A retrospective study showed a close relationship between peripheral blood mRNA expression of CCL3, CCR3, IL-5, IL-8 and PTGS2 and immune-related diarrhoea, especially grade 2–4 diarrhea (Friedlander et al., 2018), while upregulation of IL-17 levels at baseline and 6 weeks after treatment with anti-CTLA-4 antibody was reported to correlate with grade 3 diarrhea and colitis in melanoma patients (Tarhini et al., 2015). Here, CTLA4 is linked to melanoma.