensitivity reactions to chemotherapy drugs pose significant difficulties in management, especially when no suitable alternative is available or acceptable and delay in continuation of treatment may be life-threatening. Such reactions may be IgE- or non-IgE-mediated and have varied manifestations. Timely recognition and treatment of life-threatening hypersensitivity reactions are essential. Identification of patients at high risk of developing hypersensitivity reactions allows risk stratification to guide clinical decision-making. Skin testing for carboplatin hypersensitivity has good predictive value but is not yet established for oxaliplatin and taxane hypersensitivity. Rapid desensitisation may be considered if no suitable alternative drug is available. Available protocols have shown good safety and efficacy but must be performed in an appropriate setting with adequate monitoring. There are many avenues for research into the utility of skin testing for other chemotherapy agents as well as in vitro tests.

Detection of paeoniflorin and albiflorin by immunostaining technique using anti-paeoniflorin monoclonal antibody.

INTRODUCTION: Paeoniae radix is one of the most important crude drugs used in Kampo medicines (KMs). A part of its pharmaceutical properties is due to the presence of paeoniflorin (PF) and albiflorin (AF). OBJECTIVE: For the specific and easy identification of PF and AF, an immunostaining technique was developed using anti-PF monoclonal antibody (MAb). METHODOLOGY: PF and AF were treated with a NaIO4 solution and reacted with bovine serum albumin (BSA) preparing PF- and AF-BSA conjugates on the polyethersulphone (PES) membrane. Anti-PF MAb was bound and then antibody labelled with peroxidase directed against anti-PF MAb. Finally, a substrate was added and then PF and AF were detected. RESULTS: Anti-PF MAb recognised not only PF but also AF when 10 µg was present on the PES membrane. As little as 0.5 µg of PF and AF were still detected under immunostaining. Various Paeoniae radix samples and KMs were qualitatively analysed, and total amounts of PF and AF were visually detected by immunostaining technique. This method was applied to investigate the distribution of PF and AF in fresh peony root using immunoblotting by transferred from peony root to the PES membrane. CONCLUSION: The technique permitted the visualisation of PF and AF on PES membrane using immunostaining. The immunostaining technique established would be a powerful tool for probing the sources of PF and AF in plant extracts.

Construction and expression of a single chain Fv fragment against pharmacologically active paeoniflorin in Escherichia coli, and its potential use in an enzyme-linked immunosorbent assay.

A recombinant single chain variable-fragment (scFv) antibody against paeoniflorin (PF) was produced using the hybridoma cell line C31B9. Variable regions of heavy (V (H)) and light (V (L)) chain antibody genes were directly cloned from cDNA resources of hybridoma C31B9 and assembled using splicing by overlap extension (SOE)-PCR using a (Gly (4)Ser) (3) linker DNA. The constructed scFv genes were cloned into pET28a vectors for the generation of recombinant proteins in Escherichia coli. Most of the recombinant proteins were expressed in inclusion bodies. The yield of refolded and purified scFv was 1.89 mg per 100 mL of cell culture. The recombinant scFv displayed cross-reactivity as its mother monoclonal antibody (MAb) C31B9. Therefore, the newly expressed scFv protein was applied to quantitative ELISA to determine the total paeoniflorin (PF) and albiflorin (Alb) concentrations in peony root samples. Using PF as a standard compound, the full linear range of the assay was extended from 0.78 to 25 microg/mL. The results obtained by ELISA employing both the recombinant scFv and the original MAbC31B9 showed a reasonably good agreement with each other.

A quantitative ELISA using monoclonal antibody to survey paeoniflorin and albiflorin in crude drugs and traditional Chinese herbal medicines.

This work describes an immunochemical approach for the quality control of Paeoniae Radix by an enzyme-linked immunosorbent assay (ELISA) based on determination of the total concentration of paeoniflorin (PF) and albiflorin (Alb), which are major bioactive constituents in Paeoniae Radix. Four hybridromas secreting monoclonal antibodies against PF and Alb were produced by fusing splenocytes from a mouse immunized by a PF-bovine serum albumin (BSA) conjugate with the hypoxanthine-aminopterin-thymidine (HAT)-sensitive mouse myeloma cell line, P3-X63-Ag8-653. A relatively higher reactivity of monoclonal antibodies (MAbs) with PF and Alb than oxypaeoniflorin (OP) and benzoylpaeoniflorin (BP) was observed, while other monoterpenes and benzoic acid did not cross-react. When PF was used as a standard, the assay can cover a measuring range of 20-600 ng/ml for PF and Alb. A series of Paeoniae Radix samples have been determined, and the results showed good agreement with that determined by traditional high-performance liquid chromatography (HPLC). The developed competitive ELISA was 100 times more sensitive than the HPLC method. Meanwhile, fifteen Chinese traditional prescriptions were determined by the competitive ELISA.

A radioimmunoassay for the measurement of paclitaxel and taxanes in biological specimens using commercially available reagents.

We have developed a rapid and sensitive radioimmunoassay for the measurement of paclitaxel and related taxanes in biological specimens using commercially available reagents. The presence of paclitaxel competitively inhibited the binding of radioactive paclitaxel to polyclonal anti-taxane antibody or anti-taxane monoclonal antibody. When using polyclonal antibody, this method detected paclitaxel in concentrations as low as 0.87 nM and was also effective in 20% methanol. This radioimmunoassay is useful for the measurement of paclitaxel and taxanes in biological specimens like culture medium of paclitaxel-producing microorganisms and may be useful for the measurement of paclitaxel and related compounds in other potential natural sources.

Catalysis of concerted reactions by antibodies: the Claisen rearrangement.

Monoclonal antibodies were prepared against a transition state analog inhibitor of chorismate mutase (EC 5.4.99.5). One of the antibodies catalyzes the rearrangement of chorismate to prephenate with rate accelerations of more than 2 orders of magnitude compared to the uncatalyzed reaction. Saturation kinetics were observed, and at 25 degrees C the values of kcat and Km were 1.2 X 10(-3) s-1 and 5.1 X 10(-5) M respectively. The transition state analog was shown to be a competitive inhibitor of the reaction with Ki equal to 0.6 microM. These results demonstrate the feasibility of using rationally designed immunogens to generate antibodies that catalyze concerted reactions.

Improved 125I radioimmunoassay for cotinine by selective removal of bridge antibodies.

We describe an 125I-based RIA for cotinine, the major metabolite of nicotine. The slope of the dose-response curve was quite shallow (6-8% change in binding per doubling dose), resulting in between-assay CVs of 15 to 20%. This effect occurred because the radioligand formed by linking a cotinine derivative to tyramine manifested greater affinity for the anti-cotinine antibodies than did cotinine itself. We absorbed the serum with a derivative of nicotine coupled to the carrier protein via a chemical bridge similar to that used to form the cotinine/carrier protein immunogen. An RIA in which we used such absorbed serum showed a significantly increased slope of the dose-response curve (11-13% change in binding per doubling dose), and between-assay CVS were only 6 to 8%. We suggest that this improvement results because absorption removes anti-bridge antibodies directed against the chemical-bond common to the cotinine/carrier-protein immunogen and to the cotinine/tyramine radioligand.