ML Flow serological test: complementary tool in leprosy

To associate the results of the ML Flow test with the clinical characteristics of leprosy cases and to verify their positivity in household contacts, in addition to describing the epidemiological profile of both.

Methods

Prospective study with patients diagnosed over the course of one year (n = 26), without prior treatment, and their household contacts (n = 44) in six municipalities in northwestern São Paulo, Brazil.

Results

There was a predominance of men among the leprosy cases, of 61.5% (16/26); 77% (20/26) were over 35 years old; 86.4% (22/26) were multibacillary; 61.5% (16/26) had a positive bacilloscopy; and 65.4% (17/26) had no physical disability. The ML Flow test was positive in 53.8% (14/26) of the leprosy cases and was associated with those who had a positive bacilloscopy and were diagnosed as multibacillary (p-value <0.05). Among the household contacts, 52.3% (23/44) were women and aged over 35 years; 81.8% (36/44) had been vaccinated with BCG ‒ Bacillus Calmette-Guérin. The ML Flow test was positive in 27.3% (12/44) of household contacts, all of whom lived with multibacillary cases; seven lived with positive bacilloscopy cases and six with consanguineous cases.

Study limitations

Difficulty in convincing the contacts to undergo the evaluation and collection of the clinical sample.

Conclusion

The ML Flow test, when positive in household contacts, can help the identification of cases that require more attention by the health team, as it indicates a predisposition to disease development, especially when they are household contacts of multibacillary cases, with positive bacilloscopy and consanguineous. The ML Flow test also helps in the correct clinical classification of the leprosy cases.

Keywords
Contact tracing; Leprosy; Public health; Serology; Surveillance

Sociodemographic data		Cases (n = 26)		Household contacts (n = 44)
Sociodemographic data		n	%	n	%
Sex	Male	16	61.5	21	47.7
Sex	Female	10	38.5	23	52.3
Age	0 to 15	1	3.8	10	22.7
	16 to 35	5	19.2	11	25.0
	36 to 55	8	30.8	14	31.8
	>55	12	46.2	9	20.5
Level of schooling	Illiterate	1	3.8	1	2.3
	Incomplete Elementary School	17	65.5	18	40.9
	Complete Elementary School	3	11.5	5	11.4
	High School	4	15.4	14	31.8
	Higher Education	1	3.8	4	9.1
	Postgraduate Education	-	-	2	4.5
Marital status	Single	5	19.2	19	43.2
	Married	12	46.2	18	40.9
	Separated/Divorced	-	-	2	4.5
	Widowed	2	7.7	1	2.3
	Common-law marriage	7	26.9	4	9.1
Employment status	Employed	14	53.8	22	50.0
	Unemployed	6	23.1	17	38.6
	Retired/medical leave	6	23.1	5	11.4
Housing status	Owned house	17	65.4	37	84.1
Housing status	Rented house	9	34.6	7	15.9

Situation of contact		ML Flow of contacts				Total	p-value^* * Fisher’s exact test.
		Positive		Negative		Total
		n	%	n	%	n (%)
Time living with the patient in the same house	Less than five years	5	11.4	6	13.6	11 (25.0)	0.46
	Five years or more	6	13.6	17	38.7	23 (52.3)
	No information	1	2.3	9	20.4	10 (22.7)
	Total	12	27.3	32	72.7	44 (100)
Degree of kinship with the case	Consanguineous	6	13.6	14	31.8	20 (45.5)	0.48
	Non-consanguineous	6	13.6	18	40.9	24 (54.5)
	Total	12	27.3	32	72.7	44 (100)
Underwent neuro-dermatological examination	Yes	7	15.9	20	45.5	27 (61.4)	0.63
	No	3	6.8	9	20.4	12 (27.3)
	Does not know	2	4.5	3	6.8	5 (11.4)
	Total	12	27.3	32	40.9	44 (100)
Received BCG vaccine	Yes	10	22.7	26	59.1	36 (81.8)	0.64
	No	1	2.3	2	4.5	3 (6.8)
	No information	1	2.3	4	9.1	5 (11.4)
	Total	12	27.3	32	40.9	44 (100)

