Clinical Spectrum of Monoclonal Protein and the Factors Associated with Lymphoplasmacytic Malignancies

<b>Background:</b> Monoclonal protein (MP) presents in various monoclonal gammopathies, ranging from benign conditions such as monoclonal gammopathy of undetermined significance (MGUS) to life-threatening conditions such as lymphoplasmacytic malignancies (LPMs), which include multiple myeloma (MM) and Waldenström macroglobulinemia (WM). Few studies have comprehensively assessed the clinical spectrum of MP and its factors associated with LPMs. This study aimed to determine the clinical spectrum of MP and identify factors associated with LPMs. <b>Methods:</b> This retrospective study included patients who were first tested for capillary electrophoresis (CEP) and identified as having MP between 2014 and 2023 at two university hospitals. Univariate (crude) and multivariate (adjusted) logistic regression analyses were performed to identify factors associated with LPMs. <b>Results:</b> Among the 1135 included patients with MP, 744 (65.6%) were diagnosed with LPMs and 391 (34.4%) with MGUS. Among the 391 patients with MGUS, 310 (79.3%) had at least 1 clinical association, including 204 with renal diseases, 35 with autoimmune diseases, 33 with chronic liver diseases, 22 with hematologic diseases, and 96 with other conditions. Multivariate analyses indicated that LPMs were associated with female sex (OR = 2.08), lower age (OR = 0.95), higher MP level (OR = 3.53), an abnormal FLC ratio (OR = 6.15), lower hemoglobin level (OR = 0.82), and higher total calcium level (OR = 1.81) (all <i>p</i> < 0.05). <b>Conclusions:</b> This study provides insight into the distribution of MPs and their clinical association with MGUS and identifies factors related to LPM. These can help clinicians manage patients more effectively in the early stages of these conditions.