Laboratory testing requirements for diagnosis and follow-up of multiple myeloma and related plasma cell dyscrasias

Abstract

Abstract:Monoclonal immunoglobulins are markers of plasma cell proliferative diseases and have been described as the first (and perhaps best) serological tumor marker. The unique structure of each monoclonal protein makes them highly specific for each plasma cell clone. The difficulties of using monoclonal proteins for diagnosing and monitoring multiple myeloma, however, stem from the diverse disease presentations and broad range of serum protein concentrations and molecular weights. Because of these challenges, no single test can confidently diagnose or monitor all patients. Panels of tests have been recommended for sensitivity and efficiency. In this review we discuss the various disease presentations and the use of various tests such as protein electrophoresis and immunofixation electrophoresis as well as immunoglobulin quantitation, free light chain quantitation, and heavy-light chain quantitation by immuno-nephelometry. The choice of tests for inclusion in diagnostic and monitoring panels may need to be tailored to each patient, and examples are provided. The panel currently recommended for diagnostic screening is serum protein electrophoresis, immunofixation electrophoresis, and free light chain quantitation.

Analytical Criticalities Associated to Different Immunological Methods for Serum Free Light Chain Detection in Plasma Cell Dyscrasias: A Description of Particular Clinical Cases

“…Serum immunofixation (sIFE), serum protein electrophoresis (SPE), and sFLC combined with urine immunofixation (uIFE) tests are actually considered the golden standard for the screening of MG. Indeed, the combination of these methods provides the highest sensitivity (98.6%) for the detection of MGs [15,16]. …”

“…The evaluation of these parameters are recommended for patient management, including screening, prognosis, therapy, and patient monitoring, as well as for the diagnosis and monitoring of all conditions where M-protein is barely detectable and hardly quantifiable [10,18,19,20]. The introduction of sFLC measurement has since then emphasized the crucial role of an altered κ/λ ratio (sFLC ratio >1.65 or <0.26) as a predictor of progression from MGUS to MM [10,15,17]. …”

Protein electrophoresis and serum free light chains in the diagnosis and monitoring of plasma cell disorders: laboratory testing and current controversies

“…In this special issue Willrich and Katzmann describe the latest recommended testing in their up-to-date review of laboratory requirements for the diagnosis and monitoring of MM and related PCD [3]. The International Myeloma Working Group (IMWG) recommends a screening panel of serum protein electrophoresis (SPEP), immunofixation electrophoresis (IFE), and serum FLC for diagnosis, and if AL amyloidosis is suspected, also urine protein electrophoresis (UPEP) and IFE.…”

Free light chains of immunoglobulins in the diagnosis and prognosis of multiple myeloma

“…Д иагностика множественной миело-мы до последнего времени основыва-лась на количественном определении циркулирующих моноклональных иммуноглобулинов. В течение длительного времени «золотым стандартом» скрининга плаз-моклеточных заболеваний был анализ белков сыворотки крови и мочи на основе электрофо-реза с последующей иммунофиксацией [1][2][3]. Парапротеин, секретируемый злокачественным клоном множественной миеломы, может быть представлен в виде молекул интактного имму-ноглобулина, свободных легких цепей (СЛЦ), а также их сочетания.…”

“…СЛЦ, не вошедшие в состав молекул интактного иммуноглобулина, высвобождаются в циркуля-торное русло, а затем фильтруются и метаболи-зируются почками в зависимости от молекуляр-ной массы. Циркулирующие в крови СЛЦ часто формируют гомодимеры, известные как белок Бенс-Джонса -маркер множественной миеломы Бенс-Джонса [1,4]. В связи с отсутствием секреции парапротеина у небольшого числа больных (3-4%) с несекрети-рующей множественной миеломой в 2014-2016 гг.…”