1179 Gut microbial profiles may predict narrowband ultraviolet B response in cutaneous T cell lymphoma patients

Despite strong evidence that gut microbiota can influence immunity and tumor microenvironments, the functional relationship between microbiome cutaneous T cell lymphoma (CTCL), a cancer associated with global dysbiosis, is unclear. Further, effect of narrowband UVB (nbUVB) on CTCL remains unexplored. Our team previously demonstrated patients harbor altered microbiomes their skin may carry predictive signals for nbUVB response. Here, we used 16S sequencing to examine 14 nbUVB-treated (12 mycosis fungoides/Sezary syndrome, 2 other CTCL; 7 responders (R), non-responders (NR)). Pre- versus post-nbUVB R NR analyses showed no significant differences in α- β-diversity. However, taxon-by-taxon analysis revealed abundance Bacteroidaceae, Ruminococcaceae, Eggerthellaceae trended towards significance (p<0.05, q>0.05). A promoter IL-17-mediated inflammation, Bacteroidaceae communities were more abundant pre-nbUVB eventual R, but Ruminicococaceae, short chain fatty acid producer anti-inflammatory activity, was R. These findings suggest contain biomarkers responsiveness CTCL. Post-nbUVB, greater than NR. As showed, significantly reduced guts higher disease burden, these new data emphasize potential modulating activity. trends are consistent our prior work accepted literature microbiome, although power likely affected statistical data. Still, exploring such microbial patterns will be important as continue unlock