Taking into account the limitations that chemical inhibitor of Pyk2 kinase activity is almost never perfect in its specificity, in subsequent experiments, we are going to use RNA-mediated interference, Pyk2-deficient PBMCs and dominant negative Pyk2 mutants to confirm the exact function of Pyk2 in regulating SLE PBMCs proliferation. Here, PTK2B is linked to systemic lupus erythematosus.