CD4 and systemic lupus erythematosus: Mouse lupus models exposed to Trichloroethylene (TCE) have increased T cell activation, particularly on CD4 + T cells expressing activation markers and increased secretion of INF-γ (20); also, a recent study on BALB/c mice exposed to TCE proposes a tendency of T cells to differentiate toward a Th1 profile, therefore altering the Th1/Th2 ratio (66).