Alterations in T-lymphocyte subpopulations in type I diabetes. Exploration of genetic influence in identical twins

To evaluate factors influencing the alteration in subsets of T-lymphocytes, we studied 24 pairs of identical twins discordant for insulin-dependent (type I) diabetes mellitus. Subsets were assessed by monoclonal antibodies and a pure preparation of peripheral blood mononuclear cells obtained by centrifugation of heparinized whole blood with a Ficoll/Triosil gradient. In 12 pairs studied within 5 yr of diagnosis, we observed a reduction in the percentage of cells reacting with OKT8 (recognizing the CD8 antigen present on the suppressor/cytotoxic subset) (P less than .05), but a similar level was detected in their nondiabetic cotwins. In 12 pairs studied greater than 5 yr after the diagnosis and in whom the nondiabetic twin is less likely to develop diabetes, the percentage of cells reacting with OKT8 was reduced in both the diabetic (P less than .05) and the nondiabetic (P less than .01) twins. Reductions were also seen with OKT3 (recognizing the CD3 antigen present on the total T-lymphocyte population) and OKT4 (recognizing the CD4 antigen present on the helper/inducer subset), but only in the diabetic twins from the group with longer discordance. We conclude that a reduced percentage of suppressor/cytotoxic cells is associated with type I diabetes, but the reduction appears to be genetically determined. Total T-lymphocytes are also reduced but mainly in the helper/inducer subset and only in diabetic patients of long duration. Such a reduction cannot therefore be primarily genetically determined.

Specific cytotoxic activity of T lymphocyte clones derived from a patient with gliosarcoma

Eleven lymphocyte clones were established from the peripheral blood lymphocytes of a patient with gliosarcoma by means of autologous tumor stimulation and the limiting-dilution technique with recombinant interleukin-2. Ten of the 11 clones were cytotoxic against the autologous tumor cell line GI-1. Seven of the 10 clones were also cytotoxic against allogeneic brain-tumor lines and HeLa cells, one clone was cytotoxic against several target cells, and two clones were specifically cytotoxic against GI-1 and allogeneic brain-tumor cells. One of the 11 clones was not cytotoxic against any target cells tested. Lymphokine-activated killer cells induced by recombinant interleukin-2 alone exhibited cytotoxic activity against all target tumor cells tested. Surface phenotypic analysis revealed that all lymphocyte clones expressed CD3 antigen, some expressed CD4 antigen, and others expressed CD8 antigen. These clones seemed to be antigen-specific cytotoxic T lymphocyte clones. Analysis with these antigen-specific cytotoxic T lymphocyte clones may be useful in the elucidation of tumor-specific or tumor-associated antigens on autologous tumor cells.

Limiting-dilution analysis of human CTL differentiation. Requirement for a lymphokine-mediated differentiation signal

The induction of human influenza virus-specific memory cytotoxic T lymphocytes (CTL) from CTL precursors (CTLp) was investigated using limiting-dilution cultures and cell lines. Differentiation of maximal numbers of CTLp in limiting-dilution cultures required at least three signals: antigen stimulation, interleukin-2 (IL-2), and a differentiation factor distinct from IL-2. Antigen-specific CTLp proliferated in response to antigen stimulation and recombinant DNA-derived IL-2, but often failed to acquire cytolytic activity unless conditioned medium (CM) from mitogen-stimulated peripheral blood mononuclear cell (PBMC) cultures was added to the cultures. Temporal analysis of the requirement for CM indicated that it was providing a late signal for CTLp differentiation. This analysis was confirmed by developing CTLp cell lines, which were found to proliferate in response to IL-2 and antigen but not to exhibit influenza virus-specific cytotoxicity until CM was added.

