Daniel M. Knowles

KAPOSI'S SARCOMA-ASSOCIATED HERPESVIRUS-LIKE DNA SEQUENCES IN AIDS-RELATED BODY-CAVITY-BASED LYMPHOMAS

BACKGROUND DNA fragments that appeared to belong to an unidentified human herpesvirus were recently found in more than 90 percent of Kaposis sarcoma lesions associated with the acquired immunodeficiency syndrome (AIDS). These fragments were also found in 6 of 39 tissue samples without Kaposis sarcoma, including 3 malignant lymphomas, from patients with AIDS, but not in samples from patients without AIDS. METHODS We examined the DNA of 193 lymphomas from 42 patients with AIDS and 151 patients who did not have AIDS. We searched the DNA for sequences of Kaposis sarcoma-associated herpesvirus (KSHV) by Southern blot hybridization, the polymerase chain reaction (PCR), or both. The PCR products in the positive samples were sequences and compared with the KSHV sequences in Kaposis sarcoma tissues from patients with AIDS. RESULTS KSHV sequences were identified in eight lymphomas in patients infected with the human immunodeficiency virus. All eight, and only these eight, were body-cavity-based lymphomas--that is, they were characterized by pleural, pericardial, or peritoneal lymphomatous effusions. All eight lymphomas also contained the Epstein-Barr viral genome. KSHV sequences were not found in the other 185 lymphomas. KSHV sequences were 40 to 80 times more abundant in the body-cavity-based lymphomas than in the Kaposis sarcoma lesions. A high degree of conservation of KSHV sequences in Kaposis sarcoma and in the eight lymphomas suggests the presence of the same agent in both lesions. CONCLUSIONS The recently discovered KSHV DNA sequences occur in an unusual subgroup of AIDS-related B-cell lymphomas, but not in any other lymphoid neoplasm studied thus far. Our finding strongly suggests that a novel herpesvirus has a pathogenic role in AIDS-related body-cavity-based lymphomas.

Non-Hodgkin's lymphoma in 90 homosexual men: relation to generalized lymphadenopathy and the acquired immunodeficiency syndrome

We describe the histologic and clinical features of non-Hodgkins lymphoma diagnosed between January 1980 and December 1983 in 90 homosexual men from San Francisco, Los Angeles, Houston, and New York. The median age was 37 years, with an age distribution identical to that for cases of AIDS reported to the Centers for Disease Control. Sixty-two per cent of the patients had high-grade (aggressive) subtypes of lymphoma, 29 per cent had subtypes of intermediate grade, and 7 per cent had low-grade subtypes. Histologic subtypes and malignant cell phenotypes were consistent with a B-cell origin. All but two men had extranodal lymphoma: central-nervous-system, bone-marrow, bowel, and mucocutaneous sites were most commonly involved. Thirty-five of 66 evaluable men (53 per cent) had complete responses to combination chemotherapy or radiotherapy or both, and thus far, 19 (54 per cent) of them have had a relapse. Mortality and morbidity were closely related to prodromal manifestations; death or illness have occurred in 19 (91 per cent) of the 21 men who presented with AIDS, in 26 (79 per cent) of the 33 who presented with generalized lymphadenopathy, and in 5 (42 per cent) of the 12 who had no prodromal manifestations. Mortality rates analyzed according to histologic grade were higher than currently reported rates in other patient populations. Kaposis sarcoma or severe opportunistic infections characteristic of AIDS developed in 14 of 33 men (42 per cent) who presented with generalized lymphadenopathy and in 3 of 12 (33 per cent) without prodromal manifestations. We conclude that non-Hodgkins lymphoma in members of an AIDS risk group is a serious manifestation of AIDS and the AIDS-related complex.

