Adult T-cell lymphoma-leukaemia in Blacks from the West Indies

T-cell chronic lymphocytic leukemia with a helper/inducer membrane phenotype: a distinct clinicopathologic subtype with a poor prognosis

T-cell chronic lymphocytic leukemia (T-CLL) accounts for about 2% of the various types of CLL and can be subtyped into helper/inducer (h/i) and cytotoxic/suppressor (c/s) cell membrane phenotypes. Seven patients with CLL were shown to have T-CLL with a h/i cell membrane phenotype; four with monoclonal antibody reagents and three by demonstration of the E-rosette receptor and focal acid alpha naphthyl acetate esterase activity. The clinical courses, treatment responses, and laboratory findings of these seven patients were reviewed to determine the prognosis and unique clinicopathologic features of this subtype. Two patients presented with skin rashes, and five were diagnosed during evaluation for other medical problems. Initially, four patients had splenomegaly and two had lymphadenopathy, but none of the patients had hepatomegaly. Morphologic examination revealed uniform, small lymphocytes in three patients, and the lymphocytes had nuclear indentations in four patients. Sera from the three patients tested were negative for antibody to the human T-cell leukemia/lymphoma virus I. Peripheral blood mononuclear cells from one patient showed normal interleukin-2 production and lacked antibody-dependent cell-mediated cellular cytotoxicity and natural killer activity. Cytogenetic analysis was done on one patient, revealing an abnormal clone with several chromosomal abnormalities, including an X;14 translocation with a break point at 14q11. All patients required chemotherapy, and all died a median of 21 months from the time of diagnosis. The findings in these patients, in addition to those in 31 patients described in the literature, indicate that h/i T-CLL is associated with a poor prognosis and has distinct clinical and pathologic features that separate it from c/s T-CLL, adult T-cell leukemia/lymphoma, the cutaneous T-cell lymphomas, and B-CLL.

The human T-cell leukemias: clinical, cytomorphologic, immunophenotypic, and genotypic characteristics

The distribution of the conventional lymphoid cell markers on T lymphocytes and the principal panels of monoclonal antibodies used to recognize distinctive T-lymphocyte-associated differentiation antigens are discussed. These reagents have been used to probe the early and late stages of T-cell differentiation, and a hypothetical schema of T-cell differentiation has been constructed. Application of these reagents to the investigation of neoplastic T cells has resulted in the determination of the subset of origin and the stage of differentiation of the neoplastic cells in T-cell-derived lymphoproliferative malignancies. Recent advances in molecular biology have made possible the Southern blot hybridization analysis of DNA extracted from neoplastic T cells for patterns of T-cell-receptor gene rearrangements. Examination of these patterns in benign and malignant T and non-T cell has provided the basis for the use of T-cell-receptor gene rearrangements as specific genetic markers of T-cell lineage, clonality, and differentiation. These and other advances have resulted in the delineation of a new category of T-cell neoplasia, the adult T-cell leukemia/lymphoma syndrome. They have also demonstrated that the majority of clinically indolent neoplasms composed of large granular lymphocytes in so-called T gamma-lymphoproliferative disease are monoclonal proliferations. Further phenotypic, functional, and genotypic analyses of the T-cell malignancies should provide better understanding of T-lymphocyte differentiation and heterogeneity. Such studies should also lead to better clinicopathologic correlations and greater understanding of the basis for the clinical diversity of the T-cell-derived lymphoproliferative malignancies.

Pathology of peripheral T-cell lymphomas and leukemias

Peripheral T-cell lymphomas and leukemias have distinct histological and cytological characteristics although there are a variety of histological patterns even in a single lymph node. Histologic features are altered by the progression of the disease. There is no significant association between histology and prognosis. The variations in histologic features and clinical manifestations of peripheral T-cell lymphomas/leukemias can now be related to the presence of the retrovirus ATLV, and anti-ATLV antibodies as well as to the immunophenotypes of the lymphoma cells utilizing monoclonal antibodies. Changing concepts of peripheral T-cell lymphomas/leukemias are discussed.

Cutaneous T cell lymphoma

Cutaneous T cell lymphoma is a malignancy of helper T cells, which have a propensity to infiltrate the skin. The incidence of the disease appears to exceed that of Hodgkin's disease, making it the most common lymphoma of adults. Advances in our knowledge of the biology of the malignant T cells should facilitate new and more effective forms of treatment.

