Serum protein pattern in sarcoidosis analysed by a proteomics approach.
BACKGROUND
An altered protein expression in bronchoalveolar lavage fluid (BALF) of sarcoidosis patients has previously been reported. As this disease is systemic, involving not only the lungs, a change in the serum components is also to be expected. In the present study we therefore analysed the total serum protein profile of the patients earlier reported, with active sarcoidosis.


METHODS
We used a proteomics approach to assess overall changes in the protein content of serum in patients with acute sarcoidosis (n = 6) compared to healthy controls (n = 4).


RESULTS
Our results show a significantly higher number of protein-spots in serum of the patients compared to the healthy individuals in the pH range 4.5-6.7 (median 886 vs. 742, p < 0.05). The total protein concentrations of the patients' sera were also significantly higher compared to the controls (median 62 vs. 56 mg/mL, p < 0.05). Measurement of the optical densities of the protein-spots from two-dimensional electrophoresis gels, covering pH interval 4.5-6.7, showed varying levels of expression of 22 different serum proteins in the patients compared to the controls. These proteins are involved in immune responses and some are known markers of inflammation. We found three proteins, which were changed concomitantly in the BALF as described in a previous report, and sera of the same patients.


CONCLUSIONS
Our results are of importance in order to identify biochemical markers in blood of sarcoidosis patients. Ideally, a combination of markers in BALF and serum may turn out to be disease specific.
Sabounchi-Schütt
Fariba
F
Karolinska Institutet, Department of Medicine, Lung Research Laboratory, L4:01, Karolinska Hospital, SE-171 76 Stockholm, Sweden. Fariba.Sabounchi@amersham.com
Mikko
Mikael
M
Eklund
Anders
A
Grunewald
Johan
J
AStröm
Jonas
J
D000328:Adult; D001798:Blood Proteins / Q000032:analysis*; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D016022:Case-Control Studies; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D040901:Proteomics; D012507:Sarcoidosis / Q000503:physiopathology*
D001798:Blood Proteins