Tumours of histiocytes and accessory dendritic cells: An immunohistochemical approach to classification from the International Lymphoma Study Group based on 61 cases

Tumours of histiocytes and accessory dendritic cells: an immunohistochemical approach to classification from the International Lymphoma Study Group based on 61 cases

Lymphoid Neoplasia Associated with the Acquired Immunodeficiency Syndrome (AIDS): The New York University Medical Center Experience with 105 Patients (1981-1986)

We identified 105 patients with lymphoid neoplasia associated with the acquired immunodeficiency syndrome (AIDS) at the New York University Medical Center from 1981 through 1986: 89 had non-Hodgkin lymphoma; 13, Hodgkin disease; and 3, chronic lymphocytic leukemia. Immunophenotypic and antigen receptor gene rearrangement analysis showed the B-cell origin of all non-Hodgkin lymphomas studied and the clonal suppressor-cytotoxic T-cell subset origin of the chronic lymphocytic leukemias. We classified 69% of the non-Hodgkin lymphomas as high grade (small, noncleaved and large cell, immunoblastic-plasmacytoid) and 31% as intermediate grade (diffuse large cell). Each histopathologic category was correlated with distinct clinical features, including a statistically significant difference in median survival. Patients with Hodgkin disease had an atypical, aggressive clinical course, whereas patients with T-cell chronic lymphocytic leukemia had an indolent clinical course. These studies show the clinical, morphologic, and immunophenotypic spectrum of AIDS-associated lymphoid neoplasia, that the natural history of Hodgkin disease is altered in patients with AIDS, and support the Centers For Disease Controls recent revision in diagnostic criteria for AIDS to include intermediate-grade diffuse, aggressive non-Hodgkin lymphomas occurring in patients seropositive for human immunodeficiency virus.

B cell–helper neutrophils stimulate the diversification and production of immunoglobulin in the marginal zone of the spleen

Neutrophils utilize immunoglobulins (Igs) to clear antigen, but their role in Ig production is unknown. Here we identified neutrophils around the marginal zone (MZ) of the spleen, a B cell area specialized in T-independent Ig responses to circulating antigen. Neutrophils colonized peri-MZ areas after post-natal mucosal colonization by microbes and enhanced their B-helper function upon receiving reprogramming signals from splenic sinusoidal endothelial cells, including interleukin 10 (IL-10). Splenic neutrophils induced Ig class switching, somatic hypermutation and antibody production by activating MZ B cells through a mechanism involving the cytokines BAFF, APRIL and IL-21. Neutropenic patients had fewer and hypomutated MZ B cells and less preimmune Igs to T-independent antigens, which indicates that neutrophils generate an innate layer of antimicrobial Ig defense by interacting with MZ B cells.Neutrophils use immunoglobulins to clear antigen, but their role in immunoglobulin production is unknown. Here we identified neutrophils around the marginal zone (MZ) of the spleen, a B cell area specialized in T cell–independent immunoglobulin responses to circulating antigen. Neutrophils colonized peri-MZ areas after postnatal mucosal colonization by microbes and enhanced their B cell–helper function after receiving reprogramming signals, including interleukin 10 (IL-10), from splenic sinusoidal endothelial cells. Splenic neutrophils induced immunoglobulin class switching, somatic hypermutation and antibody production by activating MZ B cells through a mechanism that involved the cytokines BAFF, APRIL and IL-21. Neutropenic patients had fewer and hypomutated MZ B cells and a lower abundance of preimmune immunoglobulins to T cell–independent antigens, which indicates that neutrophils generate an innate layer of antimicrobial immunoglobulin defense by interacting with MZ B cells.

Lymphoid hyperplasia and malignant lymphoma occurring in the ocular adnexa orbit conjunctiva and eyelids a prospective multiparametric analysis of 108 cases during 1977 to 1987