Intestinal nodular lymphoid hyperplasia in patients with common variable immunodeficiency: local accumulation of B and CD8(+) lymphocytes

Common variable immunodeficiency (CVI) with hypogammaglobulinemia is often complicated by nodular lymphoid hyperplasia of the intestine. In this study the lymphoid constituents of intestinal nodular hyperplasia of five CVI patients were characterized with monoclonal antibodies. Few CD4(+) but abundant CD8(+) T lymphocytes were found around the follicles. The follicles were populated mainly by B cells expressing surface IgM. A few cells in the lamina propria expressed Leu7. No intracytoplasmic immunoglobulin-containing plasma cells were seen. Peyer's patches in gut biopsies from controls were also composed of follicles with B lymphocytes. A ring of T lymphocytes surrounded the follicles. CD4(+) helper cells largely outnumbered CD8(+) cells in this ring. Moreover, plasma cells were present in the lamina propria and the mixed cell zone covering the follicles. In peripheral blood of the patients, B cells were present in normal proportions but they could not be induced to produce IgG in vitro by T cell-dependent (pokeweed mitogen) or T cell-independent (Staphylococcus aureus Cowan I) mitogens. In two of the patients, IgM production could be induced in vitro. Peripheral blood T cells were predominantly CD8(+) in three of the five patients, and in these same patients an increase in suppressor-cell activity of peripheral blood T cells on immunoglobulin production was observed. The data demonstrate a block in B-cell differentiation in the gut and in peripheral blood. Whether the local increase in CD8(+) cells in the nodular lymphoid hyperplasia is a primary event or is secondary to chronic immune stimulation and whether it contributes to local inhibition of B-cell differentiation remain to be investigated.

Application of orthogonal light scattering for routine screening of lymphocyte samples

Orthogonal and forward light-scattering properties of lymphocytes were measured from patients with different lymphocytic diseases in order to determine the potential value of light scattering as a screening device. Monitoring of orthogonal light scattering of lymphocytes of a B-cell chronic lymphocytic leukemia patient during splenic irradiation (SI) revealed the selective decrease of malignant cells and the fact that the major part of the residual lymphocytes were cytotoxic lymphocytes. By combining forward and orthogonal light scattering it was shown that lymphocytes from a patient with T gamma lymphocytosis were abnormal. Orthogonal light scattering also showed an increase in cytotoxic lymphocytes in a patient with mononucleosis infectiosa and in a splenectomized patient. Orthogonal light scattering of lymphocyte subpopulations showed that the leu8+ population of a patient with mononucleosis infectiosa was bidisperse. For elderly donors the occurrence of CD3+, CD4+, CD8+, and HNK-1+ lymphocytes with a large orthogonal light scattering varied considerably. The CD8+ lymphocytes of these donors consisted mainly of cytotoxic lymphocytes. These results show that determination of light-scattering properties of lymphocytes may yield important diagnostic information and can indicate when further investigation of the lymphocytes by means of immunofluorescence is necessary.

Activation of HLA-restricted EBV-specific cytotoxic T cells does not require CD4+ (helper) T cells or exogenous cytokines

MHC-restricted, viral Ag-specific "memory" CTL are thought to play a decisive role in the defense against pathogenic viruses. However, the requirements for activating such CTL remain controversial. In particular, the role of CD4+ helper cells and their soluble products (e.g., IL-2) are uncertain. To approach these questions as they relate to EBV-specific CTL, highly purified CD8+ T cells from healthy EBV-seropositive individuals were cultured with autologous irradiated EBV-transformed B lymphoblastoid cell lines (LCL), in the presence or absence of autologous CD4+ cells or 1 to 10 U/ml purified rIL-2. The results indicate that the induction of CTL requires neither Th cells nor exogenous IL-2. The CTL generated from isolated CD8+ cells were HLA class I restricted as demonstrated by their ability to lyse targets sharing at least one HLA-A or -B Ag with the stimulating autologous LCL. Furthermore, a mAb (W6/32) to a common determinant on HLA class I Ag blocked both the generation and effector phases of killing, whereas an HLA class II directed mAb had no effect. Addition of an IL-2R-specific antibody (anti-Tac) to the culture medium blocked induction of CTL, suggesting that endogenously produced IL-2 plays an obligatory role in this system. Paraformaldehyde fixation of LCL abrogated their ability to function as stimulator cells; however, addition of 2 U/ml exogenous IL-2 to fixed LCL cultured with CD8+ cells allowed for the induction of highly specific CTL. These results indicate that EBV-specific memory CTL can be activated in the absence of CD4+ helper cells or their soluble products, but nonetheless require Ag and IL-2.