T-cell colony formation in patients with T-cell malignancies: growth factor requirements for in-vitro proliferation of peripheral blood T-cell colony-forming cells

Peripheral blood T colony-forming cells (T-CFC) from patients with T-cell malignancies are capable of proliferation in methylcellulose, in the absence of added growth factors or mitogenic stimulation. We show here that based on the spontaneous plating efficiencies of their T-CFC, two groups of patients can be established: Group A (10 patients) with a high colony number (more than 100 colonies/10(5) seeded cells), and group B (12 patients) with less than 100 colonies/10(5) cells. The addition of interleukin 2-(IL2) containing PHA-leukocyte conditioned medium enhanced colony growth from group B but not group A patients. Moreover, both biochemically purified and recombinant IL2 induced the colony growth from group B but not group A patients without any other stimulation. In addition, a monoclonal antibody (moAb) against the IL2 receptor (IL2-R; anti-Tac) inhibited the spontaneous colony formation from T-CFC of both groups of patients. These observations strongly suggest that IL2-R are involved in the spontaneous colony growth of T-CFC. To determine whether IL2 is also involved in the spontaneous colony formation, media conditioned (LCM) by unstimulated leukemic cells were tested for IL2 activity. A constitutive release of IL2 was detected in LCM from only 2 out of 10 patients tested, and some of them were capable to inhibit thymidine incorporation by IL2-dependent cells cultured in the presence of highly purified IL2. However, most of these LCM contained a T-cell colony-promoting activity (TCPA) inducing colony formation from both normal resting and PHA-stimulated E+ clonogenic cells without added IL2 or mitogenic stimulation. TCPA-containing LCM induced the expression of functional IL2-R and IL2 release by normal resting lymphocytes. TCPA was constitutively released by blast-enriched cell fractions suggesting that it is released by the leukemic cells.

Immunobiology of the expanded T cells in T-cell leukemia and T-gamma lymphocytosis

A review is presented of functional studies performed with the expanded T cells in Sézary syndrome, T-cell chronic lymphocytic leukemia (T-CLL), T-prolymphocytic leukemia (T-PLL), adult T-cell leukemia lymphoma (ATLL), T-cell acute lymphoblastic leukemia (T-ALL) and T gamma lymphocytosis. The immunological and clinical relevance of immunological studies of functional properties of T-cell expansions is discussed.

Peripheral T-cell lymphoma simulating Hodgkin's disease with initial bone marrow involvement

In a patient who had fever and cytopenias but no peripheral lymphadenopathy, bone marrow biopsy revealed findings consistent with Hodgkin's disease. Subsequently lymph node biopsy specimens showed lymphoma with features more consistent with peripheral T-cell lymphoma. The clinical features of this patient were those that have been ascribed to an atypical clinical form of Hodgkin's disease. This case illustrates the inadequacy of bone marrow examination as the sole criterion for establishing an initial diagnosis of Hodgkin's disease, particularly in relationship to the newly recognized pleomorphic variants of T-cell malignant lymphoma.

Peripheral T-cell lymphoma. A clinical, histologic, and immunologic study of five cases

The authors describe five white patients with peripheral T-cell lymphoma. Four patients were older than 65 years. All cases presented with a short clinical course and advanced stage at the time of diagnosis. Clinical manifestations included asthenia, weight loss, peripheral and abdominal lymphadenopathy. One case showed tonsillar involvement and subcutaneous lymph node enlargement; hepatomegaly was present in four cases, two of them with splenomegaly. Only one case presented peripheral lymphocytosis and antibodies to human T-leukemia virus. Although three cases were classified as diffuse mixed lymphomas and two as poorly differentiated lymphocytic lymphomas, there were some common characteristics: diffuse infiltration by different proportions of small lymphoid cells and large immunoblasts, some of them multinucleated and similar to Reed-Sternberg cells; accumulation of histiocytes, plasmacytosis, eosinophilia, venular proliferation and compartmentalization were also found. Bone marrow infiltration was observed in two patients. Results of monoclonal markers showed four cases to be OKT4+ and the other OKT8+. The morphologic and immunologic characteristics of these patients were typical and similar to those reported from other geographical areas.

