Role Of Chronic Antigenic Stimulation Research Articles

Hyper-N-glycosylated SEL1L3 as auto-antigenic B-cell receptor target of primary vitreoretinal lymphomas

Primary vitreoretinal lymphoma (PVRL) is a rare subtype of DLBCL and can progress into primary central nervous system lymphoma (PCNSL). To investigate the role of chronic antigenic stimulation in PVRL, we cloned and expressed B-cell receptors (BCR) from PVRL patients and tested for binding against human auto-antigens. SEL1L3, a protein with multiple glycosylation sites, was identified as the BCR target in 3/20 PVRL cases. SEL1L3 induces proliferation and BCR pathway activation in aggressive lymphoma cell lines. Moreover, SEL1L3 conjugated to a toxin killed exclusively lymphoma cells with respective BCR-reactivity. Western Blot analysis indicates the occurrence of hyper-N-glycosylation of SEL1L3 at aa 527 in PVRL patients with SEL1L3-reactive BCRs. The BCR of a PVRL patient with serum antibodies against SEL1L3 was cloned from a vitreous body biopsy at diagnosis and of a systemic manifestation at relapse. VH4-04*07 was used in both lymphoma manifestations with highly conserved CDR3 regions. Both BCRs showed binding to SEL1L3, suggesting continued dependence of lymphoma cells on antigen stimulation. These results indicate an important role of antigenic stimulation by post-translationally modified auto-antigens in the genesis of PVRL. They also provide the basis for a new treatment approach targeting unique lymphoma BCRs with ultimate specificity.

Hyper N-Glycosylated SEL1L3 As B-Cell Receptor Autoantigen of Primary Vitreoretinal Lymphoma

Chronic antigenic stimulation of B lymphocytes through their B-cell receptor (BCR) is thought to play an important role in the genesis of B-cell lymphomas. SAMD14/neurabin-I has been described as auto-antigenic target of primary central nervous system lymphoma (PCNSL) BCRs. Primary vitreoretinal lymphoma (PVRL) is a rare subtype of DLBCL and can progress to PCNSL. Besides manifestation in an immunologically privileged site, PVRL and PCNSL share frequent recurrent genetic alterations like MYD88 and CD79B mutations. Both PVRL and PCNSL are considered being related to the MCD subtype of DLBCLs and may depend on chronic BCR signaling through antigenic stimulation. To investigate the role of chronic antigenic stimulation in PVRL, we cloned and expressed BCRs from PVRL patients as antibody fragments (Fabs) and tested for specific binding against common antigens. All cases with corresponding BCR sequences were previously reported by Belhouachi et al. (Blood Adv. 2020;4(7):1357-1366). For 20 of 55 PVRL BCR sequences both immunoglobulin heavy and light chain variable region (V) genes were available. DNA clones comprising an ApaLI restriction site, the complete light chain V gene, a κ- or λ-constant region gene, a ribosome binding site, a signal sequence, the heavy chain V gene and a BstEII restriction site were ordered from GeneCust® (GeneCust, 5690 Ellange, Luxembourg) in a pUC57 vector. DNA fragments were cloned in front of a γ-1 constant region gene and a Histidine-tag into a modified pCES-1 vector for expression as Fabs. PVRL-BCRs were screened on protein macroarrays representing clones of UniPEx human cDNA expression libraries expressed in E. coli (Bioscience, Dublin, Ireland). SEL1L3 was identified as the auto-antigenic target of the B-cell receptors in 3 out of 20 PVRL cases. None of the PVRL Fabs bound to LRPAP1 (common BCR antigen of mantle cell lymphomas), RpoC (Moraxella catarrhalis bacterial antigen and target of nodular lymphocyte-predominant Hodgkin lymphoma cells) or galectin-3 (member of the lectin family). SEL1L3 is a 1132 amino acid long protein with multiple glycosylation and phosphorylation sites (uniprot.org). This is especially important since previously identified BCR antigens from different lymphoma entities showed post-translational modifications such as hyper-N-glycosylation or hypo-phosphorylation. Furthermore, SEL1L3 is highly expressed in the pigmented layer of the retina. Western Blot analysis of the blood of a PVRL patient with serum antibodies against SEL1L3 showed an increased molecular weight of SEL1L3 as compared to SEL1L3 of controls. After treatment with N-acetyl-β-d-glucosaminidase or PNGase F, this difference in molecular weight disappeared, indicating a hyper N-glycosylation of SEL1L3 in PVRL patients with SEL1L3-reactive BCRs as trigger for its' immunogenicity. SEL1L3 induced proliferation of aggressive lymphoma cell lines transfected with SEL1L3-reactive BCRs. Moreover, the BCR binding epitope of SEL1L3 (aa 560 - 585) conjugated to a truncated form of Pseudomonasaeruginosa exotoxin A, killed exclusively lymphoma cells expressing BCRs with the respective reactivity. Additionally, BCRs of a locally treated PVRL patient with serum antibodies against SEL1L3 were cloned from biopsies of the vitreous body at initial diagnosis and of a lymphoma manifestation in the breast at relapse. Both BCRs showed binding to SEL1L3 suggesting a continued dependence of the BCR on antigen stimulation. These results suggest an important role of chronic antigenic stimulation by the post-translationally modified auto-antigen SEL1L3 in the genesis of a subgroup of patients with PVRL, might give an explanation for the selective tropism of PVRLs and provide the basis for a new treatment approach with high specificity.

