Production and roles of IL-6, IL-10, and IL-13 in B-lymphocyte malignancies and in B-lymphocyte hyperactivity of HIV infection and autoimmunity

Analysis of Notch1 protein expression in methotrexate-associated lymphoproliferative disorders

Methotrexate (MTX)-associated lymphoproliferative disorder (MTX-LPD) is a lymphoproliferative disorder in patients treated with MTX. The mechanism of pathogenesis is still elusive, but it is thought to be a complex interplay of factors, such as underlying autoimmune disease activity, MTX use, Epstein-Barr virus infection, and aging. The NOTCH genes encode receptors for a signaling pathway that regulates various fundamental cellular processes, such as proliferation and differentiation during embryonic development. Mutations of NOTCH1 have been reported in B-cell tumors, including chronic lymphocytic leukemia/lymphoma, mantle cell lymphoma, and diffuse large B-cell lymphoma (DLBCL). Recently, it has also been reported that NOTCH1 mutations are found in post-transplant lymphoproliferative disorders, and in CD20-positive cells in angioimmunoblastic T-cell lymphoma, which might be associated with lymphomagenesis in immunodeficiency. In this study, to investigate the association of NOTCH1 in the pathogenesis of MTX-LPD, we evaluated protein expression of Notch1 in nuclei immunohistochemically in MTX-LPD cases [histologically DLBCL-type (n = 24) and classical Hodgkin lymphoma (CHL)-type (n = 24)] and de novo lymphoma cases [DLBCL (n = 19) and CHL (n = 15)]. The results showed that among MTX-LPD cases, the expression of Notch1 protein was significantly higher in the DLBCL type than in the CHL type (P < 0.001). In addition, among DLBCL morphology cases, expression of Notch1 tended to be higher in MTX-LPD than in the de novo group; however this difference was not significant (P = 0.0605). The results showed that NOTCH1 may be involved in the proliferation and tumorigenesis of B cells under the use of MTX. Further research, including genetic studies, is necessary.

Epstein‐Barr virus‐related diffuse large B‐cell lymphoma type methotrexate‐associated lymphoproliferative disorders presenting in the adrenal gland

Introduction

Case presentation

Conclusion

Dual Role of Interleukin-10 in Murine NZB/W F1 Lupus

As a key anti-inflammatory cytokine, IL-10 is crucial in preventing inflammatory and autoimmune diseases. However, in human and murine lupus, its role remains controversial. Our aim was to understand regulation and immunologic effects of IL-10 on different immune functions in the setting of lupus. This was explored in lupus-prone NZB/W F1 mice in vitro and vivo to understand IL-10 effects on individual immune cells as well as in the complex in vivo setting. We found pleiotropic IL-10 expression that largely increased with progressing lupus, while IL-10 receptor (IL-10R) levels remained relatively stable. In vitro experiments revealed pro- and anti-inflammatory IL-10 effects. Particularly, IL-10 decreased pro-inflammatory cytokines and slowed B cell proliferation, thereby triggering plasma cell differentiation. The frequent co-expression of ICOS, IL-21 and cMAF suggests that IL-10-producing CD4 T cells are important B cell helpers in this context. In vitro and in vivo effects of IL-10 were not fully concordant. In vivo IL-10R blockade slightly accelerated clinical lupus manifestations and immune dysregulation. Altogether, our side-by-side in vitro and in vivo comparison of the influence of IL-10 on different aspects of immunity shows that IL-10 has dual effects. Our results further reveal that the overall outcome may depend on the interplay of different factors such as target cell, inflammatory and stimulatory microenvironment, disease model and state. A comprehensive understanding of such influences is important to exploit IL-10 as a therapeutic target.

Immune response in LPD during methotrexate administration (MTX-LPD) in rheumatoid arthritis patients

Methotrexate (MTX) is known as a first-line synthetic disease-modifying anti-rheumatic drug (DMARD) for the treatment of rheumatoid arthritis (RA). Although the risk of LPD development increases by RA inflammation itself, observation of spontaneous regression of LPD after MTX discontinuation lead to the theory of lymphomagenic role of MTX. In this review, we focused on the several immune response involved in LPD that developed under MTX administration in RA patients.

