Final answer:
In a malignant pleural effusion, proteins such as monoclonal proteins (M proteins) characteristic of multiple myeloma may be present, leading to elevated serum protein levels and distinct electrophoresis patterns.
Step-by-step explanation:
In a malignant pleural effusion, the protein content will be altered from the norm due to the presence of cancer cells in the pleural fluid. One way to analyze these protein changes is through Immunoelectrophoresis (IEP), which is particularly useful in the diagnosis of multiple myeloma, a type of cancer where antibody-secreting cells are affected. In multiple myeloma, patients produce abnormal antibodies known as monoclonal proteins (M proteins).
IEP reveals that patients with multiple myeloma typically present with elevated serum protein levels that exhibit a distinct band in the gamma globulin region of a protein electrophoresis gel. Furthermore, the densitometer scan will show a sharp spike indicative of the M protein, in contrast to the normal broad smear. The M protein will also cause distinctly skewed arcs in immunofixation tests.
This is evident in electrophoresis patterns where the abnormal spike in the gamma-globulin region is clearly seen compared to normal sera. These diagnostic features of multiple myeloma could hypothetically also be seen in the protein profile of a malignant pleural effusion if the cancer had similar characteristics to multiple myeloma or if the patient had both conditions concurrently.