Number of leprosy reactions during treatment : clinical correlations and laboratory diagnosis

Introduction: The occurrence of leprosy reactions, a common event during treatment, may be mostly related to the action of multidrug therapy on Mycobacterium leprae. The clinical and laboratory monitoring of patients with reactions is important, since collecting data that assists in predicting the risk of reactions may help to prevent disability. Methods: This was a sectional study, in order to correlate clinical and laboratory diagnosis with the number of reactions during treatment. Spearman’s correlation was used to verify the degree of association between the assessed variables. Results: This study was conducted with 211 patients with leprosy reactions during treatment of M. leprae. The borderline tuberculoid group was the most prevalent clinical form (74/211; 35.1%) and the type one reaction showed the highest frequency (136/211; 64.5%). It was observed that 73.5% (155/211) of reactions occurred within 3 months of the initiation of multidrug therapy. The diagnostic values, including the bacterial indices (BIs) of dermal smears (r = 0.21, p < 0.05) and skin biopsies (r = 0.20; p < 0.05), showed a positive correlation with the number of reactions during treatment. Conclusions: This research showed a positive correlation between bacillary load markers and the number of leprosy reactions. This study provided scientifi c support to future research aiming to elucidate the infl uence of antigenic load on the number of leprosy reactions during treatment.


INTRODUCTION
Leprosy, an infectious disease caused by Mycobacterium leprae (ML), causes immunological phenomena called leprosy reactions which tend to increase after starting Multidrug therapy (MDT), resulting primarily in neural damage [1].
The mixed reaction, a type of leprosy reaction of lower occurrence and rarely described in literature, occurs mainly in the clinical form borderline-lepromatous (BL) showing symptoms common to type one and 2 reactions concurrently [4].
Since 1981, the World Health Organization (WHO) has recommended MDT for the treatment of leprosy, to fight bacterial infection [5].However, with the use of MDT the risk of developing reaction increases, a fact related to the release of antigens after disruption of the mycobacterial cell wall, caused by the antimicrobial action of MDT, and therefore stimulates the occurrence of leprosy reactions [6].
The use of correlations between the number of reactions and variables that reflect the level of the bacterial load, like the number of skin lesions, anti-PGL-1 ELISA serology and indices microscopy of skin biopsies and dermal smear are important for clinical practice, since they help the team in monitoring patients who will represent risk groups during treatment.There are few studies that use the correlation between the number of reactions and clinical and laboratory data, because to quantify the leprosy reactions is not yet a routine practice in reference centers in Brazil and the world, since there is no survey of health indicators related to leprosy reactions.Also, it is clear that there is an absence of criteria to quantify the leprosy reactions and a lack of information technology to support that procedure or serve as a database for future research.

Study and sample type
This is an observational cross-sectional study, consisting of a sample containing 211 patients, who had leprosy reaction during treatment, clinically classified according to the criteria of Ridley & Jopling [7].

Data collection
The data was collected through secondary sources (medical records) which most of epidemiological, clinical and laboratorial variables extracted for correlation analysis purposes were: clinical and operational classification; type of reaction; amount of leprosy reactions; period of occurrence of the first reaction episode during treatment; number of inspected skin lesions in the diagnosis and values of bacterial indexes of dermal smears and skin biopsy.

Inclusion and exclusion criteria
The study included only patients affected by leprosy reactions during treatment with MDT at National Reference Center for Sanitary Dermatology and Leprosy, from January 2002 to December 2009.We excluded all patients with incomplete information on files, decentralized to other locations during the treatment and those with leprosy reaction at the time of diagnosis.

Criteria for Clinical and Operational Classification
The clinical classification of patients included in the study was based on the classification suggested by Ridley & Jopling.The operational classification was based on the criteria of the World Health Organization (WHO), together with laboratory tests of the diagnosis, so that the patients were classified strictly in paucibacillary (PB) or multibacillary (MB).Individuals with up to five lesions, negative dermal smears, negative anti-PGL-1 ELISA serology and negative PCR and dermal smear of skin or blood were grouped as paucibacillary.Patients with more than five lesions, a positive dermal smear, positive anti-PGL-1 ELISA serology, positive PCR dermal smears, skin or blood, were included multibacillary.

