Reappraisal of relative frequency of monoclonal immunoglobulins.

Among 20,158 patients studied we detected 107 cases of primary and 84 cases of secondary plasma-cell dyscrasia (PCD). A strikingly high frequency of IgD myeloma was observed. The most common disease associated with the secondary cases was chronic hepatitis/liver cirrhosis. Monoclonal immunoglobulins have many special physicochemical properties which could easily escape detection or defy proper interpretation. It is speculated that the relative frequency of monoclonal immunoglobulins, both H chain class and L chain type, does not reflect the physiological serum level.