PS1303 CHRONIC TCR STIMULATION PROMOTES PERIPHERAL T‐CELL LYMPHOMAGENESIS AND INDUCES ADDICTION TO SYK AND NK RECEPTOR SIGNALING

Background:Peripheral T cell lymphomas (PTCL) represent about 10% of non‐Hodgkin lymphomas and are associated with poor prognosis. T‐cell receptor (TCR) signaling is the major growth‐regulatory machinery of normal T cells. Although its involvement in T‐cell lymphomagenesis has not been extensively investigated, various genes coding components of the TCR signaling are found altered in human PTCL and several reports indicates a predominant role of chronic antigenic stimulation in some PTCL.Aims:This study was conducted to investigate the role of TCR chronic stimulation in T‐cell lymphomagenesis and to identify crucial survival factors for lymphoma cells.Methods:To mimic chronic TCR stimulation, we took advantage of a phenomenon called homeostatic proliferation, which is known to be driven by TCR signaling generated by self‐MHC/TCR interactions. To this end, purified mature T cells from p53‐deficient mice were transferred into CD3epsilon‐deficient mice.Peripheral T‐cell lymphomas generated were analyzed using different approaches; flow cytometry, transcriptomic analysis, kinome, western blot, immunohistochemistry and by various in vitro or in vivo functional experiments.Human PTCL cases from Grenoble, Lyon and Tenomic or CeVi collections were analyzed using flow cytometry and immunochemistry.Results:Sixty percent of mice died from PTCL originating from conventional alpha‐beta T cells with an effector‐memory (CD44hi, CD62Llo, CD122hi) and exhausted (PD1hi) phenotype. Transcriptomic analysis reveals a chronic TCR activation signature, showing the role of TCR in lymphomagenesis.To study signals involved in lymphoma survival, we performed a kinome analysis showing a constitutive activation of the Syk kinase. Syk expression and activation was confirmed by western blot and constitutive activation of downstream targets of Syk such as PLCg1&2 and the PI3K‐Akt‐mTOR pathway was demonstrated. However, using in vivo experiments, we demonstrated that TCR signaling is not required for PTCL survival, suggesting that Syk may be involved in other signaling pathways. Interestingly, transcriptomic analyses of both mouse and human PTCLs showed an upregulation of a subset of genes involved in Natural Killer (NK) cells biology, such as NK receptors (NKRs) and signaling effectors of NKR, compared to normal T‐cells. This suggests that PTCL acquire “innate‐like” features during chronic TCR stimulation that would be implicated in cell survival and we next show that activatory NKRs are functional and signalize through SYK in murine PTCL. We also demonstrate that activatory NKRs participate to murine PTCL survival as in vivo NKR blockade delays PTCL evolution as well as Syk inhibition.We studied NKRs and Syk expression in a large subset of human PTCL and confirmed their various expression by many PTCL entities.Summary/Conclusion:Using a murine model, we show that chronic TCR stimulation is crucial for T‐cell lymphomagenesis and is associated with an ”innate like“ reprogramming. We characterized potential novel mechanisms of PTCL survival involving NKR and Syk signaling in murine PTCL that could lead to new therapeutic strategy development as a large proportion of human PTCL shares some common features with this murine PTCL generated in this experimental model.

