To determine the role of T cells in the pathogenesis of lupus nephritis (LN).

Renal biopsy specimens from 12 patients with systemic lupus erythematosus were used for the experiments. We analyzed T cell receptor (TCR) Vβ1–20 family genes on intrarenal T cells and on peripheral blood lymphocytes (PBLs) by nested reverse transcriptase–polymerase chain reaction (PCR) and Southern blot analysis. Nucleotide sequence was determined in the third complementarity‐determining region of the TCR Vβ gene in expanded T cells. Messenger RNA (mRNA) expression levels of Th1 and Th2 cytokines on infiltrating T cells were measured by nested PCR.

The repertoire of TCR Vβ in intrarenal T cells was relatively restricted compared with that in PBLs. The TCR Vβ8 and TCR Vβ20 genes were preferentially expressed in 6 of 12 patients (50%) and the TCR Vβ9 and TCR Vβ14 genes were expressed in 5 of 12 patients (42%). Junctional sequences of complementary DNA encoding the TCR Vβ8 and TCR Vβ20 genes in intrarenal T cells showed oligoclonal expansion, indicating antigen‐driven stimulation. Interleukin‐4 (IL‐4) and IL‐10 mRNA were highly expressed on intrarenal T cells, while interferon‐γ mRNA was not detected.

Our findings suggest that T cells infiltrating the kidneys of patients with LN may recognize restricted epitopes on antigens and function as Th2‐type T cells.