[PCR definition of B-cell clonality: which electrophoretic method is better]

To compare diagnostic efficacy of B-cell clonality determination in application of different electrophoretic methods.

B-cell clonality was determined with different techniques in 89 patients having B-cell lymphoma (n = 48), B-cell lymphoma in remission (n = 11), reactive processes (n = 24), lymphogranulomatosis and T-cell lymphoma (n = 6). Healthy donors served control. Clonality was defined by rearrangements of Ig heavy chain genes with usage of primers to FR2 region of Ig gene. Electrophoretic methods were the following: agarose electrophoresis and SSCP.

Clonality was detected in the presence of more than 5.9% clonal cells from total count of mononuclear cells or more than 20% of clonal cells from total number of B-lymphocytes in the sample. We achieved detectability of B-clonality in B-cell tumors 87.5% (42 of 48 cases). False negative tests were also investigated with kits of primers to FR1 and FR3 regions, but clonality was not determined. Among reactive processes, non-B-cell tumors and healthy donors clonality was found in 1 of 41 cases. This patient had acute respiratory viral infection. Agarose electrophoresis and SSCP test results coincided.

Determination of B-cell clonality with agarose electrophoresis proved to be a simple, reliable, cost-effective and reproducible method of differential diagnosis of tumor and reactive lymphoproliferation. This method is not suitable for verification of tumor remission or assessment of minimal residual disease because of its low sensitivity.