Pulmonary
lymphangioleiomyomatosis (
LAM) is a rare genetic multisystem disease characterized by the nodular proliferation of smooth muscle-like
LAM cells, progressive cystic changes of the lung,
lymphatic abnormalities, and renal
angiomyolipomas (AMLs).
LAM can arise sporadically or in women with the autosomal dominant disorder,
tuberous sclerosis complex (
TSC), in which hamartomatous
tumors of brain, heart, skin, kidney, and lung are found.
LAM and
TSC are caused by mutations in the TSC1 or TSC2 tumor suppressor genes leading to elevated mechanistic/
mammalian target of rapamycin complex activity. Recent data indicate that T cells within
LAM nodules and renal AMLs exhibit features of T-cell exhaustion, with coinhibitory receptor
programmed cell death protein 1 (PD-1) expression on
tumor-infiltrating T cells. Treatment of animal models of
TSC and
LAM with anti-PD-1
antibodies or with the combination of anti-PD-1 and anti-CTLA4
antibodies has led to remarkable results, suppressing TSC2-null
tumor growth and inducing
tumor rejection. Here we review our current knowledge about the potential for
immunotherapy for the treatment of
LAM and
TSC and highlight critical unknowns and key next steps.