Pizarro R, Samanez C, Cartolin M, Delgado F

Language: Spanish
References: 23
Page: 99-106
PDF size: 345.68 Kb.

ABSTRACT

Background: Monoclonal free light chains (FLCs) are important disease biomarkers in patients with plasma cell-proliferative disorders. The increasing scientific evidence that supports clonal diversity and evolution in multiple myeloma highlights the importance of using appropriate laboratory algorithms that could be able to measure intact immunoglobulins or monoclonal free light chains, both at diagnosis and during the follow up of the response to treatment. Particularly in this area, a focus has been set on the utility of serum FLC (sFLC) assays to replace urine electrophoresis for monoclonal FLC measurement. Due to the limited sensitivity and practical disadvantages of urine analysis, the serum-based algorithm of SPE and sFLC has been adopted by many laboratories around the world as a first line screen in patients with suspected monoclonal gammopathies. The advantages are many and the clinical validation has shown to add value to this scheme that has an increasing acceptance in daily laboratory routine worldwide. In this study we evaluate a local population of patients from our institution with plasma cell dyscrasia and we compare different screening algorithms with the aim to simplify and improve the sensitivity of our initial diagnosis scheme for these pathologies, mainly for multiple myeloma patients.
Objetive: To assess the impact of diagnostic sensitivity of the incorporation of serum free light chain to the original algorithm used in our patients with proliferative disorders of cells B in our institution.
Material and Method: A prospective study was done including 102 patients with diagnosis of monoclonal gammopathy, confirmed by bone marrow biopsy. This cohort was conformed by 92 patients from National Institute of Neoplastic Diseases, Lima, Peru, diagnosed with multiple myeloma, 54 (59%) had IgG production, 23 patients (25%) IgA production and two patients (2%) IgD production as main monoclonal protein.
Results: Out of 92 patients diagnosed with multiple myeloma, 12 patients (13% of the total) had exclusive production of light chain (light chains multiple myeloma; six patients κ y six patients λ) and a patient was found with undetectable production of monoclonal protein, so, he was classified a priori as non secretor multipel myeloma, 1%, added then to the group of light chains multiple myeloma due to his protein production; 14% of the total of patients. Electrophoresis of urine proteins and immunofixation were very unefficient, because only evidenced correct results in 39 (42%) patients of the 92 analyzed.
Conclusion: the incorporation of immunoassay of serum light chains to the diagnostic algorithm of the institution allowed to detect two aditional patients, comparing the results with electrophoresis of serum proteins.

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