Impaired nonrestricted cytolytic activity in systemic lupus erythematosus: involvement of a pathway independent of Fas, tumor necrosis factor, and extracellular ATP that is associated with little detectable perforin.
OBJECTIVE
To determine the cytolytic effector pathway involved in impaired generation of nonrestricted cytolytic activity in systemic lupus erythematosus (SLE).


METHODS
Peripheral blood mononuclear cells (PBMC) from normal subjects and SLE patients were stimulated in vitro with anti-CD3 monoclonal antibody (MAb) and interleukin-2 to promote the generation of nonrestricted cytolytic activity. On day 13 of culture, the PBMC were assayed for cytolytic activity against Fas-Daudi cells and Fas+ Jurkat cells. The effects on cytotoxicity of calcium chelation, antagonist anti-Fas MAb, tumor necrosis factor (TNF) alpha and beta, and ATP were measured. Intracellular perforin expression was determined by intracellular staining, and perforin messenger RNA levels were determined by quantitative competitive reverse transcription-polymerase chain reaction.


RESULTS
We demonstrated the existence of a cytolytic pathway that is independent of Fas, TNF alpha, TNF beta, and ATP, but is dependent upon extracellular calcium. Despite its calcium dependence, this pathway is associated with low-to-undetectable levels of perforin.


CONCLUSIONS
Impaired generation of nonrestricted cytolytic activity in SLE is likely due to decreased activity of this Fas-, TNF alpha-, TNF beta-, ATP-independent pathway associated with very low levels of perforin.
Stohl
W
W
Los Angeles County + University of Southern California Medical Center and University of Southern California School of Medicine, USA.
Elliott
J E
JE
Li
L
L
Podack
E R
ER
Lynch
D H
DH
Jacob
C O
CO
D000255:Adenosine Triphosphate / Q000502:physiology; D002051:Burkitt Lymphoma / Q000473:pathology; D002118:Calcium / Q000494:pharmacology; D003602:Cytotoxicity, Immunologic / Q000276:immunology; D005110:Extracellular Space / Q000737:chemistry; D006801:Humans; D019169:Jurkat Cells / Q000276:immunology / Q000378:metabolism; D008180:Lupus Erythematosus, Systemic / Q000276:immunology* / Q000378:metabolism; D008233:Lymphotoxin-alpha / Q000502:physiology; D008562:Membrane Glycoproteins / Q000096:biosynthesis; D054353:Perforin; D052899:Pore Forming Cytotoxic Proteins; D013602:T-Lymphocytes, Cytotoxic / Q000737:chemistry; D014407:Tumor Cells, Cultured / Q000276:immunology / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology / Q000502:physiology; D019014:fas Receptor / Q000502:physiology*
D008233:Lymphotoxin-alpha; D008562:Membrane Glycoproteins; D052899:Pore Forming Cytotoxic Proteins; D014409:Tumor Necrosis Factor-alpha; D019014:fas Receptor; D054353:Perforin; D000255:Adenosine Triphosphate; D002118:Calcium