Extramedullary Hematopoiesis in the Mandibular Lymph Node of Simian-Human Immunodeficiency Virus-Infected Rhesus Monkeys (Macaca mulatta): A Report of Three Cases

Three cases of extramedullary hematopoiesis (EMH) in the mandibular lymph nodes of rhesus monkeys, experimentally infected intravenously with a chimeric simian human immunodeficiency virus, are described. On histopathologic evaluation, multiple sections of mandibular lymph node from all animals showed evidence of EMH, which included erythroid, myeloid, or megakaryocytic precursor cells (or all) within the medullary sinuses. Immunohistochemistry was used for positive identification of multiple cell types. Evidence of EMH was not observed in numerous sections of axillary, inguinal, cervical, hilar, or mesenteric lymph nodes or in any other tissues examined. To our knowledge, this is the first report on EMH within the lymph nodes of rhesus monkeys without an obvious underlying disease process or stringent blood-sampling schedule warranting the need for increased hematopoiesis outside the confines of the bone marrow.

High expression levels of B lymphocyte stimulator (BLyS) by dendritic cells correlate with HIV-related B-cell disease progression in humans

In view of assessing the possible contribution of dendritic cells (DCs) to HIV-related B-cell disorders, we have longitudinally measured B lymphocyte stimulator (BLyS) surface expression by myeloid DCs (mDCs) and concentrations of B-cell growth factors in the blood of subjects undergoing primary HIV infection with different rates of disease progression. We report that BLyS surface expression by mature mDCs and precursors as well as blood levels of BLyS, a proliferation-inducing ligand (APRIL), interleukin-6 (IL-6), and IL-10 increased above normal levels in both rapid and normal HIV progressors as quickly as in the acute phase of infection and persisting throughout the course of disease despite successful therapy. Consequently, hyperglobulinemia and high blood levels of circulating activated mature B cells and precursor/activated marginal zone (MZ)-like B cells were found throughout follow-up for both rapid and normal progressors. In contrast, mDC cell-surface expression of BLyS as well as blood levels of BLyS, immunoglobulin, activated mature B cells, and precursor/activated MZ-like B cells in aviremic slow progressors were similar to those observed in healthy donors. Interestingly, the levels of mature MZ B cells were significantly reduced in slow progressors. Our results suggest that DCs might modulate the outcome of the HIV-related B-cell disease progression through the expression of BLyS.

Multiple myeloma: A review of the epidemiologic literature

Multiple myeloma, a neoplasm of plasma cells, accounts for approximately approximately 15% of lymphatohematopoietic cancers (LHC) and 2% of all cancers in the US. Incidence rates increase with age, particularly after age 40, and are higher in men, particularly African American men. The etiology is unknown with no established lifestyle, occupational or environmental risk factors. Although several factors have been implicated as potentially etiologic, findings are inconsistent. We reviewed epidemiologic studies that evaluated lifestyle, dietary, occupational and environmental factors; immune function, family history and genetic factors; and the hypothesized precursor, monoclonal gammopathies of undetermined significance (MGUS). Because multiple myeloma is an uncommon disease, etiologic assessments can be difficult because of small numbers of cases in occupational cohort studies, and few subjects reporting exposure to specific agents in case-control studies. Elevated risks have been reported consistently among persons with a positive family history of LHC. A few studies have reported a relationship between obesity and multiple myeloma, and this may be a promising area of research. Factors underlying higher incidence rates of multiple myeloma in African Americans are not understood. The progression from MGUS to multiple myeloma has been reported in several studies; however, there are no established risk factors for MGUS. To improve our understanding of the causes of multiple myeloma, future research efforts should seek the causes of MGUS. More research is also needed on the genetic factors of multiple myeloma, given the strong familial clustering of the disease.

