Early serodiagnosis of leprosy by indirect immunofluorescence.

A method of fluorescent leprosy antibody absorption (FLA-ABS) test was described. This test was so sensitive that 81.8% of tuberculoid leprosy cases gave positive reaction even in early stage of the disease. More than 50% of indeterminate and contact cases were also positive in this test. The positive percentages as well as antibody-titers were increasing with clinical spectrum of leprosy, from TT to LL, being the highest in the latter. Using absorbed and diluted serum from known lepromatous patient, enumeration of M. leprae in skin smear showed a good coincidence with the bacterial index expressed by Ridley's scale. Therefore, FLA-ABS test will be useful for early serodiagnosis of leprosy not only by the detection of antibodies but also by the identification of M. leprae.