Stimulation and proliferation of CD4+ peripheral blood T lymphocytes induced by an anti-CD4 monoclonal antibody

There is experimental evidence that the CD4 molecule participates in the antigen-driven activation of T cells expressing this surface glycoprotein. Whether CD4, a member of the immunoglobulin supergene family, acts as a ligand-binding molecule and/or is directly involved in the activation pathway has yet to be established. In this study, we show that human CD4+ lymphocytes can be activated by exposure to the anti-CD4 monoclonal antibody (mAb) B66. Normal peripheral blood CD4+ cells were induced to proliferate and to synthesize interleukin 2 (IL 2) by the antibody. The specificity of the antibody stimulatory activity was tested by using IL 2-producing clones bearing either CD4 or CD8 on their surface. IL 2 production was induced by mAb B66 in CD4+, but not CD8+, clones, whereas both types of clones responded to stimulation by the anti-CD3 mAb Leu-4. Despite its unique stimulatory activity, mAb B66 shared with other anti-CD4 antibodies the ability to inhibit the specific cytolytic activity of CD4+ effector cells. These results clearly indicate that cross-linking of surface CD4 molecules with appropriate antibodies can fully activate CD4+ lymphocytes. Whether the natural ligand for CD4 can trigger this activation pathway remains to be defined.

Conjunctival lymphocyte subsets in trachoma

Monoclonal antibodies were used to assess the lymphocyte populations in conjunctival biopsy specimens obtained from patients with trachoma (active or inactive) undergoing tarsotomy for the correction of trachoma-induced entropion and in three control patients. Peroxidase-labelled monoclonal antibodies OKT4 (identifies T-helper/inducer lymphocytes), OKT8 (identifies T-suppressor/cytotoxic lymphocytes), OKIal (identifies B-lymphocytes) and antisera specific for IgG, IgA and IgM were used to identify lymphocyte subpopulations and immunoglobulins in the conjunctival biopsy specimens. When grouped by disease activity, conjunctival tissue specimens revealed predominant T-helper/inducer lymphocytes in the substantia propria of patients with active trachoma while inactive trachoma patients had predominant T-suppressor/cytotoxic lymphocytes in the conjunctival biopsy specimens. B-lymphocytes were seen in moderate numbers in all conjunctival biopsy specimens from patients with active trachoma and all specimens from active cases stained for IgG, IgM, and IgA. Immunoglobulin staining was strongest with IgG and IgM.

Immunologic identification of lymphocyte subsets in experimental murine myocarditis with encephalomyocarditis virus. Different kinetics of lymphocyte subsets between the heart and the peripheral blood, and significance of Thy 1.2+ (pan T) and Lyt 1+, 23+ (immature T) subsets in the development of myocarditis

