Immunochemical study in two cases of alpha chain disease

Area of Science:

• Immunology
• Protein chemistry

Background:

• Alpha-chain deposition disease (alpha-CD) is a rare disorder characterized by the deposition of immunoglobulin alpha-chains.
• Understanding the immunochemical characteristics and diagnostic markers of alpha-CD is crucial for patient management.

Observation:

• The study details the first two recognized cases of alpha-CD in the USSR.
• Immunochemical analysis revealed typical patterns consistent with alpha-CD.
• Alpha-chain proteins were detected in patient sera using specific antisera against IgA and its components.

Findings:

• Both immunoelectrophoresis (IEP) and single radial immunodiffusion (SRID) proved effective for alpha-CD detection, with SRID showing distinct double rings.
• Alpha-chain proteins were present in various secretions, including coprofiltrates, saliva, and urine.
• In coprofiltrates, alpha-chain proteins were bound to the secretory component (SC), while in urine and saliva, free alpha-chain proteins were observed.
• Polymeric (dimeric) forms of alpha-chain proteins were confirmed only in coprofiltrates, not in urine or saliva.
• One patient exhibited a significant shift in the kappa/lambda ratio towards kappa chains in serum and IgG fractions.

Implications:

• The findings highlight the utility of specific immunochemical techniques for diagnosing alpha-CD.
• The differential binding of secretory component in various secretions provides insights into the disease's pathophysiology.
• The observed kappa/lambda ratio shift may indicate an altered immune response or an early stage of monoclonal gammopathy.