Microbial diversity investigation using 16S metagenomics in Tunisian patients with systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is a multisystemic autoimmune disease associated with significant morbidity and mortality. It is characterized by a loss of self-immune tolerance and autoantibody production, leading to multiple organ damage. Emerging investigations have confirmed the role of gut microbiota dysbiosis in patients with SLE, although the underlying mechanisms remain unclear to date. In this study, we aim to investigate the bacterial profile of SLE including phylum/class/genus relative abundance and diversity, to compare them with healthy controls and to study the correlation of relative abundance of different patterns with clinical/biological parameters. In this case-control study, the bacterial profile was investigated in 7 SLE patients and 7 healthy controls using 16S metagenomics clustering. The present study reported a low abundance of the class Bacilli (0.58% in SLE vs 1.26% in the controls), the genus Lactobacillus (0.43% vs 0.74%), as well as a higher abundance of the genera Gammaproteobacteria (2.37% vs 0.77%) and Escherichia-Shigella (2.04% vs 0.51%) in SLE samples compared to the controls (p<0.05). We also found an association between the class Betaproteobacteria (4.42% vs 1.57%) and the genus Faecalibacterium (11.34% vs 3.35%) and renal manifestations (p<0.05). The phylum Actinobacteria (0.21% vs 3.8%, p=0.036) and the genus Bifidobacterium levels were lower in active SLE compared to the healthy controls. This study is the first report on the gut microbiota of SLE and the first case-control study in Tunisia and North Africa. We obtained a particular profile of bacterial gut microbiota for the SLE group. We found a specific clustering when compared to the healthy controls.