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Functional subsets of CD4 T cells in rheumatoid synovitis
T Namekawa1, U G Wagner, J J Goronzy
1Mayo Clinic, Rochester, Minnesota 55905, USA.
Arthritis and Rheumatism
|December 31, 1998
Summary
CD4+ CD28- T cells in rheumatoid arthritis (RA) patients are specialized killers lacking B cell help. These cytotoxic cells, expressing perforin, are found in RA synovial tissue and may drive severe disease complications.
Area of Science:
- Immunology
- Rheumatology
Background:
- Rheumatoid arthritis (RA) is characterized by immune cell accumulation and expansion.
- CD4+ CD28- T cells are a subset that expands clonally in RA patients.
Purpose of the Study:
- To elucidate the functional characteristics of CD4+ CD28- T cells in RA.
- To investigate the role of these cells in RA pathogenesis.
Main Methods:
- Gene expression analysis of T cell clones (CD4+ CD28- vs. CD4+ CD28+).
- Flow cytometry and immunohistochemistry to confirm gene expression.
- Functional assays assessing T cell cytotoxicity.
Main Results:
- CD4+ CD28- T cells transcribe perforin and exhibit cytotoxicity against target cells.
- These cells lack CD40 ligand (CD40L) expression, indicating impaired B cell help.
- Perforin-positive CD4+ T cells are present in RA synovial tissue, correlating with peripheral CD4+ CD28- expansion.
Conclusions:
- Clonally expanded CD4+ CD28- T cells are cytotoxic effectors, not helper cells, in RA.
- RA T cells can be functionally divided into perforin+ (cytotoxic) and CD40L+ (helper) subsets.
- T cell-mediated cytotoxicity by CD4+ CD28- cells may contribute to severe extra-articular RA manifestations.