HTLV-I is endemic in southern Italy: detection of the first infectious cluster in a white population

Human T-cell leukemia virus (HTLV-I) infection is observed among black and Japanese populations in well-delimited endemic spots in association with a high incidence of adult T-cell leukemia (ATL). We present evidence of HTLV-I infection in two ATL patients from southeastern Italy who have not travelled and who have no known relations abroad, and in 8% of non-leukemic controls from the same area. Thus, populations exhibiting HTLV-I infection appear more widespread than supposed up to now.

Adult T-cell leukemia/lymphoma in Taiwan. A clinicopathologic observation

The retrovirus-associated adult T-cell leukemia/lymphoma (ATL) has not been previously documented in Taiwan. Five cases identified recently by the authors are reported. Three of the patients were women, and their ages ranged from 36 to 60 years. The most important diagnostic clue was the observation of polylobated lymphoid cells in the peripheral blood. Other variably observed significant features included hypercalcemia, cutaneous eruptions, osteolytic bone lesion, hepatomegaly, and lymphadenopathy. Surface marker studies revealed that the leukemic or lymphoma cells were T-helper cells. Histopathologic examination revealed one case of pleomorphic type and three cases of medium-sized cell type. No tissue was available for study in one case. The diagnosis of ATL was confirmed by the indirect immunofluorescence test on MT-1 cell for antibodies to adult T-cell leukemia virus-associated antigen (ATLA). Three patients were dead within 6 months, and two patients had been in clinical remission for 7 and 10 months, respectively. These two latter cases were similar to the so-called smoldering type of ATL. Two descendents among nine relatives of the patients were also positive for anti-ATLA (22%). Two husbands were negative. Four of the five patients lived in the same county in northeastern coastal Taiwan, which suggested a possible clustering of ATL in that region.

Suppression of retroviral propagation and disease by suramin in murine systems

Retroviral propagation crucially depends on reverse transcriptase (RT). We have developed murine models to test the biological effectiveness of the RT inhibitor suramin. The drug was active in our assay system, which includes (i) inhibition of RT activity in the murine T-cell tropic virus SL3-3 and Rauscher murine leukemia virus (MuLV), (ii) inhibition of plaque formation in the XC plaque assay, (iii) inhibition of viral infection of cultured murine T cells, and (iv) inhibition of splenomegaly induced by Rauscher MuLV in BALB/c mice. Suramin decreases viral titers significantly, even if started 36 hr after infection. Viral titers and number of infected cells increased to control levels after removal of the drug. BALB/c mice treated i.v. with 40 mg of suramin per kg twice per week following infection with Rauscher MuLV showed a 35% decrease in splenomegaly. Suramin is an active antiretroviral agent whose effect on retroviral propagation is reversible. We conclude that it acts as a virustatic drug and that long-term administration of suramin will be necessary if it is used for experimental treatment of human retroviral illnesses such as the acquired immune deficiency syndrome.

Peripheral T-cell lymphoma. A clinicopathologic study of a morphologically diverse entity

We analyzed the clinicopathologic features of 13 patients with immunologically confirmed peripheral T-cell lymphoma. The lymphomas were classified into poorly differentiated lymphocytic, mixed cell, and large cell types. Marked morphologic heterogeneity was noted within the mixed cell and large cell categories, and the various subtypes are described. Twelve of the 13 patients received multiagent chemotherapy. Only three of the nine patients with poorly differentiated or mixed cell lymphomas achieved a complete remission, and the median survival for this group was 11 months. In contrast, all three of the treated patients with large cell lymphomas achieved a complete remission, two of whom are alive without disease (14 and 29 months, respectively). Classification of peripheral T-cell lymphomas into lymphocytic, mixed cell, and large cell types, as well as further subclassification within the heterogeneous groups, is suggested so that pathologic features of prognostic significance can be identified.

Human T-lymphotropic retroviruses

The first human retroviruses have been discovered during the past six years. They cause two diseases which involve disturbances of the growth of the T4 lymphocyte, a remarkably specific target cell type. This cell, which is central to the regulation of the immune system, is induced by human T-lymphotropic virus type I (HTLV-I) to excessive proliferation (leukaemia) and by HTLV-III to premature death (acquired immune deficiency syndrome, AIDS). Both also seem to be indirectly involved in several other disorders. The genetic structures of these retroviruses and the mechanisms by which they usurp host-cell functions are novel among retroviruses.

