Figure 2

Combination of cellular and humoral markers improves the detection of leprosy patients. Pie charts showing the percentage of individuals with a positive test result for anti-PGL-I IgM (light green), cellular markers (yellow), both anti-PGL-I IgM and cellular markers (blue) or without positive test results (light grey; Supplementary Fig. S4) per test group (lepromatous leprosy/borderline lepromatous (LL/BL), borderline tuberculoid / tuberculoid (BT/TT) patients, healthy household contacts (HHC) and endemic controls (EC)). PGL-I IgM was included to identify LL/BL patients. The threshold for positivity was determined based on the Youden’s index, resulting in a cut-off of >0,205, >0,61 and >1,195 for Brazil, China and Ethiopia respectively for PGL-I IgM. The threshold for positivity was determined as well for two cellular markers that were selected per cohort based on the areas under the curve (AUC) depicted in Fig. 1: CCL4_Nil and IP-10_Nil (China; cut-off >0,355 and >0,105 respectively), IP-10_Nil and IP-10_WCS (Brazil; cut-off >0,395 and >0,855 respectively); CCL4_WCS and CCL4_Mlep (Ethiopia; cut-off <1,03 and <1,13 respectively)_. China: 47 LL/BL patients, 10 BT/TT patients, 87 HHC and 56 EC. Brazil: 30 LL/BL patients, 41 BT/TT patients, 103 HHC and 237 EC. Ethiopia: 17 LL/BL patients, 4 BT/TT patients, 24 HHC and 25 EC. For comparison data obtained from a previous study performed in Bangladesh, using IP-10_WCS and CCL4_WCS as cellular markers, was shown (8 LL/BL, 71 BT/TT, 54 HHC and 51 EC).