Abstract
Sjögren's syndrome is characterized by lymphoid cell infiltration of exocrine glands, hypergammaglobulinemia and presense of autoantibodies. In Sjögren's syndrome, there is a broad spectrum of lymphoproliferation, from benign disease, through non-malignant extraglandular lymphoproliferation (Pseudolymphoma), to malignant disease, either macroglobulinemia or lymphomas. Cellmediated immune responses may be also depressed in Sjogren's syndrome. In the present study, two cases of intraglandular benign lymphoproliferative disorders developing in patinets with Sjögren's syndrome are reported. Pathological and immunological investigations are performed by using lymphocytes infiltrating into the parotid gland (PGL). In addition, peripheral blood lymphocytes (PBL) from patients with Sjögren's syndrome were examined for their capacity to product of Interleukin-2 (IL-2) and to proliferate in the course of autologous mixed lymphocyte reaction (AMLR).
Pathologically, there is a periductal mononuclear cell infiltrate consisting of lymphocytes and plasma cells. The acinar tissue is almost replaced by marked lymphocytic infiltrate and gerninal follicle formation is also observed. So-called"epimyoepithelial islands"arising from ductal proliferation are scattered throughout the tissue.
PGL are characterized with monoclonal antibodies to demonstrate (i) a predominance of B cells (>75%) reactive with OKIal, (ii) the ratio of OKT 4+(helper/inducer) T cells to OKT 8+(suppressor/killer) T cells is predominant (4.7) compared with PBL (2.9). PGL are also examined using membrane and direct immunofluorescence with goat anti-human IgG antiserum. IgG bearing lymphocytes have the majority in B cells.
IL-2 production by PBL after phytohemagglutinin (PHA) stimulation was markedly (p<0.01) diminished in patients with Sjögren's syndrome compared with healty controls. The AMLR was decreased in 4 of 6 patients with Sjögren's syndrome. Patients with Sjoögren's syndrome and associated disease had lower responses than patients with Sjögren's syndrome alone. The AMLR is thought to represent a self recognition that might be important in regulating the cellular interactions and essential for maintaining normal immune homeostasis. Deficient AMLR and failure to produce IL-2 may take part in the pathogenesis of Sjögren's syndrome.