To clarify the immune mechanism in myocarditis, immunofluorescence techniques with laser flow cytometry were used to examine serial changes in lymphocyte subsets in the heart, spleen, and peripheral blood of DBA/2 and BALB/c mice inoculated with encephalomyocarditis virus (Experiment I). B cells were identified by staining with fluorescein isothiocyanate-labelled rabbit anti-mouse immunoglobulin. T-cell subsets were identified with rat anti-Thy 1.2, and nonpolymorphic Lyt 1 and Lyt 2 monoclonal antibodies plus fluorescein isothiocyanate-labelled anti-mouse immunoglobulin. On days 7 and 14 postinfection, the percentage of Thy 1.2+ (pan T) cells in both strains had decreased in the peripheral blood; B cells showed no significant changes throughout the entire period. On the other hand, Thy 1.2+ (pan T) and Lyt 1+, 23+ (precursor and immature) T cells appeared to occupy the major portion of the myocardium on days 7 and 14 when congestive heart failure developed. To confirm this, serial immunohistologic studies (immunoperoxidase staining) of the hearts of DBA/2 and BALB/c mice with encephalomyocarditis virus-induced myocarditis were performed (Experiment II). In Experiment II, most of the stained cells in the hearts of both strains were Thy 1.2 positive and Lyt 1 and Lyt 2 positive on days 7 and 14. Thus, Experiments I and II demonstrated that lymphocytes at the site of inflammation in acute viral myocarditis carried antigenic markers that differed from those of peripheral lymphocytes and suggested that Thy 1.2+ (pan T) cells, especially the Lyt 1+, 23+ subset (immature T cells and T-cell subset precursors) were involved in the development of myocarditis in these animals.

T cell subsets in multiple sclerosis. Gradients at plaque borders and differences in nonplaque regions

This report provides a quantitative analysis of the distribution of helper-inducer T cells (H-I, LEU3A+) and cytotoxic-suppressor T cells (C-S, OKT8+) performed in a standardized fashion on material from 10 cases of multiple sclerosis. Particular attention was paid to cells at the plaque edge and to normal appearing white matter adjacent to plaques. Numbers of both the C-S and the H-I subset peaked directly at the edges of plaques, whether histopathologically active or inactive (P less than 0.01). Normal appearing areas outside active plaques had fewer C-S cells than equivalent areas outside inactive plaques (P less than 0.05). A study of three whole plaques showed that the sum of the two T cell subsets was significantly greater than the number of cells bearing the pan-T cell marker in two plaques and in two border regions. The present results support a crucial role for the balance of T cell subsets in the evolution of plaque margins. When taken together with similar findings in experimental allergic encephalomyelitis, they suggest that helper-inducer cell dominance at the border is necessary for plaque expansion while C-S dominance in non plaque areas is associated with controlled disease. In addition, they suggest either modulation of the OKT3 surface antigen or the presence of a non-T cell bearing OKT8 in association with the site of histopathological change.

Role of mast cells in the pathogenesis of hypersensitivity pneumonitis

To examine the possibility that mast cells have a central role in the pathogenesis of hypersensitivity pneumonitis, 20 patients with this disease were studied with the aim of seeking evidence for mast cell degranulation. The number of mast cells recovered by bronchoalveolar lavage from patients with hypersensitivity pneumonitis was more than 1,000 times greater than those recovered from normal individuals. Furthermore, discontinuation of antigen exposure resulted in an increase in the number of mast cells observed, consistent with the possibility that antigen exposure had induced mast cell degranulation. Cessation of antigen exposure also resulted in a rapid decrease in the number of neutrophils and eosinophils recovered by lavage, followed by an increase in the number of T8+ T lymphocytes present. In each case the time course of the changes was consistent with the possibility that mast cell degranulation had been important in regulating the number of the immune and inflammatory cells present in the lung. Histamine was present in lavage fluid supernatant from patients with hypersensitivity pneumonitis. The amount of histamine present was, however, closely correlated with the number of mast cells present and not with the interval since last antigen exposure. Delay in separating cells from lavage fluid supernatant resulted in an increase in histamine content. These results suggest that the free histamine in lavage fluid resulted from the degranulation of mast cells induced by the lavage procedure as histamine released in vivo has a short half life. We suggest that hypersensitivity pneumonitis results from a "late phase reaction" initiated by antigen induced mast cell degranulation.

