832 TRANSACTIONS OF THE ROYAL SOCIETY OF TROPICAL MEDICINE AND HYGIE~W, VOL. 75, No. 6,‘1981 Natural resistance against tetanus in patients with lepromatous leprosy KUNAL SAHA~, V. K. SHARMA~, V. N. SEHGAL~ AND S. K. AGARWAL~ IDept. of Bacteriology, Govind Ballabh Pant Hospital, New Delhi; 2Dept. of Microbiology and Dermatology, University College of Medical Sciences,and Safadarjung Hospital, New Delhi; 3Dept. of Medicine, Maulana Azad Medical College, New Delhi-1100.02, India Summary Tetanus antitoxin levels in the sera of un- immunized 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 haemagglutina- tion 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 in 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 anti- body of IgC class was higher in the immunized group. Neutralization test further confirmed the presence of protective antibodies in these sera. Introduction Lepromatous leprosy patients with many trau- matic ulcerations on their limbs do not usually suffer from clinical tetanus (SMITH, 1980), although they often do not ‘receive prophylactic immuniza- tion. Many authors (VERONESI et al., 1975; RAY et al., 1978; CROSSLEY et al., 1979) have also detected a protective level of tetanus anti-toxin in subjects with no previous history of immunization, while others (MACLENNAN et al., 1965; DUNCAN & HANSMAN, 1975) found no such evidence. This study was, therefore, undertaken to determine the pre-immunization status of leprosy patients against tetanus and to compare it with that of normal subjects under identical conditions. Materials and Methods 40 lepromatous leprosy patients, aged from 21 to 60 years, with no previous history of immunization against tetanus were studied. Leprosy was diagnosed on clinical, histological, bacteriological and im- munological parameters (RIDLEY & JOPLING, 1966). 35 unimmunized healthy subjects from a similar socio-economic background as the leprosy patients and aged from 20 to 55 years, were used as controls. Another 12 normal persons (aged from 28 to 40 years) with a definite history of immunization against tetanus were also studied. Correspondence to : Dr. Kunal Saha, Bacteriology Department, Govind Ballabh Pant Hospital, New Delhi-l 10002, India. Table I-Serum tetanus antitoxin titre in leprosy patients and healthy subjects Groups Sera Detectable tested antitoxin (number) (number) Treatment with 2-ME Log,, titre Before After Mean i S.D. (ranw) 2-ME resistant 2-ME sensitive Leprosy patients Unimmunized 40 18 1.20 zt 0.42 0.65 i 0.28 1.18 (O-90-2.44) (0.60-1.20) Immunized 8 8 1.16 &- 0.35 0.90 i: 0.45 3.46 (0.60-1.80) (O- 1.50) Controls Unimmunized 35 6 O-95 i 0.27 0.60 f 0.10 1.71 (0.60-l *20) (O-O * 90) Immunized 12 12 1.20 -+ 0.53 o-95 5 0.30 3.80 (0.60-2.44) (0.60-l .50) The tetanus antitoxin titres in both unimmunized and immunized lepromatous patients were comparable with those in normal subjects and the differences were not statistically significant.