Which laboratory finding supports the diagnosis of autoimmune disorders based on serum protein electrophoresis?

In the context of diagnosing autoimmune disorders, the presence of a band at the β-γ junction on serum protein electrophoresis is significant. This finding typically suggests an increase in immunoglobulin production associated with autoimmune activity. In autoimmune disorders such as systemic lupus erythematosus or rheumatoid arthritis, there is often an elevation of immunoglobulins (IgG, IgA, or IgM) due to the immune system's inappropriate response. The band at the β-γ junction indicates a spike or increase in immunoglobulins, which is a hallmark of these conditions.

This finding helps differentiate autoimmune disorders from other types of conditions, as it reflects the underlying inflammatory process and immune dysregulation that characterizes such disorders. In contrast, options like a single band at the γ globulin region may suggest a monoclonal gammopathy rather than an autoimmune process, while a high level of albumin would typically indicate a normal response rather than an autoimmune condition. The presence of a broad peak in the α globulin region might suggest inflammation but is not as specific or indicative of autoimmune disorders as a band at the β-γ junction.