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In the skin of 50–75% patients with early mycosis fungoides (MF) a dominant T-cell receptor (TCR) γ gene rearrangement can be detected. An identical T-cell clone is also detectable in the peripheral blood (PB) in 15–40% of these patients, as well as in 39–61% of skin biopsies showing histological remission after therapy. At the present time, it is still unclear if molecular analyses might be helpful to recognize an unfavourable subset of patients less responsive to skin-directed therapy or with a higher risk of disease recurrence. 89 patients (56 men, 33 women) with a median age of 60 years (range, 17–80), with a histologically confirmed diagnosis of early MF, were treated with a combination protocol of PUVA and low dose IFN-α for 14 months and then closely followed up. Only patients with a dominant clone in the affected skin at diagnosis, and in whom peripheral blood samples at diagnosis and a second tissue biopsy at the end of treatment were available, were selected for the present study. Twenty-four patients (10 men, 14 women; median age 62.5 yrs, range 17–77; 6 in stage IA, 15 IB, 3 IIA) met the inclusion criteria. PCR amplification for TCR γ gene was performed on DNA extracted from formalin-fixed and paraffin-embedded skin tissue samples and from frozen PB lymphocytes, as previously reported. Amplification products were visualised by 10% polyacrylamide gel electrophoresis at the same time, on the same gel, thereby allowing precise comparison of the dominant clonal populations. In one patient the identity of T-cell clones in the skin at diagnosis and at the end of therapy was assessed by sequencing analysis. After a mean time of 4 months (range 1–11), all 24 patients responded to the combination therapy, obtaining a clinical complete remission (CCR), even if three of them showed histological persistence of disease. During the follow-up, 11 patients had a disease recurrence (median time 70 months range 27–108). PCR analysis of TCR γ gene in the PB showed a circulating T-cell clone identical to the one detected in the skin in 9 cases (37.5%) at diagnosis. An identical T-cell clone was observed in the skin at the end of therapy in 17 cases (71%). Disease-free survival curves plotted by Kaplan-Meier method showed that patients with or without a peripheral T cell clone did not behave differently, that is, half of them would have experienced a relapse after a similar period of time in any case. The same behaviour was observed in patients showing different molecular responses after therapy. Only in one third of patients a molecular cure for the disease could be obtained by combination IFN-α and PUVA therapy, since a high rate of persistence of monoclonal PCR signals following CR was observed (71% of CR cases with a dominant clone at diagnosis); surprisingly, such a molecular outcome seems not to protect patients from subsequent disease relapses. On the other hand, our data seems to indicate that the combination of a skin-directed therapy like PUVA in addition to the systemic immunoregulatory effects of IFN-α may abolish the negative influence of a circulating clone.

In patients with early Mycosis Fungoides (MF), a dominant T-cell receptor (TCR) gene rearrangement can be detected in the skin in 50–75% of cases, while in 15–40%, an identical T-cell clone is detectable also in the peripheral blood This may indicate an unfavourable subset of patients. We observed on omogeneus group of early MF patients all receiving the some protocol. The purpuose of this study were: - T-cell receptor gene rearrangement analisys of peropheral blood samples; - evaluation of the prognostic impact of T-cell monoclonality on CR and relapse rate. 44 patients diagnosed as having MF at early stage (25 M, 19 F; mean age 58.7 yrs, range 34–77; 11 in stage IA, 28 in stage IB, 5 in stage IIB) and showing a dominant T cell clone in the skin lesions at diagnosis, were included in the present study. Peripheral blood samples were collected for DNA extraction at diagnosis. PCR amplification for TCRγ gene was performed as previously reported by Ashton-Key et al. (1997) in all 44 cases both in peripheral blood and skin and reduplicated: amplification products were visualised by 10% polyacrylamide gel electrophoresis. Peripheral blood samples were considered positive for a circulating T cell clone only if the monoclonal signals in peripheral blood and skin were reproducible and overlapping. All patients received the same treatment, consisting of a combination protocol with low-dose IFNα + PUVA for 14 months, and then followed up. Clinical response to the therapy and further disease recurrences were registered. After a mean time of 6.02 months (range, 1–21), 7 patients failed to respond to combination therapy, while 37 obtained a clinical complete remission (CCR). Among them, 15 experienced a disease recurrence during the follow-up (mean time, 29.8 months, range, 1–77 months). PCR analysis of TCRγ gene showed in the peripheral blood the same T-cell clone detected in the skin in 16 cases (36.4%). Failure to obtain a CCR was found in 3 out of 28 cases without a T cell clone in peripheral blood (10.7%) and in 4 out 16 cases with a circulating T cell clone (25%; c2 test: P=0.41, NS). Disease recurrence was observed in 9 out of 25 cases without a T cell clone in peripheral blood (36%) and in 6 out of 12 cases with a circulating T cell clone (50%; c2 test: P=0.65, NS). Disease-free survival curves plotted by Kaplan-Meier method showed that patients with and without a circulating T cell clone did not behave differently and that half of the patients would have experienced a relapse after a similar period of time (34 and 36 months, respectively, for patients with TCRg+ and − peripheral blood; log rank test, P=0.79). PCR analysis of TCRγ gene rearrangement analysis has allowed us to detect monoclonality in the peripheral blood in 36% of early MF cases with a documented monoclonality in the skin. At this stage of the disease a circulating T cell clone could indicate a subset of patients in which skin-directed therapies are more likely to fail to completely eradicate the malignant cells. Interestingly, our data seems to show that the negative influence of a circulating clone can be bypassed by the combination of a skin-directed therapy like PUVA and the systemic immunoregulatory effects of IFNα.