Serum Interleukin 6 Level and Nutrition Status as Potential Predictors of Clinical Leprosy Development Among Household Contacts in Endemic Areas

Abstract

Background Leprosy is a chronic infectious disease that can lead to severe life-long disabilities. Close contacts of leprosy patients have a higher risk of acquiring the disease. Nevertheless, there is a lack of reliable markers to predict Mycobacterium leprae infection. We aim to identify new potential markers for developing clinical leprosy among contacts. Methods Serum levels of IL-6, IL-8, IL-10, hemoglobin, ferritin and transferrin saturation were measured in 67 multibacillary leprosy (MB) patients, 65 household contacts (HC) of MB patients, and 127 endemic controls (EC). By means of multivariate logistic regression and ROC analyses, we analyze baseline variables and laboratory parameters that showed significant differences between MB with HC and EC groups and obtained the respective areas under the curve (AUC). Optimal cut-off value of the associated cytokines was also determined. Results Elevated IL-6 level was observed in MB compared to HC and EC (p=0.022 and 0.0041, respectively). Anemia and iron deficiency were also higher in MB group compared to HC or EC (p<0.001). Likewise, we observed an increased risk of having MB leprosy in underweight HC [OR 2.599 (0.991; 6.820)] and underweight EC [2.176 (1.010; 4.692)]. Further analysis with ROC showed that high serum IL-6 level, underweight, anemia, and iron deficiency can discriminate leprosy from their household contacts [AUC 0.843 (95% CI 0.771-0.914); p=0.000; optimal cut-off value of IL-6 = 9.14 pg/ml]. Conclusions Our results suggest that serum IL-6 and nutrition status could serve as potential prognostic markers for the development of clinical leprosy in infected individuals.

Positive Correlation of Plasma Interleukin-6 Levels with Immunoglobulin M (IgM) Anti Phenolic Glycolipid-1 (PGL-1) Levels in Household Contacts of Multibacillary Leprosy Patients

“…In endemic controls, the most age is 39.6 years. 5 The results also showed no significant relationship between age in the study subjects, which compared leprosy patients, household contacts, and endemic leprosy with increased IL-6 levels.…”

“…Most household contacts in Indonesia have been examined in several areas, namely in Bali, East Java, and Central Java; it was found that the average age range of household contacts of leprosy sufferers is 30-40 years old. [6][7][8][9][10][11][12] This study is not much different from a study conducted by Oktaria et al (2022), where household contacts of leprosy patients have an average age of 37.3 years. In endemic controls, the most age is 39.6 years.…”

“…IL-6 levels can be used to determine the prognosis of M.leprae infection in contact persons and healthy controls in endemic and non-endemic areas. 4,5 Virulence factors and the host's immune response to M. leprae play an essential role in leprosy. The early phase of disease development is largely determined by the natural immune response, which can determine the outcome of the clinical stage of leprosy.…”

Early diagnosis of neural impairment in seropositive leprosy household contacts: The experience of a reference center in Brazil

“…The screening of household contacts with anti-PGL-I is well established in the literature and other biomarkers have been evaluated to assess the risk of developing the disease ( 6–10 ). Furthermore, neural thickening and/or qPCR of slit skin smear and skin biopsy show a significant association with neural damage and could be used as biomarkers to initiate the treatment in these asymptomatic patients.…”

“…Even in the absence of symptoms, M. leprae is replicating and invading the host tissues ( 5 ), and biomarkers for the infection as anti-phenolic glycolipid-I (PGL-I) IgM antibodies have been recommended to detect a risk of infection in asymptomatic patients, especially household contacts. Some studies have also suggested a relation between infection in these patients and other biomarkers such as IL-6 and nutritional status ( 6 ), serum levels of IgA antibodies against NDO-HSA ( 7 ), CCL2 chemokine associated with IFN-γ ( 8 ), and IgM profile against NDO-HSA, LID-1, and NDOLID antigens, and monocytes and CD4+ lymphocyte frequency ( 9 ), beyond arginase activity ( 10 ) as a protective marker against this infection.…”