In non-malignant tissues, the polymerase chain reaction was used to study the frequency of bcl-2/IgH rearrangements in reactive lymphoid tissue obtained from American and Japanese patients to find out whether geographic variation in the incidence of follicular lymphoma was caused by differences in sporadic occurrence of the t(14;18).     ///    "Recently, bcl-2/IgH rearrangements have been detected in reactive lymphoid tissue obtained from European patients, indicating that such rearrangements occur at some low but measurable background rate. "