We performed a prospective multiparametric correlative clinical, histopathologic, and immunologic analysis of 117 ocular adnexal lymphoid proliferations developing in 108 patients between October 1977 and July 1987. The ocular adnexal lymphoid proliferations were distributed among the 108 patients as follows: orbit 69 (64%), conjunctiva 30 (28%), and eyelids nine (8%). The 117 ocular adnexal lymphoid proliferations were classified as follows: polyclonal lymphoid hyperplasia, 32 (22 orbit, nine conjunctiva, one eyelid) (27%); monoclonal B cell lymphoma, 81 (48 orbit, 25 conjunctiva, eight eyelid) (69%); null cell lymphoma, one (orbit) (1%); and histologically indeterminate, three (one each: orbit, conjunctiva, eyelid) (3%). Patients presenting with ocular adnexal polyclonal lymphoid hyperplasia and monoclonal B cell lymphoma, and patients developing unilateral and bilateral ocular adnexal lymphoid proliferations did not differ significantly with respect to age, sex, presenting complaints, duration of symptoms, or ophthalmic findings. Classifying ocular adnexal lymphoid proliferations into benign and malignant categories by histopathologic criteria and into polyclonal and monoclonal B cell categories by immunophenotypic criteria was not useful in predicting eventual outcome, including the occurrence of extraocular lymphoma. However, the clinicopathologic characteristics did differ according to the anatomic site of involvement and histopathology of the ocular adnexal lymphoid proliferations. Lymphoid infiltrates of the conjunctiva were associated with a lower incidence of extra-ocular lymphoma (20%) than were those of the orbit and eyelid, 35% and 67%, respectively (statistically significant, P less than .03). Ocular adnexal small lymphocytic and intermediate lymphocytic lymphomas were less often associated with extra-ocular lymphoma than were ocular adnexal lymphomas of all other histologic types, 27% and 46%, respectively (P less than .09). However, the single most important and statistically significant prognostic factor in these patients was the extent of disease at the time of presentation with an ocular adnexal lymphoid proliferation (P less than .001). Eighty-six percent of patients presenting with a unilateral or bilateral clinical stage lE ocular adnexal lymphoid proliferation, regardless of the histopathology or the immunophenotype, had a benign indolent clinical course and failed to develop ocular or extra-ocular lymphoma during a median follow-up period of 51 months. The results of this study substantially improve our understanding of extranodal small lymphocytic proliferations in general, and those of the ocular adnexa in particular.

Focal nodular hyperplasia of the liver: a clinicopathologic study and review of the literature.

We received the clinical records and pathologic material of 20 patients with biopsy proven hepatic focal nodular hyperplasia. The majority of the patients were females of child bearing age, five of whom had a history of oral use of contraceptives. In every instance focal nodular hyperplasia was an incidental finding; liver function tests were always normal. Focal nodular hyperplasia is a distinct histopathologic entity, distinguishable from liver cell adenoma. Specifically it consists of nodular aggregates of cytologically normal hepatocytes with foci of intranodular bile duct proliferation. Focal nodular hyperplasia appears to be a benign entity, even in patients in whom the lesion was not excised. The association between focal nodular hyperplasia and oral use of contraceptives may be coincidental, although hormonally related vascular changes may be responsible for rupture of the lesion.

Lymphoma B Cells Evade Apoptosis through the TNF Family Members BAFF/BLyS and APRIL

The mechanisms underlying the autonomous accumulation of malignant B cells remain elusive. We show in this study that non-Hodgkin’s lymphoma (NHL) B cells express B cell-activating factor of the TNF family (BAFF) and a proliferation-inducing ligand (APRIL), two powerful B cell-activating molecules usually expressed by myeloid cells. In addition, NHL B cells express BAFF receptor, which binds BAFF, as well as transmembrane activator and calcium modulator and cyclophilin ligand interactor (TACI) and B cell maturation Ag (BCMA), which bind both BAFF and APRIL. Neutralization of endogenous BAFF and APRIL by soluble TACI and BCMA decoy receptors attenuates the survival of NHL B cells, decreases activation of the prosurvival transcription factor NF-κB, down-regulates the antiapoptotic proteins Bcl-2 and Bcl-xL, and up-regulates the proapoptotic protein Bax. Conversely, exposure of NHL B cells to recombinant or myeloid cell-derived BAFF and APRIL attenuates apoptosis, increases NF-κB activation, up-regulates Bcl-2 and Bcl-xL, and down-regulates Bax. In some NHLs, exogenous BAFF and APRIL up-regulate c-Myc, an inducer of cell proliferation; down-regulate p53, an inhibitor of cell proliferation; and increase Bcl-6, an inhibitor of B cell differentiation. By showing that nonmalignant B cells up-regulate BAFF and APRIL upon stimulation by T cell CD40 ligand, our findings indicate that NHL B cells deregulate an otherwise physiological autocrine survival pathway to evade apoptosis. Thus, neutralization of BAFF and APRIL by soluble TACI and BCMA decoy receptors could be useful to dampen the accumulation of malignant B cells in NHL patients.

