Proinflammatory cytokines were reported to be implicated in the pathogenesis of perinatal white matter lesions. The authors document for the first time the in situ detection of interleukin-2 and interleukin-2 receptor (IL-2R) in these human white matter lesions. These results suggest that interleukin-2, reported to be toxic to oligodendrocytes and myelin, could play a role in the molecular cascade leading to white matter damage in periventricular leukomalacia.