Lichenoid tissue reaction (LTR) induced by local transfer of Ia-reactive T-cell clones. II. LTR by epidermal invasion of cytotoxic lymphokine-producing autoreactive T cells

Recent studies have suggested that T lymphocytes with helper phenotype may play an important role in the pathogenesis of lichenoid tissue reactions (LTR). In order to elucidate whether murine self-Ia-specific autoreactive T cells with helper phenotype can induce LTR in naive syngeneic hosts, two clones of autoreactive cloned T cells with both helper and cytotoxic activities, capable of producing the cytotoxic lymphokines gamma interferon and lymphotoxin in response to self-Ia antigens, were examined for their ability to induce LTR. One clone, BB5, when injected into footpads of syngeneic hosts, induced prominent epidermotropic cellular infiltrates that led to basal vacuolar degeneration and Civatte body formation; the other clone, C10, did not. No difference between BB5 and C10 was detected with respect to their ability to induce delayed-type hypersensitivity reactions. Immunohistochemical studies using anti-Lyt monoclonal antibodies showed that BB5-induced LTR was induced by the epidermal invasion of the injected BB5 cells themselves. We further observed that the infusion of BB5 cells not only resulted in Ia antigen expression on keratinocytes, but was also accompanied by a morphologic change in Langerhans cells at 24 h, when the epidermal invasion had not yet developed. However, similar observations were also observed with C10 cells, indicating that Ia expression on keratinocytes may not be a prerequisite for the induction of LTR.

Aberrant T cells in beige mutant mice

Cytotoxic T lymphocyte (CTL) morphology and function was examined in beige (bg/bg) mutant mice during infection with lymphocytic choriomeningitis virus (LCMV). Virus-specific, class I-restricted CTL activity mediated by total spleen leukocytes isolated from bg/+ or +/+ mice on days 7 or 9 postinfection with LCMV was moderately higher than that mediated by spleen cells isolated from bg/bg mice. The CTL generated in bg/bg mice had aberrant morphology. Lyt-2+ cells isolated from bg/+ or +/+ mice had typical large granular lymphocyte (LGL) morphology and contained numerous small azurophilic granules, whereas Lyt-2+ cells isolated from bg/bg mice contained only one or two large atypical granules in their cytoplasm. Aberrant LGL morphology correlated with reduced lytic capacity. The bg/bg CTL were inefficient killer cells mediating, on a per cell basis, only one fourth of the lysis mediated by bg/+ CTL. The bg/bg mice appeared to mount a compensatory response to regulate virus replication, because frequencies of Lyt-2+ cells and cells that specifically bound to virus-infected target cells were elevated as compared with their frequencies in bg/+ mice. The higher proportion of the CTL phenotype cells appeared to be a consequence of expanded proliferation of Lyt-2+ cells. These results demonstrate that, in comparison with bg/+ and +/+ mice, bg/bg mice have CTL with reduced lytic capacities, but may compensate during virus infection by expanding the number of these cells. Furthermore, these data suggest that the depressed lytic activity may be a consequence of aberrant granule formation.

Frequency analysis of augmented CTL production associated with Corynebacterium parvum-induced tumour regression

A limiting-dilution frequency assay was employed to estimate the increased production of cytolytic T lymphocytes (CTL) associated with Corynebacterium parvum-induced regression of the P815 mastocytoma growing subcutaneously in semisyngeneic mice. It was found that intratumour C. parvum functioned to augment greatly the underlying concomitant production of CTL that occurs normally in response to a progressively growing untreated immunogenic tumour. The lymph node draining a C. parvum-treated tumour contained about eight times more CTL than the lymph node draining a control tumour. Intratumour C. parvum also caused a large increase in CTL production in the spleen and an increase in the number of CTL that could accumulate in a peritoneal exudate. At the peak of the anti-tumour response, the largest number of CTL was found in the draining lymph node (1.66 X 10(5], followed by the spleen (3.47 X 10(4) and by a 24-hr casein-induced peritoneal exudate (6.01 X 10(3]. Presumably, this greatly augmented production of CTL explains why C. parvum given intralesionally early enough during tumour growth can cause the regression of the weakly immunogenic P815 mastocytoma.

