[Detection of IgH gene rearrangement in B-cell non-Hodgkin's lymphoma and application of gel-scan method].

OBJECTIVE: To develop a protocol for gene rearrangement study in non-Hodgkin's lymphoma (NHL) by PCR-directed gel-scan method and to set up quantitative criteria for IgH gene rearrangement which can be applied in the follow up of lymphoma patients.

METHODS: IgH gene rearrangement studies were carried out in 96 cases of B-cell NHL. The detection rate of clonality was evaluated. Sixty-five cases of IgH gene rearranged cases proven by FR3A-directed PCR and PAGE and 8 cases of benign lymphoid tissues (5 cases of reactive lymphoid hyperplasia, 3 cases of chronic tonsillitis), 5 cases of normal peripheral blood mononuclear cells were analyzed by gel-scan method and the proportion of h1/h2 (heights of peak1 and peak2 of gel-scan) was calculated.

RESULTS: The detection rate of IgH gene clonality was up to 68% using primer FR3A in the 96 B-cell NHL cases. The detection rate was up to 61% using primer FR2A. With a combination of primers FR3A and FR2A, the detection rate increased to 83%. Gel-scan curve showed that the value of h1/h2 was greater than 3 in all the 65 cases with IgH gene rearranged. In the 8 benign lymphoid tissue cases showed h1/h2 < 1.5, 5 cases with normal peripheral blood mononuclear cells showed a bell-shaped curve.

CONCLUSIONS: In the gel-scan curve of gene rearrangement studies in non-Hodgkin's lymphoma samples, the value of h1/h2 greater than 3 represents a true clonal proliferation. The peaks with relative heights less than 1.5 may not be significant and likely represent polyclonal cell population. A value between 1.5 and 3 however requires clinical follow-up. The success rate of rearrangement studies in B-cell NHL can be increased by using a combination of primers FR3A and FR2A.