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Conference

Leprosy 1984

To judge from the numbers attending the XII

International Leprosy Congress held in Delhi last month,and the enthusiastic interest shown by the 1460 participantsfrom ninety countries, leprosy is attracting some of the mostacute minds to solve its remaining puzzles. Leprosy is the bestexample of a transmissible disease that evokes a wide range ofresponse, from complete refractoriness to completesusceptibility. Its manifestations in the individual depend oncell-mediated immunity rather than on humoral antibodies.Much of the recent research in leprosy was presented

during the week, some of it not yet published. (The 510abstracts will be published in the International Journal ofLeprosy and Other Mycobacterial Diseases.) A noteworthyfeature was the strong representation of Indian workers; onereason why the International Leprosy Association acceptedthe invitation to hold this congress in India was the need to

encourage research in leprosy in India itself and to challengemore Indian doctors to participate in the leprosy campaign.With the President of India on the platform at the openingceremony, and Prime Minister Indira Gandhi giving theaddress, official interest was guaranteed.The week of the congress prqper was preceded by days of

activity during which members of seven workshops, who hadbeen cooperating by correspondence, met to thrash out thefinal wording of their reports, which emphasised the

principal advances made in the various subspecialties andindicated the problems that awaited solution. As was to beexpected, the sessions on immunology generated particularinterest. Much work is being done to develop a laboratory testfor the early detection and rapid diagnosis of leprosyinfection-clinical or subclinical-the lack of whichcontinues to hamper the screening of exposed populations.Several workers reported the isolation and investigation of aspecific phenolic glycolipid present in Mycobacterium leprae.Others are pursuing the leads provided by the elaboration ofmonoclonal antibodies (some of which are apparentlyspecific) to definable antigens present in the organism. Newwork on HLA-linked control of leprosy type was presented,but the earlier discordant results are not yet completelyresolved. The nature of the specific immune defect in

lepromatous leprosy and the precise mechanism of theassociated T cell unresponsiveness continue to challengeinvestigators, while the varied functions of different types oflymphocytes indicate the complexities of the immune

response to exposure to M leprae.The perennial question of the culture ofM leprae continues

to interest research workers. Now that the closely related andhitherto recalcitrant organism M lepraemurium has at lastbeen successfully cultured, renewed attempts are being madeto coax M leprae to multiply. However, despite the dismissalof all recent claimants, investigations have not been entirelyfruitless: several mycobacteria obtained from diverseenvironments and from patients with multibacillary leprosy,and bacilli existing as contaminants or opportunist invaders,are being studied. The antigenic pattern of some of theseresembles that of M leprae so closely that they may beregarded as potential candidates for vaccine production.At a more clinical level, the importance of the nasal mucosa

as the principal portal of exit of M leprae was confirmed.Some interesting work was reported on skin leprominconversion (to positivity, that is) after single or repeated

injection of a mixture of (live) BCG and various moietiesobtained from armadillo-derived M leprae. Exciting vistasboth of immunotherapy and immunoprophylaxis were

disclosed. Steady work is proceeding on purifying, andstandardising methods of preparing, M leprae and variousprotein components of the organism with the object ofobtaining a protective vaccine. The$64 000 questionremains: Is skin sensitivity to some mycobacterial antigenscoterminous with protective efficacy? The final answer mustawait controlled trials. Meanwhile, as the sessions ontreatment emphasised, multidrug therapy for all forms ofleprosy offers the best hope of avoiding sulphone resistanceon an unmanageable scale, of preventing the emergence offully dapsone-resistant organisms from the pool of potentialmutants, and of controlling the infection in the individualpatient. The spectre of drug resistance becomes more

menacing with the report of patients whose bacilli are

resistant to both rifampicin and dapsone. With patientcompliance still unsatisfactory in many programmes, andlaboratory cover far from adequate, the prospects for controlare not bright. Rifampicin, clofazimine, and dapsone are thedrugs advocated, but with the exception of hepatotoxic drugssuch as ethionamide and prothionamide there are no

newcomers on the chemotherapeutic horizon.It has long been a canon of orthodoxy that infection with M

leprae is confined to man, but reports of natural infection witha M leprae-like organism, producing a leprosy-like disease inferal armadillos in the USA, have lately been supplementedby similar reports concerning Mangabey monkeys in WestAfrica. Whether this reservoir de virus is of epidemiologicalimportance is debatable.The sessions on nerve damage and pathology produced

nothing spectacular, and the reconstructive surgeons and theophthalmologists pursued their undramatic investigationsinto such questions as the pros and cons of various operativeprocedures and the reasons for damage to the uveal tract inlepromatous leprosy. Perhaps the most important practicaloutcome was the narrowing of the gap between the surgeonsin the matter of operative relief of tension in the acutelyinflamed peripheral nerves at sites of predilection. Anti-inflammatory drugs certainly are useful in treatment, and ofthese, thalidomide seems assured of a place.For the first time, two full sessions were devoted to the

social aspects of leprosy, with no competing concurrentsession, indicating the increasing recognition by cliniciansand epidemiologists, by health planners, and byadministrators, that neglect of the social component of

leprosy spells disaster for any attempt at control.S. G. BROWNE

International Diary1984

First international congress on Le Vieillissement Cérébral: Saint-

Germain-en-Laye, France, April 12-14 (J. Croissandeau, 35 Boulevard desInvalides, 75007 Paris, France).XXVe Journées de Diabétologie de l’Hôtel-Dieu: Paris, France, May

10-12 (Dr Michel Rathery, Hotel-Dieu, 1 place du Parvis Notre-Dame, 75181Paris (Cedex 04).

International meeting on Controversies in Perinatal Medicine: Assisi,Italy, May 31-June 2 (Organising Secretariat, Via Piermarini 32, 06034Foligno [PG], Italy).3rd international medical symposium on Principles and Techniques of

Human Research and Therapeutics: New Orleans, Louisiana,.June11-13 (Dr F. G. McMahon, Symposium Director, Clinical Research Center,134 LaSalle Street, New Orleans, LA 70112, USA).