Clonal analysis of T lymphocytes infiltrating the thyroid gland in Hashimoto's thyroiditis

T cells isolated from thyroid tissue and peripheral blood of 2 patients with Hashimoto's thyroiditis were studied by a high cloning efficiency microculture technique. Clonal efficiencies of 37 and 24% were obtained from thyroid-derived T cell cultures, while 40 and 90% efficiencies resulted from peripheral-blood-derived cultures. A prevalence of T4-/T8+ T cell clones were found in thyroid infiltrates. The functional analysis of the clones demonstrated significantly higher proportions of clones with cytolytic activity in a lectin-dependent assay in thyroid-derived microcultures, as compared to peripheral blood-derived ones. The proportion of clones displaying natural-killer-like activity was increased in 1 patient only. Cytolytic activity was displayed not only by all T4-/T8+, but also by several T4+/T8- intrathyroid clones. Remarkable proportions of cytolytic clones were also able to release interleukin-2 upon phytohemagglutinin stimulation. Finally, the proportion of T cell clones able to release gamma-interferon following mitogen stimulation was significantly higher in thyroid- vs. peripheral-blood-derived microcultures. These results provide further data about the possible pathogenetical role of both regulatory and effector T lymphocytes in human autoimmune thyroiditis.

New aggressive variant of suppressor/cytotoxic T-CLL

Three cases of CD8+ CLL are reported. The patients are young (28, 18, 27 years old). The leukemia cells are predominantly small lymphocytes with irregular nuclei bearing notches and lobations. Cytoplasmic azurophilic granules are absent. Cytochemistry shows periodic acid-Schiff granular, alpha-naphthylacetate esterase focal, and acid phosphatase focal/granular positivities. Immunophenotypically cells are CD2+, CD3+, and CD8+ and lack CD4 as well as B-cell and NK cell antigens. All patients died within 20, 16, and 9 months, respectively. The clinicopathologic features of these cases differ clearly from those of the CD8+ CLL with azurophilic granules. These three cases represent a morphologically distinctive and more aggressive variant of CD8+ CLL.

The value of lymph node biopsy in patients with the acquired immunodeficiency syndrome (AIDS) and the AIDS-related complex (ARC): a morphological and immunohistochemical study of 90 cases

The morphological and immunohistochemical findings in lymph nodes of nine patients with the acquired immunodeficiency syndrome (AIDS) and 81 patients with the AIDS-related complex (ARC) are presented. Three basic histological patterns were observed: follicular hyperplasia (29 cases), mixed hyperplasia (49 cases) and lymphocyte depletion (12 cases). While the first two variants were detected in typical ARC patients, lymphocyte depletion was always associated with AIDS. Immunohistochemistry on frozen sections showed that the number of B-cells varied throughout the series, being higher in the follicular type and significantly lower in the lymphocyte depletion nodes. The content of T-lymphocytes of the helper/inducer (T4) phenotype was reduced in all instances; this reduction was more pronounced in the germinal centres in follicular hyperplasia, while it involved all compartments of the node in the mixed and lymphocyte depletion types. In contrast the cytotoxic/suppressor (T8) subset was increased in the follicular and mixed hyperplasias only. Partial disintegration of the dendritic network in at least some of the follicles could be demonstrated in all lymph nodes. In the follicular and mixed hyperplasias there was a high number of proliferating B-cells in the germinal centres. Our data indicate the usefulness of grading the changes occurring in lymph nodes of patients with ARC and AIDS, and allow speculation as to the pathophysiology of these conditions.