T-helper phenotype chronic lymphocytic leukaemia and "adult T-cell leukaemia" in Italy. Endemic HTLV-I-related T-cell leukaemias in southern Europe

Sixteen Italian patients with chronic T-cell lymphocytic leukaemia (T-CLL) and leukaemic T-helper phenotype lymphocytes (Thp-CLL) were investigated for serum antibodies against human T-cell leukaemia virus I (HTLV-I) or its integrated DNA sequences. Common features of this series of patients were an aggressive clinical course with poor response to treatment, high white blood-cell count, bone-marrow infiltration, splenomegaly, and chromosome abnormalities. Three patients had skin infiltration and one had hypercalcaemia. Immunological analysis showed a Thp (OKT4+) in all cases, and a heterogeneity, within the OKT4 population, of phenotypes and functional activities. Three patients had either HTLV-I integrated DNA sequences or anti-HTLV-I serum antibodies, or both. These patients had not received any blood transfusions, denied intimate contact with foreigners, and had always lived in small towns of central or southern Italy. Clinical and immunological findings in this series of patients suggest that both HTLV-I related and unrelated cases of Thp-CLL should be regarded as one disease arising from the same subpopulation of mature T-lymphocytes.

Monoclonal gammopathies in adult T-cell leukemia

Age and sex distributions of monoclonal gammopathy were studied for 12,196 healthy controls and 2056 patients with various malignancies. The frequency of monoclonal component in adult T-cell leukemia (ATL) patients was found to be much higher than that in patients with other malignancies and in healthy controls. This suggested that the occurrence of ATL and monoclonal gammopathy is not coincidental. Three cases of ATL with monoclonal gammopathy are also reported.

Antibodies to human T-lymphotropic virus type-I in patients with tropical spastic paraparesis

10 out of 17 (59%) patients with tropical spastic paraparesis (TSP) had antibodies to human T-lymphotropic virus-I (HTLV-I), as did 5 out of 5 TSP patients with systemic symptoms. Only 13 out of 303 (4%) controls, made up of blood donors, medical personnel, and other neurological patients, had such antibodies. These findings suggest either that HTLV-I is neurotropic or that the virus or a related one contributes to the pathogenesis of TSP.

Cutaneous manifestations of adult T cell leukemia/lymphoma. Report of three different forms

The clinical and pathologic features of cutaneous lesions observed in three adult T cell leukemia/lymphoma (ATL) patients identified in Taiwan are described. They represent one classical case of ATL and two "smoldering" variants. The classical ATL patient when first seen had numerous erythematous or purpuric papules, nodules, and plaques with or without ulceration. The two "smoldering" cases developed encrusted purpuric plaques with subcutaneous erythematous nodules in one patient and pompholyx-like vesicular eruptions with tumor masses in another patient. The pompholyx-like eruptions have not been described before. Pruritus was the major complaint in two patients. Histopathologic studies revealed pleomorphic infiltration in the classical case and monomorphic infiltration with medium-sized cells in the two "smoldering" variants. Therefore, the cutaneous lesions of ATL are diverse and not pathognomonic. The diagnosis requires a high index of suspicion, detection of circulating characteristic multilobated lymphoid cells with T helper/inducer cell marker, and demonstration of serum antibody against the adult T cell leukemia virus-associated antigen.

Multiple myeloma in a pair of monozygotic twins: the first reported case

A pair of monozygotic twins both developed multiple myeloma within a 2 year period. The first patient is alive with stable disease 4 years later, his twin brother died within a year of diagnosis. Monozygosity is well established and in both cases the paraprotein was IgG kappa. The relative influence of environmental and hereditary factors on the aetiology of myeloma is discussed. We believe this to be the first case of myeloma in twins to be reported.

Nucleotide sequence analysis of a variant human T-cell leukemia virus (HTLV-Ib) provirus with a deletion in pX-I

