Leprosy Mailing List – July 7, 2018
Ref.: (LML) Manifest against the implementation of MDT-U
From: Jaison Barreto, Bauru, Brazil
I agree with some aspects described by Dr Lockwood about MDTU (LML, July 6, 2018).
I am based in Lauro Souza Lima Institute (national leprosy referral centre, Bauru, São Paulo, Brazil), but as I am also working in an extremely high endemic state of Brazil, i.e. Tocantins. I saw that most cases that "relapsed" after 5 years were indeed initial borderline patients. They often do not cure with MDT PB regimen. Initial borderline patients are often misdiagnosed as having PB leprosy. But which cases must we call PB leprosy? As many as 80% of children diagnosed with leprosy, found in Palmas, capital of the state of Tocantins, in the last two years, were borderline.
According to Chatterjee and Ridley, indeterminate and tuberculoid leprosy are uncommon, and often found only during surveys, and most cases are found in children. For these patients, I fully agree that they should be treated as MB, avoiding the risk of early "relapse".
How long must we treat a patient with almost no cellular immunity response to M. Leprae: 6 months; 12 months; 24 months? We just do not know. What we know, however, is that the higher bacterial load, the highest risk of relapse, and also that the lower specific immunity, the high risk of that dormant bacilli causing a new crop of disease. This axioma is the same for all infectious disease. Why should not for leprosy? The prognosis for a lepromatous leprosy patient could be the same as for a BT patient after 6-month MDT? Of course, no!!!
The biggest problem is the time of follow up we need in order to confirm that the patient is cured. In a retrospective cohort made in Rondonopolis, state of Mato Grosso, with more than 1800 patients followed for more than 10 years, all of them with histo-pathological evaluation according to R&J classification, the mean time interval for relapses, clinically and histo-pathologically confirmed, were 5.9 years for PB treated patients and 7.25 years for MB treated patients. Why this occurs? Because Rifampin regimens kill almost all alive M.leprae, and it causes a lag phase (dormant) for long time. In most instances, a not well experienced leprologist can assume that the patient is cured, when the follow up is less than five years.
I think the best and more accurate results could be achieved if the patients treated with the two MDT regimens (6 and 12 doses) were underwent to a clinically and histo-pathologically evaluation after a minimum of 7 years. 5 years is not enough to rule out relapses even for PB regimens.
LML - S Deepak, B Naafs, S Noto and P Schreuder
LML blog link: http://leprosymailinglist.blogspot.it/
Contact: Dr Pieter Schreuder << email@example.com