Comparative Analysis of the Informative Value of Radioimmunoassay and Laser Correlation Spectroscopy in Myasthenia Gravis

The objective of this study was to compare informative value of traditional approach (anti-AChR antibody radioimmunoassay) and evaluation of metabolic shifts by laser correlation spectroscopy in myasthenia gravis. The method based on changes in spectral characteristics of laser radiation caused by scattering in a disperse system yields a histogram reflecting particle contribution into light scatter as a function of particle radius in nanometers. The spectrum of anti-AChR-positive serum is characterized by appreciably increased contribution of particles with a radius 4.6–6.2 nm. Binding of serum components with solubilized AChR confirms that this peak is determined by elevated concentration of antibodies to this receptor. The search for the relationship between the disease severity and the distribution pattern of subfraction serum components revealed three informative zones: 6–15, 27–67, and 127–223 nm. In patients without disturbances of vital functions, the contribution of the first zone particles into light scatter increases and that of the third zone particles decreases. Considerable differences attaining the level of statistical significance in zones 4–6 and 20 nm were revealed in the spectra of serum from patients with myasthenia gravis of the same severity with and without thymoma. This opens prospects for dynamic monitoring of the efficiency of therapy.