Leukemic cells arise from cloned cytotoxic lymphocytes during cell culture

In spite of many promising attempts to apply T cell clones to questions of in vitro and in vivo function of T cells it is still unclear to what extent continuous propagation of T lymphocytes in vitro effects their original properties. This study describes the appearance of malignant cells from long-term cultured C57BL/6 (B6) cytotoxic T lymphocytes (CTL). Four out of five T cell lines (CTLL.1,3,4,5) representing distinct stages of development of T effector cells in vitro were repeatedly cloned and all five CTLL were tested for various cellular parameters. It is shown that transformation of H-Y-specific CTLL into malignant cells in vitro was accompanied by alterations in growth characteristics, successive loss of specificity and cytolytic function and by quantitative changes in the expression of cell surface markers. Whereas growth of the H-Y-specific CTLL (CTLL.1) was dependent on antigen and concanavalin A (Con A) supernatant (Con ASN) the CTLL variants could be either maintained in Con ASN alone (CTLL.3) or in the absence of both antigen and lymphokine sources (CTLL.4,5). CTLL.1 was cytolytic for male B6 target cells and lysed P815 tumor targets in the presence but not the absence of lectin. In contrast, CTLL.3 lost its original specificity but lysed P815 cells in the absence or presence of lectin. CTLL.2 representing an intermediary stage showed cytolytic activity on both male B6 and P815 target cells. In contrast, CTLL.4 and CTLL.5 lost the ability to lyse any of the indicated target cells. Although all CTLL expressed the surface markers Thy-1, Lyt-2, Kb, Db and interleukin 2 receptor (IL 2 R), Thy-1 and Lyt-2 markers were drastically reduced and Kb/Db and IL 2 R structures significantly increased on CTLL.4 and CTLL.5 compared to CTLL.1,2,3. In addition, multiple karyotypic alterations including the appearance of metacentric chromosomes were observed in long-term cultured CTLL. Investigations on the expression of the alpha-, beta-, and gamma-chains of the T cell antigen receptor in CTLL.1-5 indicate that all three chains were expressed as mRNA irrespective of whether the lymphocytes expressed their original specificity and/or function. However, distinct beta variable chain genes were used by H-Y-specific CTLL and its long-term culture variants CTLL.2 and CTLL.3 suggesting that the expression of the new specificity was accompanied by the rearrangement of a new beta-chain gene in T effector cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Nephrotic syndrome associated with a clonal T-cell leukemia of large granular lymphocytes with cytotoxic function

A 51-year-old man presented with a T-cell leukemia of large granular lymphocytes and rapidly developed a nephrotic syndrome due to presumptive minimal-change glomerulopathy. The E-rosette+, Ia+ cells demonstrated cytotoxic activity similar to that of natural killer lymphocytes but lacked other T-subset markers, except that one third of them bore Fc(IgG) receptors. Cytogenetic analysis revealed loss of chromosome 10 and the translocation (1;10)(p11;q11) in all metaphases. Regression of the leukemia after chemotherapy was accompanied by a dramatic resolution of the nephrotic syndrome, suggesting that the activated granular lymphocytes induced the renal lesion. The close association of a clonal T-lymphoproliferative disorder with minimal-change nephrotic syndrome lends further support to current views implicating activated T cells or their products in the pathogenesis of this glomerulopathy.

Characterization of a tumorigenic murine T-lymphoid-cell line spontaneously derived from an IL-2-dependent T-cell line

The establishment of IL-2-independent T-cell lines spontaneously derived from long-term IL-2-dependent cytotoxic T-cell lines is described. Two lines (cloned and uncloned) studied in detail have shown the following characteristics: (1) Permanent loss of IL-2 dependence. (2) Partial or complete loss of both cytotoxic activity and the IL-2 receptor. (3) Increased expression of T-cell membrane markers (Thy1.2, Lyt1.2) compared with the parental line. (4) Lower level of DNA methylation than in freshly obtained lymphoid cells. (5) Different karyotypic pattern from the parental IL-2-dependent line, with a mean number of 39-40 chromosomes and a resemblance to T leukemic lines. (6) Leukemia caused in normal syngeneic C57BL/6 mice by the uncloned line, in contrast to the cloned IL-2-independent line or the parental dependent line. Unlike established leukemic lines, however, the independent line gave rise to tumors which regressed in some mice within a few days of their appearance. These findings suggest that T-cell lines maintained with IL-2 for prolonged periods of time (greater than 3 months) can undergo transformation and, therefore, should not be utilized for immunotherapeutic purposes.