Hyper-N-glycosylated SAMD14 and neurabin-I as driver autoantigens of primary central nervous system lymphoma

AbstractTo address the role of chronic antigenic stimulation in primary central nervous system lymphoma (PCNSL), we searched for autoantigens and identified sterile α-motif domain containing protein 14 (SAMD14) and neural tissue-specific F-actin binding protein I (neurabin-I) as autoantigenic targets of the B-cell receptors (BCRs) from 8/12 PCNSLs. In the respective cases, SAMD14 and neurabin-I were atypically hyper-N-glycosylated (SAMD14 at ASN339 and neurabin-I at ASN1277), explaining their autoimmunogenicity. SAMD14 and neurabin-I induced BCR pathway activation and proliferation of aggressive lymphoma cell lines transfected with SAMD14- and neurabin-I-reactive BCRs. Moreover, the BCR binding epitope of neurabin-I conjugated to truncated Pseudomonas exotoxin-killed lymphoma cells expressing the respective BCRs. These results support the role of chronic antigenic stimulation by posttranslationally modified central nervous system (CNS) driver autoantigens in the pathogenesis of PCNSL, serve as an explanation for their CNS tropism, and provide the basis for a novel specific treatment approach.

BARs (B -cell receptor a ntigens for r everse targeting): A Novel and Ultimately Specific Treatment Concept for B-Cell Neoplasms

Introduction: The major task of a B-cell receptor is the binding and internalization of its antigenic target, and its processing for antigen presentation to T-cells. Chronic antigenic stimulation has been discussed to play a role in the pathogenesis of malignant B-cell lymphomas. We therefore systematically searched for the antigenic targets of BCRs from various B-cell neoplasms.Methods: Recombinant BCRs were expressed as recombinant Fabs (rFabs) based on corresponding pairs of functional variable region heavy and light chain genes, which had been amplified from isolated genomic DNA lymphoma biopsies. Whenever possible, "natural" Fabs (nFabs) were also obtained by papain digestion of fresh or cultured lymphoma cells. Both nFab and rFab were used to screen for binding to proteins expressed on macroarrays derived from human cDNA expression libraries and identical binding pattern of nFabs and rFabs was demonstrated by an antigen competition assay.Results: Two antigens (paratarg-7 and sumoylated HSP-90 which are hyperphosphorylated and sumoylated, respectively, in patients compared to healthy controls) are the targets of paraproteins from (depending on ethnicity) 30-50% of all multiple myeloma patients; the BCR from 67% of patients with primary CNS lymphoma target hyperglycosylated neurabin, 26% of the BCR from ABC-type DLBCL target hypophosphorylated ARS2 and 45% of all mantle cell BCR target LRPAP1; optineurin is the BCR target of 12% follicular lymphomas and various autoantigens have been identified as the targets of roughly 30% of all CLL cases. For all autoantigens binding to its specific BCR, rapid internalization and induction of proliferation was demonstrated, indicating partial dependence on antigenic stimulation even in cell lines that had been in culture for years. Most importantly, BCR-specific cytotoxicity of recombinant pseudomonas-exotoxin conjugated ARS2 against an ABC-DLBCL cell line with BCR specific for ARS2 (OCI-Ly3) was demonstrated in vitro and in vivo after establishment of OCI-Ly3 lymphomas in SCID beige mice.Conclusions: Assuming that only a minority of BCR targets have been identified to date, the prevalence of posttranslationally modified autoantigens strongly supports a role of chronic antigenic stimulation in many B-cell neoplasms. Due to the predominance of a single or few BCR antigens in each malignant B-cell entity studied, BARs represent an attractive and novel therapeutic concept for a broad spectrum of B-cell neoplasms and are the first therapeutic approach in oncology that targets exclusively the malignant cells. BARs can be used for conjugation with toxins, radionuclides and small molecules as well as for bispecific constructs (e. g. with CD3 or CD16) and CAR T-cells, the toxicity of which should be drastically reduced due to the ultimate specificity of BARs that spares normal B-cells. Supported by Wilhelm-Sander-Stiftung DisclosuresPfreundschuh:Roche, Janssen, Celgene: Honoraria, Research Funding.

