[Blood zinc in patients with Down's syndrome and its relations with their immune status].

Studies performed in the last decade have shown the importance of zinc in human physiology particularly in cell mediated immunity. Blood zinc values were assayed with the atomic absorption method using a Perkin/Elmer 2.380 spectrophotometer in 35 Down's syndrome subjects (DS) (16 boys and 19 girls aged 6 months 20 years) and in normal subjects in good health. The immunological picture was determined as previously described. Zinc values in normal subjects were in the range 92-128 micrograms/dl (mean value 107 +/- 10.46 micrograms/dl). The values are in the normal range. The range of blood zinc values of DS children was 60-138 micrograms/dl (mean value 92.22 +/- 19.76 micrograms/dl). Of the 35 subjects with DS, 16 had values of 60-84 micrograms/dl (mean 74.25 +/- 8.29 micrograms/dl) (table I), which are well below normal. Blood zinc values were not correlated to age and sex. A relationship was found with mortality. Out of 16 patients with low zinc values 10 (68.5%) were particularly susceptible to infections. These data were then related to results concerning the immunological status of a previous study. The only three negative skin tests were observed in subjects with low blood zinc. 62.5% of DS subjects with low blood zinc also had a complete lymphocyte deficit (table I) as compared to 42.1% of DS cases with normal zinc levels. Respectively 56.25% and 36.8% of DS cases with low blood zinc values had an abnormal and normal T helper/T suppressor ratio. Only 3 (8.57% of all cases and 18.75% of low blood zinc values) subjects had an alteration of all the parameter evaluated (including morbility).(ABSTRACT TRUNCATED AT 250 WORDS)