Comparative proteomic analysis of serum from patients with systemic sclerosis and sclerodermatous GVHD. Evidence of defective function of factor H.
BACKGROUND
Systemic sclerosis (SSc) is an autoimmune disease characterized by immunological and vascular abnormalities. Until now, the cause of SSc remains unclear. Sclerodermatous graft-versus-host disease (ScGVHD) is one of the most severe complications following bone marrow transplantation (BMT) for haematological disorders. Since the first cases, the similarity of ScGVHD to SSc has been reported. However, both diseases could have different etiopathogeneses. The objective of this study was to identify new serum biomarkers involved in SSc and ScGVHD.


METHODS
Serum was obtained from patients with SSc and ScGVHD, patients without ScGVHD who received BMT for haematological disorders and healthy controls. Bi-dimensional electrophoresis (2D) was carried out to generate maps of serum proteins from patients and controls. The 2D maps underwent image analysis and differently expressed proteins were identified. Immuno-blot analysis and ELISA assay were used to validate the proteomic data. Hemolytic assay with sheep erythrocytes was performed to evaluate the capacity of Factor H (FH) to control complement activation on the cellular surface. FH binding to endothelial cells (ECs) was also analysed in order to assess possible dysfunctions of this protein.


RESULTS
Fourteen differentially expressed proteins were identified. We detected pneumococcal antibody cross-reacting with double stranded DNA in serum of all bone marrow transplanted patients with ScGVHD. We documented higher levels of FH in serum of SSc and ScGVHD patients compared healthy controls and increased sheep erythrocytes lysis after incubation with serum of diffuse SSc patients. In addition, we observed that FH binding to ECs was reduced when we used serum from these patients.


CONCLUSIONS
The comparative proteomic analysis of serum from SSc and ScGVHD patients highlighted proteins involved in either promoting or maintaining an inflammatory state. We also found a defective function of Factor H, possibly associated with ECs damage.
Scambi
Cinzia
C
Section of Rheumatology, Department of Clinical and Experimental Medicine, University of Verona, Verona, Italy. cinzia.scambi@univr.it
La Verde
Valentina
V
De Franceschi
Lucia
L
Barausse
Giovanni
G
Poli
Fabio
F
Benedetti
Fabio
F
Sorio
Marco
M
Deriu
Francesca
F
Roncada
Paola
P
Bortolami
Oscar
O
Turrini
Francesco
F
Caramaschi
Paola
P
Stranieri
Chiara
C
Bambara
Lisa M
LM
Biasi
Domenico
D
D000328:Adult; D000368:Aged; D000906:Antibodies / Q000276:immunology; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D017242:Complement Factor H / Q000378:metabolism*; D005260:Female; D020869:Gene Expression Profiling; D006086:Graft vs Host Disease / Q000097:blood*; D006801:Humans; D007249:Inflammation / Q000097:blood; D008297:Male; D008875:Middle Aged; D040901:Proteomics / Q000379:methods*; D045743:Scleroderma, Diffuse / Q000097:blood*; D045745:Scleroderma, Limited / Q000097:blood*; D013296:Streptococcus pneumoniae / Q000276:immunology
D000906:Antibodies; D015415:Biomarkers; D017242:Complement Factor H