Prolidase Deficiency Causes Spontaneous T Cell Activation and Lupus-like Autoimmunity.

Area of Science:

• Immunology
• Genetics
• Metabolic Disorders

Background:

• Prolidase deficiency (PD) is a genetic disorder affecting multiple systems.
• PD is linked to autoimmune conditions, potentially mimicking systemic lupus erythematosus (SLE).
• The exact cause of autoimmune associations in PD remains unclear.

Purpose of the Study:

• To investigate the causal link between prolidase deficiency and autoimmune disease.
• To elucidate the mechanisms underlying autoimmune manifestations in PD.

Main Methods:

• Utilized Pepd-null mouse models to study PD.
• Analyzed autoantibody levels, immune complex deposition, and T cell populations.
• Employed mixed chimera experiments to assess cell-intrinsic effects.

Main Results:

• Pepd-null mice exhibited increased antinuclear autoantibodies and IgA, with kidney immune complex deposition, resembling SLE.
• Accumulation of CD4 and CD8 effector T cells was observed in spleen and liver.
• Pepd deficiency induced spontaneous, cell-intrinsic T cell activation and proliferation.

Conclusions:

• Prolidase deficiency contributes to autoimmune susceptibility through spontaneous T cell dysfunction.
• This dysfunction, possibly combined with external immune activators, leads to SLE-like disease.
• Understanding prolidase's role in self-tolerance highlights the need for treatments targeting T cell activation in PD.