Circulating natural killer cells in Sjögren's syndrome

Area of Science:

• Immunology
• Rheumatology

Background:

• Natural killer (NK) cell activity is reportedly reduced in various diseases, including Sjögren's syndrome (SS).
• Previous studies suggest diminished NK cell function in SS patients.

Purpose of the Study:

• To investigate NK cell activity and subsets in patients with primary and secondary Sjögren's syndrome.
• To compare NK cell markers and function between SS patients and healthy controls.

Main Methods:

• Utilized monoclonal antibodies (anti-Leu-7 and anti-Leu-11) to identify NK cell subsets.
• Assessed peripheral blood lymphocyte (PBL) NK activity using the 51Cr release assay with K562 target cells.
• Compared results between 29 SS patients and sex- and age-matched healthy controls.

Main Results:

• Contrary to prior reports, no significant reduction in PBL NK activity was observed in SS patients.
• The percentage of Leu-7+ cells was higher in SS patients, but absolute numbers did not differ.
• A significant decrease in the number of circulating Leu-11+ cells was found in SS patients.
• NK activity correlated significantly with the percentage of Leu-11+ cells in both SS patients and controls.

Conclusions:

• Sjögren's syndrome patients do not exhibit reduced NK cell activity, challenging previous findings.
• A decrease in circulating Leu-11+ NK cells may be a characteristic feature of SS.
• NK cell activity is associated with Leu-11+ cell numbers in both SS and healthy individuals.