New capacities of the diagnosis and monitoring of the course of AL-amyloidosis

Aim: to define the clinical value of various concentrations of immunoglobulin light chains (ILCs) in patients with AL amyloidosis.
Subjects and methods. The content of free ILCs was studied by a nephelometric technique after their fixation in the blood of 31 patients with AL amyloidosis; monoclonal gammapathy was associated with the hyperproduction of monoclonal ILCs of λ- and κ-type in 14 and 17 patients, respectively. The obtained value was compared with the data of physical examination and laboratory and instrumental studies indicating lesions to target organs and with the course of the disease.
Results. In patients with the good course of AL amyloidosis, the average level of free ILCs was 1.8 (range 0.77-3) times greater than the normal values (the range of ILCs of λ and k-type was 20.24 to 67.4 and 20.14 to 81.38 mg/l, respectively); in those with the poor course, the excess of ILCs was 5.8 (range 3.7-13) times higher than the normal values (the range of ILCs of λ and κ-type was 54.32 to 286.7 and 117.06 to 2606.0 mg/l, respectively). The optimal range of diagnostic sensitivity (75%) and specificity (75%) in the estimation of prognosis was determined at the ILC levels that were three times greater (64.5 mg/l for κ-ILCs and 80 mg/l for λ-ILCs). Among the patients with a blood free ILC level of m 3 times more than the normal values, the good and poor courses of AL amyloidosis were noted in 13 and 4 cases, respectively.
Conclusion. The determination of serum ILC concentration by the Freelite method may be used to diagnose AL amyloidosis and to specify the presence of appropriate organ dysfunction; this study over time makes it possible to monitor the course of the disease and to estimate its response to therapy.

amyloidosis, immunoglobulin light chains, nephritic syndrome, serum amyloid precursor protein, tissue amyloid precursor protein