Gut Microbiota Dysbiosis in Lupus Nephritis

Systemic Lupus Erythematosus (SLE) is an autoimmune disease resulting in multi-organ inflammation with complex clinical manifestation including neuropsychiatric, lupus nephritis..etc. However, the actual cause of SLE is still unknown \[1\].

Various etiologies have been postulated which can be categorized into genetic and environmental such as age, gender, ultra-violet exposure, dietary intake, alcohol, and lifestyle behavior \[2\].

Lupus nephritis is one of the most severe manifestations of SLE with high mortality rate and 10% of them eventually develop end-stage renal disease within 5 years after diagnosis \[3,4\].

There are trillion of microbes inhabited human gut which dominated by 4 phyla; Firmicutes, Bacteroidetes, Proteobacteria and Actinobacteria. In healthy human gut, 98% of gut microbiota is dominated by Bacteroidetes and Firmicutes. Every species of gut microbiota play their own role in modulating immune system. Many factors could alter gut communities such as infant transition, dietary habit, age, gender and antibiotic consumption \[5, 6\].

Firmicutes responsive in fatty acids and carbohydrates absorption whereas Bacteroidetes correspond to polysaccharides absorption \[7\].

Recently, enormous reports highlighted on the association of autoimmune diseases with dysbiosis of gut microbiota \[8-11\], During the autoimmune disease condition, the symbiotic relationship is broken due to various factor such as dietary habit that change microbiota diversity. The decrease of microbial diversity was found in autoimmune diseases such as SLE and inflammatory bowel disease (IBD), presented by reduce commensal bacteria (Firmicutes and Bacteroidetes) and increase of detrimental bacteria (Proteobacteria and Actinobacteria) \[12\].

Alteration of gut microbiota expresses as Firmicutes/Bacteroidetes ratio (F/B) potentially act as the measurement for pathological condition in SLE patients which cause systemic inflammation. The decreased ratio of F/B microbiome in SLE patients occur either by the reduction in Firmicutes or increase abundance of Bacteroidetes \[13\]. In human study, altered short chain fatty acids (SCFA) fecal level in lupus patient with low F/B ratio suggest the potential link of gut absorption function with microbes \[14\].

Hence, it is necessary to identify the exact mechanism on how the gut microbiota promote SLE and LN pathogenesis in human studies.