A variant of human T-cell leukemia virus subgroup I (HTLV-I), designated HTLV-Ib, has been isolated from a transformed T-lymphocytic cell line established from a Zairian patient with adult T-cell lymphoma. A recombinant phage clone of the variant provirus, denoted lambda MC-1, hybridizes under high stringency to HTLV-I DNA probes, but 17 of 43 restriction enzyme sites differ from those of HTLV-I, 10 of them clustering within 1.5 kilobases in the env-pX region. Since this variant virus retains its capacity to transform T-cells in vitro, and since a pX product is suspected to be important in transformation, we have determined the nucleotide sequence of the entire pX region of this virus for comparison to the prototype HTLV-I. In addition, the region between the gag and pol genes, parts of the pol and env genes, and a portion of the U3 region of the long terminal repeat sequence were also analyzed. We noted 141 single-base-pair changes among 3,897 base pairs, which were relatively well distributed over those portions of the provirus that were examined. In addition, an 11-base-pair deletion was found which included the potential initiator ATG codon of the first open reading frame of pX (pX-I). The next potential initiator codon predicted by the sequence is followed by 10 codons and then a termination codon. An identical deletion was also demonstrated in the only provirus present in another cell line established from the same patient on a different occasion after transformation in vitro of normal human umbilical cord blood cells. These results indicate that pX-I is not required for transformation.

Methylation pattern of human T-cell leukemia virus in vivo and in vitro: pX and LTR regions are hypomethylated in vivo

The methylation patterns of the gag, pol, env, pX and LTR regions of proviral DNA of human T-cell leukemia/lymphoma virus type I (HTLV) in fresh leukemic cells and established cell lines were examined using HpaII/MspI endonuclease. Peripheral blood lymphocytes (PBL) isolated from patients with adult T-cell leukemia/lymphoma (ATL) did not express viral antigens of HTLV, but PBL that had been cultured for 2 days did express these viral antigens. Most parts of the gag, pol and env regions of the HTLV provirus in PBL isolated from 12 ATL patients and PBL cultured for 2 days were hypermethylated as reported by others. In contrast, in 10 established cell lines that harbored HTLV genomes and expressed viral antigens, HTLV proviruses were hypomethylated. In one cell line, ATL-IK, which harbored an HTLV genome but did not produce viral antigens, the gag, pol and env regions were hypermethylated. However, two HpaII sites, one in the middle of the gag region and the other in the middle of the pol region, were not methylated even in PBL from most ATL patients. Furthermore, the pX and LTR regions were hypomethylated not only in established cell lines but also in PBL of ATL patients. The hypomethylation of the pX and LTR regions detected in fresh leukemic cells of ATL patients may have some etiological significance in cell transformation by controlling the level of transcription of these regions, or modulating the binding of some factors to these regions.

Occurrence of HTLV-I antibodies in Danish patients with cutaneous T-cell lymphoma

10 of 68 CTCL (cutaneous T-cell lymphoma) patients without features of ATLL had antibodies against HTLV-I (human T-cell leukaemia virus, type I). The titre of antibody in these positive patients was generally much lower than that seen in cases of ATLL (adult T-cell leukaemia/lymphoma); geometric mean of 80 for CTCL vs. 8000 for Caribbean ATLL. The presence of HTLV-I antibody was unrelated to clinical remission, relapse, or stages of the disease, and some positives were detected in the earliest phases of mycosis fungoides. Among controls and normal donors between the ages of 40 and 65, only 1 of 36 and 3 of 113, respectively, had low titre antibodies to HTLV-I in their sera. Only 5 of 354 Danish normal donors of all ages had antibody, which was identical to the rate in over 2000 US normal donors. In negative control experiments, these antibodies were unreactive with bovine leukaemia virus. These data suggest that HTLV-I or a related retrovirus crossreactive with HTLV-I occurs in a low percentage of the Danish population and patients with CTCL have such antibodies at an increased rate, but less than the rate seen for ATLL (greater than 90%).

Racial and other characteristics of human T cell leukemia/lymphoma (HTLV-I) and AIDS (HTLV-III) in Trinidad

Adult T cell leukaemia/lymphoma was first recognised as a clinical entity in southwest Japan. Subsequently the Caribbean has been found to be another area where the disease is endemic, and sporadic cases have been identified in different parts of the world. The human T cell leukaemia/lymphoma virus (HTLV-I) is causally related to adult T cell leukaemia/lymphoma. A subgroup of HTLV, designated HTLV-III, has recently been isolated from many patients with the acquired immunodeficiency syndrome (AIDS) and preAIDS, and there is now evidence that this variant is the primary cause of AIDS. This is the first report from Trinidad to describe 12 cases of adult T cell leukaemia/lymphoma and 14 of AIDS. All were in patients of African descent. No cases were seen in subjects of East Indian descent, who, like those of African descent, comprise as much as 40% of the population. West Indians of African descent may have increased susceptibility to infection with both HTLV-I and HTLV-III.

