Half-cocked T reg cells

Sarcoidosis is a mysterious, long-recognized disease characterized by the formation of tuberculosis-like granulomas in the lungs. The mystery of sarcoidosis stems from both its unknown etiology and its paradoxical effects on the immune system. The disease has been attributed to a hyperactivation of CD4⁺ T helper type 1 cells that infiltrate the lungs but, in patients with sarcoidosis, these very cells fail to proliferate in response to recall antigens.

On page 359, Miyara and colleagues suggest that half-cocked regulatory T (T reg) cells that inhibit proliferation by T cells but not their cytokine production might be to blame for this immune contradiction.

T reg cells normally help suppress chronic inflammation by inhibiting both effector T cell proliferation and cytokine production. Miyara et al. now show...