Tetanus antitoxin levels in the sera of unimmunized lepromatous patients, often suffering from many ulcerations on their limbs due to physical and thermal
trauma, but not developing clinical
tetanus, were studied. Sera from 40 such patients with no history of immunization against
tetanus, 35 unimmunized matched controls and 12 immunized controls were tested for the presence of
tetanus antitoxin by the passive haemagglutination technique. 45% of patients, 17% of controls and all the immunized patients showed adequate serum antibody levels. Eight of the 22
leprosy patients, with no detectable
antitoxin on their sera, were immunized with a single dose of
tetanus toxoid and all showed sero-conversion four weeks later.
2-Mercaptoethanol (2ME) treatment of these sera showed both
IgM and
IgG classes of specific antibody in all groups but the level of mature antibody of IgC class was higher in the immunized group. Neutralization test further confirmed the presence of protective
antibodies in these sera.