Criteria for definition of leprosy reactions
The categorization of leprosy reactions (type one, type two and mixed) were based on clinical and immunological criteria described in the literature [8].

Method of quantification of leprosy reactions
For the purpose of counting the number of reactions of type one, type two and mixed, it was established that: if there was exacerbation of symptoms seven days or more after completion of the reaction treatment, it was considered to be a new reaction (New leprosy reaction).But if there was exacerbation of symptoms in less than seven days after completion of treatment were considered to be a continuation of the previous reaction (same leprosy reaction).These criteria were based in the biological half-life of prednisone and thalidomide [9,10].

Statistical analysis
We used the non-parametric test called Spearman correlation to verify the degree of association between the amount of reactions during treatment and other clinical and laboratory variables studied.The Analysis was processed using the Bioestat software, version 5.3, where hypotheses were tested at a 0.05 significance level.

Ethical considerations
This study was approved by the Ethics Committee on Human Research of the Federal University of Uberlandia under the registration number 449/10 and protocol number 193/10.The ethical principles of this study support its methodology with the resolution of the National Health Council, number 466/2012.

RESULTS
The study had 211 (84%) patients who developed leprosy reactions during treatment.According to (Table 1), the BT group (74/211, 35.1%) and lepromatous-lepromatous (LL) (55/211, 26.1%) were the clinical forms that had a higher frequency among the others.Also according to (Table 1), the reverse reaction (RR) was seen in 64.5% (136/211) of subjects, followed by type two reactions with 30.8% (65/211) of patients developing this type of immune response.
Table 2 shows the occurrence period of the first leprosy reaction after starting treatment.It shows that the majority of reactions occurred during the first 3 months of treatment and that the BT groups (68/211, 32.2%), borderline-borderline (BB) (29/211, 13.7%) and LL (29/211, 13.7%), are the ones which exposed earliest reactions during treatment.It is noteworthy also that 83•6% (46/55) of patients of the LL form showed reaction in the first year of treatment.
Table 3 shows the amount of leprosy reactions per clinical form.The average number of reactions during treatment was 1.6 per patient.However, the average of the subpolar-lepromatous group (M LLS : 2.6) and lepromatous-lepromatous group (M LL : 2.1) were above 1.6.
The observation of (Figure 1) confirms the correlation between the amount of leprosy reactions during treatment and the number of skin lesions inspected in the clinical diagnosis Email: Clin Res Infect Dis 2(2): 1016 (2015) of the patients, showing that there was therefore positive association between these two variables (r= 0.215, p= 0.0018).

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(Figure 2) indicates a positive visible correlation between the amount of leprosy reactions during treatment and the bacterial index (BI) obtained from fragments of skin biopsy samples at diagnosis (r= 0.201, p= 0.0097).Regarding the association between the amount of leprosy reactions during treatment and the bacterial index obtained after dermal smears (Figure 3) in the same period, depending on other results, there was a positive correlation between these two factors (r= 0.217, p= 0.0019).

