Effects of ciclosporin A, tacrolimus and sirolimus on cytokine production in neonatal immune cells.
BACKGROUND
It was the aim of this study to evaluate the effects of the well-known immunosuppressive drugs ciclosporin A (CsA), tacrolimus and sirolimus on the intracytoplasmic cytokine expression of neonatal immune cells.


METHODS
Immunosuppressive drugs were added to whole blood cultures of neonatal cord blood samples (n = 17) and peripheral blood samples of adults (n = 17) in vitro prior to stimulation of lymphocytes with phorbol 12-myristate 13-acetate (PMA)/ionomycin or monocytes.


RESULTS
Upon exposure to ciclosporin A (500 ng/mL) or tacrolimus (25 ng/mL) the number of cytokine expressing T cells was almost completely blocked in neonatal T cells while sirolimus (10 ng/mL) only inhibited intracytoplasmatic tumour necrosis factor alpha (TNF-alpha) expression (mean% positive cells; 4.0 +/- 2.1% vs. 1.09 +/- 0.6%, p = 0.003), but mildly stimulated the intracellular expression of interleukin (IL)-2 (24.4 +/- 6.5% vs. 28.1 +/- 7.1%, p = 0.041). In cord blood lymphocytes, the inhibitory effect of ciclosporin A and tacrolimus was dose-dependent (e.g. IL-2: control, 12.3 +/- 5.33%, ciclosporin A 5 ng/mL, 10.1 +/- 5.5%; 50 ng/mL, 7.1 +/- 4.7%; 500 ng/mL, 1.2 +/- 0.3%; tacrolimus 0.25 ng/mL, 9.3 +/- 4.9%; 2.5 ng/mL, 6.1 +/- 3.3%; 25 ng/mL, 1.0 +/- 0.6%), while the function of adult lymphocytes was only impaired at high doses of both compounds. In contrast, the number of cytokine expressing monocytes was not influenced by ciclosporin A and tacrolimus except for a minor decrease of TNF-alpha producing neonatal monocytes after addition of tacrolimus (17.9% vs. 13.9%, p = 0.031). Interestingly, sirolimus was shown to inhibit intracellular IL-6 production in adults (63.1 +/- 12.7% vs. 52.0 +/- 16.0%, p = 0.005), but in neonatal monocytes intracellular IL-6 expression was stimulated (53.5 +/- 22.0% vs. 64.7 +/- 19.1%, p = 0.041).


CONCLUSIONS
The potent dose-dependent inhibitory effect of ciclosporin A and tacrolimus in cord blood lymphocytes provides the basis for further studies on functional immaturity of the neonatal immune system and for future strategies to optimize umbilical cord blood transplantion. Sirolimus was demonstrated to have a distinct effect on neonatal immune cells as shown by increased expression of IL-2 in lymphocytes and IL-6 in monocytes, while only lymphocytic TNF-alpha expression was inhibited.
Puzik
Alexander
A
Department of Pediatrics, University of Lübeck Medical School, Ratzeburger Allee 160, 23538 Lübeck, Germany.
Schultz
Christian
C
Iblher
Peter
P
Müller-Steinhardt
Michael
M
Härtel
Christoph
C
D016572:Cyclosporine / Q000494:pharmacology*; D016207:Cytokines / Q000096:biosynthesis / Q000187:drug effects*; D005260:Female; D005858:Germany; D006801:Humans; D007107:Immune System / Q000166:cytology / Q000187:drug effects*; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D066298:In Vitro Techniques; D007223:Infant; D007231:Infant, Newborn; D008214:Lymphocytes / Q000187:drug effects; D008297:Male; D009000:Monocytes / Q000187:drug effects; D010865:Pilot Projects; D020123:Sirolimus / Q000494:pharmacology*; D016559:Tacrolimus / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000187:drug effects; D014470:Umbilical Cord / Q000187:drug effects
D016207:Cytokines; D007166:Immunosuppressive Agents; D014409:Tumor Necrosis Factor-alpha; D016572:Cyclosporine; D020123:Sirolimus; D016559:Tacrolimus