Characteristics of B-Cell Lymphomas in HIV/HCV-Coinfected Patients During the Combined Antiretroviral Therapy Era

Hepatitis C virus (HCV) infection is frequent among HIV-infected patients. We describe, the characteristics of 6 HIV/HCV-coinfected patients with B-cell non-Hodgkin lymphoma (NHL) included in a prospective cohort study of HIV-related lymphomas. Five of the 6 cases had features of marginal zone/lymphoplasmacytic NHL versus 1 of 33 HIV only-infected patients. Remarkably, anti-HCV treatment led to a hematological response in a patient with splenic marginal zone lymphoma. This supports the role of chronic antigenic stimulation by HCV on lymphomagenesis and further evaluation of HCV antiviral therapy in coinfected patients with NHL.

Reduced diversity of immunoglobulin and T-cell receptor gene rearrangements in chronic inflammatory gastrointestinal diseases in dogs

Inflammatory bowel disease has a multifactorial etiology in dogs as it does in humans. Evidence has been accumulated showing an abnormal response of the immune system, mostly represented by lymphocyte infiltration in the lamina propria of the gastrointestinal tract and in the epithelium, likely driven by chronic antigenic stimulation against luminal microorganisms. A relevant role is also ascribed to the genetic predisposition typical of some canine breeds. The role of chronic antigenic stimulation is still under debate. It may be responsible for selective pressure on the lymphoid population, favouring the emergence of some lymphocyte clones. This cross-sectional study is aimed at investigating the immunoglobulin and T-cell receptor gene rearrangements in a group of dogs affected by inflammatory bowel disease. The database of a referral Veterinary Laboratory was investigated. Based upon the histological evaluation of the bioptic samples collected during endoscopy, 54 canine cases met the WSAVA criteria for diagnosing IBD and were included in the study. The histological slides were retrieved and the gDNA was purified using protocols for formalin-fixed tissue. The gDNA was PCR amplified using fluorescent-labelled primers specific for canine immunoglobulin and T-cell receptor gene rearrangements; the PCR products were analysed with fragment analysis by means of capillary electrophoresis on an automatic sequencer (GeneScanning). In 47/54 (87.3%) cases, it was possible to amplify the gDNA. Twenty-one patients out of 47 (44.7%) showed polyclonal patterns in both the immunoglobulin and the T-cell receptors, 18/47 (38.3%) showed at least one oligoclonal pattern without monoclonal ones while 8/47 (17.0%) cases showed an Ig (7/47; 14.9%) or TCR (1/47: 2.1%) monoclonal pattern. These findings indicate that reduced diversity of the immunoglobulin and T-cell receptor repertoire occurs in canine inflammatory bowel disease. The reduced diversity correlated significantly with the severity of the histological lesions and carried a significantly increased risk of death. Beside its possible role as a reliable ancillary assay, immunoglobulin and T-cell receptor GeneScanning analysis points to the possible role of aberrant chronic antigenic stimulation, leading to clonal expansion of certain lymphocyte subsets in the pathogenesis of canine IBD.

Prevalence and clinical impact of autoimmune diseases and chronic infections in malignant lymphomas at diagnosis

There is increasing evidence for the role of chronic antigenic stimulation (CS) in the development of cancer. Clinical data, however, are rare as is the information on outcome. In this study, the occurrence of chronic infections (CI) and autoimmune diseases (AI) in patients with malignant lymphoma at diagnosis was assessed. Of 367 patients [non-Hodgkin's lymphoma (NHL) N = 297, Hodgkin's lymphoma N = 70], 9.8% (N = 36) had a history of chronic antigenic stimulation (4.4% AI, 5.4% CI) at diagnosis. After a median observation time of 74.7 months, 118 patients have died. There were more male patients in this cohort. However, sex ratio among patients with chronic antigenic stimulation was skewed in favor of women (p = 0.018), in particular among lymphoma patients with AI (p = 0.001). NHL patients with autoimmune diseases showed a tendency to develop diffuse large B cell lymphoma [8 of 12 AI + NHL patients (66.7%) vs. 100 of 266 non-CS NHL (37.6%); p = 0.066]. No significant difference in overall survival (OS) between CS and non-CS patients could be observed (median OS after 48 months was: CS 77.7% vs. non-CS 71.8%). In conclusion, chronic antigenic stimulation at diagnosis appears to be associated with a higher prevalence in women, in particular among patients with autoimmune disease. However, no difference in overall survival was observed. This suggests that the presence of chronic inflammatory conditions does not decisively influence the outcome of lymphoma patients.

