# P-184. Helminth co-infection in leprosy: Innocent bystander or immune dysregulator?

## TL;DR

This study explores whether helminth infections affect the immune response in people at risk for leprosy in Brazil.

## Contribution

The study presents preliminary data on immune responses in leprosy patients with helminth co-infections.

## Key findings

- Helminth seropositivity was associated with a lower likelihood of leprosy in anti-LID1+ individuals.
- Cytokine and chemokine levels, such as CXCL8, IL17, IL2, and IL6, showed interesting trends in co-infected individuals.
- Findings suggest helminth co-infection may alter immune responses in leprosy.

## Abstract

Leprosy, a neglected tropical disease also called Hansen’s disease, remains a public health challenge in Brazil. Helminth infections have been shown to be associated with leprosy, but results have been mixed. We present preliminary results from a longitudinal cohort to address this question.

Figure 1.Cytokine and chemokine comparisons across infection groups.Comparison of log transformed cytokine and chemokine concentrations across 4 clinical groups. Helminth infection is defined as being seropositive for either Schistosoma mansoni and Strongyloides stercoralis. LID+/ LID- signifies seropositivity for anti-LID1 antibodies. Boxes represent median (line), first and third quartiles. Outliers represented by dots.

Cytokine and chemokine comparisons across infection groups.

Comparison of log transformed cytokine and chemokine concentrations across 4 clinical groups. Helminth infection is defined as being seropositive for either Schistosoma mansoni and Strongyloides stercoralis. LID+/ LID- signifies seropositivity for anti-LID1 antibodies. Boxes represent median (line), first and third quartiles. Outliers represented by dots.

Individuals ages 3 years and up (n=1315) were enrolled in eastern Minas Gerais, Brazil, and screened for anti-LID1, a Mycobacterium leprae specific antibody. Those positive without a history of leprosy and anti-LID1 negative controls were enrolled in the longitudinal study and evaluated for leprosy over time. Helminth serology (Schistosoma mansoni (SM) and Strongyloides stercoralis (SS)) by multiplexed beaded assay and stool helminth exams were performed at the onset. We then measured cytokines and chemokines from PBMC stimulated by M. leprae (ML) antigen at time 0.

Seventy-seven (6%) individuals tested positive for anti-LID1. Of the longitudinal cohort (n = 153), 17 (11%) were seropositive for SM and 11 (7%) for SS. One individual tested positive for SM by stool. Twenty (26%) anti-LID1+ individuals were diagnosed with leprosy, half at the initial visit. Seropositivity for either SM or SS was associated with a lower likelihood of leprosy (RR = 0.83, 95% CI 0.69, 0.99) in anti-LID1+ individuals. Median concentrations of CXCL8 (p=0.07) were lower in SM-ML seropositive individuals compared to anti-LID1+ alone, and IL17, IL2, IL6 showed interesting trends in co-infection (Figure 1).

While helminths have not been associated with risk of leprosy in our cohort to date, the immune findings suggest a potential alteration of cytokine / chemokine response in co-infected (or co-seropositive) individuals. Interestingly, we found similar results with CXCL8 and IL17 in a previous study on co-infection, highlighting a potential mechanistic pathway that should be further studied.

All Authors: No reported disclosures