Barbara M. Wilkes

Immune control of HIV-1 after early treatment of acute infection

Virus-specific T-helper cells are considered critical for the control of chronic viral infections. Successful treatment of acute HIV-1 infection leads to augmentation of these responses, but whether this enhances immune control has not been determined. We administered one or two supervised treatment interruptions to eight subjects with treated acute infection, with the plan to restart therapy if viral load exceeded 5,000 copies of HIV-1 RNA per millilitre of plasma (the level at which therapy has been typically recommended) for three consecutive weeks, or 50,000 RNA copies per ml at one time. Here we show that, despite rebound in viraemia, all subjects were able to achieve at least a transient steady state off therapy with viral load below 5,000 RNA copies per ml. At present, five out of eight subjects remain off therapy with viral loads of less than 500 RNA copies per ml plasma after a median 6.5 months (range 5–8.7 months). We observed increased virus-specific cytotoxic T lymphocytes and maintained T-helper-cell responses in all. Our data indicate that functional immune responses can be augmented in a chronic viral infection, and provide rationale for immunotherapy in HIV-1 infection.

T-Cell chronic lymphocytic leukemia: Report of a case studied with monoclonal antibody

A previously healthy 74 year old woman presented with T-cell chronic lymphocytic leukemia, lymphadenopathy, hepatosplenomegaly and a mediastinal mass. The circulating lymphocytes were small to medium in size (some with convoluted nuclei) and W rosette-positive; they could be assigned to the inducer-helper subset of T cells with the acid of monoclonal antisera. These cells reacted with OKT3, which detects peripheral T cells; OKT4, which detects the inducer-helper subset of T cells; and OKT11, which detects the sheep cell receptor. It is noteworthy that they were also positive for the la-like antigen found on T cells only after activation. Microscopic examination of a lymph node biopsy specimen revealed a diffuse pattern of pleomorphic large cells characteristic of the T-cell lymphomas and lymphocytic leukemias reported from Japan. However, the lymph node cells lacked the T-cell differentiation antigens present on the circulating lymphocytes. The findings in this case provide insight into the pathogenesis of this unusual disorder and are relevant to our understanding of the spectrum of surface antigens in the more common malignant lymphomas.

Rearrangement of the gene for the beta chain of the T-cell receptor in T-cell chronic lymphocytic leukemia and related disorders

Although monoclonal B-cell populations can be identified both by surface-marker analysis and by immunoglobulin-gene rearrangements, this has not been possible with T cells. We have employed cDNA probes that are specific for the entire beta chain of the T-cell receptor, and for its constant and variable regions, to investigate gene rearrangements in T-cell chronic lymphocytic leukemia and related disorders. In three malignant proliferations of helper (T4-positive) T cells, rearrangements of the beta-chain constant-region gene were readily demonstrated. A patient from the Caribbean who had adult T-cell lymphoma and antibody to human T-cell lymphotrophic virus Type I (HTLV-I), a patient with virus-negative chronic lymphocytic leukemia, and a patient with cutaneous T-cell lymphoma (Sézary variant) made up the T4-positive group. Three additional patients with chronic T8 (cytotoxic-suppressor) lymphocytosis and neutropenia were studied; in two; rearrangements were found. In all five patients with constant-region rearrangements, deletions of variable-region restriction fragments were observed as well. The presence of rearrangements of a T-cell receptor gene provides presumptive evidence for the clonal nature of T-cell proliferation and for its neoplastic character.

bcl‐2 Rearrangements in de novo diffuse large cell lymphoma. Association with distinctive clinical features

Background. The frequency and clinical significance of bcl‐2 rearrangement in de novo B‐cell diffuse large cell lymphoma is largely unknown.

Cell surface phenotype in lymphoproliferative disease.

Abstract The surface phenotype of peripheral blood lymphocytes from 45 patients with chronic lymphocytic leukemia (CLL) and of lymphoid tissue from 100 patients with other lymphoproliferative disease was determined. Surface immunoglobulin (SIg) and complement receptor were employed as B cell markers, and reactivity with sheep erythrocytes (E rosettes) and antithymocyte globulin was used to identify T cells. Of these markers, only SIg and E rosettes reliably identified cells of the respective lineages. SIg identification with fluorescent antiserums had the added advantages of allowing the discrimination between different B cell subsets on the basis of staining intensity, and establishing the clonal character of a proliferation by the presence of predominant light and heavy chains. A uniform surface phenotype was observed in CLL, characterized by faintly staining SIgM with or without SIgD (one sixth of the patients were SIgG-positive instead), the presence of complement receptor, and the absence of reactivity with either sheep erythrocytes or antithymocyte globulin. Nodular (poorly differentiated lymphocytic) lymphoma was also uniformly of B cell lineage, but staining for SIgM was brighter (one third of these tumors were instead SIgG-bearing): Although cell suspensions of these neoplasms were uniformly E rosette-negative, the presence of complement receptor and reactivity with antithymocyte globulin were variable. Diffuse poorly differentiated lymphocytic lymphoma and two cases of Burkitts lymphoma were very bright SIgM-positive, E rosette-negative neoplasms. Sixty per cent of the diffuse histiocytic lymphomas exhibited either SIgM- or SIgG-positive B cells which stained brightly, but the other 40 per cent comprised tumors either of T cell lineage or of a phenotype which could not be conclusively identified. The mixed histiocytic and lymphocytic lymphomas, which occupy an awkward place in pathology, could not be defined by surface markers. Surface markers should not replace routine pathologic criteria as the basis of classifying lymphoma, but cell phenotype is proving an increasingly useful added dimension for understanding and classifying this complex group of diseases.

