Derangement of the T-cell repertoire in patients with B-cell non-Hodgkin's lymphoma.

Although a number of studies suggest that different immune pathways may play a role in the pathogenesis of non-Hodgkin's lymphomas (NHL), the shape of the T-cell compartment has been only superficially explored in these patients. In our study, we analyzed the peripheral T-cell receptor (TCR) repertoire and the distribution of different T-cell subsets - including regulatory T cells (Treg) - in 30 patients with NHL, by combining flow cytometry and spectratyping. We first demonstrated by flow cytometry an increased frequency of expanded T-cell subpopulations expressing the same TCR beta variable (BV) subfamilies in CD8+ cells from NHL patients when compared with healthy controls, beside a higher frequency of Treg. Moreover, NHL patients were characterized by a higher percentage of BVs showing a skewed CDR3 profile both in CD4+ and CD8+ cells when analyzed by spectratyping. Our data suggest that the T-cell branch of the immune system of patients with B-cell NHL is deeply deranged, as witnessed by the increased degree of activation and skewing of their TCR repertoire along with the higher frequency of Treg.

A 30-year epidemiologic survey (1974-2003) of haematological malignancies on the island of Sardinia: temporal changes in incidence and a geographic comparison of incidence rates.

In a previous survey of newly diagnosed haematological malignancies (HMs) in Sardinia from 1974 to 1993, we observed a marked increase in the incidence of many HMs that we chiefly attributed to improvements in case ascertainment. To better define the nature of this increase, we extended the survey by an additional decade (1994-2003), applying the same previously used methods. The incidence of HMs further increased from 1994 to 2003. The incidence rate of total HMs (THMs), standardised to the world population, was 30.15 × 10(5) person-years vs. 21.58 from 1984 to 1993 and 15.26 from 1974 to 1983. The temporal variations in the incidence differed in different HMs and were correlated with the diseases clinical characteristics and the increased availability of diagnostic tools and skills in Sardinia. These observations support the hypothesis that the temporal differences in the incidence rates observed for many HMs in Sardinia over the 30-year survey period were caused by temporal differences in diagnostic efficiency rather than by disease occurrence. An important exception was the increase in non-Hodgkin's lymphoma, which represents a true increase in occurrence, similarly to most Western countries. The incidence rates of HMs already having or reaching stable values in the decade 1994-2003 were similar to those of most Western countries. No significant evidence emerged to suggest that Sardinian particularities influenced the occurrence of HMs. This study demonstrates the extent to which diagnostic efficiency can influence incidence evaluations and emphasises the importance of prolonged observation to determine the validity of incidence rates for both temporal and geographic comparisons.

Hematological malignancies in the island of Sardinia, 1974-1993: age and sex distributions and temporal changes in incidence.

We have collected, by an active retrospective survey, all the cases of hematologic malignancies (HM) newly diagnosed during the time period 1974-1993 in the resident population of Sardinia. Diagnosis was deemed valid, after consultation of clinical records, in more than 90% of the 7264 collected cases. The number of newly diagnosed cases by year more than doubled during the 20-year period investigated. This striking increase can be only partially accounted for by ageing of population. Indeed, age-specific and age-adjusted rates of most of HM increased during this period, although Hodgkin Disease (HD), Chronic Myeloid Leukemia (CML) and Acute Lymphoblastic Leukemia (ALL) were notable exceptions. The observed increase in rates is likely, in a large part, to be fictitious, due to easier access to a health care system, which in the meantime, improved its diagnostic efficiency. This was particularly evident for Chronic Lymphocytic Leukemia (CLL), Multiple Myeloma (MM) and some others myelo- and lympho-proliferative disorders, but its relevance declined after 1984-1989. A likely true increase in occurrence was evidenced for Non-Hodgkin Lymphomas (NHL) and similarly, although to a lesser extent and more doubtful, for Myelodysplasias (MDS) and Acute Myeloid Leukemia (AML). At the end of the studied period each type of HM presented age and sex distributions and age-adjusted rates that show only minor differences from those reported for other western countries. No argument emerged to suggest that any genetic peculiarities of the Sardinian population might have affected the occurrence of HM. The confounding effects of improved diagnostic efficiency have prevented a reliable assessment of influence on incidences of environmental and socio-economic changes that, in relatively recent times, have occurred in Sardinia.