Citations

Abstract Abstract 1909 AL amyloidosis is the most common type of systemic amyloidosis. It is caused by extracellular deposition of circulating immunoglobulin light chains (LC) thought to be secreted by a primarily bone marrow based clonal plasma cell proliferative disorder. Although, invariably, the type of LC secreted by the plasma cell clone is identical to the LC deposited in the amyloid plaque, a comprehensive analysis of the re-arranged clonal LC gene coding secreted LC protein, the protein sequence of the serum and urine monoclonal band and the LC protein deposited in the amyloid plaques have not been previously performed. In this study, we compared the protein sequence predicted by the clonal LC gene sequence with the protein sequence identified in the serum and urine monoclonal bands and protein plaques by mass spectrometry (MS) based proteomics. 10 cases with systemic AL amyloidosis were studied. Bone marrow samples containing the clonal plasma cells were obtained and clonal LC variable gene sequences were determined by PCR amplification, cloning and sequencing as described previously (Abraham et al, Blood 2003, 101: 3801). For protein analysis, monoclonal protein bands identified in serum and/or urine protein electrophoresis and immunofixation were isolated from archival gels. For amyloid plaque protein analysis, the plaques were microdissected from paraffin embedded tissue. To identify the protein amino acid sequence of serum and urine bands and amyloid plaques, the samples were digested into peptides by trypsin and analyzed by MS based proteomic analysis. (see Vrana et al. and Blood 2009; 114: 4957 for methods). The results for amino acid sequence predicted from the clonal LC gene sequence, determined directly by MS from the serum and/or urine monoclonal band and amyloid plaques were then aligned and compared. In all 10 cases, the LC amino acid sequences predicted by sequencing of the clonal LC gene from bone marrow plasma cells, the amino acid sequence obtained directly from the monoclonal serum and/or urine protein and the amino acid sequence obtained from the amyloid plaque were identical. In most cases, both the complete variable region and constant regions were deposited as amyloid plaques. Some amyloid plaques showed cleavage of first 16 amino acids of the variable region suggesting that this part was not required for amyloid deposition. All LC variable region gene sequences were affected by somatic hypermutation, and identical mutations were present in both the serum and urine bands and in the amyloid plaques. In conclusion, these results, for the first time, comprehensively show that the monoclonal protein secreted by the neoplastic plasma cells is the pathogenetic protein causing the amyloid deposits in AL amyloidosis. Amyloid deposits contain virtually all of the LC protein identified in the serum or urine including both variable and constant regions, suggesting that the presence of the constant region may also play a role in amyloidogenesis. The technological capability to determine the complete protein sequence of the amyloidogenic monoclonal serum and urine LC protein isolated from archived gels will create new opportunities to develop diagnostic, predictive and prognostic serum or urine based tests for amyloidosis. Disclosures: Theis: Mayo Clinic: Patents & Royalties. Vrana:Mayo Clinic: Patents & Royalties. Dogan:Mayo Clinic: Patents & Royalties.

