Increased cytokine levels, especially tumor necrosis factor (TNF)-α, were previously detected in peripheral blood mononuclear cells (PBMCs) from X-ALD patients stimulated by lipopolysaccharide (LPS) (24); additionally, elevated levels of interleukin (IL)-2 and IL-1α were found (25). Here, IL2 is linked to X-linked adrenoleukodystrophy.