Semi-automated serum steroid profiling with tandem mass spectrometry

Objectives

Highly selective and sensitive multi-analyte methods for the analysis of steroids are attractive for the diagnosis of endocrine diseases. Commercially available kits are increasingly used for this purpose. These methods involve laborious solid phase extraction, and the respective panels of target analytes are incomplete. We wanted to investigate whether an improvement of kit solutions is possible by introducing automated on-line solid phase extraction (SPE) and combining originally separate analyte panels.

Methods

Sample preparation was performed using automated on-line SPE on a high-pressure stable extraction column. Chromatographic separation, including isobaric compounds, was achieved using a 0.25 mM ammonium fluoride-methanol gradient on a small particle size biphenyl column. Standard compounds and internal standard mixtures of two panels of a commercially available kit were combined to achieve an optimized and straightforward detection of 15 endogenous steroids. Validation was performed according to the European Medicines Agency (EMA) guidelines with slight modifications.

Results

Validation was successfully performed for all steroids over a clinically relevant calibration range. Deviations of intra- and inter-assay accuracy and precision results passed the criteria and no relevant matrix effects were detected due to highly effective sample preparation. External quality assessment samples showed the applicability as a routine diagnostic method, which was affirmed by the analyses of anonymized clinical samples.

Conclusions

It was found possible to complement a commercially available kit for quantitative serum steroid profiling based on isotope dilution LC-MS/MS by implementing automated on-line SPE, thereby improving the practicality and robustness of the measurement procedure.

Efficacy predictors of omalizumab in Chinese patients with moderate-to-severe allergic asthma: Findings from a post-hoc analysis of a randomised phase III study

Background

Omalizumab has demonstrated efficacy as an add-on therapy in Chinese patients with moderate-to-severe allergic asthma. This post-hoc analysis assessed the potential predictors for the efficacy of omalizumab in these patients.

Methods

A post-hoc analysis was performed on a Phase III, randomised, controlled study conducted in Chinese patients with moderate-to-severe persistent allergic asthma (NCT01202903). We evaluated if levels of pre-treatment serum total immunoglobulin-E (IgE) and blood eosinophil (EOS), asthma severity, allergen profile, history of perennial allergic rhinitis (PAR), and free IgE level during omalizumab treatment were predictive of omalizumab's efficacy.

Results

This analysis included 608 patients (omalizumab, N = 306; placebo, N = 302). Improvements in forced expiratory volume in 1 s (FEV₁), standardized Asthma Quality of Life Questionnaire (AQLQ), Asthma Control Questionnaire (ACQ), and Global Evaluation of Treatment Effectiveness (GETE) scores with omalizumab treatment compared with placebo were observed in patients with baseline IgE levels ≥76 IU/mL (irrespective of the EOS count). Relatively greater improvements with omalizumab treatment was also noted in patients with both moderate or severe allergic asthma (regardless of asthma severity), and patients sensitised to >3 allergens and with a history of PAR. All patients who were treated with omalizumab achieved free IgE levels below 50 ng/mL by Week 1. Similar clinical outcomes were observed in the subset of patients who achieved free IgE levels of <25 and ≥ 25 ng/mL.

Conclusions

In Chinese patients with moderate-to-severe allergic asthma, baseline IgE and allergen profile (number/PAR history) are potential predictors of treatment response to omalizumab.

Trial registration

NCT01202903 (www.clinicaltrials.gov).

Survival of recombinant monoclonal and naturally-occurring human milk immunoglobulins A and G specific to respiratory syncytial virus F protein across simulated human infant gastrointestinal digestion

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Naturally-occurring antibodies were more resistant to degradation than monoclonal antibodies.

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Monoclonal sIgA was more resistant to degradation than IgG and IgA.

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Monoclonal antibodies may need to be provided at a higher dose to compensate for digestive losses.

To help rationally design an antibody for oral administration, we examined how different isotypes (IgG, IgA and sIgA) with the same variable sequence affect antibody stability across digestion. We compared the degradation of recombinant palivizumab (IgG1), and recombinant IgA and sIgA versions of palivizumab spiked in human milk to the degradation of naturally-occurring anti-respiratory syncytial virus (RSV) sIgA/IgA and IgG in human milk from four donors across gastric and intestinal phases of an in vitro model of infant digestion via a validated RSV F protein ELISA. Palivizumab IgG and IgA formats were less stable than the sIgA version after complete simulated gastrointestinal digestion: palivizumab IgG, IgA and sIgA decreased across complete simulated gastrointestinal digestion by 55%, 48% and 28%, respectively. Naturally-occurring RSV F protein-specific IgG was stable across digestion, whereas naturally-occurring sIgA/IgA was stable in the gastric phase but decreased 33% in the intestinal phase of simulated digestion.