High Frequency of Marginal Zone Lymphomas Among Patients Coinfected with Human Immunodeficiency Virus and Hepatitis C Virus - ANRS CO16 LYMPHOVIR Cohort Study

AbstractAbstract 4156 Introduction:Human Immunodeficiency Virus (HIV) and hepatitis C virus (HCV) infections are both associated with an increased risk of B-cell non-Hodgkin lymphoma (B-NHL). They are known to be preferentially diffuse large B-cell lymphoma (DLBCL), and Burkitt lymphoma subtypes in HIV infection, while marginal zone lymphoma (MZL) and DLBCL represent the main subtypes in HCV infected patients. The absence of increased risk of B-NHL in HIV-HCV co-infected patients compared to HIV infected patients was reported in epidemiological studies, but the clinico-pathological characteristics of B-NHL in the setting of such co-infection particularly in the era of HAART remains unclear. Patients and methods:We present the data of adult patients with B-NHL and HIV-HCV co-infection from the French ANRS CO16 Lymphovir cohort. This multicentric prospective cohort includes HIV infected patients with lymphoma. Each patient is followed every 6 months during 5 years. At each follow-up, a blood sample is withdrawn allowing ancillary studies. Data collection concerns clinical presentation, treatment and evolution of B-NHL and HIV and HCV infections. Pathological and cytological materials are centralized in order to allow their review and a concerted analysis by a group of expert hematopathologists (MR, SP, DC), haematologists and immunologists. Results:Among the 49 patients with B-NHL included in the cohort, 6 were HIV-HCV coinfected, [5 men and 1 woman, median age 47 years (range 36–67)]. They were included between october 2007 and august 2009 in 6 French centres. Transmission risk was intravenous drug abuse (n=4) and heterosexual transmission (n=2). Median duration from HIV diagnosis to B-NHL was 11 years (range 1–20), and the median nadir CD4 T-cell count was 194/mm3 (range 151–746) (nadir not available for 2 patients). Only one patient had developed AIDS before the diagnosis of NHL. HCV genotypic distribution was: genotype 1 (n=3), 2 (n=1), 4 (n=1), and not available (n=1). Median HCV viral load was 6.0 log (range 5.4–7.1). One patient had compensated cirrhosis and none of the patients were tested for cryoglobulinemia. Immunological assays showed the presence of monoclonal IgM Kappa in 1 patient and no positive rheumatoid factor.At the diagnosis of B-NHL, 4 patients received HAART and had an undetectable HIV load. In contrast, none of the patients were treated for HCV infection. The median interval between B-NHL diagnosis and last follow-up is 17 months (range 0.1–32 months). The histological subtype distribution is 4 MZL -including 2 extranodal MZL of MALT, 1 splenic lymphoma with villous lymphocytes (SLVL) and 1 lymphoplasmacytic lymphoma- and 2 EBV-negative DLBCL. All patients have extranodal involvement, including digestive tract (n=3), liver (n=2), bone marrow (n=2) and spleen (n=1). Median CD4 T-cell count at B-NHL diagnosis was 582/mm3 (range 235–1322) in MZL patients and 274/mm3 (200 and 347) in DLBCL patients.Following diagnosis, all patients were treated with HAART, associated with peg-interferon plus ribavirin in 1 patient. The 2 patients with DLBCL received R-CHOP, associated with methotrexate in 1 case. One patient with a partial response exhibited a neuromeningeal relapse and was treated with COPADM and CYVE regimen, allowing a complete and sustained response. The other patient died of serious infection after 2 courses of chemotherapy. Among patients with MZL, one patient received R-CVP and one received chlorambucil, allowing a complete response in both patients. The patient with SLVL received HAART then peg-interferon plus ribavirin, allowing normalization of lymphocytes count (5.89 at baseline vs. 1.69 × 109/L at 12 weeks of anti-HCV therapy) with a correlation between HCV virological and hematological response. Patient with lymphoplasmacytic lymphoma died of cardiac ischemia before the initiation of chemotherapy. Conclusions:This study describes the resurgence of MZL in HIV-HCV co-infected patients with restored immunity under HAART. Such B-NHL, very rarely described in HIV patients, occurs mainly in patients with control of HIV without history of AIDS but with active HCV infection. Histological subtypes and localizations resemble more to that observed in HCV infected patients than in HIV infected patients. These findings suggest the role of chronic antigenic stimulation by HCV and/or HIV and question about the interest of HCV antiviral therapy on NHL in co-infected patients. Disclosures:No relevant conflicts of interest to declare.

