Regional lymphadenitis following antileprosy vaccine BCG with killed Mycobacterium leprae

International Journal of Leprosy and Other Mycobacterial Diseases, Mar 1997 by R Lourduraj John De Britto, Vadakkupattu D Ramanathan, Mohan D Gupte

Regional Lymphadenitis Following Antileprosy Vaccine

BCG with Killed Mycobacterium leprae1

R. Lourduraj John De Britto, Vadakkupattu D. Ramanathan, and

Mohan D. Gupte2

An effective antileprosy vaccine should protect against infection by Mycobacterium leprae or have therapeutic value against the disease. A number of potential vaccines based on either live BCG alone or with killed M. leprae (KML) or other killed mycobacteria such as ICRC, Mycobacterium w. and M. vaccae have been developed and have been claimed to be immunotherapeutic (2,4,18,20). Some of them are currently being evaluated for their immunoprophylactic efficacy against leprosy (6). The combination vaccine BCG plus KML was also tested for immunoprophylactic efficacy, and it was seen that there were 18% fewer cases from the vaccine group BCG plus KML than from the BCG group (3). But, no difference was seen between the BCG plus KML group and the BCG group among the general population in the Karonga Prevention Trial (11). Apart from being effective, a good vaccine needs to be safe with minimal side effects so that it is acceptable to the population using it. In Phase-II and extended Phase-II studies, three different population sets in Thiruthani taluk of ChengaiMGR District in Tamil Nadu, India, were tested during the period between August 1989 and October 1990 to ascertain the acceptability of the vaccines and the side effects, if any. In this communication, we are reporting on episodes of regional lymphadenitis in subjects who received BCG plus KML.

MATERIALS AND METHODS

Skin-test antigens and vaccines

The following biologicals were used in the study: a) BCG batch 308, June 1989 (viability count of 6.6 x 10^sup 6^ per m1) supplied by BCG Laboratory, Madras, India, as 0.1 mg per dose; b) armadillo-derived killed M. leprae Lot IV; c) Rees' M. leprae soluble skin test antigen (MLSA) Lot Wel-4EFI as 1 mu g protein per dose and d) lepromin-A Lot J-15-4, 21 7 88 as 30-40 million bacilli per ml supplied by IMMLEP. The doses of the various vaccines/placebos per 0.1 ml used for the Phase-II study were: a) BCG 0.1 mg 6 x 10^sup 8^ KML; b) BCG 0.1 mg 5 x 101 KML; c) BCG 0.1 mg 5 x 10^sup 6^ KML; d) BCG 0.1 mg, or e) normal saline. For the extended Phase-II study they were: a) BCG 0.05 mg 6 x 10^sup 8^ KML; b) BCG 0.05 mg 5 x 10^sup 7^ KML; c) BCG 0.01 mg 5 x 10^sup 7^ KML, or d) normal saline. Subjects and follow up

In the Phase-II study, a total of 997 healthy volunteers (free from clinical leprosy and free from other contraindications for vaccines) in the age group 1-70 years were vaccinated on randomization with one of the four vaccines in 0.1 ml or with the control preparation. The study population included 247 children in the 1-6-year age group and 250 children in the 7-12-year age group; the remaining 500 individuals were in the 13-70-year age group. Vaccine was administered intradermally into the left deltoid region.

Further, the vaccinees were skin tested with Rees' MLSA on the upper third of the dorsum of the left forearm and with lepromin-A on the midvolar aspect of the right forearm at the time of vaccination and at 12 weeks post-vaccination. Readings were taken for induration to ascertain the sensitization potential of the vaccines. The vaccine site was examined at 3, 8, 12 and 15 weeks post-vaccination. Details have been published earlier (7,9).

In the extended Phase-II study, in one group of villages, 860 healthy volunteers in the age group 1-70 years were vaccinated similarly with one of the three combination vaccines or placebo, skin tested with Rees' MLSA and lepromin-A at 12 weeks postvaccination, and readings were taken as in the Phase-lI study. In another village, 437 healthy subjects in the age group 13-70 years were vaccinated with BCG 0.1 mg in 0.1 ml. Details have been published earlier (9).

Follow up

All of the vaccinees were kept under surveillance to monitor for post-vaccination side effects, if any. In the Phase-II study, the study villages were visited once a week by a medical officer and vaccine-related complaints were recorded and followed up subsequently as detailed earlier (7' 9).

In the extended Phase-II study, the study subjects were visited on a weekly basis and specific enquiries were made for vaccinerelated side effects, particularly regional lymph node enlargement. Clinical findings were recorded every week until healing took place.

Laboratory methods

In the Phase-II study, blood samples were collected from all vaccinees, and the serum was tested for phenolic glycolipid-I (PGL-I) antibody level by an ELISA and anti-35kDa protein antibody by the serum antibody competition test (SACT).

In the extended Phase-II study, lymph node biopsies were obtained under local anesthesia and were divided into two parts. One part was processed for culture for acidfast bacilli (AFB) and also for non-AFB organisms. The other part was fixed in 10% formalin and routinely processed. Paraffinembedded sections were stained with a) hematoxylin and eosin and b) by the FiteFarraco method for AFB. Further, the tissues were stained with anti-BCG antibody (DAKO Corporation, Copenhagen, Denmark) using the indirect immunoperoxidase method) (12).