Immunoglobulin gene rearrangements in adult non-hodgkin's lymphoma

Southern blotting was employed to analyze the immunoglobulin heavy and light chain genes and the gene for the T cell receptor beta chain in genomic DNA derived from the tumor specimens of 120 adults with pathologically classified and immunotyped non-Hodgkins lymphoma and B cell chronic lymphocytic leukemia. In a consecutive series of 100 patients, one or two rearranged heavy chain genes could be detected in each of the 80 samples expressing clonal surface immunoglobulin. The kappa gene was rearranged in 70 percent of kappa-bearing tumors and in 23 percent of lambda-bearing specimens. Furthermore, a rearranged immunoglobulin gene was also observed in 21 of 29 lymphomas (nine from the consecutive series and 20 selected for surface immunoglobulin-negative status) in which B cell lineage was in doubt because of absent clonal surface immunoglobulin. These findings indicate that most cases of lymphoma and lymphocytic leukemia in adults are of B cell lineage, even when phenotypic evidence is inconclusive. The exceptional cases (only 3 percent in the consecutive series) were of either follicular lymphoma or diffuse large cell (histiocytic) lymphoma subtype; the lineage in cases of diffuse lymphocytic lymphoma or chronic lymphocytic leukemia was never in doubt. Although the convenience of surface marker analysis assures its continuing clinical application, gene study resolves indeterminate cases and extends the understanding of the pathogenesis of lymphoproliferative disease.

The predominant lymphocyte in most thymomas and in nonneoplastic thymus from patients with myasthenia gravis is the cortical thymocyte

Cell suspensions prepared from 12 specimens of nonneoplastic thymus (6 normal and 6 from patients with myasthenia gravis) and from 17 thymomas were investigated with a panel of monoclonal antibodies. The great preponderance of thymocytes from the 12 nonneoplastic specimens and from 13 of the 17 thymomas (2 of 3 predominantly lymphocytic tumors and 11 of 12 mixed tumors) displayed the surface phenotype of cortical or common thymocytes. These cells formed rosettes with unsensitized sheep erythrocytes (E-rosettes) at both 4 and 37 degrees C, and reacted with the following monoclonal antibodies: OKT1 (thymic and peripheral T cells), OKT6 (common thymocytes), OKT10 (replicating lymphoid cells), OKT11 (sheep cell receptor), and both OKT4 (inducer-helper T cells) and OKT8 (cytotoxic-suppressor T cells). Few B cells (lymphocytes with either immunoglobulin or Ia-like antigen on the cell surface), and few cells with receptors for transferrin and interleukin 2 were detected. Thymocytes from 3 of the 4 remaining thymomas (2 predominantly epithelial tumors and 1 mixed tumor) displayed surface marker characteristics of medullary thymocytes or peripheral T cells; i.e., they were reactive with OKT1, OKT3 (peripheral T cells), OKT11, and either OKT4 or OKT8, and were also E-rosette positive only at 4 degrees C and TdT negative. Thymocytes from the final tumor, a lymphocytic thymoma, exhibited an intermediate phenotype. Thus, almost all mixed (11 of 12) and lymphocytic (2 of 3) thymomas were composed predominantly of cortical thymocytes, while the medullary cell was the rule in the two tumors that were predominantly epithelial.

Rearrangement of the genes for the beta and gamma chains of the T cell receptor is rarely observed in adult B cell lymphoma and chronic lymphocytic leukemia.

We determined the configuration of the genes for the beta (T beta) and gamma (T gamma) chains of the T cell receptor in DNA from 100 consecutive cases of B cell lymphoma and B cell chronic lymphocytic leukemia (B-CLL), and compared the findings with those in 18 T cell neoplasms. In 7 of the 100 B cell specimens, a single nongermline band was detected after digestion with the restriction enzyme BamHI, but the rearrangement could be confirmed with a second restriction enzyme in only two. The B cell fragments were small in size and of limited size diversity when compared with the T cell cases, and germline bands of equal intensity were present. A rearrangement of the T gamma gene was never seen in a B cell sample. In contrast, T cell specimens usually rearranged both alleles of T beta (15 of 18), the rearrangement could be confirmed with a second restriction enzyme (17 of 18), both alleles of the first constant region gene segment of T beta always underwent either rearrangement or deletion, and the T gamma gene was also rearranged or deleted (17 of 18). We conclude that ordered rearrangement of the T cell receptor is a rare event in B cell lymphoma and B-CLL. T cell receptor gene studies allow B and T cell lymphomas to be distinguished from each other and from common acute lymphoblastic leukemia antigen-positive non-T, non-B acute lymphoblastic leukemia.

Lymphocyte surface markers in orbital lymphoid neoplasms.

Since the malignant nature of many orbital lymphoid infiltrates is difficult to assess from pathologic examination alone, over the past four years lymphocyte surface marker studies have been added to the evaluation of 23 such cases. Only 10 of the 23 could be confidently classified as malignant lymphoma by histology alone. However, monoclonal surface immunoglobulin was found in 15, supporting the pathologic diagnosis of malignancy in eight and adding seven that could not have been diagnosed otherwise. Clinical evaluation, including a median follow-up of 18 months, revealed manifestations of systemic lymphoma in six of those 15; two had been diagnosed only by surface markers. In contrast, only one of eight cases lacking monoclonal surface immunoglobulin exhibited clinical evidence of malignancy (that case was also indeterminate by histologic criteria). The addition of surface marker analysis permits more accurate diagnosis of orbital lymphoma than is possible from pathologic study alone. This technique can suggest the subtype of lymphoma.