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Decreased T cell reactivity to trypsinized group A, type M22 streptococci in psoriasis
B S Baker1, S Bokth, J J Garioch
1Department of Dermatology, St Mary's Hospital, London, UK.
Abstract:
The proliferative responses of peripheral blood mononuclear cells from patients with guttate and chronic plaque psoriasis to streptococcal M protein were investigated using whole and trypsinized group A M22-positive streptococci. Peripheral blood mononuclear cell responses to whole type M22 group A streptococci were significantly increased in guttate, but not chronic plaque, psoriasis patients compared to 17 non-psoriatic controls (p < 0.05; n = 17). A significant reduction of this response was observed in both guttate (p < 0.001; n = 17) and chronic plaque (p < 0.01; n = 27) psoriatic patients, but not in the control group, after repeated trypsinization to remove M protein from the streptococci. Furthermore, the difference between the peripheral blood mononuclear cell response to untrypsinized and trypsinized streptococci was significantly greater in the guttate patients than in the controls (p < 0.02). This preliminary study has shown an increased reactivity of T lymphocytes with specificity for trypsin-sensitive protein expressed by type M22 streptococci in the peripheral blood of patients with psoriasis.
Insights
Psoriasis patients show increased T lymphocyte reactivity to streptococcal M protein. This suggests a potential link between streptococcal infections and psoriasis development, particularly in guttate psoriasis.
Area of Science:
- Immunology
- Dermatology
- Microbiology
Background:
- Psoriasis is a chronic inflammatory skin condition.
- The role of streptococcal infections in psoriasis pathogenesis is under investigation.
- Group A streptococci, particularly M protein, are implicated in triggering immune responses.
Purpose of the Study:
- To investigate the proliferative responses of peripheral blood mononuclear cells (PBMCs) to streptococcal M protein in patients with guttate and chronic plaque psoriasis.
- To determine if M protein removal affects PBMC reactivity in psoriasis patients.
- To explore the potential role of T lymphocytes specific to streptococcal M protein in psoriasis.
Main Methods:
- Studied PBMCs from guttate psoriasis, chronic plaque psoriasis patients, and healthy controls.
- Used whole and trypsinized (M protein-removed) group A M22-positive streptococci.
- Assessed PBMC proliferative responses via cell culture and stimulation assays.
- Statistical analysis (p-values, n-counts) was used to compare responses between groups.
Main Results:
- PBMCs from guttate psoriasis patients showed significantly increased responses to whole streptococci compared to controls.
- Chronic plaque psoriasis patients did not show a significant increase with whole streptococci.
- Trypsinization significantly reduced PBMC responses in both guttate and chronic plaque psoriasis patients, but not controls.
- The difference in response to untrypsinized versus trypsinized streptococci was greater in guttate psoriasis patients.
Conclusions:
- Patients with psoriasis, especially guttate psoriasis, exhibit heightened T lymphocyte reactivity to trypsin-sensitive proteins of type M22 streptococci.
- This suggests a specific immune response targeting streptococcal M protein may contribute to psoriasis development.
- Further research is warranted to elucidate the precise mechanisms linking streptococcal M protein to psoriasis pathogenesis.