IL-10 regulation of lupus in the NZM2410 murine model

Multiple studies have reported high levels of IL-10 in SLE patients and in murine models of lupus. IL-10 is a regulatory cytokine mainly produced by B cells, which use this cytokine to support their proliferation, and by myeloid cells, which use IL-10 to reduce proinflammatory responses. IL-10 is also produced by a subset of CD4+ T regulatory cells. Various manipulations of IL-10 levels with repeated administrations of anti-IL-10 neutralizing antibodies, genetic ablation or injections of recombinant cytokine have shown contradictory results, which is likely to reflect the opposite effects of this cytokine on the two major effector arms of lupus pathologenesis, namely B cells and inflammation. We have investigated the role of IL-10 in a novel congenic model of lupus, B6.Sle1.Sle2.Sle3 (B6.TC), which consists of the three NZM2410-derived SLE susceptibility loci combined on a C57BL/6 background. We first investigated in this model the source of elevated IL-10 and shown that it results from a larger number of CD4+ T cells producing the cytokine, and from a greatly increased B1-a cell pool, which is the main IL-10 producing compartment. We have then used AAV-mediated skeletal muscle gene delivery to overexpress IL-10 in young B6.TC mice and follow disease marker expression up to 7 months of age. We show here that continuous overexpression of low levels of IL-10 significantly delayed antinuclear auto-antibody production and decreased clinical nephritis. B cell phenotypes were largely unaffected, while T-cell activation was significantly reduced. This highlighted the pivotal role played by T-cell activation in this model, and suggested that this pathway could be effectively targeted for therapeutic interventions. These results also reinforce the notion that IL-10 exerts multiple functions and commend caution in equating high levels of IL-10 and increased pathogenesis in systemic autoimmunity.

Malignant lymphomas in autoimmunity and inflammation: a review of risks, risk factors, and lymphoma characteristics

Certain autoimmune and chronic inflammatory conditions, such as Sjögren's syndrome and rheumatoid arthritis (RA), have consistently been associated with an increased risk of malignant lymphomas, but it is unclear whether elevated lymphoma risk is a phenomenon that accompanies inflammatory conditions in general. Likewise, it is debated whether the increased risk identified in association with some disorders pertains equally to all individuals or whether it varies among groups of patients with different phenotypic or treatment-related characteristics. It is similarly unclear to what extent the increased lymphoma occurrence is mediated through specific lymphoma subtypes. This update reviews the many findings on risks, risk levels, and lymphoma characteristics that have been presented recently in relation to a broad range of chronic inflammatory, including autoimmune, conditions. Recent results clearly indicate an association between severity of chronic inflammation and lymphoma risk in RA and Sjögren's syndrome. Thus, the average risk of lymphoma in RA may be composed of a markedly increased risk in those with most severe disease and little or no increase in those with mild or moderate disease. The roles of immunosuppressive therapy and EBV infection seem to be limited. Furthermore, RA, Sjögren's syndrome, systemic lupus erythematosus, and possibly celiac disease may share an association with risk of diffuse large B-cell lymphoma, in addition to well-established links of Sjögren's syndrome with risk of mucosa-associated lymphoid tissue lymphoma and of celiac disease with risk of small intestinal lymphoma. However, there is also obvious heterogeneity in risk and risk mediators among different inflammatory diseases.

Non-Hodgkin's B cell lymphoma in persons with acquired immunodeficiency syndrome is associated with increased serum levels of IL10, or the IL10 promoter -592 C/C genotype

Interleukin-10 (IL10) may contribute to the development of non-Hodgkin's B cell lymphoma, especially in the context of acquired immunodeficiency syndrome (AIDS), where lymphoma incidence is greatly increased. Utilizing specimens from the Multicenter AIDS Cohort Study (MACS) obtained prior to diagnosis of AIDS-associated lymphoma, detectable serum human IL10 was seen much more frequently in lymphoma cases (n = 61, 26%) compared to CD4-matched AIDS controls (5%, P = 0.004), or to HIV-infected (2%, P = 0.002) or HIV uninfected subjects (0%, P = 0.0003). In longitudinal studies, detectable IL10 occurred at times closest to but preceding lymphoma diagnosis (P = 0.01). In an independent genetic analysis of single-nucleotide polymorphisms within the promoter region of the IL10 gene in 1157 MACS subjects, a high IL10-expressing genotype (-592 C/C) was overrepresented among lymphoma subjects (P = 0.009), even when controlling for race (P = 0.006). These results suggest that elevated serum IL10 or the IL10 promoter -592 C/C genotype are associated with development of AIDS lymphoma.

