TABLE 1.
Anti-PGL-1 serology (ELISA) and Mycobacterium leprae DNA detection (PCR) in 41 blood donors who presented positive markers in 2009 and were followed up for at least 5 years (2009 to 2014)
| Donor no. | ELISA follow-up (yearly) |
PCR (blood) | PCR slit-skin smeara | Mitsuda testf (mm) | Disease onset (clinical manifestationb) | ||||
|---|---|---|---|---|---|---|---|---|---|
| 2009 | 2010 | 2011 | 2012 | 2013 | 2009 | ||||
| 01 | + | + | − | − | − | − | − | 8 | No |
| 02 | + | − | − | − | NDd | − | ND | 9 | No |
| 03 | + | + | + | + | +e | − | + | 7 | Yes (I) |
| 04 | + | + | + | + | +e | − | + | 10 | Yes (T) |
| 05c | + | ND | ND | ND | ND | − | ND | ND | No |
| 06 | + | ND | ND | ND | + | − | − | 10 | No |
| 07 | + | + | + | − | − | − | − | 10 | No |
| 08 | + | ND | − | − | − | − | ND | 8 | No |
| 09 | + | + | ND | ND | ND | − | − | 5 | No |
| 10 | + | + | + | + | + | − | − | 5 | No |
| 11 | + | ND | ND | ND | ND | − | ND | 4 | No |
| 12 | + | + | + | + | − | − | − | 5 | No |
| 13 | + | + | + | + | + | − | − | 7 | No |
| 14 | + | ND | ND | ND | − | − | ND | 12 | No |
| 15 | + | ND | ND | ND | − | − | ND | 0 | No |
| 16 | + | + | − | − | − | − | − | 7 | No |
| 17 | + | − | − | ND | ND | − | ND | 8 | No |
| 18c | + | ND | ND | ND | ND | − | ND | ND | No |
| 19 | + | ND | ND | ND | + | − | − | 7 | N |
| 20 | + | + | + | + | +e | − | + | 11 | Yes (BT) |
| 21 | + | + | + | + | + | − | − | 9 | N |
| 22 | + | + | + | + | + | − | − | 9 | No |
| 23 | + | − | + | − | + | − | − | 7 | No |
| 24c | + | ND | ND | ND | ND | − | ND | ND | No |
| 25 | + | + | − | + | + | − | − | 10 | No |
| 26 | + | ND | ND | + | + | − | − | 10 | No |
| 27 | + | ND | ND | − | − | − | ND | 9 | No |
| 28 | + | + | + | + | + | − | − | 10 | No |
| 29c | + | ND | ND | ND | ND | − | ND | ND | No |
| 30 | + | + | + | − | + | − | − | 9 | No |
| 31 | + | ND | ND | ND | ND | − | − | 0 | No |
| 32 | + | − | + | − | − | − | − | 8 | No |
| 33 | + | ND | ND | ND | ND | − | ND | 13 | No |
| 34 | + | + | + | + | +e | − | + | 6 | Yes (BT) |
| 35 | + | + | + | + | +e | − | + | 0 | Yes (BT) |
| 36c | + | ND | ND | ND | ND | − | ND | ND | No |
| 37 | + | − | − | − | − | − | ND | 10 | No |
| 38 | + | ND | ND | ND | ND | − | ND | 10 | No |
| 39 | − | − | − | − | +e | + | + | 13 | Yes (I) |
| 40 | − | − | − | − | − | + | ND | 9 | No |
| 41c | − | ND | ND | ND | ND | + | ND | ND | No |
Criteria for PCR in slit-skin smears: PCR was performed in individuals positive for both ELISA and PCR or with two positive ELISA results.
Clinical manifestation: T, tuberculoid leprosy; BT, borderline-tuberculoid leprosy; I, indeterminate leprosy.
Blood donors who did not return for analysis.
ND, test not done due to participant's decision.
Disease onset.
The Mitsuda test involves an intradermal injection of a heat-killed M. leprae suspension. As the cell-mediated immunity is closely related to the clinical manifestation of leprosy, the response elicited against M. leprae antigens can be visually observed 28 days later by the formation of a nodular epithelioid granuloma at the site of injection. Multibacillary (MB) patients often do not show any reaction, and at the opposite end of the spectrum, paucibacillary (PB) patients usually display strong positive reaction. For healthy individuals, a positive response to the Mitsuda test is associated with greater chance of protection against disease.