Seroepidemiology of human T-lymphotropic retrovirus type I (HTLV-I) in residents of Niigata Prefecture, Japan. Comparative studies by indirect immunofluorescence microscopy and enzyme-linked immunosorbent assay

A large sample of carriers of human T-lymphotropic retrovirus type I (HTLV-I) in Niigata Prefecture was examined for the detection of natural antibodies to HTLV-I-related antigens in sera using both indirect immunofluorescence microscopy (IFM) and enzyme-linked immunosorbent assay (ELISA). The present findings are based on multiple surveys, using each assay technique at least twice. Although Niigata Prefecture has been considered a non-endemic region for HTLV-I, Sado Island has been proven by this study to be a relatively endemic pocket within this non-endemic area. Seropositivity was highest in residents of Sado Island; 97/1, 117 (8.7%) by IFM and 33/1,061 (3.1%) by ELISA; followed by Niigata City, 18/650 (2.8%) by IFM and 16/638 (2.5%) by ELISA; and lowest in the remaining areas, 57/2,631 (2.2%) by IFM and 20/2,551 (0.8%) by ELISA. Seropositivity was demonstrated in 172/4,398 (3.9%) by IFM and 69/4,250 (1.6%) by ELISA in Niigata Prefecture taken as a whole. In general, the incidence of seropositive residents increased gradually with age. The sex difference was not significant. The serum samples tested were categorized into 4 groups; (1) IFM and ELISA both positive, (2) IFM positive but ELISA negative, (3) IFM negative but ELISA positive, and (4) IFM and ELISA both negative. By absorption tests, IFM and ELISA seemed to recognize different specific antibodies in sera; IFM recognized antibodies to HTLV-I-related cellular antigens in addition to HTLV-I viral antigens, but ELISA recognized antibodies to HTLV-I viral antigens alone. Thus, IFM detected a broader spectrum of antigens, resulting in recognition of more positive sera than those detected by ELISA.

Hypercalcemia, unusual bone lesions, and human T-cell leukemia-lymphoma virus in adult T-cell lymphoma

Extensive generalized and subperiosteal bone resorption was demonstrated in a patient with adult T-cell lymphoma and marked hypercalcemia of unclear pathogenesis. Antibody to the human T-cell leukemia-lymphoma virus (HTLV) was present in the serum of the patient, consistent with the recently reported association of adult T-cell lymphoma, hypercalcemia, and HTLV. The unique feature of this case was the presence of bone radiographic and pathologic findings consistent with hyperparathyroidism, in the absence of elevated parathormone levels. These findings contrast with the few previously reported cases of adult T-cell lymphoma with hypercalcemia, which showed lytic, sclerotic, or osteoporotic bone lesions. The authors suggest that the patient's malignant T-lymphocytes may have produced an osteoclast-activating-factor-like substance or a parathormone-like substance, which caused the striking bone changes. The exact role of HTLV in the pathogenesis of such cases remains to be determined.

Infectious transmission of human T-cell leukemia virus to rabbits

A rabbit lymphoid cell line (Ra-1) was established by co-cultivation with a human T-cell line (MT-2) carrying human T-cell leukemia virus (HTLV). The Ra-1 cell line is chromosomally male and is persistently infected with HTLV. Ra-1 cells, with or without mitomycin C treatment, were inoculated intravenously (i.v.) into 3 female rabbits. All 3 animals responded with the production of antibodies to HTLV antigens. Lymphocytes from one of these seroconverters were cultured in the presence of T-cell growth factor (TCGF) and HTLV particles were detected in the TCGF-grown lymphocytes which were chromosomally female. Co-cultivation of lymphocytes from the 2 other seroconverters with lymphocytes from 2 anti-HTLV-negative healthy men gave rise to the establishment of an HTLV-producing T-cell line derived from each individual. Blood transfusion from one of the HTLV-infected rabbits into 2 female rabbits also resulted in the seroconversion of both recipients. An HTLV-carrying lymphoid cell line (Ra-2) was established from one of the transfusion-related seroconverters. The Ra-2 cell line was initially TCGF-dependent but later became TCGF-independent. There results indicate that HTLV can be transmitted to rabbits. These animals may provide a suitable model system for studying the mode of transmission and pathogenicity of HTLV.

