Comparison of cutaneous and circulating T-cell clones detected by polymerase chain reaction γ–denaturing gradient gel electrophoresis.

For each patient, PCR-γ–DGGE was performed by using DNA extracted from a cutaneous biopsy (CB) sample and a peripheral blood (PB) sample obtained on the same day. The 2 PCR products were analyzed on the same gel, thereby allowing precise comparison of the dominant clonal populations. Four of the 5 patterns are shown: presence of a dominant T-cell clone in the CB sample but not in PB (patient 1); simultaneous presence of a dominant T-cell clone in the CB sample and PB, with the 2 clones being different (patient 2); identical T-cell clones in the CB sample and PB (patients 3 and 4); and no dominant clone in either the CB sample or PB (patient 5). An example of a positive PB sample and a negative CB sample is not shown.