Abstract Background : Celiac disease (gluten sensitive enteropathy) is a systemic disease with hematological manifestations including; iron deficiency anemia, vitamin B12 and folate deficiency, leukopenia/neutropenia, hyposplenism, venous thromboembolism, and the enteropathy associated T cell lymphoma (E-TCL). Leukopenia/neutropenia is rare, and can result from folate or copper deficiency, but in many cases remains idiopathic. The consequences of neutropenia and neutrophil responses to a gluten free diet are not well described. We carried out this study to assess the incidence and outcomes of neutropenia in patients with celiac disease. Methods : The Mayo clinic celiac disease database (n=1729) was retrospectively analyzed for all patients with a confirmed diagnosis of celiac disease that had leukopenia (<3.5 x10(9)/L) and/or neutropenia (<1.5 x 10(9)/L). The diagnosis of celiac disease was established by positive tissue transglutaminase antibodies (TTG) and confirmatory small bowel biopsy findings. Additional causes of neutropenia such as copper and folate deficiency, drugs, benign ethnic and cyclic neutropenia, chemotherapy, hematological malignancies, combined variable immunodeficiency (CVID), and autoimmune diseases were meticulously excluded. Data abstracted included demographics, temporal association with diagnosis, nadir counts, associated hematological findings, relationship with infections, the use and effect of G-CSF, response to gluten free diet and survival outcomes. Results: 21(1.2%) of 1729 cases screened had idiopathic-celiac related neutropenia; 17 (81%) Caucasian, 15 (48%) females. In 12(57%) patients the neutropenia preceded or occurred near the time of the diagnosis of celiac disease, while in 7 (33.3%) it occurred subsequently. In 2 cases the temporal association could not be established. The median age at diagnosis of celiac disease was 46 years (10-67) and the median follow up for this group was 41.7 months (0-207.3). At last follow up 1 (4.8%) death has been documented; 0 from infectious complications, with no cases of E-TCL. The median laboratory values at diagnosis of celiac disease were available in 11 (52%) patients and included; hemoglobin 12.9 g/dL (10.5-16.8), MCV 91.5 fl (79.6-102.8), WBC 3.2 x109/L (2.3-5.2), ANC 1.29x109/L (0.33-3.24), ALC 1.34x109/L (0.75-2.17), AMC 0.39x109/L (0.15-0.71), and platelet counts 225x109/L (168-711). Anti-granulocyte antibodies were assessed in 7 patients and were negative in all cases. None of these patients had coexistent hyposplenism and three cases of neutropenia that occurred in the setting of celiac disease and CVID were excluded. In 15 (71%) patients the neutropenia was incidentally detected during routine laboratory work and in 4 (19%) it came to light secondary to infections. Ten (48%) patients had recurrent infections (≥1) as documented by their providers, including 7 with sinopulmonary infections, 1 with urinary tract infections, and 1 with skin and soft tissue infections. Additional immunological assessments were not available in these patients. Three (14%) patients had an ANC <500 (significant neutropenia); of which 2 had recurrent sinopulmonary infections. The third patient remained largely asymptomatic. Two of the 3 patients received G-CSF support during infections and responded adequately (ANC improvement > 1 x 10(9)/L). The ANC in patients in this cohort did not correlate with severity of infections. Five (23%) of 21 patients had improvement in neutrophil counts after adopting a gluten free diet, while there was no response in 10 and data was unavailable in 6. The median time to ANC response was 14.5 months (10-15.3) and the median increment in ANC was 0.67 x 10(9)/L (0.48-0.98). Conclusions: Celiac disease associated neutropenia, especially significant neutropenia (ANC <500) is a rare occurrence (~1%). It can often pre-date the diagnosis of celiac disease or occur subsequently. It is potentially associated with an increased incidence of infections, with-out good correlation with the severity of neutropenia. Less than half the patients do seem to respond to a gluten free diet. G-CSF responses seem to be adequate and G-CSF can be used in the setting of severe infections. Disclosures No relevant conflicts of interest to declare.