Pro- and anti-inflammatory cytokines in human immunodeficiency virus infection and acquired immunodeficiency syndrome

In persons with human immunodeficiency virus (HIV) infection and/or acquired immunodeficiency syndrome (AIDS), the immune system becomes dysfunctional in many ways. There is both immunodeficiency due to the loss of CD4-positive T helper cells and hyperactivity as a result of B-cell activation. Likewise, both decreases and increases are seen in the production and/or activity of cytokines. Cytokine changes in HIV infection have been assessed by a variety of techniques, ranging from determination of cytokine gene expression at the mRNA level to secretion of cytokine proteins in vivo and in vitro. Changes in cytokine levels in HIV-infected persons can affect the function of the immune system, and have the potential to directly impact the course of HIV disease by enhancing or suppressing HIV replication. In particular, the balance between the pro-inflammatory cytokines interleukin (IL)-1, IL-6, and tumor necrosis factor-alpha, which up-regulate HIV expression, and IL-10, which can act both as an anti-inflammatory cytokine and a B-cell stimulatory factor, may play an important role in the progression to AIDS. In light of its ability to suppress the production of pro-inflammatory cytokines and, under some conditions, suppress HIV replication, increased IL-10 may be viewed as beneficial in slowing HIV disease progression. However, an association between increased IL-10 and the development of AIDS-associated B-cell lymphoma highlights the bifunctional nature of IL-10 as both an anti-inflammatory and B-cell-stimulatory cytokine that could have beneficial and detrimental effects on the course of HIV infection and AIDS.

Malignancy and systemic lupus erythematosus

The association of malignancy with systemic lupus erythematosus (SLE) has been investigated for years. The findings of cohort studies lend support for an increased risk of malignancy in SLE but are difficult to interpret definitively. In addition, several cohort studies have suggested an increased risk of non-Hodgkin's lymphoma but with imprecise estimation. There is inadequate evidence for any conclusions about the risk of solid tumors in these patients. A multicenter international research effort is in progress to elucidate these issues and to establish the role of exposures such as cytotoxic or immunomodulatory therapy. The recommendations advocated for cancer screening policies and for minimizing known risk factors for cancer in the general population should not be neglected in persons with SLE.

The AIDS disease of CD4C/HIV transgenic mice shows impaired germinal centers and autoantibodies and develops in the absence of IFN-gamma and IL-6

The mechanisms responsible for degeneration of germinal centers (GC) and follicular dendritic cell (FDC) networks during progression to AIDS remain elusive. Here, we show that CD4(+) T cells from CD4C/HIV-1 Tg mice, which develop a severe AIDS-like disease, express low levels of CD40 ligand. Accordingly, GC formation, FDC networks, and immunoglobulin isotype switching are impaired in these animals. However, Tg B cells respond to in vitro CD40 stimulation. Total serum IgG levels are reduced in Tg mice, whereas total IgM levels are increased with a significant amount showing DNA specificity. IFN-gamma- and IL-6-deficient CD4C/HIV Tg mice also develop the AIDS-like disease and produce auto-Ab. Thus, CD4C/HIV Tg mice have immune dysfunction accompanied by autoimmune responses.

Interleukin-10 gene promoter polymorphisms in multiple myeloma

Multiple myeloma (MM) is a B-cell malignancy characterized by an accumulation of malignant plasma cells in the bone marrow. It is unclear whether genetic background could have an etiological impact on MM or influence the course of the disease. Interleukin-10 (IL-10) has been implicated in the growth and differentiation of normal B cells, and has also been shown to enhance the proliferation of MM cells. To address the putative involvement of IL-10 genetic variation in MM, we analyzed previously defined loci for bi-allelic polymorphism at position -1082 and two microsatellite loci (IL10.G and IL10.R) in the IL-10 promoter region. Seventy-three patients with MM, 27 with monoclonal gammopathy of undetermined significance, and 109 ethnically matched individuals as controls were included in the study. Significantly increased frequencies of the IL10.G genotype 136/136 and the IL10.R genotype 112/114, in addition to a decreased frequency of the IL10.R genotype 114/116, were found among the MM patients. Increased production of IL-10 was detected in the supernatants of lipopolysaccharide-stimulated peripheral blood mononuclear cells from MM patients who were homozygotes (136/136) and heterozygotes (136/non-136) for the IL10.G allele 136, as compared with the other IL10.G genotype carriers (non-136/non-136). These results suggest that the genetic variation in the IL-10 promoter region may play a role in the development of MM.

