Tyrosine phosphorylation in psoriatic T cells is modulated by drugs that induce or improve psoriasis.
BACKGROUND
The induction of protein tyrosine kinases (PTKs) is known to be a key element in the activation of lymphocytes.


OBJECTIVE
Because immunologic mechanisms are important in the pathogenesis of psoriasis, we examined the time course of tyrosine-phosphorylated proteins (p-tyr) as a marker for cellular PTK activity in phytohemagglutinin (PHA)-stimulated T cells of psoriatic patients and healthy controls.


RESULTS
PHA-stimulated T cells from both groups expressed peaks of p-tyr after 15 min and 4 h. In T cells from psoriatics, the 15-min peak was smaller but the 4-hour peak reached an enormous maximum, which was 270% higher than the basic p-tyr value. PHA-stimulated T cells were additionally treated with psoriasis-provoking drugs (lithium, chloroquine, propranolol and ethanol) and the two immunosuppressive drugs cyclosporin A and FK 506. Lithium and propranolol were able to increase the p-tyr level after 15 min in PHA-stimulated T cells from psoriatics in contrast to controls. Chloroquine and ethanol did not have a significant effect on T cells of both groups. CsA markedly diminished the phosphorylation of intracellular tyrosines in T cells of psoriatics and controls, whereas FK 506 diminished the p-tyr level in controls only slightly.


CONCLUSIONS
We have characterized important differences in p-tyr phosphorylation activities of psoriatic T cells compared to controls. This could be a hint to explain the known abnormalities of psoriatic T cells.
Ockenfels
H M
HM
Department of Dermatology, University of Essen, Germany.
Nussbaum
G
G
Schultewolter
T
T
Mertins
K
K
Wagner
S N
SN
Goos
M
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D002478:Cells, Cultured; D002738:Chloroquine / Q000494:pharmacology; D016572:Cyclosporine / Q000494:pharmacology; D000431:Ethanol / Q000494:pharmacology; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000494:pharmacology; D007509:Irritants / Q000494:pharmacology; D008094:Lithium / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000187:drug effects; D008297:Male; D008875:Middle Aged; D010766:Phosphorylation; D010835:Phytohemagglutinins / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011565:Psoriasis / Q000276:immunology / Q000378:metabolism* / Q000503:physiopathology; D013601:T-Lymphocytes / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism*; D016559:Tacrolimus / Q000494:pharmacology; D013997:Time Factors; D014443:Tyrosine / Q000187:drug effects / Q000378:metabolism*
D007166:Immunosuppressive Agents; D007509:Irritants; D010835:Phytohemagglutinins; D000431:Ethanol; D014443:Tyrosine; D016572:Cyclosporine; D002738:Chloroquine; D008094:Lithium; D011433:Propranolol; D011505:Protein-Tyrosine Kinases; D016559:Tacrolimus