Lymphocyte phenotype and function in pseudolymphoma associated with Sjogren's syndrome

Abstract

Lymph node (LNL) and salivary gland lymphocytes (SGL) from three patients with pseudolymphoma and primary Sjogren's syndrome (10SS) were characterized with monoclonal antibodies to demonstrate (a) a predominance of T cell (>80%) reactive with anti-T cell antibodies OKT4 (>70%) and OKT8 (<20%); (b) a high prevalence of activation antigens (>50% of cells reactive with antibody OKT10 and anti-Ia antibody); (c) polyclonal B cells (8-15% of all cells expressing kappa or lambda); and (d) a specific B cells subset defined by reactivity with antibody B532 that was not present in their peripheral blood. In vitro functional studies showed that both SGL and LNL provided T helper activity for immunoglobulin synthesis and that this activity could be abolished by treatment with antibody OKT4 plus complement. The SGL and LNL exhibted little natural killer, antibody-dependent cellular cytotoxicity, or cytotoxic T cell activity. Normal karyotype was observed in SGL, LNL, and peripheral blood lymphocytes (PBL) from these patients. These findings indicate that pseudolymphoma in 10SS results from the infiltration of salivary glands and extraglandular tissues by nonneoplastic T helper cells. Monoclonal antibodies provide an important tool to distinguish pseudolymphoma from non-Hodgkins (B cell) lymphomas that have a markedly elevated incidence in 10SS patients. Our finding of T helper cells in pseudolymphoma tissues supports the hypothesis that chronic stimulation of B cells by helper T cells leads to eventual escape of a malignant B cell clone.