Author(s) : A. Tété-Bénissan, P. Duriez, H.J. Parra, Laboratoire de microbiologie-biologie cellulaire, Faculté des sciences, Université du Bénin, BP 1515, Lomé, Togo..
Summary : Plasma proteins provide precise information about the physiological status of an individual. In this study, we compared the plasma protein profiles of 168 individuals from the Adélé ethnic group, from an isolated rural area of Togo, with those of 159 individuals from an urban population from the capital, Lomé. The Adélé villages are located in the Atakora mountains. The subjects were volunteers, all apparently healthy and aged between 18 and 65 years. We separated serum proteins by electrophoresis and identified proteins specific for nutritional, inflammatory and immune status. The Adélé significantly higher total serum protein concentrations than the urban individuals, with higher concentrations of a1 globulins (2.35 ± 0.57 g/L versus 1.94 ± 0.52 g/L) and g globulins (22.19 ± 5.67 g/L versus 16.98 ± 5.23 g/L) and lower concentrations of b globulins (6.83 ± 1.56 g/L versus 7.34 ± 1.52 g/L). The Adélé also had lower plasma concentrations of albumin (41.91 ± 5.74 g/L versus 44.56 ± 6.32 g/L), tranferrin (2.5 ± 0.52 g/L versus 3.03 ± 0.6 g/L), haptoglobin (0.57 ± 0.59 g/L versus 1.32 ± 0.89 g/L) and IgA (2.3 ± 0.89 g/L versus 2.88 ± 1.12 g/L) and higher plasma concentrations of orosomucoid (0.85 ± 0.26 g/L versus 0.69 ± 0.27 g/L); IgG (25.3 ± 7.11 g/L versus 21.79 ± 6.5 g/L) and IgM (4.25 ± 2.83 g/L versus 2.25 ± 1.0 g/L). The data obtained for the Adélé and urban populations were similar to those obtained for European populations except for IgM (higher in the Adélé than in the urban and European populations), IgG and CRP (higher for the Adélé and urban populations than for European populations).
Nutritional status, as estimated by albumin and transferrin concentrations, was higher in the urban population of Lomé than in the Adélé population but the Adélé population suffered no malnutrition problems. These results are consistent with those of a previous study, using apo A-I concentrations as an index of nutritional status. Apo A-I has also been shown to be a reliable indicator of nutritional status, as prealbumin concentration alone is sufficient for the early diagnosis of protein malnutrition.
The very high concentrations of plasma CRP obtained indicate the presence of an inflammatory syndrome in the Adélé and urban populations, as this protein is the first acute phase protein to be detected. However, the orosomucoid concentrations obtain-ed provide no evidence of significant inflammation. The high affinity of haptoglobin (Hp) for hemoglobin (Hb) results in the formation of soluble Hp-Hb complexes, reducing the value of Hp as a marker of the acute phase of inflammation. The frequency os sickle cell disease was higher in the Adélé population than in the urban population (10-25% versus 2-6%). Hemoglobinopathies are correlated with haptoglobin concentration and thus plasma haptoglobin concentration was lower in the Adélé population than in the urban population.
The plasma concentrations of a1-antitrypsin in this study were similar to those reported for Europeans. The plasma concentration of protease inhibitors, such as a1-antitrypsin, increased as protease levels increased. These data confirm that the Adélé and urban populations suffer no disease due to high levels of protease release into the bloodstream. They also show that a1-antitrypsin is of some value as an acute phase marker protein.
The acute nature of the inflammatory syndrome (as assessed by CRP concentration) in the Adélé and urban populations was confirmed by the hyperglobulinemia (high levels of production of IgM and IgG antibodies) observed in these populations. The Adélé and Lomé urban populations live in a tropical environment in which they are continuously in contact with infectious agents. This results in repeated stimulation of the immune system in both these populations.
This study of plasma proteins in the Adélé provides insight into the physiological conditions of this ethnic group, which has remained isolated from modern civilization for several centuries. Our results for the Adélé population confirm those for other black African populations, showing the specificity of the black African protein profile and demonstrating that the Adélé live in balance with their en environment.
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