Th60 - High Salivary IgA-coating Levels of the Oral Microbiota in Patients with Systemic Lupus Erythematosus (SLE)

Immunoglobulin A (IgA) is the primary antibody isotype present in the body fluids. There are two
subtypes of IgA in humans: IgA1, mainly present in blood and mucosal sites, and IgA2,
preferentially expressed in mucosal sites like the colon. In clinical practice, immunoglobulins are
typically measured in venous or capillary blood; however, alternative samples, including saliva, are
now being considered given its non-invasive and easy collection nature.
Several autoimmune diseases have been related to intestinal microbiota dysbiosis, such as
rheumatoid arthritis, systemic sclerosis, and systemic lupus erythematosus (SLE). However, little is
known about the oral microbiota, and the role of IgA in these diseases, specifically SLE, since about
40-70% of these patients present alterations in the oral cavity. Thus, we decided to evaluate the
levels of both IgA subtypes in the saliva of SLE patients measured by ELISA in a cohort of 27
patients with SLE that were compared with antibody levels of healthy volunteers. At the same
time, we evaluated the percentage of coating of oral microbiota by salivary IgA using flow
cytometry.
Surprisingly, our results indicated that the oral microbiota of SLE patients is high coverage by
salivary IgA1, and both IgA subtypes were elevated, but IgA1 was significantly elevated.
Interestingly, we also found that salivary IgA levels, specifically IgA1, positively correlate with
serum anti-dsDNA IgG related to the SLEDAI values.
According to our results, there may be an alteration in the oral microbiota of patients with SLE due
to the increase in IgA1 coating.

CONACyT A3-5-36875/UNAM-DGAPA-PAPIIT IN212122