Izdelava protokola za izbiro metode imunotipizacije pri bolnikih s sumom na monoklonsko gamapatijo

Velkovski, Lucija (author), Jeras, Matjaž (mentor), Šegulja, Dragana (co-mentor)

Do pred kratkim je bila imunofiksacija (IFE) edina razpoložljiva metoda imunotipizacije (IT) oz. "zlati standard" v diagnostiki monoklonskih gamapatij. Z uporabo kapilarne elektroforeze, je postal dostopen tudi postopek imunosubtrakcije (ISE). Občutljivost detekcije proteinov-M z metodo imunosubtrakcije pa je odvisna od uporabe poliklonskih molekul specifičnega imunoglobulina in serumskih koncentracij proteinov, ki v električnem polju potujejo skupaj z proteinom-M, še posebej v predelu beta globulina. Namen našega dela je bil ugotoviti, katere koncentracije serumskih proteinov in njihovih značilnosti v elferogramu nam zagotavljajo najboljše zaznavanje proteinov-M ter nedvoumno interpretacijo rezultatov, ko uporabljamo metodo imunosubtrakcije. V okviru magistrske naloge smo vzorce serumov bolnikov analizirali z obema omenjenima metodama imunotipizacije (IFE in ISE) ter na podlagi primerjave rezultatov in značilnosti proteinogramov ocenili, pri katerih bolnikih je diagnostično upravičeno izvajati imunofiksacijo (IFE) in pri katerih imunosubtrakcijo (ISE). S pregledom rezultatov smo ugotovili, da obstajajo statistično značilne razlike med uporabljenima metodama imunotipizacije (IT). Od 102 analiziranih vzorcev je bilo 86 (84,31%) takih, v katerih smo z metodo ISE pravilno in nedvoumno izvedli analizo proteinov-M. Za analizo preostalih 16 vzorcev pa smo morali uporabiti metodo IFE, ki trenutno še vedno predstavlja „zlati standard“. Z uporabo statističnega orodja, in sicer odločitvenega drevesa, v statističnem programu JASP, smo izdelali 2 modela, s katerima bi si lahko pomagali pri odločanju za izbor najustreznejše metode IT pri posameznih serumskih vzorcih. Identificirali smo tudi spremenljivke, ki imajo največji vpliv na protokol izbire najustreznejše metode IT s pomočjo omenjenih modelov, in sicer so to: koncentracija IgM, delež IgM v celokupni koncentraciji imunoglobulinov ter koncentracija celokupnih serumskih proteinov. Pri tem pa velja, da moramo serumske vzorce bolnikov s hipogamaglobulinemijo in tistih z biklonalnimi gamopatijami ter polimernimi oblikami proteinov-M obvezno analizirati z uporabo metode IFE.

• Language: Slovenian
• Keywords: monoklonske gamopatije, protein-M, imunofiksacija, imunosubtrakcija, kapilarna elektroforeza
• Work type: Master's thesis/paper
• Organization: FFA - Faculty of Pharmacy
• Year: 2023
• PID: 20.500.12556/RUL-150954
• Publication date in RUL: 26.09.2023

Secondary language

• Language: English
• Title: Elaboration of a protocol for selecting immunotyping method of patients suspected for monoclonal gammopathy

Abstract

Until recently, immunofixation (IFE) was the only available method of immunotyping (IT) or the "gold standard" in the diagnosis of monoclonal gammopathy. With the use of capillary electrophoresis, the immunosubtraction (ISE) procedure also became available. The sensitivity of detecting M-proteins using the immunosubtraction method depends on the use of polyclonal molecules of a specific immunoglobulin and the serum concentrations of proteins that travel together with M-protein in the electric field, especially in the beta globulin. The purpose of our work was to determine which concentrations of serum proteins and their characteristics in the elpherogram provide us with the best detection of M-proteins and an unambiguous interpretation of the results when using the immunosubtraction method. As part of the master's thesis, we analyzed patient sera samples using the two mentioned methods of immunotyping (IFE and ISE) and based on a comparison of the results and characteristics of the proteinograms, we assessed which patients are diagnostically justified to perform immunofixation (IFE) and which immunosubtraction (ISE). By examining the results, we found that there are statistically significant differences between the used immunotyping (IT) methods. Of the 102 analyzed samples, 86 (84.31%) were those in which the ISE method was correctly and unambiguously analyzed for proteinM. For the analysis of the remaining 16 samples, we had to use the IFE method, which currently still represents the "gold standard". By using the statistical tool, namely the decision tree, in the statistical program JASP, we created 2 models that could be used to help decide on the selection of the most appropriate IT method for individual serum samples. We also identified the variables that have the greatest influence on the protocol for choosing the most appropriate IT method with the help of the mentioned models, namely: IgM concentration, the proportion of IgM in the total concentration of immunoglobulins and the concentration of total serum proteins. In this regard, serum samples of patients with hypogammaglobulinemia and those with biclonal gammopathy and polymeric forms of M-proteins must be analyzed using the IFE method.

• Keywords: monoclonal gammopathy, protein-M, immunofixation, immunosubtraction, capillary electrophoresis