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Natural killer cell activity in the systemic connective tissue diseases
R Gonzalez-Amaro1, J Alcocer-Varela, D Alarcón-Segovia
1Department of Immunology and Rheumatology, Instituto Nacional de la Nutrición Salvador Zubirán, Mexico City, Mexico.
The Journal of Rheumatology
|August 1, 1988
Summary
Natural killer (NK) cell activity varies across systemic connective tissue diseases. Systemic lupus erythematosus shows reduced NK cell function, while other conditions like mixed connective tissue disease and Sjögren's syndrome exhibit distinct NK cell impairments.
Area of Science:
- Immunology
- Rheumatology
- Cell Biology
Background:
- Systemic connective tissue diseases (SCTDs) encompass a group of autoimmune disorders affecting connective tissues.
- Natural killer (NK) cells are crucial immune cells involved in innate immunity and surveillance.
- Dysregulation of NK cell function is implicated in various autoimmune and inflammatory conditions.
Purpose of the Study:
- To investigate and delineate the functional characteristics of NK cells in patients with different systemic connective tissue diseases.
- To compare NK cell activity, responsiveness to interleukin-2 (IL-2), and cellular kinetics across various SCTDs.
Main Methods:
- Utilized 51Cr release assays to measure NK cell cytotoxic activity against K562 target cells.
- Employed single NK cell assays, with and without IL-2 stimulation, to assess individual cell function and responsiveness.
- Analyzed NK cell proportions, activity levels, and IL-2 response in patients with systemic lupus erythematosus, mixed connective tissue disease, primary Sjögren's syndrome, scleroderma, and dermatomyositis/polymyositis.
Main Results:
- Systemic lupus erythematosus (SLE) patients exhibited decreased NK cell activity due to a paucity of active, IL-2-responsive NK cells.
- Mixed connective tissue disease (MCTD) patients showed normal baseline NK activity maintained by a small subset of highly active NK cells, with poor IL-2 responsiveness.
- Primary Sjögren's syndrome (pSS) patients presented with very low NK activity, characterized by few NK cells with low recycling indices and poor IL-2 response.
- Scleroderma patients displayed normal NK cell function, while active dermatomyositis/polymyositis patients had diminished NK cell function and numbers, which normalized upon disease inactivation.
Conclusions:
- NK cell dysfunction is a prominent feature in several systemic connective tissue diseases, manifesting differently across conditions.
- Specific patterns of NK cell impairment, including reduced activity, altered IL-2 responsiveness, and changes in cell numbers, are associated with distinct SCTDs.
- These findings highlight the diverse roles of NK cells in the immunopathogenesis of systemic connective tissue diseases and suggest potential therapeutic targets.