Abstract BACKGROUND: Complement-mediated thrombotic microangiopathies (TMAs) are a subset of TMAs in which the thrombocytopenia, microangiopathic hemolytic anemia, and end organ damage are caused by mutations in genes encoding the alternative complement pathway. Numerous complement genes have been implicated in complement-mediated TMAs including complement factor H (CFH), CD46 (MCP), complement factor I (CFI), complement component 3 (C3), complement factor B (CFB), factor H related 5 (CFHR5), and thrombomodulin (THBD) among others. Genetic analysis typically yields a mutation in 60% of patients whose TMA is presumed to be mediated by complement dysregulation. However, the description of novel disease-associated variants may increase this proportion. METHODS: A retrospective study of patients with TMAs diagnosed between 2000 and 2014 was performed. TMA diagnosis was made based on thrombocytopenia and evidence of microangiopathic hemolytic anemia. Analysis was performed with Alamut¨ software with additional in silico prediction tools (SIFT, MutationTaster, and Polyphen) for classification of gene variants. Variants of unknown significance (VUS) and likely pathogenic variants were further assessed using several mutation databases, including HGMD, ClinVar, and Factor H database RESULTS: Of patients diagnosed with a TMA, genetic analysis was performed in only a 10% of patients. Of the 29 patients with genetic studies performed, mutations were identified in 18 patients (62%). The majority of the mutations had been described previously in the literature, but four novel variants were identified: three missense and one splice-site. The table below summarizes these variants as well as laboratory findings on presentation. These were two variants of CFH, one variant of CFHR5, and one variant of CFI. In silico modeling of these variants revealed two polymorphisms likely to be pathogenic, one polymorphism likely benign given the lack of predicted splicing changes, and one VUS. Table 1. Protein Mutation Classification Age Sex Hemoglobin (g/dL) Platelets (thousands) Creatinine (mg/dL) CFH c.245-10_245-9dup Likely benign 61 F 11.6 51 6.7 CFH c.476G>A, p.Ser159Asn Likely pathogenic 43 F 9.1 101 9.1 CFHR5 c.1412G>A p.Gly471Glu Likely pathogenic 30 F 9.8 129 4.9 CFI c.1190T>A p.Val397Glu Unknown significance 51 M 9.4 125 6.1 DISCUSSION: With therapy available to target the alternative complement pathway, genetic analysis to identify genetic variants capable of causing complement mediated TMAs is an essential part of the evaluation. This genetic data must be interpreted and correlated with functional analysis and clinical phenotype. The reporting of novel variants in clinical databases, with inclusion of relevant clinical findings, is necessary to accurately classify and verify variants as pathologic mutations or benign polymorphisms. The full understanding of this diverse disease requires a more complete understanding of its genetics. While complement pathway-directed therapies are available, their rational use requires thorough interpretation of laboratory data, including genetic analysis. Disclosures Murray: Mayo Clinic: Patents & Royalties: Patent Application Filed.

Abstract It is well-recognized that Helicobacter pylori infection causes gastrointestinal blood loss and iron deficiency. H. pylori gastritis has also been implicated in iron deficiency refractory to oral iron replacement therapy. Although H. pylori infection is common in multiple populations, less is known about the extent to which H. pylori contributes to iron deficiency in different racial/ethnic groups. To address this question, we tested the serum collected from men aged ≥ 25 y and women ≥ 50 y in the Hemochromatosis and Iron Overload Screening (HEIRS) Study to identify those with iron deficiency (defined as serum ferritin ≤ 12 mg/L [cases]) and iron-replete controls (serum ferritin > 100 mg/L in men, serum ferritin > 50 mg/L in women). All samples were tested for H. pylori IgG antibodies and for antibodies to CagA (cytotoxin-associated gene-bearing strain). We tested 571 cases and 1142 controls. Participants were considered to have evidence of H. pylori infection if they had positive results for both antibodies or for either antibody alone. Participants who did not have a result for either test were excluded. We examined the association between the presence of H. pylori in cases and controls among Caucasians, Asian/Pacific Islanders, African Americans, and Hispanics. Among Caucasians, evidence of H. pylori infection was comparable in cases and controls; 170 of 735 controls (23.1%) and 97 of 363 cases (26.7%), respectively, were positive. Similar results were found in African Americans (56.3% of 144 controls; 55.8% of 77 cases) and Hispanics (66.7% of 159 controls; 59.5% of 79 cases). However, in Asian/Pacific Islanders, the prevalence of H. pylori was higher among cases (62.8% of 51) than controls (44.1% of 102), p=0.029 by the likelihood ratio Chi-Square test. The relative risk (RR) of iron deficiency among those with H. pylori-positivity was significantly greater than in those without (RR, 1.66; 95% CI [1.04, 2.66]). A comparison of subgroups by positivity for IgG or CagA showed that the relative risk of iron deficiency was increased among those with IgG positivity, with or without Cag A positivity (RR, 1.80 and 1.90, respectively), but not among those with CagA positivity alone (RR, 1.00). H. pylori infection is a frequent contributor to iron deficiency but is also common in the general population. Our results indicate that among HEIRS Study Asian/Pacific Islander participants, H. pylori infection is more prevalent in cases with iron deficiency than in controls. In contrast, there was no difference in the prevalence of H. pylori infection between cases and controls among Caucasians, African Americans, and Hispanics. These results have implications for the investigation of iron deficiency in Asians and Pacific Islanders. Disclosures No relevant conflicts of interest to declare.

