Natural killing activity in sjögren's syndrome

Abstract

Natural killing (NK) by peripheral blood mono‐nuclear cells (PBMC) against K562 cells was examined in 27 patients with Sjögren's syndrome and 17 normal controls. NK activity in the patients was significantly reduced compared with normal controls (34.6 ± 3.4% versus 52.2 ± 3.4%, P < 0.001). Patients with secondary Sjögren's had lower cytotoxicity compared with those who had primary Sjögren's (28.5 ± 5.5% versus 37.3 ± 4.2%, P < 0.01). The proportion of PBMC with characteristics of NK cells was not decreased in the patients. NK by normal PBMC was diminished both in the presence of sera from patients with reduced NK and when the effector cells were pretreated with the sera. Pretreatment of target K562 cells did not alter NK activity. Suppression of NK by sera from patients did not correlate with levels of immune complexes or with antilymphocyte antibodies. Some patients had adherent cells which inhibited NK function. Addition of either indomethacin or catalase partially restored NK activity in such patients, indicating that both prostaglandins and hydrogen peroxide play a role in suppression. These data suggest that multiple mechanisms are involved in the defective NK activity seen in patients with Sjögren's syndrome. The reduction of NK activity in Sjögren's syndrome may contribute to the increased incidence of lymphoid malignancy.

A novel role for interleukin-18 in human natural killer cell death: High serum levels and low natural killer cell numbers in patients with systemic autoimmune diseases

“…Patients with systemic autoimmune diseases have reduced numbers of peripheral blood NK cells and impaired NK cell function (28–34). Our results suggest that one reason for this phenomenon might be cytokine‐induced NK cell death.…”

Conjunctival biopsy in Sjögren's syndrome: correlations between histological and immunohistochemical features

“…In previous studies Fox et al (1985) could not demonstrate natural killer cells in salivary glands in Sjogren's syndrome. Natural killing activity is decreased in the peripheral blood in Sjogren's syndrome (Miyasaka et al 1983). The possible role of such a defect in the pathogenesis of Sjogren's syndrome is unclear.…”

The Natural Killer Cell – Friend or Foe in Autoimmune Disease?

“…in rheumatoid synovial tissue [34–36] and among infiltrating mononuclear cells of MS patient brain lesions [37]). Reduced peripheral NK cell activities and, in some studies, also differences in NK cell numbers are found when patients suffering from various autoimmune syndromes, such as remitting/relapsing (r/r) MS [38–42], Sjögren's Syndrome (SS) [41, 43–45], MG [46], rheumatoid arthritis (RA) [47–50], SLE [43, 47, 51, 52] and type 1 diabetes [53–56], are studied and compared with controls. It has, however, been difficult to determine whether these qualitative and quantitative alterations stem from metabolic disturbances, the therapy used or whether they represent a primary NK cell defect that could have played a pathogenic role [55–60].…”