The Protective or Curative Element in Type B H. influenzae Rabbit Serum *

The value of a quantitative approach to serum therapy of type b H. influenzae meningitis has been established by the experience of a number of institutions. It is recognized that whereas some patients respond promptly following the administration of 50 mg. of specific type b H. influenzae antibody nitrogen others need several hundred milligrams before recovery from infection is complete. The requirements for efficient application of the quantitative approach have been described.' They can be met by three steps: 1. Accurate standardization of serum: A quantitative chemical method which determines milligrams of agglutinin or anti-polysaccharide nitrogen per ml. has been used.3 Either measure seems suitable, since the anticarbohydrate usually varies from about 70 to 100 per cent of the total agglutinin nitrogen. 2. Appraisal of severity of infection: As a guide to the number of milligrams of antibody nitrogen needed initially for a given patient, the concentration of dextrose in the cerebrospinal fluid has been recommended.2 It is aimed to administer at one time a dose deemed sufficient for recovery. 3. Criteria for sufficiency of dose adnxm'stered: Both of the methods recommended, the capacity of the patient's serum to produce capsular swelling when diluted 1:10, and the immediate wheal reaction to the intracutanreous injection of the specific carbohydrate,6 establish the presence of an excess of anticarbohydrate. It is apparent that the validity of these measures as guides is dependent upon a premise which at first was assumed to be true; ilamely, that the protective or curative element of therapeutic typespecific rabbit H. influenzae antiserum is the anticarbohydrate antibody. Subsequently, Seidman, Dingle, and Fothergill" published a summary of investigations which also led to this conclusion.