Figure 5. IgA-Binding of Bacteria in the Gut Is Reduced in MS Patients during an Acute Relapse.
(A) Study overview: fresh-frozen fecal samples of 33 patients with clinically Isolated syndrome (CIS) or relapslng-remlttlng multiple sclerosis (RRMS) (n = 22 during disease remission, n = 11 during an acute relapse) and 32 healthy controls were collected. Fecal bacteria were isolated and IgA-binding of autologous gut bacteria was quantified by bacterial flow cytometry (BUGFlow) and ELISA.
(B) BUGFlow: bacteria were identified based on forward and side scatter and the IgA-positive population was defined based on an isotype control. Shown is an example of staining of fecal bacteria from an RRMS patient with an isotype control (left) as well as with anti-IgA during remission (middle) and during relapse (right).
(C) Percentage of fecal-bound IgA by BUG Flow: 1 × 106 fecal bacteria were stained with anti-IgA and % of IgA binding was assessed by flow cytometry. Values shown are replicates from 2 experiments.
(D) Quantification of fecal-bound IgA by ELISA: 1 × 106 fecal bacteria were assessed for IgA binding using a commercially available quantitative IgA ELISA assay. Values shown are mean values of duplicate measurements. *p < 0.05, t test with Welch correction with mean and SEM depicted.
See also Table S2.