Prognostic Biomarkers of Sarcoidosis: A Comparative Study of Serum Chitotriosidase, ACE, Lysozyme, and KL-6.

PURPOSE: Sarcoidosis is a systemic granulomatous disease with unknown etiology. Many clinical presentations have been reported, and acute disease needs to be distinguished from subacute and chronic disease. The unpredictable clinical course of the disease prompted us to evaluate the clinical utility of biomarker serum detection in sarcoidosis follow-up. METHODS: Serum concentrations of chitotriosidase, ACE, KL-6, and lysozyme were analyzed by different methods in a population of 74 sarcoidosis patients (46 on steroid therapy at sampling) regularly monitored at Siena Sarcoidosis Regional Referral Centre and in a group of controls with the aim of comparing their contribution to clinical management of sarcoidosis patients. RESULTS: KL-6 concentrations were significantly elevated in sarcoidosis patients with lung fibrosis and were significantly correlated with DLco and CPI score, while chitotriosidase was significantly higher in patients with extrapulmonary localizations. With a cut-off value of 303.5 IU/ml, KL-6 showed the best sensitivity (78%), while chitotriosidase reported the best specificity (85%) among the biomarkers. CONCLUSIONS: KL-6 is a reliable biomarker of fibrotic lung involvement in sarcoidosis patients. Among biomarkers, KL-6 showed the best sensitivity and serum chitotriosidase the best specificity, even in patients on chronic steroid therapy, and seemed to correlate with extrapulmonary localizations.

Use of lysozyme as a standard for evaluating the effectiveness of a proteomics process.

Automated sequencing of unknowns in bottom-up proteomics makes the data produced susceptible to process control errors, which can be propagated into mistakes in analyte identification. Inclusion of an unintrusive internal standard, such as lysozyme, allows monitoring all phases of the proteomics process including sample preparation, enzymatic digestion, HPLC, mass spectrometry, and database searching. By using this internal standard, digestion issues including rearrangements, semi-tryptic fragments, and modifications were monitored. In addition, control of the HPLC process including column performance was achieved. The use of the lysozyme standard allowed easy optimization of mass spectral conditions including data dependent and collision induced dissociation settings. The use of this internal standard in a study of differential protein expression in rat serum samples is presented.

Determination of egg white lysozyme by on-line coupled capillary isotachophoresis with capillary zone electrophoresis.

An on-line coupled capillary isotachophoresis - capillary zone electrophoresis method for the determination of lysozyme in selected food products is described. The optimized electrolyte system consisted of 10 mM NH(4)OH + 20 mM acetic acid (leading electrolyte), 5 mM epsilon -aminocaproic acid +5 mM acetic acid (terminating electrolyte), and 20 mM epsilon -aminocaproic acid +5 mM acetic acid +0.1% m/v hydroxypropylmethylcellulose (background electrolyte). A clear separation of lysozyme from other components of acidic sample extract was achieved within 15 min. Method characteristics, i.e., linearity (0-50 micrograms/mL), accuracy (recovery 96+/-5%), intra-assay (3.8%), quantification limit (1 microgram/ml), and detection limit (0.25 microgram/mL) were determined. Low laboriousness, sufficient sensitivity and low running costs are important attributes of this method. The developed method is suitable for the quantification of the egg content in egg pasta.

[Lysozyme Reference Standard (Control 031) of National Institute of Health Sciences].

The "Lysozyme Reference Standard (Control 951031)" of the National Institute of Health Sciences was prepared. The lysozyme potency of the standard material was assayed against the Lysozyme Reference Standard (Control 951) by turbidimetric method two turbidimetric methods using the dried y-cells of Micrococcus luteus as a substrate. The potency of the standard material was in satisfactory agreement with that of Lysozyme Reference Standard (Control 951) and was defined as 1 mg [potency] per mg.

Macromolecular impurities and disorder in protein crystals.

