Large plaque parapsoriasis: clinical and genotypic correlations

Twelve patients with large plaque parapsoriasis (LPP) were investigated for the presence of predominant T-cell clones, analyzing the T-cell receptor ( TCR) gamma-chain gene. The diagnostic and prognostic significance of TCR ge ne rearrangement status was assessed by a correlation with the long-term cl inical follow-up. Six out of 12 patients showed a clonal T-cell population. Clinically, among the patients with clonal disease one developed clearcut mycosis fungoides (MF) after a follow-up of 8 years, in the other 5 patient s no such diagnosis could be made after follow-up of 2-21 years (median: 9 years). In patients with Polyclonal infiltrates the lesions remained virtua lly unchanged. These findings indicate that in LPP TCR gene rearrangement s tatus has no prognostic significance and does not allow distinction of LPP and early MF. Both conditions show a clonal T-cell infiltrate with similar frequency, are very similar in clinical and histologic presentation and acc ording to recent: studies share the same low risk to develop overt MF. Ther efore both terms refer to the identical clinical situation. This should be designated as early MF and efforts should concentrate on identifying those patients that are at risk to develop aggressive disease.