TNF alpha mRNA and protein in cardiac transplant biopsies: comparison with serum TNF alpha levels.
OBJECTIVE
To examine the role of TNF alpha (TNF alpha) in cardiac transplant rejection by simultaneous analysis of protein expression and its messenger RNA within serum and grafted tissue.


METHODS
54 endomyocardial biopsy specimens were taken from 19 patients at various times after transplantation. TNF alpha messenger RNA was localised using a digoxygenin labelled complementary DNA probe. An anti-TNF alpha antibody was used to immunohistochemically label the protein product. Serum TNF alpha levels at the time of biopsy were analysed using a specific enzyme-linked immunosorbent assay.


RESULTS
TNF alpha mRNA was present in 22/34 endomyocardial biopsies. Eight also contained TNF alpha protein. None had protein alone. Expression did not relate to the grade of rejection in the present or subsequent biopsies. Serum TNF alpha was undetectable (assay sensitivity 30-330 pg/ml) for the majority of specimens. In the nine cases with elevated serum levels, eight samples were from cases within the first 30 days post transplant (r = -0.379; P < 0.05).


CONCLUSIONS
Neither tissue TNF alpha mRNA, tissue protein, nor serum TNF alpha relate to the grade of rejection. Furthermore, TNF alpha expression within endomyocardial biopsies is not reflected in the serum. These findings argue against the use of serum analysis as an indicator of cytokine profiles within cardiac tissue allografts. The demonstration of a trend in the early expression of TNF alpha after transplantation suggests that its release may not be specific to the process of rejection.
Azzawi
M
M
Immunology Research Group, Manchester University, UK.
Grant
S D
SD
Hasleton
P S
PS
Yonan
N
N
Campbell
C S
CS
Deiraniya
A K
AK
Rahman
A
A
Hutchinson
I V
IV
D000328:Adult; D005260:Female; D006084:Graft Rejection / Q000503:physiopathology*; D016027:Heart Transplantation; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000737:chemistry*; D012313:RNA / Q000032:analysis; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis* / Q000235:genetics
D014409:Tumor Necrosis Factor-alpha; D012313:RNA