Prevalence of heterophilic antibodies in serum samples from horses in an equine hospital, and elimination of interference using chicken IgY

Bo Dong,Daniel Bergman,Bodil Ström Holst

doi:10.1186/s13028-021-00575-1

Bo Dong, Daniel Bergman + Show 1 more

Open Access

https://doi.org/10.1186/s13028-021-00575-1

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Abstract

BackgroundHeterophilic antibodies in serum and plasma can interfere with mammalian antibodies in immunoassays and result in false test results, usually false positive. Although studies screening for heterophilic antibodies as well as elimination studies have been conducted in dogs and cats, knowledge of the presence of heterophilic antibodies in other species in veterinary medicine is limited. In this study, a 2-site sandwich-type interference assay that detects anti-mouse antibodies was used to detect heterophilic antibodies in a population of horses treated in an animal hospital.ResultsA total of 194 serum samples from 127 individual horses were analyzed. There were 11/127 (8.7%) interference-positive horses, and these were analyzed in an assay exchanging the capture mouse IgG with chicken IgY. The positive samples were negative in the chicken IgY assay, indicating elimination of a possible interference, with the chicken-based assay. Four interference-positive samples were from geldings, and anti-Müllerian hormone (AMH) was analyzed from these samples. AMH concentrations were negative in these samples as expected in geldings, indicating that the heterophilic antibodies did not cause interference in the AMH assay.ConclusionThe present study shows that there are heterophilic antibodies in horse serum samples like in samples from humans, dogs, and cats. The use of chicken-based reagents, such as chicken IgY, which do not cross-react with mammalian IgG, eliminates the effects of interfering antibodies in the samples. Equine heterophilic antibodies do not necessarily cause interference in commercial immunoassays.

Highlights

Heterophilic antibodies in serum and plasma can interfere with mammalian antibodies in immunoassays and result in false test results, usually false positive
An interference assay was used to study the prevalence of heterophilic antibodies in the serum of dogs and cats, and the prevalence was reported to be 5–9% [13]
The goals of this study were to use a previously developed species-independent interference assay to screen a population of horses treated in animal hospitals for presence of heterophilic antibodies, to assess whether chicken Immunoglobulin Y (IgY)-based tests eliminate interference and if detected heterophilic antibodies cause interference in a commercial sandwich immunoassay for analysis of anti-Müllerian hormone (AMH)

Summary

Introduction

Heterophilic antibodies in serum and plasma can interfere with mammalian antibodies in immunoassays and result in false test results, usually false positive. A double-antibody sandwich immunoassay that does not cross-link with any known substance can be used to screen for heterophilic antibodies. In such an assay, signals may be generated by the cross-linking of the assay antibodies by heterophilic antibodies [1]. An interference assay was used to study the prevalence of heterophilic antibodies in the serum of dogs and cats, and the prevalence was reported to be 5–9% [13]. The frequency of interference in human serum samples has been reported to be from 0.5 to 2% to around 4% [15, 16] It will vary with the assay used but will be lower than the prevalence of heterophilic antibodies [8, 16]

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