Immunotherapy in patients with diphtheria

Abstract

Patients with suspected diphtheria were treated with 600–18,000 IU human antidiphtheria immunoglobulin in 13 cases and with 80,000 IU equine anti-diphtheria immunoglobulin in one case. There were three fatal cases of diphtheria; two attended hospital too late for an expected effect of therapy (> day 5), while one was treated with 10,000 IU human anti-diphtheria immunoglobulin on the third day of disease. Four patients with diphtheria and later neurological complications were given immunotherapy on days 2–4 after the start of the disease. Antitoxin antibody levels, assessed by microculture neutralization test in Vero cells, following therapy with human immunoglobulin did not reach above 2 IU per ml during the first week of disease. The higher dose of equine immunoglobulin resulted in an antitoxin level of 12·8 IU per ml on the second day after therapy. Equine immunoglobulin with higher antitoxin concentration than human immunoglobulin may be the preferable therapy in severe diphtheria.