Sociodemographic data		ML Flow contacts				Total	p-value^a a Fishers' exact test.
Sociodemographic data		Positive		Negative		Total
		n	%	n	%	n (%)
Gender	Male	5	11.3	16	36.4	21 (47.7)	0.44
Gender	Female	7	15.9	16	36.4	23 (52.3)	0.44
Age	0 to 15	2	4.6	8	18.2	10 (22.8)	0.55
	16 to 35	4	9.1	7	15.9	11 (25.0)
	36 to 55	3	6.8	11	25.0	14 (31.8)
	Over 55	3	6.8	6	13.6	9 (20.4)
Level of schooling	Illiterate	1	2.3	‒	‒	1 (2.3)	0.09
	Incomplete Grade School	7	15.9	11	25.0	18 (40.9)
	Complete Grade School	‒	‒	5	11.4	5 (11.4)
	High School	3	6.8	11	25.0	14 (31.8)
	Higher Education	1	2.3	3	6.8	4 (9.1)
	Postgraduate Education	-	-	2	4.5	2 (4.5)
Degree of kinship	Son/Daughter	2	4.5	10	22.7	12 (27.2)	0.48
	Spouse	4	9.1	11	25.0	15 (34.1)
	Brother/Sister	3	6.8	1	2.3	4 (9.1)
	Father/Mother	1	2.3	2	4.5	3 (6.8)
	Brother/Sister-in-law	‒	‒	2	4.5	2 (4.5)
	Stepson/daughter	‒	‒	4	9.1	4 (9.1)
	Grandson/daughter	‒	‒	1	2.3	1 (2.3)
	Daughter-in-law	1	2.3	1	2.3	2 (4.6)
	Stepfather	1	2.3	‒	‒	1 (2.3)

Clinical data of cases		ML Flow cases				Total	p-value^a a Fishers' exact test.
		Positive		Negative		Total
		n	%	n	%	n (%)
Clinical form	Indeterminate	‒	‒	1	3.8	1 (3.8)	0.01
	Tuberculoid	‒	‒	3	11.5	3 (11.5)
	Borderline	4	15.4	1	3.8	5 (19.2)
	Lepromatous	10	38.5	7	27.0	16 (65.5)
Bacilloscopy	Positive	12	46.1	4	15.4	16 (61.5)	0.00
Bacilloscopy	Negative	2	7.7	8	30.8	10 (38.5)	0.00
Biopsy ^b b 14 cases had no information about the biopsy in their medical records.	Suggestive of leprosy	5	41.7	5	41.7	10 (83.4)	0.31
	Negative	‒	‒	2	16.6	2 (16.6)	0.31
Degree of disability	With DPD	5	19.2	4	15.4	9 (34.6)	0.61
Degree of disability	Without DPD	9	34.6	8	30.8	17 (65.4)	0.61
Operational classification	Paucibacillary	‒	‒	5	19.2	5 (19.2)	0.01
Operational classification	Multibacillary	14	53.8	7	27.0	21 (80.8)	0.01

	Result of the ML Flow test of household contacts
Result of the ML Flow test in leprosy cases	Positive (n = 12)	Negative (n = 32)
Positive	7 (15.9%)	17 (38.6%)
Negative	5 (11.4%)	15 (34.1%)
Total	12 (27.3%)	32 (72.7%)

Sociedade Brasileira de Dermatologia Av. Rio Branco, 39 18. and., 20090-003 Rio de Janeiro RJ, Tel./Fax: +55 21 2253-6747 - Rio de Janeiro - RJ - Brazil
E-mail: revista@sbd.org.br

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[1] ⁎ Corresponding author. janaina.montanha@ial.sp.gov.br (J.O. Montanha).

Brasil

Brasil

ML Flow serological test: complementary tool in leprosy☆ ⋆ Study conducted at the Centro de Laboratório Regional de São José do Rio Preto, Instituto Adolfo Lutz, São José do Rio Preto, SP, Brazil.

Abstract

Background

Objective

Methods

Results

Study limitations

Conclusion

ML Flow serological test: complementary tool in leprosy^☆ ⋆ Study conducted at the Centro de Laboratório Regional de São José do Rio Preto, Instituto Adolfo Lutz, São José do Rio Preto, SP, Brazil.