C3 and systemic lupus erythematosus: As shown in Fig 5, IL-2, TNF-α and the numbers of peripheral blood γδT cells, γ9-δT cells, CD4-CD8-γδT cells, CD4-CD8-CD27+γδT cells, IL17+CD4-CD8-γδT cells and CD27+γδT cells showed positive correlation with serum C3 level in SLE patients.