Multiplexed gene expression analysis of HLA class II-associated podoconiosis implicates chronic immune activation in its pathogenesis

Abstract

Background Podoconiosis is a tropical lymphoedema of the leg resulting from barefoot exposure to irritant volcanic soils. Approximately 4 million people are affected, mainly in African highland regions. The pathogenesis of this neglected tropical disease is still largely unknown, although HLA class II (HLAII) polymorphisms are associated with the disease. Methods NanoString technology was used to assess expression of 579 immune-related genes in formalin-fixed and paraffin-embedded lymph node archival samples from podoconiosis patients and unaffected controls. Results Forty-eight genes were upregulated and 21 downregulated in podoconiosis samples compared with controls. Gene ontology analysis showed differentially expressed genes to be closely related to major histocompatibility complex protein, cytokine and TNF receptor binding genes. Pathway enrichment analysis revealed involvement of lymphocyte activation, adaptive immunity, cytokine signalling, antigen processing and the IL-12 pathways. Conclusions This exploratory study reports a multiplex gene expression analysis in podoconiosis and shows upregulation of pro-inflammatory transcripts compatible with the notion of local, chronic immune activation in this HLAII-associated disease. Implicated pathways will inform future research into podoconiosis immunopathogenesis.

A geochemical and mineralogical characterization of soils associated with podoconiosis

“…The last decade has seen a significant increase in studies of Podoconiosis. Improvements are occurring in the understanding of its medical and public health aspects, such as prevention and management, genetic factors, and even community understanding (Alcantara et al, 2020 ; Davey et al, 2007 ; Deribe et al, 2018 ; Florence & Fuller, 2017 ; Gebresilase et al, 2021 ; Molla et al, 2012 ; Tora et al, 2016 ; van‘t Noordende et al, 2020 ). However, research into the soils has not received the same attention, though recent years suggest growing interest (Cooper et al, 2019 ; Gislam et al, 2020 ; Le Blond et al, 2015 ; Molla et al, 2014 ).…”