Teste sorológico ML Flow: ferramenta complementar na hanseníase

Abstract

Leprosy, an infectious disease, caused by Mycobacterium leprae is manifested by dermatoneurological signs and symptoms. Examination of household contacts is a pillar of disease control and increases the likelihood of early diagnosis of new cases of leprosy. The high association between PGL-I positivity and illness points out to the fact that the ML Flow serological test can be a useful test for identifying contacts at higher risk of developing illness. Objectives: To associate the results of the ML Flow test with the predisposition for the development of the disease among household contact and in the index case with its clinical classification, and to outline the epidemiological profile of cases and contacts. Material and Methods: A prospective study with all patients diagnosed with leprosy over one year, treatment virgins and their household contacts, in six municipalities of the Epidemiological Surveillance Group XXIX, São José do Rio Preto, São Paulo, Brazil (SJRP/SP). The project was approved by the Research Ethics Committee of the Adolfo Lutz Institute. All cases and contacts have performed dermatological tests, simplified neurological assessment and ML Flow test.The patients' blood samples and contacts were sent to Adolfo Lutz Institute of SJRP-SP for ML Flow. Data were analyzed in EPI INFO.7 The frequency distribution of the studied variables was performed and to assess their association, the value p≤0.05 was considered significant. Results: Examinations were performed on 26 new cases of leprosy and 72.4% (n=44) of their household contacts. Most cases were male (n=16/61.5%), older than 35 years (n=20/77%), incomplete primary education (n=18/69.3%), married (n=12/46.2%), employed (n=14/53.8%), owned their own home (n=17/65.4%). As for clinical data, there was a predominance of multibacillary forms (n=22/86.4%), positive smear (n=16/61.5%) and no physical impairment (n=17/65.4%). In the cases,the positivity of the ML Flow test was 53.8% (n=14) and was associated with positive bacilloscopy and multibacillary forms (p-value<0.05). The increase in the ML Flow test for the diagnosis of leprosy was 7.7%. The mean, in months, of appearance of symptoms for cases with positive ML Flow was lower (31.7) than for those with negative ML Flow (38.75). Regarding the contacts, there was a predominance of women (n=23/52.3%) over 35 years of age (n=23/52.3%) with complete elementary education (n=25/56.8%), single (n=19/43.2%) and employees (n=22/50%). Bacillus Calmette-Guérin (BCG) vaccine was administered in 81.8% (n=36) of contacts. Of the 12 (27.3%) positive household contacts for ML Flow, all were living with multibacillary cases, seven with cases that also had positive bacilloscopy and six with consanguineous relatives. Conclusion: The ML Flow test has been shown to be effective both in selecting household contacts that are predisposed to the development of the disease and in helping to correctly classify leprosy cases. Contacts of multibacillary patients with positive and consanguineous bacilloscopy seem to be more exposed to the leprosy bacillus. ML Flow represents a fast, easy to perform test that can be carried out in reference laboratories and in basic healthcare facilities, according to SUS, where the diagnosis and treatment of leprosy should beperformed.