An integrated analysis of the structural changes and gene expression of spleen in human visceral leishmaniasis with and without HIV coinfection

Abstract

The spleen plays a pivotal role in the pathogenesis of visceral leishmaniasis. In severe forms of the disease, the spleen undergoes changes that can compromise its function in surveilling blood-circulating pathogens. In this study, we present an integrated analysis of the structural and gene expression alterations in the spleens of three patients with relapsing visceral leishmaniasis, two of whom were coinfected with HIV. Our findings reveal that the IL6 signaling pathway plays a significant role in the disorganization of the white pulp, while BCL10 and ICOSLG are associated with spleen organization. Patients coinfected with HIV and visceral leishmaniasis exhibited lower splenic CD4+ cell density and reduced expression of genes such as IL15. These effects may contribute to a compromised immune response against L. infantum in coinfected individuals, further impacting the structural organization of the spleen.

Fig 1. Histological and leukocyte distribution in spleen from patients with VL.

Patient VL1 presents a spleen type 3, with atrophy of lymphoid follicles. Patient VL2 presents a spleen type 1, with slight organized lymphoid follicle. Patient VL3 presents a well-structured WP and well-defined sub compartments, classified as spleen type 1.

Fig 2. Gene expression analysis of spleen from patients with VL.

A) Heatmap demonstrate that gene signature differs from patients with VL to normal donors and each band correspond to a different gene. Scale bar represents Log2 of Fold Change. Data were organized based on the gene expression of VL1 from the most expressed to the last expressed. B) Using an unsupervised analysis, we demonstrate that gene profile differs among VL patients, clustering organized spleen (patients VL2 and VL3) separated from disorganized spleen (patient VL1). Each dot represents the PCA value of each patient based on PCA analysis. Blue dot–Normal donor; Yellow dot–VL patient. C) IL6 signaling pathway adapted from Kandasamy and colleagues (2010) [18]. This pathway represents the signaling mechanism of IL6 in humans, genes upregulated in the spleen of patients with VL found on our analysis are highlighted in red, other genes presented at this graphic did not present expression change statistically significant or were not analyzed in our data set.