Accurate identification of paraprotein antigen targets by epitope reconstruction

We describe the first successful clinical application of a new discovery technology, epitope-mediated antigen prediction (E-MAP), to the investigation of multiple myeloma. Until now, there has been no reliable, systematic method to identify the cognate antigens of paraproteins. E-MAP is a variation of previous efforts to reconstruct the epitopes of paraproteins, with the significant difference that it provides enough epitope sequence data so as to enable successful protein database searches. We first reconstruct the paraprotein's epitope by analyzing the peptides that strongly bind. Then, we compile the data and interrogate the nonredundant protein database, searching for a close match. As a clinical proof-of-concept, we apply this technology to uncovering the protein targets of para-proteins in multiple myeloma (MM). E-MAP analysis of 2 MM paraproteins identified human cytomegalovirus (HCMV) as a target in both. E-MAP sequence analysis determined that one para-protein binds to the AD-2S1 epitope of HCMV glycoprotein B. The other binds to the amino terminus of the HCMV UL-48 gene product. We confirmed these predictions using immunoassays and immunoblot analyses. E-MAP represents a new investigative tool for analyzing the role of chronic antigenic stimulation in B-lymphoproliferative disorders.

Identification of antigenic targets of paraproteins by expression cloning does not support a causal role of chronic antigenic stimulation in the pathogenesis of multiple myeloma and MGUS

Antigenic targets of monoclonal gammopathy of undetermined significance (MGUS) and multiple myeloma (MM) paraproteins have been suggested to play an important role as growth stimulators in the pathogenesis of these neoplasms. To identify such targets, we screened cDNA libraries from human testis, lung and breast cancer, bovine and porcine muscle and wheat germ for reactivity with paraproteins in the sera from 115 patients with MGUS and MM. Of >6 x 10(8) paraprotein-antigen interactions screened, an IgA paraprotein from a female patient bound to sperm-specific cylicin-2, and 3 IgG paraproteins bound to tripeptidyl-peptidase-II (TPP-2), insulin-like growth-factor binding-protein-2 (IGFBP-2) and porcine kinesin. Specificity was confirmed by reverse Western blots using recombinant antigens. The broad spectrum of auto-, allo- and heteroantigens as targets of human paraproteins in patients without signs of chronic antigenic stimulation renders a causal role of the antigenic stimulus in the pathogenesis of MGUS and MM unlikely.

Myeloma paraprotein epitope identification using a phage library of sterically constrained peptides

6626 Background: Chronic antigenic stimulation has been hypothesized to be a causative factor in rare cases of multiple myeloma (MM). If true, one might identify relevant antigens by using phage display technology and biopanning to analyze epitopes of m-proteins in sera of MM patients (pts). This method obviates the need to prospectively identify candidate antigens. Methods: The Ig fractions of 17 pts with IgG paraproteins were purified on Protein G beads. The bead-bound m-proteins were then used to biopan a T7 library of random heptapeptides sterically constrained by intramolecular disulfide bridges (Gift of G. Froman). Phage selected via 3–5 rounds of biopanning were cloned by plaque isolation. Binding specificity was confirmed by blotting and chemiluminescent detection. The cloned phage inserts’ DNA was sequenced and the amino acid sequences of each insert deduced. Proteins containing homologies with these peptides were found by short-peptide BLAST search. To test whether the identified epitopes are common among MM pts, the phage clones were screened against IgG m-proteins from sera of 70 additional pts. Results: Phage clones were identified which reacted specifically with 3 of the 17 pt m-proteins in the panel. There were 7 selected clones in total, as multiple clones were found for two pts. None of the peptide sequences displayed strong homology with known human autoantigens. However, the peptide inserts of the isolated clones exhibited strong homologies with proteins of pathogens including Mycoplasma sp., Fusobacterium sp., influenza A, and Candida sp., some of which are antigens ubiquitously present in the environment. None of the Ig from 70 other sera cross-reacted with any of the selected phage. Conclusions: We have shown at least some MM paraproteins bind epitopes expressed by known human pathogens, supporting the possible role of chronic antigenic stimulation in myeloma pathogenesis. These findings are consistent with a previously published report (Scand. J. Immunol. 57:583;2003). In addition, the lack of any cross-reacting Igs from the large panel of sera makes it statistically unlikely that any of these pathogens, even if contributory to individual cases, are commonly causative. No significant financial relationships to disclose.