The role of cytokines in the pathogenesis and management of AIDS-related lymphomas

AIDS-related non-Hodgkin lymphomas (AIDS-NHL) consistently derive from B-cells and are characterized by extreme clinical aggressiveness. At histological level, AIDS-NHL are classified as AIDS-related Burkitt's lymphoma (AIDS-BL), AIDS-related diffuse large cell lymphoma (AIDS-DLCL) and AIDS-related primary effusion lymphoma (AIDS-PEL). The role of cytokines in the pathogenesis and management of AIDS-NHL has been studied to a certain extent. Production of large quantities of human IL-10 occurs frequently in AIDS-BL and correlates with latent EBV infection of the tumor clone. Lesser amounts of the cytokine are released in EBV negative cases. The pathogenetic role of IL-10 in AIDS-BL is suggested by the observation that IL-10 antisense oligonucleotides inhibit proliferation of the lymphoma. A significant fraction of AIDS-BL cell lines produce TNFbeta. Among AIDS-NHL, the release of TNFbeta appears to be specific for AIDS-BL. The pathogenetic relevance of TNFbeta in lymphomagenesis is suggested by the observation that some BL cell lines use TNFbeta as an autocrine growth factor. Some cases of AIDS-BL, particularly those carrying EBV infection, also secrete IL-6, IL-7 and IL-12. With respect to AIDS-DLCL, many cases express the IL-6R, rendering these cells responsive to the paracrine stimulation by the IL-6 produced by nearby T-cells, macrophages and endothelial cells which are frequently abundant in these tumor samples. The tumor clone itself, however, generally fails to release IL-6. AIDS-PEL is characterized by secretion of large amounts of IL-6 and IL-10. Some PEL cases also release oncostatin M. Apart from human IL-6, PEL also express viral IL-6, which is encoded by the HHV-8 genome. The biological relevance of both IL-6 and IL-10 in PEL proliferation and growth has been recently clarified in vitro and in vivo. Overall, these data suggest that activation of different cytokine loops clusters with different clinico-pathologic categories of AIDS-NHL and may represent the potential target of novel therapeutic strategies.

Cytokines in the evolution and treatment of AIDS-lymphoma

AIDS-lymphoma is a heterogeneous disease that most likely results from the complex interaction of several contributing factors, including chronic antigenic activation of B lymphocytes, dysregulated cytokine and co-stimulatory networks, infection with potentially oncogenic viruses (human herpesvirus-8 [HHV-8], Epstein-Barr virus), and accumulation of secondary genetic mutations. Cytokines are believed to play an important role in the immunologic decline that favors opportunistic infection and malignancy in advanced HIV infection. Recent work has provided some evidence that cytokine therapy can partially reverse the immune dysregulation seen in AIDS. This suggests that cytokines are likely to have an important role in both the pathogenesis and treatment or prevention of AIDS-lymphoma.

Cellular tropism and viral interleukin-6 expression distinguish human herpesvirus 8 involvement in Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease

Human herpesvirus 8 (HHV-8) infection has been implicated in the etiology of Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman's disease (MCD), three diseases that frequently develop in immunocompromised, human immunodeficiency virus-positive individuals. One hypothesis that would account for different pathological manifestations of infection by the same virus is that viral genes are differentially expressed in heterogeneous cell types. To test this hypothesis, we analyzed the localization and levels of expression of two viral genes expressed in latent and lytic infections and the viral homologue of interleukin-6 (vIL-6). We show that PEL parallels KS in the pattern of latent and lytic cycle viral gene expression but that the predominant infected cell type is a B cell. We also show that MCD differs from KS not only in the infected cell type (B-cell and T-cell lineage) but also in the pattern of viral gene expression. Only a few cells in the lesion are infected and all of these cells express lytic-cycle genes. Of possibly greater significance is the fact that in a comparison of KS, PEL, and MCD, we found dramatic differences in the levels of expression of vIL-6. Interleukin-6 is a B-cell growth and differentiation factor whose altered expression has been linked to plasma cell abnormalities, as well as myeloid and lymphoid malignancies. Our findings support the hypothesis that HHV-8 plays an important role in the pathogenesis of PEL and MCD, in which vIL-6 acts as an autocrine or paracrine factor in the lymphoproliferative processes common to both.

Immune dysfunction and the pathogenesis of AIDS-associated non-Hodgkin's lymphoma

Much has been learned about how HIV-induced immune dysfunction contributes to B cell hyperactivation, and potentially, to the pathogenesis of AIDS-lymphoma. However, further studies are needed to fully understand how HIV infection and immune dysfunction promote B cell hyperactivation and the development/growth of AIDS-lymphoma. In particular, studies are needed to define the role of HHV8 vIL6, IL6 receptor-expression, and lymphocyte surface stimulatory molecules, in promoting B cell hyperactivation or lymphoma cell growth.