The mechanisms by which macromolecular impurities degrade the diffraction properties of protein crystals have been investigated using X-ray topography, high-resolution diffraction line shape measurements, crystallographic data collection, chemical analysis, and two-photon excitation fluorescence microscopy. Hen egg-white lysozyme crystals grown from solutions containing a structurally unrelated protein (ovotransferrin) and a related protein (turkey egg-white lysozyme) can exhibit significantly broadened mosaicity due to formation of cracks and dislocations but have overall B factors and diffraction resolutions comparable to those of crystals grown from uncontaminated lysozyme. Direct fluorescence imaging of the three-dimensional impurity distribution shows that impurities incorporate with different densities in sectors formed by growth on different crystal faces, and that impurity densities in the crystal core and along boundaries between growth sectors can be much larger than in other parts of the crystal. These nonuniformities create stresses that drive formation of the defects responsible for the mosaic broadening. Our results provide a rationale for the use of seeding to obtain high-quality crystals from heavily contaminated solutions and have implications for the use of crystallization for protein purification. Proteins 1999;36:270-281.

[Lysozyme Reference Standard (Control 951) of the National Institute of Health Sciences].

The "Lysozyme Reference Standard (Control 951)" of the National Institute of Health Sciences was prepared. The lysozyme potency of the standard material was assayed against the Lysozyme Reference Standard (Control 915) by two turbidimetric methods using the drycells of Micrococcus luteus as the substrate. The potency of the standard material was in satisfactory agreement with that of Lysozyme Reference Standard (Control 915) and was defined as 1 mg [potency] per mg.

[Studies on the quality of enzyme preparations (XII)--lysozyme preparations].

This paper was described the results of the weight variation test and the assay for the potency of the commercially available lysozyme preparations (samples: 13 kinds of granules, in which 10 kinds are granules (folded)) collected for the legal sampling inspection in 1992. The potencies of 10 samples were found to be within the range of permissible content, when the all samples extracted with phosphate buffer were determined by the method described in Japanese Standards of Pharmaceutical Ingredients. However, the potencies of 3 samples were not more than 65% of the labeled potencies. These low potency samples showed the potencies of 98-106%, when 0.4M sodium chloride solution or 0.1N hydrochloric acid was used instead of phosphate buffer for enzyme extraction. The weight variation test showed all preparations to be within the permissible JP XII deviation range (10%) for "granules (folded)".

[On a minor component found in the lysozyme reference standard].

A minor component separated by HPLC from egg-white lysozyme was found to have a different substrate specificity from the main component, lysozyme. However, it did not show any difference in molecular weight and immuno-cross reactivity from lysozyme. There was no evidence based on our study that this minor component is an artificially-produced substance.

[Lysozyme Reference Standard (Control 871) of the National Institute of Hygienic Sciences].

A candidate for the Lysozyme Reference Standard (Control 871) of the National Institute of Hygienic Sciences was prepared. Purity of the standard material examined electrophoretically was more than 99.5%. Lysozyme potency of the standard material was assayed turbidimetrically using dry-cells of Micrococcus luteus as a substrate and compared with that of the Lysozyme Reference Standard (Control 865). Potency of the standard material was in satisfactory agreement with that of the standard and was defined as 1 mg [potency] per mg.

Improved turbidimetric assay for lysozyme in urine.

I describe an improved turbidimetric assay for lysozyme in urine. This method is simple, reproducible, linear over a 100-fold concentration range, sensitive to concentrations as low as 10 micrograms/L, and only commercially available products are required. Evaluation of urinary lysozyme concentration with this assay demonstrated a within-run and between-run CV of 9.9% and 4.8%, respectively, for normal urine, minimal chemical interference, and a mean analytical recovery of 104.8%. There were differences in the rate of clearing and in the linearity of the assay with use of three commercial preparations of Micrococcus lysodeikticus, and significant differences in results when different lysozyme standards were used. Reference values were established by use of data on 169 healthy subjects, ages six months to 61 years. Clinical efficacy of the assay was demonstrated in children with renal disorders, especially those associated with chronic renal failure or tubular dysfunction.