DISCUSSION
The high number of leprosy reactions during treatment seen in the first three months, represented in this study by 73.5% (155/211) of patients, is related to the effectiveness of MDT in the destruction of the ML, with a massive release of antigens after starting this therapy [11].The BT (74/211, 35.1%) and LL (55/211, 26.1%) were the clinical forms that reported higher frequency than the others.
The borderline group consisting of the BT, BB and BL, represented the majority of patients in this study, which, by immunological mechanisms developed, type one reaction only, except for BL, which can develop type one , mixed and type two reactions.This explains why the reaction type one has the highest incidence in this study, remembering also that in this group, there      5/6 is a high immune instability and when bacteriological levels rise, the influence of bacterial load in leprosy reactions exist, which stimulates hypersensitivity phenomenon mediated by cells [12].Patients with high bacterial index like those of the clinical form LL are exposed to greater risk for experiencing reaction when the bacterial index is greater than 4 demonstrating the high number of type two reactions in the present study [13].
As for the occurrence period of the first leprosy reaction during more than half of the patients had the first reaction in the first 3 months of treatment.This is in compliance with studies reporting the occurrence of type one reaction in the first 6 months as observed in borderline groups (BT and BB) [14].Those groups showed early reaction because of the large population of these individuals in the study.On the other hand the form LL involves greater risk for the occurrence of these events, because for others author's type two reactions appear more often during the first year of MDT, according to data from this study also involve, as mentioned above, the intense release of antigens leading to the formation of immune complexes [15].
There are few studies that quantify the number of reactive states per patient.This is because of the difficulty of monitoring these individuals and the lack of criteria for determining the beginning and end of the reaction states.In the present study, we calculated the number of responses and average number of reactions during treatment with more detail, like recent studies by [16,17].Our study verifies what the scientific consensus reports on MB forms, that is, that the forms are more likely to develop reactions by high bacterial load, which is represented in this study by the forms subpolar-lepromatous and lepromatouslepromatous which had an average of more than 2 leprosy reactions per patient during treatment [3].
The non-parametric Spearman correlation between the amount of leprosy reactions during treatment and the number of skin lesions inspected in the clinical diagnosis of patients indicated the consequent positive relationship between these two variables, and, few studies have evaluated this relationship directly, but another study detected a relationship between the occurrence of leprosy reactions of type one and the size of the lesion, in which lesions > 5 cm indicates a risk factor [18].The borderline-tuberculoid form present two classifications in the spectrum of Ridley and Jopling, paucibacillary or multibacillary.This study showed that 59,4% (44/74) of patients borderline tuberculoid were multibacillary, which explains how increased bacteriological index and skin lesions can be risk factors for Type 1 reactions [19].
A positive correlation between the amount of leprosy reactions during treatment and BI skin biopsies collected at diagnosis was demonstrated by the analysis of Spearman correlation which indicated a weak, but statistically significant correlation.Seeing that the BI biopsies reliably refers to the bacterial load of patients and this, in turn, is predictive for the occurrence of reactions as cited in recent studies on the analysis of correlation between anti-PGL-1 ELISA serology diagnosis and the amount of reactions during treatment, as this also refers to the amount of antigen present in the individuals [20].
Just as the BI, obtained through the skin biopsies, the index obtained after dermal smear shows an association with the amount of leprosy reactions during treatment, indicating strong influence again of the bacterial load in the outcome of leprosy reactions.This fact was quoted in a study about the association of leprosy reaction and the bacterial load which calculated the odds ratio to measure the chance that patients with positive initial dermal smear have on developing a leprosy reaction during and/ or after treatment.The study found a result of 2.94, but was not statistically significant [21].

CONCLUSION
This study about leprosy reactions showed that a diagnostic approach based on the correlation of clinical and laboratory data can help determine risk groups and provide monitoring of these patients prevent neural injury.

Figure 1
Figure 1 Spearman correlation between the quantity of leprosy reactions during treatment and the number of skin lesions inspected in clinical diagnosis of the patients (r= 0.215; p= 0.0018).

Figure 2
Figure 2 Spearman correlation between the quantity of leprosy reactions during treatment and bacteriological index obtained after skin biopsy in the diagnosis (r= 0.201; p= 0.0097).

Figure 3
Figure 3 Spearman correlation between the quantity of leprosy reactions during treatment and bacteriological index obtained after dermal smear in the diagnosis (r= 0.217; p= 0.0019).

Figure 4
Figure 4 Spearman correlation between the quantity of leprosy reactions during treatment and bacteriological index obtained after dermal smear during leprosy reaction (r= 0.287; p= 0.0073).

Figure 5
Figure 5 Spearman correlation between the quantity of leprosy reactions during treatment and bacteriological index obtained after skin biopsies during leprosy reactions (r= 0.324; p= 0.0084).

Table 1 :
Frequency distribution of reactive patients during treatment second clinical form and type of reaction Uberlândia, state of Minas Gerais, Brazil.2002-2009.

Table 2 :
Frequency distribution of the period of occurrence of the first episode reaction during treatment by clinical form Uberlândia, state of Minas Gerais, Brazil.2002 -2009.

Table 3 :
Distribution of the quantity of leprosy reactions during treatment by clinical form Uberlândia MG -Brasil, 2002-2009.