Discordance between phenotype and function of Japanese adult T cell leukemia cells

Expression of CD26/dipeptidyl peptidase IV in adult T cell leukemia/lymphoma (ATLL)

The association of CD26/dipeptidyl peptidase IV (DPPIV) and human T lymphotropic virus type I (HTLV-I) was studied by two approaches. First, we examined the expression of CD26 in peripheral blood mononuclear cells (PBMC) from the patients with adult T cell leukemia/lymphoma (ATLL), an HTLV-I-related malignancy. The expression of CD26 on the surface of PBMC was decreased in all 20 patients with ATLL compared with those from normal individuals (P < 0.01) and the expression of the CD26 gene transcript was not detectable in seven out of eight patients with ATLL. Then we compared the quantity of viral DNA in CD26-negative (CD26-) and CD26-positive (CD26+) cells obtained from 17 HTLV-I healthy carries by using a polymerase chain reaction method. The CD26-cells had a higher copy number of viral DNA than CD26+ cells. These findings indicate that HTLV-I has in vivo tropism to CD26- cells, suggesting that some phenotypes of ATLL cells reflect the in vivo cellular tropism of HTLV-I.

Familial hemophagocytic lymphohistiocytosis associated with disseminated T-cell lymphoma: a report of two siblings

Two siblings with evidence of disseminated T-cell lymphoma at the time of diagnosis of familial hemophagocytic lymphohistiocytosis (FHL) are reported, an association which has not been described previously. The first child with typical clinical and laboratory features of FHL died shortly after admission, before diagnosis could be established. Retrospective analysis of autoptic tissue revealed marked hemophagocytosis as well as morphological and immunohistochemical features suggestive of disseminated T-cell lymphoma. In the second child, FHL was diagnosed in time. Subsequent histologic investigation of bone marrow biopsies displayed a focal infiltration by T-cell lymphoma. DNA hybridization studies provided evidence of a monoclonal T-cell receptor beta chain gene rearrangement. Following conventional chemotherapeutic induction for FHL, the patient received an allogeneic bone marrow transplant (BMT) from a related healthy donor. Currently, 17 months after BMT, the boy is in unmaintained remission from FHL and T-cell lymphoma. The current pathogenetic concepts for FHL and a possible relationship between T-cell lymphoma and FHL are discussed.

Expression of CD45RA (naive) and CD45RO (memory) antigens in T-acute lymphoblastic leukaemia

We have determined the distribution of CD45RO (memory) and CD45RA (naive) antigens in the bone marrow blasts from 25 patients with T-acute lymphoblastic leukaemia (T-ALL). Four groups of patients were identified on the basis of reactivity with specific antibodies by flow cytometric analysis: (a) CD45RA-/CD45RO+ (16 patients): four CD4-/CD8+, seven CD4+/CD8+ and five CD4-/CD8-; (b) CD45RA+/CD45RO- (three patients): three CD4-/CD8-; (c) five CD45RA-/CD45RO-: one CD4+/CD8-; one CD4-/CD8+; three CD4+/CD8+; (d) CD45RA+/CD45RO+ (one case): CD4+/CD8-. There was no correlation between the expression of the naive and the memory phenotypes and the presence of CD4, CD8 or any other antigen except the CD10 antigen which was expressed by all CD45RA-/CD45RO- patients. The predominance of the CD45RA-/CD45RO+ phenotype (65%) and the low incidence of the hybrid phenotype CD45RA+/CD45RO+ (5%) in T-ALL, differs from the results reported by others for chronic or prolymphocytic T-cell leukaemias, in which the simultaneous expression of these maturational antigens was detected in approximately half of the cases.

Association between ATL and non-hematopoietic neoplasms

A high incidence of multiple primary neoplasms has been observed in our patients with ATL in comparison to persons with other forms of hematologic malignancy who we have observed during the past 23 years (1963-1985). Five of 15 patients with ATL (33.3 per cent) have had at least one other associated neoplasm in comparison to only 44 of 1156 patients with other forms of hematological malignancy (3.8 per cent). The incidence figures for secondary neoplasms associated with the other hematologic malignancies were 4.3 per cent (16/370) for acute non-lymphocytic leukemia (ANLL), 2.2 per cent (2/90) for acute lymphocytic leukemia (ALL), 4.8 per cent (1/21) for acute unclassifiable leukemia, 2.2 per cent (5/225) for chronic myelogenous leukemia, 4.7 per cent (2/43) for chronic lymphocytic leukemia, 5.9 per cent (8/136) for malignant monoclonal gammopathy and 3.7 per cent (10/271) for malignant lymphoma. The incidence of multiple neoplasms in patients with ATL in comparison to those with other hematological malignancies was statistically significant (p < 0.01 or p < 0.001). The neoplasms associated with ATL have been adenocarcinoma of the thyroid or stomach, and squamous cell carcinoma of the larynx, lip or lung. We identified ATL-derived factor (ADF) in the cytoplasm of the secondary neoplasms of the ATL patients by means of indirect immunofluoroscopy and immunohistochemical techniques utilizing anti-ADF antibody. We also identified ras p21 products in these neoplasms by means of p21 ras monoclonal antibody studies. The possibility that HTLV-I was the cause of the secondary neoplasms thus was investigated. HTLV-I provirus genome was not found in all the six cases of non-ATL leukemic cells of the patients with anti-HTLV-I antibodies as determined by means of Southern blot analysis utilizing pX DNA probe. These findings suggest that there is some association between ATL cells and pre-malignant cells through ADF or other unknown factors in the activation of ras oncogenes. Subsequent suppression of host immune defence mechanisms in ATL patients permits evolution of the secondary neoplasms.

Cutaneous lesions of hemophagocytic syndrome in a patient with T-cell lymphoma and active Epstein-Barr infection

The hemophagocytic syndrome (HPS) was first described in immune-compromised patients with secondary viral infections. Immunodeficiency has not always been diagnosed before the onset of HPS, but most patients who develop HPS have known immune deficits. HPS has also been reported in association with lymphoreticular malignancies. In HPS the most prominent histologic change is phagocytosis of red blood cells and other bone marrow-derived elements by cytologically benign histiocytes. Considerable confusion exists about the similarities and differences between HPS and other conditions in which hemophagocytosis may occur, for example, histiocytic medullary reticulosis, T-gamma lymphoma, malignant histiocytic lymphoma, and cytophagic histiocytic panniculitis. We report a patient with HPS and cutaneous lesions of cytophagic histiocytic panniculitis who also had an active Epstein-Barr virus infection, and a CD8+ T-cell lymphoma.