OBJECTIVETo 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.

METHODSIgH 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.

RESULTSThe 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.

CONCLUSIONSIn 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.