The pathophysiological effect of scarlet fever toxin

The intravenous injection of scarlet fever toxin leads to acute changes in the white blood picture. The changes are correlated to the dose; a small dose causes lymphopenia and granulocytosis, while higher doses are followed by initial granulocytopenia. Tolerant rabbits do not have granulocytopenia, but lymphopenia persists. Tolerance to the leucopenic effect of the toxin probably develops somewhat sooner and lasts longer than tolerance to its pyrogenic effect. The blood picture of a cortisone-treated rabbit after the intravenous injection of scarlet fever toxin resembles the blood picture of a tolerant rabbit. The significance and associations of these observations are briefly discussed.