[Detection of clonal T-cell receptor gamma gene rearrangement with the use of PCR-DGGE for diagnosis of erythroderma].
BACKGROUND
It is often difficult to establish the etiological diagnosis of erythroderma because clinical findings and immunohistology cannot always distinguish between lymphomatous erythroderma and inflammatory erythroderma. The purpose of this work was to assess the contribution of PCR-DGGE for detecting clonal T-cell receptor gamma gene rearrangement to the etiological diagnosis of erythroderma.


METHODS
The following inclusion criteria were used: patient with erythroderma; skin biopsy for histologic study, immunophenotyping and molecular biology; minimal follow-up of 12 months after initial diagnosis. Thirty patients were included from May 1, 1995 to November 30, 1998. Histology slides were reread by one of the authors blinded to other data who classed them in three categories: probable lymphoma, probable inflammatory disease, uncertain diagnosis. Molecular data were also analyzed in the same blinded manner. Immunohistology diagnosis was compared with the molecular data and the final diagnosis retained from clinical, histological and molecular findings as well as the disease course to last follow-up (November 1, 1999) after a mean 12 +/- 18 months follow-up.


RESULTS
Eight biopsies were classed as probable lymphomas; a T-cell clonal rearrangement of the TCR genes was detected in 7/8 cases. The one sample with no detectable T clone was a drug-induced Sézary pseudolymphoma. The histologial classification identified 16 cases of probable inflammatory disease; no clonal rearrangement of the TCR genes was found in these cases. One of these patients had fungoid mycosis treated with caryolysin for three months and developed treatment intolerance at the time of the skin biopsy. For six biopsies the histological diagnosis was "uncertain"; a clonal rearrangement of the TCR genes was found in 2/3 of the fungoid mycosis cases and in none of the three cases of toxic dermal reactions.


CONCLUSIONS
This study demonstrated the contribution of genotypic analysis with PCR-DGGE to the diagnosis of erythroderma. Monoclonal TCR gene rearrangement was detected in 9/11 (82 p. 100) of the patients with lymphoma and in 0/19 of the patients with an inflammatory dermatosis. The etiological diagnosis of erythroderma is an excellent indication for molecular stud of skin biopsies with PCR-DGGE.
Cordel
N
N
Clinique Dermatologique, Unité Inserm U519, Hôpital Charles Nicolle, 76031 Rouen Cedex, France.
Lenormand
B
B
Courville
P
P
Lauret
P
P
Joly
P
P
D003873:Dermatitis, Exfoliative / Q000175:diagnosis* / Q000235:genetics*; D005500:Follow-Up Studies; D015329:Gene Rearrangement, T-Lymphocyte / Q000235:genetics*; D006801:Humans; D016410:Lymphoma, T-Cell, Cutaneous / Q000175:diagnosis / Q000235:genetics; D016133:Polymerase Chain Reaction / Q000379:methods*; D012878:Skin Neoplasms / Q000175:diagnosis / Q000235:genetics