HTLV-positive and -negative T-cell lymphomas. Morphological and immunohistochemical differences between European and HTLV-positive Japanese T-cell lymphomas

A total of 56 cases of malignant lymphoma presumed to be of peripheral T-cell origin were investigated with regard to histological and immunohistochemical features. The goal of the study was to determine whether virus-associated T-cell lymphomas can be morphologically or immunohistochemically distinguished from presumably virus-negative T-cell lymphomas. The cases came from endemic and non-endemic regions of Japan, the United Kingdom (including 4 Caribbean cases) and the Federal Republic of Germany. Sera of all Japanese and Caribbean patients and 8 German patients were tested for antibodies to adult T-cell leukaemia virus-associated antigen HTLV-A. In all cases sections were examined blind by 5 well-trained histopathologists. In most cases cryostat sections could be prepared from fresh tissue specimens and stained with a large panel of monoclonal antibodies. All HTLV-A-positive cases were morphologically classifiable as the pleomorphic type of T-cell lymphoma. Approximately 70% of the tested cases of pleomorphic T-cell lymphoma, however, showed a positive serum reaction for HTLV-A. All other types of peripheral T-cell lymphoma (T-immunoblastic lymphoma, chronic lymphocytic leukaemia of T type, T-zone lymphoma, "AILD type" and lymphoepithelioid cell lymphoma) were HTLV-A-negative and mostly observed in European patients. Thus virus-associated T-cell lymphomas appear to be invariably of the pleomorphic type; but pleomorphism is not specific to HTLV-A-positive cases. This was also evident from the results of an experiment in which 2 Japanese histopathologists attempted to recognize HTLV-A positivity in a blind study of pleomorphic T-cell lymphomas. A maximum of about 80% of cases were correctly identified, with about 10% false-positive diagnoses (in HTLV-A-negative or presumably negative cases) and 10% false-negative diagnoses. The immunohistochemical analysis revealed not only many common features but also 2 distinct differences between HTLV-A-positive and -negative T-cell lymphomas. All but one of the HTLV-A-positive cases showed reactivity with anti-Tac and all cases in the virus-positive group were negative for TU14. All other cases were Tac-negative and approximately 65% of these cases exhibited reactivity with TU14. Preliminary cytogenetic observations suggest that there are also differences in specific chromosome aberrations.

Immunoglobulin subclasses of antibodies to human T-cell leukemia/lymphoma virus I-associated antigens in acquired immune deficiency syndrome and lymphadenopathy syndrome

Immunoglobulin G (IgG) and IgM antibodies to human T-cell leukemia/lymphoma virus-I (HTLV-I)-associated membrane antigens (HTLV-I-MA) were assayed by indirect cytospin immunofluorescence, and IgG and IgM antibodies to purified HTLV-I were assayed by enzyme-linked immunosorbent assay in sera from 119 immunologically well-characterized promiscuous male homosexuals in The Netherlands, of whom 9 suffered from acquired immune deficiency syndrome (AIDS), 18 suffered from lymphadenopathy syndrome (LAS), and 5 suffered from gay bowel syndrome. Antibodies to HTLV-I-MA were present in four of nine AIDS patients, including one patient with antibodies to purified HTLV-I. Antibodies to HTLV-I-MA were present in 6 of 18 LAS patients, including 3 patients with antibodies to purified HTLV-I. Of five patients with gay bowel syndrome, one had IgG and IgM antibodies to HTLV-I-MA. Of the four HTLV-I seropositive AIDS patients, two had IgG and IgM antibodies to HTLV-I or HTLV-I-MA, one had only IgG antibodies, and one had only IgM antibodies. Of the six HTLV-I seropositive LAS patients, four had IgG and IgM antibodies to HTLV-I or HTLV-I-MA, and two had only IgM antibodies. In the sera from 27 healthy homosexuals with and 60 without T-cell subset imbalances, no antibodies to HTLV-I or HTLV-I-MA were detected.