KSHV-positive solid lymphomas represent an extra-cavitary variant of primary effusion lymphoma.

Primary effusion lymphoma (PEL) is a unique form of non-Hodgkin lymphoma (NHL) associated with Kaposi sarcoma-associated herpesvirus (KSHV; HHV-8) that displays a distinct constellation of clinical, morphologic, immunologic, and molecular characteristics. Rare KSHV-containing immunoblastic lymphomas occurring in solid tissues have been described. Whether they represent part of the spectrum of PEL has not been determined. The morphologic, immunophenotypic, and molecular features of KSHV-positive solid lymphomas occurring in 8 HIV+/AIDS patients were systematically investigated and compared with those of 29 similarly analyzed PELs. The 8 KSHV-positive solid lymphomas were virtually indistinguishable from the 29 PELs based on morphology (immunoblastic/anaplastic), immunophenotype (CD45 positive; T cell antigen negative; CD30, EMA, CD138 positive; CD10, CD15, BCL6 negative) and genotype (100% immunoglobulin genes rearranged; no identifiable abnormalities in C-MYC, BCL6, BCL1, BCL2; and uniformly EBV positive). The only identifiable phenotypic difference was that the KSHV-positive solid lymphomas appeared to express B cell-associated antigens (25%) and immunoglobulin (25%) slightly more often than the PELs (<5% and 15%, respectively; P = 0.11 and P = 0.08, respectively). The clinical presentation and course of the patients who develop KSHV-positive solid lymphomas were also similar, except for the lack of an effusion and somewhat better survival (median 11 months vs. 3 months). However, the 3 KSHV-positive solid lymphoma patients alive without disease 11, 25, and 44 months following initial presentation were recently diagnosed patients and, unlike the other patients with KSHV-positive solid lymphomas, received anti-retroviral therapy. These findings strongly suggest that these decidedly rare KSHV-positive solid lymphomas belong to the spectrum of PEL. Therefore, we propose that the KSHV-positive solid lymphomas be designated extra-cavitary PELs.

HIV-1 Envelope Triggers Polyclonal Ig Class Switch Recombination through a CD40-Independent Mechanism Involving BAFF and C-Type Lectin Receptors

Switching from IgM to IgG and IgA is essential for antiviral immunity and requires engagement of CD40 on B cells by CD40L on CD4+ T cells. HIV-1 is thought to impair CD40-dependent production of protective IgG and IgA by inducing progressive loss of CD4+ T cells. Paradoxically, this humoral immunodeficiency is associated with B cell hyperactivation and increased production of nonprotective IgG and IgA that are either nonspecific or specific for HIV-1 envelope glycoproteins, including gp120. Nonspecific and gp120-specific IgG and IgA are sensitive to antiretroviral therapy and remain sustained in infected individuals with very few CD4+ T cells. One interpretation is that some HIV-1 Ags elicit IgG and IgA class switch DNA recombination (CSR) in a CD40-independent fashion. We show that a subset of B cells binds gp120 through mannose C-type lectin receptors (MCLRs). In the presence of gp120, MCLR-expressing B cells up-regulate the CSR-inducing enzyme, activation-induced cytidine deaminase, and undergo CSR from IgM to IgG and IgA. CSR is further enhanced by IL-4 or IL-10, whereas Ab secretion requires a B cell-activating factor of the TNF family. This CD40L-related molecule is produced by monocytes upon CD4, CCR5, and CXCR4 engagement by gp120 and cooperates with IL-4 and IL-10 to up-regulate MCLRs on B cells. Thus, gp120 may elicit polyclonal IgG and IgA responses by linking the innate and adaptive immune systems through the B cell-activating factor of the TNF family. Chronic activation of B cells through this CD40-independent pathway could impair protective T cell-dependent Ab responses by inducing immune exhaustion.