Multiple myeloma among blacks and whites in the United States: the role of chronic antigenic stimulation.

Multiple myeloma (MM) is twice as common among Blacks than Whites in the United States. The reasons for this racial disparity are unknown, and the etiology of this cancer, in general, is poorly understood. Repeated or chronic antigenic stimulation (CAS) of the immune system has been suggested as a risk factor. Previous case-control studies have reported inconsistent CAS associations based on evaluations of individual and biologic categories of medical conditions. Interview data from 573 cases and 2,131 population-based controls were used to investigate further the CAS hypothesis using an immunologically based approach, and to determine whether CAS accounts for the excess of myeloma among Blacks. Over 50 medical conditions were grouped into biologically and immunologically related categories, and B-cell- and T-cell-mediated response groups. Except for urinary tract infections among Black men (odds ratio [OR] = 2.0), no significantly increased risks of MM were observed. However, there was a suggestion of increased risk among Blacks with an increased exposure to anaphylactic conditions. Analysis by immunoglobulin type revealed significantly elevated risks of IgG myeloma with eczema (OR = 2.1), the biologic category 'allergic conditions' (OR = 1.6), and the immunologic category 'anaphylaxis response' (OR = 1.6) among Whites, with Blacks having slightly lower risks. Our findings do not support a causal relationship between CAS and MM, nor do they explain the higher incidence among Blacks.

Antigenic Stimulation and the Occurrence of Chronic Lymphocytic Leukemia

Data from a population-based case-control study of chronic lymphocytic leukemia were analyzed to assess the possible etiologic role of chronic antigenic stimulation. The study, conducted in four geographic areas of the United States (the metropolitan areas surrounding Seattle, Washington, Salt Lake City, Utah, Detroit, Michigan, and Atlanta, Georgia) sought to identify all incident cases (n = 430) among residents diagnosed between July 1, 1977 and December 31, 1981. The responses of these cases to questions about possible sources of antigenic stimulation were compared with the responses of controls selected from the populations of these areas. Little difference between cases and controls was present for a history of most forms of viral and bacterial infection and for a history of allergies or allergy treatment. However, a relation was observed with antecedent syphilis infection (odds ratio (OR) = 5.0, 95% confidence interval (Cl) 2.0-12.9). Associations of smaller magnitude were observed with a history of tuberculosis (OR = 1.9, 95% Cl 1.0-3.7) and of urinary tract infection (OR = 1.4, 95% Cl 1.1-1.9). Overall, however, the authors found little evidence of a relation between chronic antigenic stimulation and the occurrence of chronic lymphocytic leukemia. Nonetheless, because the measure of prior antigenic stimulation was restricted to that obtained through interviews and undoubtedly was an insensitive one, these negative results should not be interpreted as ruling out antigenic stimulation as a possible cause of some cases of chronic lymphocytic leukemia.

Immunologic abnormalities in patients receiving multiple blood transfusions.

Concern for the potential risk of the acquired immunodeficiency syndrome among blood cell recipients led us to measure immunologic functions in patients who had received multiple transfusions. Abnormalities of two immunologic tests, natural killer cell function and helper/suppressor (T4/T8) lymphocyte subpopulation ratio, have characterized patients with the acquired immunodeficiency syndrome and are prevalent in populations at risk for this syndrome. Natural killer cell function was severely depressed in multiply transfused patients. However, T4/T8 ratios were normal in this population. The role of chronic antigenic stimulation was studied by measurement of HLA-DR expression on T cells. The expression of HLA-DR antigen is markedly elevated in multiply transfused patients. These results show that chronic exposure to foreign antigens may be associated with abnormalities of immunologic function, but that chronically transfused patients do not have the same immunologic profile as reported in some homosexuals and hemophiliacs.