Cell surface markers in leukemia: biological and clinical correlations

Recent advances in analysis of leukemic cell phenotypes using cell surface markers have provided important insights into leukocyte differentiation and the cellular origin of leukemia. In addition to the traditional cell surface markers, i.e., surface membrane immunoglobulin and receptors for sheep erythrocytes that define B and T lymphocytes, highly specific monoclonal antibodies have been developed that discriminate various stages of human lymphocyte and granulocyte differentiation. Explorations of the detailed phenotypes of leukemic cells in relation to normal hemopoietic differentiation reveal that consistent, composite phenotypes of different subclasses of lymphoid malignancies closely mimic those of corresponding normal cells at equivalent levels of maturation. This is exemplified in lymphoma cells (chronic lymphocytic leukemia of B or T type, Sezary Syndrome, immunocytoma) that resemble mature and immunocompetent T and B cells, in T cell acute lymphoblastic leukemia (T-ALL) (equivalent to thymus cells) and in non-T ALL (corresponding to lymphoid progenitor cells in the bone marrow). The major phenotypes documented in different leukemias represent the level of maturation arrest imposed on the dominant subclone; this is determined by, but not necessarily synonymous with, the target cell and associated clonogenic cell population in the leukemia. The clinical significance of immunodiagnosis of leukemia cell types becomes best evidenced in acute leukemias. Besides the improvement of diagnosis by using objective criteria, clinically useful subclassifications became evident: five major subtypes of ALL are now recognized, including unclassified or null ALL, common ALL, pre-B-ALL, B-ALL and pre-T/T-ALL. In addition to disclosing that ALL is an heterogeneous disease, such classifications have proved to be prognostically significant. This is exemplified in 248 children and 145 adults with ALL which were analysed for cell type and clinical data. In addition to their utility in leukemia classification, monoclonal antibodies that identify leukemia associated antigens are becoming used therapeutically, e.g., to lyse residual leukemia cells from remission bone marrows removed from leukemia patients before reinfusion. New approaches to the treatment of leukemia in which the objective is to encourage maturation of leukemia cells rather than to achieve leukemia eradication, can be monitored by phenotyping the alterations of the cell surface, and cell markers may hopefully be useful in identifying cell types that can be induced to differentiate.

Antibodies to adult T-cell leukemia virus (ATLV/HTLV-I) in AIDS patients and people at risk of AIDS in Germany

A total of 2048 serum samples from Germany were examined for antibodies to adult T-cell leukemia virus (ATLV) structural polypeptides with an enzyme-linked immuno sorbent assay (ELISA) and confirmative immuno precipitation. The origin of the sera samples was: 850 samples taken for virological or protozoal diagnosis; 626 samples from male homosexuals, about 20% of whom had lymphadenopathy syndrome; 164 from hemophiliacs; 184 were from multiple transfused, mostly dialysis patients; 9 from intravenous drug abusers; 182 from suspected cases of acquired immuno deficiency syndrome (AIDS) and 33 from AIDS-patients. In none of these sera did we detect antibodies to ATLV, except in the serum of one patient who had been on hemodialysis for over 11 years. Obviously infection with ATLV or a serologically related agent is very rare in our country and an association with AIDS could not be observed.

Clinical features of OKT4+/OKT8+ adult T-cell leukemia

Adult T-cell leukemia (ATL) has a range of clinical characteristics. Phenotypically the leukemic cells usually express the helper/inducer associated antigen OKT4 with lack of OKT8. We have observed three patients with acute ATL cytologically indistinguishable from OKT4+/OKT8- ATL but whose neoplastic cells had the unusual phenotype, OKT3+, OKT4+, OKT6-, OKT8+ OKT9+/-, OKT11+, Tac+/-, TdT-. All patients had abnormal karyotypes and antibodies against anti-ATL associated antigens as well as proviral DNA of human T-cell leukemia virus in the leukemic cells. The clinical course was complicated by skin eruptions, hypercalcemia, pulmonary infection and disseminated intravascular coagulopathy. All died of complications shortly after diagnosis. The clinical features of these patients were similar to those of OKT4+/OKT8- ATL. However, their acute course suggests that co-expression surface antigens OKT4 and OKT8 may be a sign of aggressive nature of the disease with poor prognosis.

Monoclonal antibodies and cutaneous T cell lymphoma. Theoretical and practical considerations

The T cell nature of mycosis fungoides and Sézary syndrome was established a decade ago. The recent advent of monoclonal antibodies to T cells and other lymphoid subpopulations has resulted in an explosion of knowledge on the biology of this group of disorders. These reagents have increased our knowledge on thymic differentiation status, pathogenesis, the phenotype of premalignant vs malignant lymphocytic infiltrates, the identification of other previously unrecognized cells within lymphomas, and the phenotype of circulating vs skin lymphocytes. Therapeutic applications may result. These new developments are discussed.