POLYMERASE-CHAIN-REACTION SINGLE-STRAND CONFORMATIONAL POLYMORPHISM ANALYSIS OF ANTIGEN RECEPTOR REARRANGEMENTS IN MONITORING THERAPEUTIC EFFECT IN CHILDHOOD ALL

The rearrangement of the immunoglobulin heavy chain (IgH) genes can be used as a marker of cell lineage and clonality. The polymerase chain reaction (PCR) technique using consensus primers for the IgH gene was used for remission and minimal residual disease (MRD) analysis in the follow-up of childhood acute lymphoblastic leukemia (ALL) of B-cell li neage. Single-strand conformational polymorphism (SSCP) was used to di stinguish the specific clonal amplicons from the background. The Autho rs found that, in a series of 22 patients followed-up for 5.3 to 11.1 years, the PCR-SSCP technique could detect at least one rearrangement at initial diagnosis in 21 (95%). All patients who remained in continu ous complete remission were PCR-SSCP negative at remission controls. T en of the 22 patients had one or more bone marrow relapses. The PCR-SS CP method demonstrated MRD in three of them. In 6 of the 7 (86%) of pa tients with disease recurrence from whom samples were taken within 6 m onths before a clinically overt relapse, PCR-SSCP became positive. The Authors conclude that PCR-SSCP of a rearrangement marker might have a role as a convenient technique for monitoring emerging relapse. It ma y also detect unrelated clones or ongoing secondary recombination even ts during progression. However, PCR-SSCP is not sensitive enough to de tect MRD in all patients in whom disease will later recur.