Transient Bcl-2 gene down-expression in circulating mononuclear cells of severe sepsis patients who died despite appropriate intensive care.
OBJECTIVE
To assess the levels of expression of the antiapoptotic gene Bcl-2 and the proapoptotic gene Bax in circulating mononuclear cells (CMNC) harvested during the course of severe sepsis (SS) in formerly non-immunocompromised patients undergoing hospital-acquired infection, in parallel to cytokine levels.


METHODS
Prospective study.


METHODS
Intensive care unit.


METHODS
A total of 24 patients without immunodeficiency undergoing standard goal-directed therapy for nosocomial SS, 10 critically ill patients without sepsis, and 10 healthy controls.


METHODS
Blood was collected before infection and within 12 h, 1, 3 and 7 days after fever onset, to determine plasma concentrations of IL-6, IL-10, TNF-alpha, C-reactive protein, whole blood cell counts, lymphocyte subsets, annexin V labelling for apoptosis, and Bax and Bcl-2 relative RNA expression by real-time polymerase chain reaction.


RESULTS
SS patients displayed increased cytokine concentrations, TNF-alpha being significantly increased at full-blown sepsis. Within 12 h after onset of infection, lymphocyte counts were lower in SS patients than in critically ill controls ( p=0.001), and this phenomenon was marked in CD4+ and CD8+ subsets ( p<0.001). This was associated with enhanced apoptosis in CMNC (15.7+/-8.7% vs 3.4+/-2.1%, p<0.001) and a significant down-expression of the Bcl-2 gene throughout the study ( p<0.05). In contrast, the expression of Bax did not change significantly. Within 12 h of fever onset, non-survivors expressed a 10-fold down-expression of Bcl-2 when compared to survivors ( p<0.001).


CONCLUSIONS
An early transient down-expression of the gene Bcl-2 occurred in CMNC harvested from SS patients who died despite intensive care. In contrast, the expression of the gene Bax did not change significantly.
Bilbault
Pascal
P
Services de Réanimation Médicale, Hôpital de Hautepierre, Avenue Molière, 67098 Strasbourg, France.
Lavaux
Thomas
T
Lahlou
Abdeslam
A
Uring-Lambert
Béatrice
B
Gaub
Marie-Pierre
MP
Ratomponirina
Charline
C
Meyer
Nicolas
N
Oudet
Pierre
P
Schneider
Francis
F
D000704:Analysis of Variance; D017209:Apoptosis / Q000235:genetics; D016022:Case-Control Studies; D016207:Cytokines / Q000097:blood; D015536:Down-Regulation; D005260:Female; D015870:Gene Expression; D019254:Genes, bcl-2; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D016131:Lymphocyte Subsets / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011518:Proto-Oncogene Proteins / Q000235:genetics; D019253:Proto-Oncogene Proteins c-bcl-2; D018709:Statistics, Nonparametric; D018746:Systemic Inflammatory Response Syndrome / Q000235:genetics*; D051028:bcl-2-Associated X Protein
C494826:BAX protein, human; D016207:Cytokines; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein