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Bcl-2 expression by CD4 T lymphocytes in Vogt-Koyanagi-Harada disease
Kouichi Ohta1, Nagahisa Yoshimura
1Department of Ophthalmology, Shinshu University School of Medicine, Matsumoto, Japan. kohta@hsp.md.shinshu-u.ac.jp
Insights
In Vogt-Koyanagi-Harada (VKH) disease, CD4(+) lymphocytes in aqueous humor and cerebrospinal fluid express Bcl-2. Despite Fas expression and soluble Fas ligand presence, apoptosis was not induced, suggesting Bcl-2 regulates inflammatory cell apoptosis in VKH patients.
Area of Science:
- Immunology
- Ophthalmology
- Neurology
Background:
- Vogt-Koyanagi-Harada (VKH) disease is a systemic autoimmune disorder affecting ocular and neurological tissues.
- Immune cell infiltration, particularly T lymphocytes, plays a crucial role in the pathogenesis of VKH disease.
- Understanding the mechanisms regulating lymphocyte survival and apoptosis is vital for managing VKH disease.
Purpose of the Study:
- To investigate the expression of Bcl-2 on CD4(+) lymphocytes in the aqueous humor (AH) and cerebrospinal fluid (CSF) of VKH patients.
- To determine if Fas signaling induces apoptosis in lymphocytes within the CSF of VKH patients.
- To explore the role of Bcl-2 in regulating apoptosis of inflammatory cells in the context of VKH disease.
Main Methods:
- Flow cytometry was used to quantify CD4, CD8, CD45RO, Fas, and Bcl-2 positive T lymphocytes in AH and CSF from VKH patients and healthy controls.
- Enzyme-linked immunosorbent assay (ELISA) measured soluble Fas ligand (sFasL) levels in the CSF.
- The TUNEL method assessed apoptosis in cultured CSF cells treated with anti-Fas antibody (Ab).
Main Results:
- CD4(+) lymphocytes expressing Fas and Bcl-2 were predominant in the AH and CSF of VKH patients.
- Soluble Fas ligand (sFasL) was detected in the CSF of VKH patients.
- Treatment with anti-Fas antibody did not significantly increase the number of apoptotic cells in the CSF.
Conclusions:
- High expression of Fas and the presence of sFasL in the CSF did not lead to significant apoptosis of lymphocytes in VKH patients.
- Bcl-2 expression on CD4(+) lymphocytes may play a regulatory role in preventing apoptosis of inflammatory cells within the CSF during VKH disease.
Purpose:
To determine whether Bcl-2 is expressed on CD4(+ ) lymphocytes in the aqueous humor (AH) and cerebrospinal fluid (CSF) of patients with Vogt-Koyanagi-Harada (VKH) disease, and to determine whether Fas will induce apoptosis of lymphocytes in the CSF.
Methods:
The percentages of CD4, CD8, CD45RO, Fas, and Bcl-2 positive T lymphocytes in the AH and CSF of eight patients with active VKH and five healthy controls were determined by flow cytometry. Soluble Fas ligand (sFasL) in the CSF was measured by ELISA. Freshly isolated cells from the CSF were cultured with anti-Fas antibody (Ab) and apoptosis was assessed by the TUNEL method.
Results:
Fas(+) CD4(+) lymphocytes were the predominant lymphocytes in the AH and CSF of VKH patients. Bcl-2 was strongly expressed in these cells. Soluble FasL was also detected in the CSF. The number of apoptotic cells detected by anti-Fas Ab was not significantly increased in the CSF of VKH patients.
Conclusions:
In spite of the high expression of Fas antigen on CD4(+) cells and the presence of sFasL in the CSF, apoptosis was not observed. Bcl-2 expression may contribute to the regulation of apoptosis of inflammatory cells in the CSF of VKH patients.