PDCD1 and systemic lupus erythematosus: Controversially, in vivo blockade of PD-1 receptor in a lupus murine model (NZB/WF1) has been shown to delay the disease progression [34–36], and might, owing to the high affinity and doses of commercial PD-1 antibodies administered to mice, result in the dissolution of T cells instead of the inhibition of T cells function.