Systemic lupus erythematosus (SLE) is an autoimmune disease, which predominantly affects females, and causes multiple organ dysfunctions. Recent studies have revealed the underlying immunological abnormalities, especially in lymphocytes from SLE patients. T lymphocytes from SLE patients present abnormalities in T cell receptor (TCR) signaling, for example, decreased expression of TCR zeta chain, PKC theta, and NF-kB p65, decreased PKC dependent protein phosphorylation, impaired translocation of NF-kB p65, decreased production of IL-2 etc. Recently, it is known that reconstitution of deficient TCR zeta chain in T lymphocytes from SLE patients leads to restoration of impaired IL-2 production upon CD3/CD28 stimulation. This time, analysis of abnormal TCR signaling in SLE patients and attempt to correct the impaired IL-2 production by replenishing missing signaling molecules are to be discussed.