Evolution of methods to detect paraneoplastic antibodies

An adaptive immune response in less than 1% of people who develop cancer produces antibodies against neuronal proteins. These antibodies can be associated with paraneoplastic syndromes, and their accurate detection should instigate a search for a specific cancer. Over the years, multiple systems, from indirect immunofluorescence to live cell-based assays, have been developed to identify these antibodies. As the specific antigens were identified, high throughput, multi-antigen substrates such as line blots and ELISAs were developed for clinical laboratories. However, the evolution of assays required to identify antibodies to membrane targets has shone a light on the importance of antigen conformation for antibody detection. This chapter discusses the early antibody assays used to detect antibodies to nuclear and cytosolic targets and how new approaches are required to detect antibodies to membrane targets. The chapter presents recent data that support international recommendations against the sole use of line blots for antibody detection and highlights a new antigen-specific approach that appears promising for the detection of submembrane targets.

A novel SARS-CoV-2 IgG line-blot for evaluating discrepant IgG test results - Observations in pre-pandemic and follow-up samples of five patients

To confirm discrepant SARS-CoV-2-IgG results in four standard assays we applied for the first time a prototype of a coronavirus IgG-line-blot which employs antigens from seasonal coronaviruses, SARS-1 and SARS-CoV-2 combined with avidity testing as a confirmatory tool in a follow-up of five cases including pre-pandemic samples.

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

Accelerated identification of autoantibodies associated with previously idiopathic neurological disease has provided insights into disease mechanisms, enhanced understanding of neurological function, and opportunities for improved therapeutic interventions. The role of the laboratory in the expanding field of neuroimmunology is critical as specific autoantibody identification provides guidance to clinicians in diagnosis, prognosis, tumor search strategies, and therapeutic interventions. The number of specific autoantibodies identified continues to increase and newer testing strategies increase efficiencies in the laboratory and availability to clinicians. The need for broadly targeted efficient testing is underscored by the variability in clinical presentation and tumor associations attributable to a specific autoantibody, and conversely the various autoantibody specificities that can be the cause of a given clinical presentation. While many of the antineural antibodies were first recognized in the setting of neoplastic disease, idiopathic autoimmune neurological disease in the absence of underlying tumor is increasingly recognized. Appropriation of therapeutic modalities used to treat autoimmune disease to treat these autoantibody mediated neurological diseases has improved patient outcomes. Interaction between clinicians and laboratorians is critical to our understanding of these diseases and optimization of the clinical benefits of our increasing knowledge in neuroimmunology.

Epstein-Barr Virus: Clinical Diagnostics

The vast majority of the human adult population is infected with Epstein-Barr virus (EBV), and the majority of the EBV-infected individuals tolerates the infection well, without any further symptoms after primary infection. In cases of individuals which undergo primary infection in the form of an infectious mononucleosis, or which have undergone primary infection in their past, it is sometimes important to appraise symptomatic disease or differentiate infectious mononucleosis from other conditions. In these cases, serological methods, i.e., immunofluorescence, ELISA, or Western blot, are the methods of choice to come to an unequivocal diagnostic conclusion, while the detection and quantification of viral DNA through PCR plays a minor role.On the other hand, in a minority of the human population, EBV infection is associated or causally linked with autoimmune or malignant disease. Especially in the bone marrow or solid organ transplanted, or in otherwise severely immune-suppressed patients, prolonged EBV primary infection or EBV reactivation from latency may be a serious and life-threatening complication which needs to be diagnosed the faster the better, in order to take therapeutic steps in time. Determining the serostatus correctly is also important in these cases. However, the direct and quantitative detection of viral DNA are of importance for the diagnosis of serious EBV disease and its monitoring.In the following, we give an overview of diagnostic methods to accurately determine EBV serostatus and viral load. We evaluate the advantages and disadvantages of each method and report on the diagnostic significance of each and how to resolve diagnostic problems in case of uncertainties. For practical procedures, we refer to the detailed instruction manuals of the respective test kit manufacturers which have to be closely followed for reliable results.