The role of the laboratory in the expanding field of neuroimmunology: Autoantibodies to neural targets

The study of neural antibodies in neurology: A practical summary

The field of Autoimmune Neurology is expanding rapidly, with new neural antibodies being identified each year. However, these disorders remain rare. Deciding when to test for these antibodies, when and what samples are to be obtained, how to handle and study them correctly, and how to interpret test results, is complex. In this article we review current diagnostic techniques and provide a comprehensive explanation on the study of these patients, in an effort to help with correct diagnosis minimizing false positive and false negative results. We also propose routine storage of samples and referral of certain cases to specialized research laboratories.

The Development of New Diagnostic Tests for Neurologic Disorders in the Commercial Laboratory Environment

Development of new diagnostic tests in a commercial laboratory for neurologic disorders is challenging. Development occurs in a highly regulated environment. Relevant research infrastructure may not be readily available in-house and may require outsourcing with additional management and costs. Clinically characterized specimens for validation of biomarkers for esoteric diseases may be difficult to acquire, and market size may be difficult to predict. More common diseases with heterogeneous subsets may require better clinical definition. Absence of guidelines may delay health provider acceptance of novel testing. Regulatory agency approval and categorization of tests affects validation requirements and impacts market acceptance and reimbursement.

The clinical significance of atypical indirect immunofluorescence patterns on primate cerebellum in paraneoplastic antibody screening

Purpose

Screening for paraneoplastic antibodies is often performed by means of indirect immunofluorescence on primate cerebellar slices. However, atypical immunofluorescence patterns, i.e. patterns that are not specifically related to paraneoplastic antibodies, are often reported. The clinical significance of these patterns is not clear. Therefore, the purpose of this study was to determine the significance and diagnostic value—in terms of a paraneoplastic neurological syndrome or other neurological disease being diagnosed in the patient—of such atypical immunofluorescence screening patterns on primate cerebellum.

Methods

This study is a retrospective single center study including atypical indirect immunofluorescence screening patterns of patients with a negative or absent typing assay for intraneuronal and anti-amphiphysin paraneoplastic antibodies. Patients with a positive typing assay or without final diagnosis were excluded. Included patients were grouped according to (i) reported immunofluorescence pattern and (ii) established diagnosis, after which contingency table analyses were performed to investigate an interrelation between reported pattern and diagnostic group.

Results

In 3.7% of cases, patients with an atypical pattern obtained a final diagnosis of a paraneoplastic neurological syndrome. The presence of atypical patterns was more prominent in patients with epilepsy or peripheral neuropathies (p_{Monte Carlo simulation}= 0.026), without, however, adding any diagnostic information.

Conclusions

An atypical indirect immunofluorescence pattern on primate cerebellum in the screening for paraneoplastic antibodies has only very minor relevance with respect to paraneoplastic neurological syndromes or any other neurological disease, recommending clinicians to interpret the results of positive screening assays for such antibodies with care.

Electronic supplementary material

The online version of this article (10.1186/s13317-019-0116-6) contains supplementary material, which is available to authorized users.