Clemens von Pirquet, when working on horse serum injections, coined the word allergy in 1906. It is largely unknown that his Vienna clinic was also hightly active in “vitamin D” research as described in a new review by Bouillon which cites the Dame Chick lecture
From January 1921 until May 1922, with a nearly laboratory experiment accuracy, 75 very young children (mostly illegitimate babies, aged 1 week to 5 months) without radiologic signs of rickets at baseline, were randomized to receive different diets with or without cod liver oil.
This seems to be a further link that I have missed in my earlier paper on the historical events covering allergy and vitamin D.
In the Kinderklinik a system of accurate diet control had been developed by von Pirquet which was well suited to careful study upon young infants. This NEM (Nahrungs-Einheit-Milch) system was a means of allotting and controlling food required for correct nutrition, relating energy requirements to energy value of food … In the light of such dietary conditions it seemed possible to observe the growth and development of a series of infants during the first year of life upon the regular diet of the clinic, and for comparison upon a diet which would be as great a contrast as possible, with a larger supply of whole milk and fat-soluble vitamins and without addition of extra carbohydrate. Professor von Pirquet was willing to co-operate in such a scheme, and offered a ward of twenty cots and all other facilities for the purpose.
But why didn’t Chick and colleagues observe any increased allergy rate in the cod-liver treated children?
Age at admission varied from one week to five months, and in fiftyseven cases was under three and one-half months. It was necessary to admit infants at this age because rickets was often present in those aged four months and upwards.
Of course there was no problem in the placebo group and also not in the UV quartz lamp group. Most children in the cod-liver oil group had already their first allergen contact BEFORE the vitamin D exposure. So from the series of 75 children only very few will have been sensitized to milk which would have even been even difficult to notice in the absence of any severe clinical reaction as IgE was only discovered in 1968.