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alpha 2-Macroglobulin in vitamin A-deficient children
Insights
This study found a significant correlation between vitamin A levels and alpha 2-macroglobulin (alpha 2-M) in children. Measles infection can elevate alpha 2-M, counteracting vitamin A deficiency effects.
Area of Science:
- Biochemistry
- Clinical Chemistry
- Nutritional Science
Background:
- Serum glycoprotein alpha 2-macroglobulin (alpha 2-M) plays a role in various physiological processes.
- Vitamin A deficiency is a common concern in pediatric populations, particularly in developing regions.
- Understanding the interplay between vitamin A status and acute phase reactants like alpha 2-M is crucial for assessing child health.
Purpose of the Study:
- To investigate the relationship between serum vitamin A concentrations and alpha 2-macroglobulin levels in children.
- To explore the influence of infections, specifically measles, on this relationship.
- To determine if protein-calorie malnutrition affects alpha 2-M levels independently of vitamin A status.
Main Methods:
- Serum samples were collected from 43 children (≤14 years) in Malaysia and Guatemala.
- Alpha 2-macroglobulin (alpha 2-M) levels were measured using both trypsin-binding and radial immunodiffusion assays.
- Statistical analysis was performed to correlate vitamin A levels with alpha 2-M concentrations and assess group differences.
Main Results:
- A significant positive correlation was observed between serum vitamin A and alpha 2-M levels (r = 0.505, P < 0.001).
- Children with higher vitamin A levels (>40 µg/100 ml) had significantly higher alpha 2-M levels (3.71 ± 0.79 mg/ml) compared to those with lower levels (2.78 ± 0.51 mg/ml).
- Measles infection appeared to normalize or elevate alpha 2-M levels in vitamin A-deficient children, masking the deficiency effect.
Conclusions:
- Serum vitamin A concentration is a significant determinant of alpha 2-macroglobulin levels in children.
- Infections, particularly measles, can modulate alpha 2-M levels, potentially confounding the assessment of vitamin A status.
- The observed effects on alpha 2-M are not attributable to protein-calorie malnutrition alone, highlighting a specific interaction with vitamin A and infection status.
Abstract:
Serum samples were obtained from 43 children 14 years old or younger in Malaysia and Guatemala. The levels of the serum glycoprotein alpha 2-macroglobulin (alpha 2-M) were assayed by two methods: the trypsin-binding assay of Ganrot (Clin. Chim. Acta 14:493, 1960) and a radial immunodiffusion assay against alpha 2-M antiserum. The two methods gave the same results. When serum alpha 2-M levels were plotted against serum vitamin A concentrations, they were significantly correlated (r = 0.505, P less than 0.001); children with serum vitamin A levels greater than 40 micrograms/100 ml had alpha 2-M levels of 3.71 +/- 0.79 mg/ml (mean +/- SD, n = 13), while those with level less than 40 micrograms/100 ml had alpha 2-M levels of 2.78 +/- 0.51 mg/ml (n = 30); the difference was significant (P less than 0.001). Normal, apparently healthy children had alpha 2-M levels of 3.90 +/- 0.39 mg/ml. Most of the children sampled suffered from a variety of infections; of these, measles appeared to counteract the effect of vitamin A deficiency by elevating alpha 2-M levels. Vitamin A-deficient children with measles had alpha 2-M levels not significantly lower than those of normal children. The difference between deficient and normal values of alpha 2-M was still significant (P less than 0.05) when expressed per milligram of serum protein, showing that the effect was not caused by lowered serum protein concentrations associated with protein-calorie malnutrition, from which most of the deficiency children suffered.