Background: Identification, quantification and typing of M-Proteins (MP) play an important role in the diagnosis, classification and monitoring of monoclonal gammopathies both of malignant origin (eg. Multiple Myeloma) and of unknown origin. Previous evidence attests that MGUS (Monoclonal Gammopathy of Undetermined Significance) detected by agarose gel electrophoresis has a prevalence of 3.2% in the general population. Therefore, our study aimed to verify this data by means of capillary zone electrophoresis (CZE).
Methods: CZE was performed to evaluate the prevalence of M-Protein (MP) in 44.474 consecutive outpatients of all ages with a prescription for serum protein electrophoresis over a 2-year period (2008 and 2009). All MPs that were identified were then typed by immunofixation electrophoresis on agarose gel (IFE).
Results: In subjects aged over 50 (23.408, i.e., 52.6% of the whole cohort) MP ≤30 g/L (MGUS) was identified in 6.0% of cases, with a frequency nearly double than that previously reported. The population was then divided into ten-year age groups: the 71-80 age group had the highest percentage of MP (29%), followed by 61-70 (27%), 51-60 (18%), 81-90 (12%), 41-50 (8%), 31-40 (3%), >90 (2%) and <30 (1%). The frequency of MP types (IFE) was the same in each age group, with IgG Kappa being the most represented class.
Conclusions: According to the high MGUS prevalence observed in this study, these results may be useful especially for general practitioners, because the identification even of small MP (analytical sensitivity: 0.5 g/L) may help optimize clinical management.
Uvod: Identifikacija, kvantifikacija i tipizacija M-proteina (MP) imaju važnu ulogu u dijagnostikovanju, klasifikovanju i praćenju monoklonskih gamapatija kako malignog (npr. multipli mijelom) tako i nepoznatog porekla. Prethodni do-kazi pokazuju da monoklonska gamapatija neodrelenog značaja (MGNZ) koja se otkriva elektroforezom na agaroznom gelu ima prevalenciju od 3,2% u opštoj populaciji. Stoga je cilj ove studije bio da verifikuje navedene podatke putem elektroforeze kapilarne zone.
Metode: Kapilarna elektroforeza je izvršena da bi se utvrdila prevalencija M-proteina (MP) kod 44.474 uzastopnih kliničkih pacijenata svih uzrasta kod kojih je u toku dve godine (2008. i 2009) prepisana elektroforeza proteina u serumu. Identifikovani su svi MP a zatim tipizirani imunofik-sacionom elektroforezom na agaroznom gelu.
Rezultati: Kod ispitanika starijih od 50 godina (23.408, tj. 52,6% ukupnog broja) MP ≤30 g/L (MGNZ) identifikovan je u 6,0% slučajeva, sa gotovo dva puta većom učestalošću nego što je prethodno procenjeno. Populacija je zatim podeljena na starosne grupe raspona po deset godina: grupa 71–80 imala je najveci procenat MP (29%), a slede grupe 61–70 (27%), 51–60 (18%), 81–90 (12%), 41–50 (8%), 31–40 (3%), > 90 (2%) i < 30 (1%). Učestalost tipova MP (imunofiksaciona elektroforeza na agaroznom gelu) bila je ista u svim starosnim grupama, dok je najzastupljenija klasa bila IgG Kappa.
Zaključak: Na osnovu velike uočene prevalencije MGNZ, zaključujemo da ovi rezultati mogu biti naročito korisni za lekare opšte prakse, pošto identifikacija čak i malih MP (analitička osetljivost: 0,5 g/L) može doprineti optimizaciji kliničkog menadžmenta.
Keywords: MGUS; capillary electrophoresis; monoclonal component prevalence.