CD38 and B-cell chronic lymphocytic leukemia: We observed a higher value of log F/B ratio in CLL patients with more advanced disease stage and negative prognostic features (high CD38 expression and unmutated IGHV) and the association of an increased value of this parameter with a significantly shorter TTFT, which is in line with Faitova et al study (83) showing that lower diversity of the gut microbiome in CLL patients is associated with more aggressive and/or more progressive disease development.