[Specific immunity in patients with diphtheria]

To study features of specific immunity in patients with diphtheria using data from clinic as well as from animal experiments.

Serum samples of 80 patients hospitalized to Infectious Diseases Clinical Hospital No. 2 in Moscow and treated with anti-diphtheria serum (manufactured by "Immunogen" Concern, Stavropol) were studied. Localized diphtheria of the oropharynx was diagnosed in 29 patients, diffused diphtheria--in 8, subtoxic--in 3, grade 1 toxic--in 19, grade 2 toxic--in 12, grade 3 toxic--in 9. Experimental part of the study was performed on outbred rabbits weighted 3-3.5 kg. Level of antitoxin in serum was measured in reaction of passive hemagglutination using commercial antigenic erythrocyte diagnostic kit (manufactured by Mechnikov Research Institute of Vaccines and Sera, Moscow).

Intermittent administration of toxin to control rabbits which lack background immunity did not lead to changes in their immune status and after administration of anti-diphtheria antitoxin kinetics of its level in serum was analogous to that observed after administration of antitoxin to intact animals. Highest level of antitoxin (1.0-2.0 IU/ml) was observed 1-3 days after its administration, and to day 13-15 antitoxin was not detected in serum samples. Diphtheria antitoxin in concentration from 0.03 to 40.0 IU/ml was detected in serum samples in 59 of 80 (74%) studied patients. Only in 21 patients (26%) the antitoxin was not detected.

Presence of antitoxin in serum argue for active immune response to infection and activation of immune memory mechansisms, which allow to predict less severe course of the disease. Absence of antitoxin in serum of patient admitted to hospital points that infectious process is developing on the background of no immunity that predicts the probable development of severe diphtheria.