Transient human anti-mouse antibodies (HAMA) interference in CA 125 measurements during monitoring of ovarian cancer patients treated with murine monoclonal antibody

Hormone Immunoassay Interference: A 2021 Update

Immunoassays are powerful qualitative and quantitative analytical techniques. Since the first description of an immunoassay method in 1959, advances have been made in assay designs and analytical characteristics, opening the door for their widespread implementation in clinical laboratories. Clinical endocrinology is closely linked to laboratory medicine because hormone quantification is important for the diagnosis, treatment, and prognosis of endocrine disorders. Several interferences in immunoassays have been identified through the years; although some are no longer encountered in daily practice, cross-reaction, heterophile antibodies, biotin, and anti-analyte antibodies still cause problems. Newer interferences are also emerging with the development of new therapies. The interfering substance may be exogenous (e.g., a drug or substance absorbed by the patient) or endogenous (e.g., antibodies produced by the patient), and the bias caused by interference can be positive or negative. The consequences of interference can be deleterious when clinicians consider erroneous results to establish a diagnosis, leading to unnecessary explorations or inappropriate treatments. Clinical laboratories and manufacturers continue to investigate methods for the detection, elimination, and prevention of interferences. However, no system is completely devoid of such incidents. In this review, we focus on the analytical interferences encountered in daily practice and possible solutions for their detection or elimination.

False-positive semiquantitative immunochromatography assays for procalcitonin in three patients with rheumatoid arthritis-A case series

We report three rheumatoid arthritis (RA) patients with false-positive procalcitonin (PCT) based on semiquantitative immunochromatography assays without infection, but who had negative PCT assay results based on quantitative methods. Immunochromatography was useful for screening; however, other heterophilic antibodies rather than rheumatoid factor were possible to affect, especially in RA flare.

Immunotherapy Using Chimeric Antigen Receptor-Engineered T Cells: A Novel Cellular Therapy with Important Implications for the Clinical Laboratory

BACKGROUND

We have entered a new era of cancer therapy, with a number of immune-based therapies already used clinically as a standard of care. Adoptive cellular immunotherapy using T cells genetically modified with chimeric antigen receptors (CAR-T cells) represents a novel therapeutic approach. CAR-T cells have produced clinical responses in B-cell malignancies that are otherwise refractory to conventional therapies. Two CAR-T cell therapies obtained regulatory approval in 2017, with many more of these therapies under clinical development.

CONTENT

This review focuses on the current state of adoptive cellular immunotherapy, specifically CAR-T cells, in the clinic and how this therapy differs from traditional small molecule and biologic therapies. Areas in which the clinical laboratory is affected by these novel therapies are discussed. Opportunities for the clinical laboratory to help guide these therapies are also highlighted.

SUMMARY

The clinical laboratory will play an integral role in the care of patients undergoing adoptive cellular therapy with engineered T cells. There are many ways that this new therapeutic approach affects the clinical laboratory, and the clinical laboratory will likely play a critical role in managing patients that are treated with CAR-T cell therapy.

Transient human anti-mouse antibody generated with immune enhancement in a carbohydrate antigen 19-9 immunoassay after surgical resection of recurrent cancer

We report a case of transient human anti-mouse antibody from a 64-year-old man in a carbohydrate antigen 19-9 immunoassay using an AIA 1800 analyser that generated immune enhancement after surgical resection of recurrent cancer.

METHODS

The carbohydrate antigen 19-9 concentration was measured using an AIA 1800 analyser and a UniCel Dxl 800. Size-exclusion high-performance liquid chromatography was carried out on a Superose 12 column to estimate the carbohydrate antigen 19-9 elution profile using an AIA 1800 analyser. To determine whether IgM in the patient contributed to the carbohydrate antigen 19-9 immunoassay, immunoprecipitation was performed. Furthermore, mouse immunoglobulins were added to the patient's serum to verify that the patient's IgM reacted with it.

RESULTS

The carbohydrate antigen 19-9 concentration was >400 and 9.5 kU/L using an AIA 1800 analyser and using a UniCel Dxl 800, respectively. In the single carbohydrate antigen 19-9 peak, the molecular weight corresponded to IgM by size-exclusion high-performance liquid chromatography on a Superose 12 column. In the immunoprecipitation reaction and addition of mouse immunoglobulins, there was interference for anti-human IgM and mouse immunoglobulins whose recoveries were 3.2 and 14.2%, respectively. These results indicated that IgM in the patient's serum interfered with the carbohydrate antigen 19-9 immunoassay using an AIA 1800 analyser.

CONCLUSION

A novel transient human anti-mouse antibody generated with immune activation in a carbohydrate antigen 19-9 immunoassay using an AIA 1800 analyser was identified in a patient with rectal cancer after surgical resection. These findings demonstrate the importance of monitoring tumour markers in patients after treatment with mouse monoclonal antibody.

Current approaches and challenges in managing and monitoring treatment response in ovarian cancer

Epithelial ovarian cancer is the leading cause of death among gynecologic malignancies. Treatment of recurrent ovarian cancer remains a challenge despite advances in surgical and chemotherapeutic options. A goal of many providers is to detect recurrences as early as possible and initiate treatment though there is controversy as to whether this impacts outcome. Elevations in CA125 and radiological findings may precede symptoms of recurrence by several months. While detection of recurrences by physical exam alone is unusual, a thorough exam in conjunction with reported symptoms and elevated CA125 is sufficient to detect 80-90% of recurrences. A spiral CT scan may be used to confirm recurrence in the setting of asymptomatic CA125 elevation and a PET/CT can yield additional insight if the CT is inconclusive. Initiating chemotherapy prior to the development of symptoms, even in the setting of elevated CA125, does not impact overall survival primarily because the efficacy of available treatments in the recurrent setting is poor. More information about tumor biology and ways to predict which patients will benefit from available treatment options is required. Consequently, the approach to post-treatment surveillance should be individualized taking into account the clinical benefit of the second-line therapy, versus the costs and morbidity of the surveillance method.

Construction and characterization of a novel fusion protein MG7-scFv/SEB against gastric cancer

Antibody-targeted superantigen has been developed into a new strategy to treat many malignant tumors. In this study, for specific targeting to gastric cancer cell, superantigen SEB (Staphylococcal Enterotoxin B) was genetically fused to the single-chain variable fragment of gastric carcinoma-associated antibody MG7(MG7-scFv) that recognizes the MG7 antigen frequently expressed in gastric cancer cell. The recombinant MG7-scFv/SEB fusion proteins are expressed in E. coli as inclusion bodies, and the purified MG7-scFv/SEB retains high binding affinity with gastric cancer cell SGC-7901 (positive MG7 antigen expression). When incubated with effector cell-peripheral blood mononuclear cells (PBMCs), MG7-scFv/SEB could effectively inhibit the proliferation and induce apoptosis of SGC-7901. After being treated with MG7-scFv/SEB, PBMCs remarkably increased the production of Th1 cytokines (IFN-gamma, IL-2), and slightly increased the production of Th2 cytokines (IL-4, IL-10) in vitro. It was observed that gastric-tumor-bearing rats administrated with MG7-scFv/SEB showed more inflammatory cell infiltration, more significant tumor inhibition, and longer survival time than those of rats treated with SEB or NS (Normal Saline). The data indicated that MG7-scFv/SEB fusion protein could specifically target gastric cancer cell, enhance the activity of T cells and induce tumor cell apoptosis to exert the antitumor effect on gastric cancer.