Abstract Abstract 2095 Celiac disease (CD) is an increasingly recognized disorder in Caucasian populations of European origin. Little is known about its prevalence in non-Caucasians. While CD is thought to be a cause of iron deficiency anemia, the extent to which CD contributes to iron deficiency in Caucasians and especially non-Caucasians is unknown. Iron deficiency is one of the most common nutritional deficiencies in both the developed world and in developing countries. Thus, it is important to know the prevalence of CD in different populations and in iron-deficient and iron-replete persons. To answer these questions, we tested serum collected from Caucasian and non-Caucasian men aged ≥ 25 y and women ≥ 50 y in the Hemochromatosis and Iron Overload Screening (HEIRS) Study. In the HEIRS Study, 101,168 participants were screened with serum biochemical tests of iron status, which not only detected participants with iron overload but also identified a unique multiethnic population of participants with iron deficiency. We hypothesized that CD is more common in those with iron deficiency than in iron-replete individuals. We also examined the difference in frequency of CD between Caucasians and non-Caucasians with iron deficiency. Cases with iron deficiency (defined as serum ferritin ≤ 12 μg/L [cases]) and iron-replete controls (serum ferritin > 100 μg/L in men, serum ferritin > 50 μg/L in women) were further evaluated by using a sequential serological testing scheme whereby all samples were tested with an ELISA for human recombinant tissue transglutaminase IgA antibodies, and positive values were confirmed by endomysial antibodies. Those positive for both tests were considered double positives and were presumed to have untreated CD. Those positive for tissue transglutaminase IgA antibodies but not for endomysial antibodies were termed single positives and were considered indeterminate and excluded from analysis. We further hypothesized that low serum ferritin and an appropriate human leukocyte antigen (HLA) variant, may be predictive of CD. We used SNP-based analysis to determine HLA genotype and DQ8, DQ2.2 or DQ4, and DQ2.5 risk variants. Fisher's exact test was used to examine the association between iron−deficient case and control status and the presence of celiac disease. Log-binomial regression was applied to estimate the odds of celiac disease in iron-deficient cases relative to that of controls. A total of 1713 subjects were tested for tissue transglutaminase IgA antibodies. Participants included 1100 Caucasians, 221 African Americans, 153 Asians, and 239 Hispanics. Fourteen of 571 iron-deficient cases were positive for the double serology compared to just one of 1142 controls. All of the seropositive tests were seen in Caucasians and none in the non-Caucasians. Excluding data from participants with indeterminate serological screen results (6 Caucasians, 4 non-Caucasians), we found that CD occurred in 14 of 567 cases (2.5%) and in only 1 of 1136 (0.1%) controls (Fisher's exact test, p=1.92 10−6). CD was more common in Caucasian cases (14 of 363, 4%) than in non-Caucasian cases (0 of 204, p=0.003). Only one Caucasian control and none of the non-Caucasian controls had CD. The odds of CD in individuals with iron deficiency was 28 (3.7, 212.8) times that in controls. Thirteen of 14 iron-deficient cases with CD carried the DQ2.5 variant of the HLA genotype. Presence of DQ2.5 was highly significantly associated with celiac disease status in iron-deficient cases compared to controls (Fisher's exact test, p = 7.183 × 10−8). The results indicate that CD is a small but significant contributor to iron deficiency in Caucasians. CD is very rare in other races, even among individuals with features frequently seen in CD, such as iron deficiency. CD is also rare in Caucasians who are iron replete. CD testing should be considered for adult Caucasian males or post-menopausal females having iron deficiency without evidence of other etiologies such as gastrointestinal blood loss. Patients identified with CD may benefit from appropriate treatment. