ANGIOIMMUNOBLASTIC LYMPHADENOPATHY WITH DYSPROTEINEMIA AND DERMAL T-CELL LYMPHOMA

Background. T-cell receptor (TCR)-gamma gene rearrangements provide a specific clonal marker for T-cell malignancies of both the alpha beta and gamma delta varieties. A polymerase chain reaction (PCR)-based method was used in this study for investigation of clonal TCR-gamma gene rearrangements in a patient with a classical presentation of angioimmunoblastic lymphadenopathy with dysproteinemia (AILD) that subsequently progressed into an indolent form of dermal T-cell lymphoma. Methods. TCR gene rearrangements in patients with cutaneous T-cell lymphoma (CTCL) were examined using conventional Southern blot analysis and a newly developed PCR-based technique for clonal TCR gene rearrangements. The oligoprimers amplified rearranged V gamma and J gamma segments (including the N region) of the TCR-gamma gene, and PCR products were resolved using high resolution nondenaturing polyacrylamide gel electrophoresis. Results. The authors' results demonstrated good correlation between the two techniques in 10 patients with CTCL (9 patients with C beta and 1 patient with delta 2 rearrangements) and 10 control subjects. The PCR-based technique allowed the authors to detect the presence of an identical T-cell clone in all skin nodules, but not in the original lymph node affected by AILD. Conclusions. This PCR-based method for detecting clonal TCR rearrangements is a highly sensitive and specific technique for detecting T-cell clones in fresh and paraffin embedded tissues. The presence of a T-cell clone in all skin nodules of this patient, but not in the original lymph node affected by AILD, confirms previous findings that in some cases of AILD, clonal T-cell expansion may not be detectable until a later stage of the disease.