Serum protein electrophoresis remains a widely used analytical method in clinical biology   . This examination currently makes it possible to link the electrophoretic profile to a certain number of pathologies, including immune, inflammatory and hepatic diseases, nephrotic syndrome and cancers    . It thus helps to refine the diagnosis, treatment and therapeutic monitoring of patients     . In Congo Brazzaville, the electrophoretic profile of patients passing through our laboratories is not known. Hence this study proposes an analysis of the different electrophoretic profiles encountered during the analysis of sera. The aim of the study was to show the electrophoretic profile of patients who had been received at the Biochemistry laboratory at the Brazzaville Hospital and University Center.
This is a retrospective study of 350 patients aged 12 to 85 received at the Biochemistry laboratory of the Brazzaville University Hospital from January to December 2015. The electrophoresis of serum proteins was carried out on fasting samples, taken on dry tubes after centrifugation at 3000 revolutions for 5 minutes. Hemolyzed, opalescent and lactescent samples were excluded. These samples were stored at +4˚C and then analyzed within 2 days of receipt in the laboratory, without exceeding one week. The capillary electrophoresis technique on a Minicap Flex piercing automaton made it possible to define the different profiles and the total protein assay was carried out by the Biuret method on a Cobas C111 automaton from Roche.
Analysis of the 350 identified cases revealed that 275 came from the different departments of the CHU, whose distribution was 155 sera from women and 195 sera from men (Figure 1).
The ages of our patients ranged from 12 to 85 years (Figure 2). The age group over 55 was more represented with a frequency of 50%.
The most demanding departments were the gastroenterology department (33%), rheumatology (31%), hematology (22%) and the pediatric department (14%) (Figure 3).
Relevant clinical information was missing in over 80% of requests. When indicated, the reasons for prescribing in descending order were liver disease, long-term fever, rheumatoid arthritis and 24 hour proteinuria elevation (Table 1).
Figure 1. Distribution of the study population by sex.
Figure 2. Distribution of the study population by age.
Figure 3. Distribution of the study population according to the requesting services.
Table 1. Distribution of the study population according to the reasons for prescriptions.
In Table 2, we noted that 26% of the exam performed was normal and 74% had returned pathological. Inflammation was noted in 194 (55%) of cases of which 145 (41%) were chronic and 49 (14%) acute. Forty two (12%) of our patients had beta-gamma block. Eleven (3%) patients presented with a picture of nephrotic syndrome accompanied by severe hypoalbuminemia. We observed monoclonal peaks in 12 patients (3%) located in the gamma globulin zone, indicating dysglobulinemia (Table 2).
Capillary electrophoresis allowed us to observe the morphology of the different fractions, and to make a consistent interpretation. It is a very sensitive method which allows a very fine definition of the different peaks but which nevertheless requires a critical interpretation. Capillary electrophoresis allows a complete automation of the analysis associated with a fast and resolving free solution separation into six protein fractions major (albumin, α1-, α2-, β1-, β2-, and γ-globulins)  . This analytical tool makes it possible to detect the major syndromes confronting clinicians throughout their practice in a hospital environment   .
Since their application in clinical biology, electrophoresis techniques have shown all their interest in the detection of monoclonal dysglobulinemia at low cost  and have benefited from significant developments  .
In our study, 12 monoclonal peaks were found, all of which (100%) migrated to the gamma globulin zone. A study by Sunita Tripathy et al. carried out on a series of 150 patients suspected of having multiple myeloma revealed 87.5% of the monoclonal bands detected in the gammaglobulin area and only 12.5% of the peaks are detected in the beta area      . On the other hand, the study by Ouardia Bouayadi et al. carried out on 410 patients, 72.5% of monoclonal bands are detected in the gammaglobulin zone and barely 27.5% in the beta zone      . Faced with the presence of these monoclonal-looking bands, an indication of immunotyping was essential to characterize the peaks, which was undoubtedly the limitation of this study.
Electrophoresis of serum proteins is a frequently prescribed biomedical practice
Table 2. Distribution of the study population according to profile type.
for the demonstration of qualitative and/or quantitative abnormalities of serum proteins. Its main and indisputable indication is the low-cost screening for monoclonal dysglobulinemia. The interpretation of this examination turns out to be easy, especially if good medical prescription practices are followed and if the medical biologist takes into account certain interpretation difficulties.
State of current knowledge on the subject is:
・ Routine examination in the medical biochemistry laboratory;
・ Diagnosis of monoclonal gammopathies;
Contribution of our study to knowledge is:
・ Interest of the clinician-biologist collaboration for a correct interpretation;
・ Know how to have EPS interpretation recommendations.
Contributions from the Authors
Principal editors: Fylla Onanga Koumou, Etienne Mokondjimobé.
Critical readers: Benjamin Longo Mbenza, Etienne Mokondjimobé.
Biological analyzes: Aliocha Nkodila, Monde Ikia, Barnes Yoyo, Rod Ibara, Jeanne Gambomi Kiba.
CR Dobhat-Doukakini, Reine F. Eboka-Loumingou Sakou, Childerick Lekana.
Supervision: Benjamin Longo Mbenza, Etienne Mokondjimobé.
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