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 132 Multiple myeloma (MM), an incurable neoplasia of terminally differentiated plasma cells, are critically dependent on their interactions with bone marrow stromal cells (BMSC) for essential survival signals, growth and immunosuppressive factors. Very little is known about the specific BM cell type or the molecular elements in these interactions, an understanding of which could provide novel targets that could be interdicted to enhance conventional chemotherapy. A potential MM surface protein that could be involved in these interactions is CD28, based on its known pro-survival role in T cells. Clinical studies have shown that expression of CD28 in multiple myeloma highly correlates (p=0.006) with myeloma tumoral expansion. Moreover, CD28+ MM cells invariably express the CD28 ligand CD86. A survival role for MM-CD28 might involve interactions with BM cells that express B7 (CD80/CD86) such as dendritic cells (DCs, that are known to be closely associated with MM cells in the BM) or with CD86+ MM cells themselves. We had previously shown (ASH2008, #I-769) that blocking CD28-CD86 interactions between myeloma cells with high affinity B7 ligand CTLA4Ig (Abatacept®) sensitized myeloma cells to chemotherapy. Now we show that myeloma cells co-cultured with myeloid DCs in vitro derive both direct and indirect survival signals from DCs, and this can be partially blocked by commercially available reagents. Our data show that flow cytometric analysis of mononuclear cells (MNC) from BM aspirates of myeloma patients with increased CD138+ plasma cell populations (9-58%), show an increased CD11b+ (myeloid) population (20-37%) as well, which is in contrast to healthy transplant donor controls (12-15% CD11b+, 4–6% CD138+). Moreover, a larger fraction (11-47%) of the myeloma CD138+ plasma cells expressed CD28 compared to healthy control (3.3-7.7%). Also, when we analyzed gene expression datasets (NCBI #GSE5900 and GSE4204) from plasma cells (PC) of normal donors, monoclonal gammopathy of undetermined significance (MGUS), smoldering myeloma (SM) and newly diagnosed multiple myeloma (MM), we found a progressive increase in patients showing CD28 expression with increasing severity of disease (normal<MGUS<SM<MM) (Fig 1A). When we sorted the highest scoring MM group (n=538) into 8 genetic subgroups as defined earlier, CD28 expression was found to peak in the MF subgroup (typically associated with poor survival in myeloma patients) (Zhan et al. 2006, Blood 108, pp. 2020) relative to total population (p<0.0001) (Fig 1B). Antibody mediated activation of MM-CD28 over 48 hrs increased viability of myeloma cell line MM.1S cultured under serum starvation (3.7%) or with drugs ATO (1.9%), melphalan (18%) or dexamethasone (3.3%) to 66%, 21%, 33% and 11% respectively. Viability of MM.1S cells or primary CD138+ plasma cells (isolated from myeloma BM aspirates) cultured under serum starvation was enhanced >3 fold (p<0.001) when co-cultured with monocyte derived DCs, and in MM.1S this was partially reversed when either MM-CD28 or DC-B7 was blocked (Fig 2). Similar protection of MM.1S was also observed against a gradient of dexamethasone or melphalan. CD28 activation was accompanied by rapid tyrosine phosphorylation of CD28, association of p85 (PI3K), activation of Vav-1 and increase in CD28 associated tyrosine kinase activity, as shown by immunoprecipitation, western and kinase activity assays. We had previously shown that MM-CD28 interaction drive DC production of pro-survival factor IL-6 and immunosuppressive factor IDO via DC-B7 “backsignaling” (ASH2008 #I-769). Now we show that MM induced DC production of IL-6 (8 ng/ml) was partially inhibited in presence of CD28 blocking αCD28(Fab) fragments (3 ng/ml) or with protein kinase C (PKC) inhibitor Bisindolylmaleimide-I (2.1ng/ml). Activity of the immunosuppressive enzyme IDO in these co-cultures was completely inhibited in the presence of a novel IDO inhibitor from Incyte corporation, and this helped partially reverse IDO mediated suppression of T-cell proliferation in proliferation assays using co-culture supernatants. In conclusion, our data characterizes CD28-B7 pathway and DCs in the BM as vital for myeloma survival and also as possible targets to include in future strategies in the treatment of myeloma. FIGURE 1 FIGURE 1. FIGURE 2 FIGURE 2. Disclosures: Boise: University of Chicago: Patents & Royalties.

