IL6 and B-cell chronic lymphocytic leukemia: While the specific elements within the CLL microenvironment that promote Th17 generation are currently unknown, we have shown that two cytokines critical for Th17 differentiation in healthy individuals, IL-1β and IL-6, are elevated in a subset of CLL patients and belong to a cluster of cytokines whose presence correlates with longer TTFT and longer overall survival in this disease [26].