Treatment of hairy-cell leukaemia with alpha-interferon (alpha-IFN)

Twenty-three patients with hairy-cell leukaemia (HCL), six of whom were previously splenectomized, were treated with alpha-interferon (alpha-IFN) 3 MU per day for 3-6 months and then with 3 MU three times per week for at least 3 further months. Seven patients (two splenectomized) showed a complete response (CR), 11 patients achieved a partial response (PR) and the remaining five experienced only a minor response (MR). All seven patients who achieved a CR are still in CR after 10-21 months from the onset of the disease. Among the 11 PRs, five showed an increase in the number of circulating hairy cells during the follow-up; they were re-started on alpha-IFN and an improvement of the haematological values was again obtained. One patient who achieved only a MR died after 1 month therapy because of severe infection. Following treatment with alpha-IFN, the improvement or normalization of the peripheral blood counts was paralleled by an improvement of the immunologic surface markers, as determined by monoclonal antibodies, and by an improvement of the response to PHA and of the natural killer activity. These findings, coupled to the mild drug-related toxicity observed, confirm that treatment with alpha-IFN represents a safe and effective therapeutic approach for both splenectomized and non-splenectomized HCL patients.

Germ-line configuration of the T-cell receptor beta-chain gene in B-cell chronic lymphoproliferative disorders which co-express T-cell antigens

In 7 cases of chronic B-cell lymphoproliferative disorders-6 chronic lymphocytic leukaemias and 1 non-Hodgkin lymphoma in leukaemic phase--which co-expressed T-cell markers (CD3, CD2) the clonal origin was investigated at the DNA level. In accordance with the diagnosis, all cases showed a monoclonally rearranged configuration of the immunoglobulin genes. On the contrary, the T-cell receptor beta chain gene always retained a germ-line organization. These findings demonstrate that B-cell chronic lymphoproliferative disorders which co-express T-cell-related markers are truly composed of monoclonal B-cell elements.

Chronic T-cell leukaemias. A variant of T-prolymphocytic leukaemias: morphological, immunological and clinical characterization of 2 cases

In this study we describe 2 patients who appear to suffer from a morphological, cytochemical and clinico-haematological variant of T-prolymphocytic leukaemia (T-PLL). The cells were smaller than typical prolymphocytes, with a regular nucleus containing a smaller and less prominent nucleolus; the alpha-naphthyl acetate esterase (ANAE) and acid phosphatase (AP) cytochemical reactions showed a weaker pattern of positivity in this variant compared to T-PLL. No immunological differences were found between the two conditions with regard to membrane expression and functional behavior of the cells. The clinical course and the outcome of the patients appears to be different: aggressive and rapidly fatal in T-PLL; thus far well-controlled in the T-PLL variant. From a molecular point of view, both cases showed a monoclonal rearrangement of the T-cell receptor beta-chain gene.

Multimarker phenotypic characterization of adult and childhood acute lymphoblastic leukaemia: an Italian multicentre study

A multicentre phenotypic study was carried out in Italy combining conventional immunological techniques with monoclonal antibody (MoAb) analysis in 190 cases of adult and childhood acute lymphoblastic leukaemia (ALL), in an attempt to define better the lineage relationship of the neoplastic cells. Of the 140 children evaluated, 79.3% expressed the common ALL (cALL) antigen (all analyses performed by MoAb), 11.4% were T-ALL and 9.3% were non-T, non-B, non-common ('null') ALL. The proportion of adult cALL cases was slightly lower (64% of the 50 cases studied) than that of childhood ALL, whilst the incidence of T-ALL was significantly higher in adults than in children (26% v. 11.4%, P less than 0.05). Because of the high proportion of cALL cases, the incidence of 'null' ALL in adult patients was similar (10%) to that of children, and lower than previously reported. The recognition of early pre-T-ALL cases (T1+, RFT2+, T10+, T6-, T11-, E-) contributed to the overall low proportion of 'null' ALL; prior to the use of MoAb, such cases would probably have been classified as undifferentiated acute leukaemia or 'null' ALL. The search for B-cell-related markers showed that the incidence of pre-B-ALL cases (cytoplasmic immunoglobulin positive cases) was similar in adults and in children (25.6% and 32%, respectively). Furthermore, the great majority of cases studied expressed the BA-1 antigen (92.8% of adults and 79% of children), whilst the BA-2 antigen was found in 53% of cases (tested only in children), confirming a hierarchy in the expression of B-cell related markers in cALL: BA-1, BA-2, CyIg. Several of the 'null' cases also expressed the BA-1 antigen on a variable proportion of cells, pointing to a possible B-cell origin of the blasts. This multicentre study shows that both in adult and in childhood ALL the combined use of conventional immunological markers and of a panel of MoAb allows identification of the cell lineage of the great majority of cases, thus reducing the number of 'null' ALL. Furthermore, these findings suggest that practically all cases of ALL belong either to the T or to the B cell compartment and that the neoplastic cells appear blocked at different levels along the lymphoid differentiation pathway.

Lineage relationship of chronic lymphocytic leukemia and hairy cell leukemia: studies with TPA

The tumor promoting agent TPA (phorbol ester; 1.6 X 10(-8)M) was used to induce the differentiation in vitro of B-chronic lymphocytic leukemia (B-CLL) cells from 14 untreated patients. The uninduced phenotype was SIg+, Mrbc+, RFT-1+, RFA-4-, FMC7-. After 72 h incubation with TPA, B-CLL cells became RFA-4+, FMC7+ and lost the capability of Mrbc rosetting. Large proportions of the "induced" cells also showed morphological and ultrastructural changes, such as undulating membranes and bleblike protusions and became strongly positive for tartrate resistant acid phosphatase (TRAP+) and also contained cytoplasmic immunoglobulins. These features are very similar to the features of hairy cell leukemia (HCL). These observations confirm previous clinical findings that B-CLL and HCL are related disorders of the B lineage. The development of "hairy" features in induced B-CLL and in HCL seems to be a malignancy-associated feature because the Mrbc+ normal B cells (B-CLL-equivalent cells) isolated from tonsil also develop TRAP positivity but no membrane aberrations.

T lymphocyte subsets and colony growth in hairy-cell leukemia

The distribution of T cell subsets and the T colony-forming capacity were assessed in 22 patients with hairy-cell leukemia. An overall increase in the proportion of T gamma cells (31 +/- 15%) and a decrease in Tmu cells (38 +/- 11%) were observed if compared with normal controls (16 +/- 6% for T gamma and 51 +/- 13% for Tmu). In half of the patients, however, these values were normal. T gamma cells were highest in the splenectomized patients and in the 15 non-splenectomized patients T gamma cells were higher in those with active disease. Patients with stable disease or in remission had values close to normal. The T colony-forming capacity of unseparated and enriched T lymphocytes was normal regardless of the T cell subset distribution and clinical stage of the disease. These findings suggest that in HCL, unlike B cell chronic lymphocytic leukemia, the imbalance in Tmu/T gamma ratio does not result in an impairment of the in vitro T colony-forming capacity.