INTRODUCTION: Patients with eosinophilic gastritis and/or gastroenteritis (EG/EGE) experience significantly reduced health-related quality of life related to the symptoms and signs of their disease. There is a need to develop a PRO questionnaire for clinical research in EG/EGE. The objectives of this study were to develop a symptom questionnaire (drafted using literature and clinician input to determine preliminary measurement concepts) and then (1) identify, describe, and substantiate signs, symptoms, and impacts of EG/EGE from the perspective of adults with the condition via concept elicitation methods; and (2) evaluate the properties of the questionnaire and make modifications via cognitive debriefing methods. METHODS: Interviews were conducted, transcribed, coded, and analyzed. Eligible adults with EG/EGE first participated in a concept elicitation segment where they described their experiences with EG/EGE, continuing until saturation was achieved, adding symptoms to the draft symptom questionnaire as needed. This was followed by a cognitive debrief to assess the appropriateness of the draft symptom questionnaire, where patients assessed readability, comprehensibility, relevance, and comprehensiveness. The questionnaire was modified based on patient feedback, then re-evaluated to confirm its appropriateness. RESULTS: In total, 16 interviews were conducted and 24 signs and symptoms were reported during concept elicitation. The most frequently reported (Figure 1) were abdominal pain, nausea, diarrhea, vomiting, and abdominal cramping; while abdominal pain, nausea, and diarrhea were the most bothersome to patients. Saturation was achieved after 12 interviews. In the cognitive debriefing, revisions included the addition of a vomiting frequency item and revision of the early satiety item for clarity. Response options were modified to instruct the participants to assess each symptom “at its worst”. For the final version of the EG/EGE-SQ©, participants were able to read, comprehend, and provide appropriate responses, and reported that the resulting questionnaire was comprehensive for their condition. CONCLUSION: The results of this research support the content validity, including comprehensiveness and interpretability, of the EG/EGE-SQ© which offers the potential for use in clinical research to assess symptoms in patients with EG/EGE. Future research is needed to assess its psychometric properties including reliability and validity, responsiveness, and potential for use in pediatric populations.

