Detection of human and murine common idiotypes of DNA antibodies in tissues and sera of patients with autoimmune diseases.

The expression in tissue and serum of a panel of murine and human common DNA antibody idiotypes (Ids) (BEG 2, PR 4, F-423, I-402, II-28, IV-228, V-88) has been investigated. The murine V-88 Id was detected in eight out of 10 and the human BEG 2 Id in five out of 10 labial biopsies from patients with Sjögren's syndrome. The murine F-423, I-402 and IV-228 Ids were identified in one out of 10 biopsies. In each case the pattern of staining was similar with staining of the acinar basement membrane and a cell population. Using double-labelling immunohistochemistry this cell population were identified as plasma cells. No staining was seen in four normal labial biopsies. The V-88 Id was detected on the epithelial aspect of the thickened basement membrane in three out of nine renal biopsies from patients with systemic lupus erythematosus (SLE). None of the other Ids (BEG 2, PR4, IV-228, F-423 or I-402) could be detected in renal tissue. None of the Ids were found in skin biopsies from SLE patients. Id V-88 may, like the 16/6 Id to which it is phenotypically related, play a role in the pathogenesis of renal lesions in SLE. The BEG 2 Id could be detected in the serum of patients with rheumatoid arthritis (RA) and active untreated tuberculosis. Ids II-28, V-88 and I-402 were elevated in serum from patients with Sjögren's syndrome and II-28 Id in serum from patients with myositis and RA. None of the Ids were elevated in serum from patients with SLE. Apart from the BEG 2 Id, none of the Ids were elevated in serum from patients with tuberculosis or Gram-negative infections. The presence of murine Ids in human tissue and serum suggests that they are cross-species idiotypes and have been conserved through evolution.