INTRODUCTION: Eosinophilic gastrointestinal diseases (EGIDs) are a set of inflammatory diseases subclassified according to the site(s) of abnormal accumulation of eosinophils (eos) in the gastrointestinal (GI) tract such as eosinophilic esophagitis (EoE), gastroenteritis (EGE), and colitis. These conditions often decrease quality of life due to debilitating symptoms. While the pathogenesis of EGIDs is primarily thought to be driven by eos, there is increasing evidence for the involvement of mast cells (MCs). AIM: To characterize symptomatic patients (pts) with suspected EG/EGE who did not meet histopathologic entry criteria for mucosal eosinophilia for a Phase 2 randomized, double-blind, placebo-controlled study of AK002, an anti-Siglec-8 antibody. METHODS: To undergo screening endoscopy for this study, pts were required to report an average symptom score ≥3 (0 to 10 scale) for abdominal pain, nausea, and/or diarrhea on a daily patient-reported outcome questionnaire for ≥2 weeks and have no other known cause for GI symptoms. During the screening endoscopy, biopsies were systematically obtained from the stomach and duodenum, and read by a single pathologist. Eos counts (eos/hpf; hpf area = 0.237 mm 2 ) were assessed on H&E slides. To quantify MCs, immunohistochemistry for tryptase was performed. We quantified eos and MCs in the stomach and duodenum. Histopathologic entry criteria for the randomized study was ≥30 eos/hpf in 5 hpfs in the stomach (EG) and/or ≥30 eos/hpf in 3 hpfs in the duodenum (EGE). A literature review was conducted to determine normal MC counts in the GI tract. RESULTS: Eighty-eight pts underwent screening endoscopy based upon suspected EG/EGE and active symptoms, and 72 pts met histopathologic eos criteria. All pts whose eos did not meet entry criteria (n = 16) were found to have elevated MC counts (Figure 1; reported normal range = 12-19 MCs/hpf). In these pts, the mean gastric eos count was 6 eos/hpf in 5 hpfs and mean duodenal eos count was 15 eos/hpf in 3 hpfs. In contrast, these pts exhibited a mean gastric MC count of 47 MC/hpf in 5 hpfs and a mean duodenal MC count of 49 MC/hpf in 3 hpfs. Almost all symptomatic pts screened (87/88; 99%) had elevated MC counts. CONCLUSION: Data from this large randomized EG/EGE study showed that symptomatic pts with suspected EG/EGE had increased mucosal MCs with or without mucosal eosinophilia. These data suggest that MCs may play a role in pts with suspected EG/EGE and raise the possibility of a unique clinical presentation driven by MCs.

INTRODUCTION: Rates of musculoskeletal (MSK) injury among gastroenterologists are estimated to be as high as 75%, exceeding rates of 35% among non-proceduralists. Specific ergonomic/procedural factors influencing these injuries have yet to be defined. We sought to characterize potential risk factors for MSK injury by analyzing the physical traits and technical procedural data of a cohort of endoscopists. METHODS: The QuickDASH (Disabilities of Arm, Shoulder, and Hand) survey was sent to all gastroenterologists across a large tertiary care system. Added questions assessed injury characteristics, glove size, and other demographic data. Endpoints defining affected vs. unaffected groups include self-reported function-limiting upper extremity or back pain, injury necessitating limiting/stopping endoscopy, and trends toward higher QuickDash, Work Impairment, or Sport/Instrument Disability scores. A procedural database capturing all endoscopic activities of each respondent from 2011 to 2018 was queried to gather procedural types, volumes, durations, and insertion times; scope types; and polyp detection rates. RESULTS: 64 surveys were completed (28.1% female, mean age 44.4 ±10.8 yrs). The average time in practice was 18.9 (±10.8) years. 51% (n = 33) of respondents reported significant activity-limiting pain, including hand/wrist (n = 31), arm/elbow (n = 12), shoulder (n = 19), and back (n = 24) pain. Characteristics between affected and non-affected groups are detailed in Table 1 with further exploratory analyses found in Table 2. Those needing to limit/stop endoscopy due to pain more frequently used pediatric scopes (31% vs. 19%, P = 0.037), took longer to perform colonoscopy (25.3 vs. 22.1 minutes, P = 0.035) and had lower yearly procedural volumes (532 vs. 807, P = 0.009). Those with hand/wrist pain had longer colonoscopy insertion times (9.35 vs. 8.21 minutes, P = 0.03) and less colonoscopy hands-on scope hours per year (81.2 vs. 111.7 hours, P = 0.039). Females had more severe shoulder pain ( P = 0.04), but there were no other associations with sex or small glove size. CONCLUSION: Activity-limiting MSK injuries affect over 50% of endoscopists. MSK symptoms were associated with longer procedure times and higher EGD or push enteroscopy volumes. Symptomatic subjects were more likely to use pediatric colonoscopes. Hand/wrist pain is the most common and (presumably) the most limiting type of injury. Further prospective monitoring is warranted to better elucidate which variables are causative versus compensatory responses to injury.