Haematological features of telomere biology disorders diagnosed in adulthood: A French nationwide study of 127 patients.

Data on haematological features of telomere biology disorders (TBD) remain scarce. We describe haematological, extra-haematological characteristics and prognosis of 127 genetically confirmed TBD patients diagnosed after the age of 15. Ninety-three index cases and 34 affected relatives were included. At diagnosis of TBD, 76.3% of index cases had haematological features, half pulmonary features and a third liver features. At diagnosis, bone marrow failure (BMF) was present in 59 (46.5%), myelodysplastic syndrome (MDS) in 22 (17.3%) and acute myeloid leukaemia (AML) in 2 (1.6%) while 13 (10.2%) developed or worsened bone marrow involvement during follow-up. At diagnosis, compared to MDS/AML patients, BMF patients were younger (median 23.1 years vs. 43.8, p = 0.007), and had a better outcome (4-year overall survival 76.3% vs. 31.8%, p < 0.001). While frequencies and burden of cytogenetical and somatic mutations increased significantly in myeloid malignancies, some abnormalities were also observed in patients with normal blood counts and BMF, notably somatic spliceosome variants. Solid cancers developed in 8.7% patients, mainly human papillomavirus-related cancers and hepatocellular carcinomas. TBD is a multiorgan progressive disease. While BMF is the main haematological disorder, high-risk myeloid malignancies are common, and are, together with age, the only factors associated with a worse outcome.

Proton pump inhibitors and risk of severe COVID-19 in older people.

INTRODUCTION: Severe acute respiratory syndrome coronavirus 2 is a viral respiratory infection that can cause systemic disorders and lead to death, particularly in older people. Proton pump inhibitors (PPIs) increase the risk of enteric and lung infections. Considering the broad use of PPIs in older people, the potential role of PPIs in COVID-19 could be of dramatic significance. The objective of our study was to evaluate the link between PPIs and severe COVID-19 in older people. METHOD: We performed a retrospective cohort study, including all patients aged ≥65, hospitalised for a diagnosis of COVID-19. Epidemiological, clinical and biological data were extracted and we performed an Inverse Probability of Treatment Weighing method based on a propensity score. RESULTS: From March 2020 to February 2021, a total of 834 patients were included, with a median age of 83 and 52.8% were male. A total of 410 patients had a PPIs prescription, 358 (87.3%) were long-term PPIs-users and 52 (12.7%) were recent PPIs-users. Among PPIs-users, 163 (39.8%) patients developed severe COVID-19 versus 113 (26.7%) in PPIs-non users (odds ratio (OR) = 1.59 [1.18-2.14]; P < 0.05). Moreover, the double dose PPI-users had a higher risk of developing severe COVID-19 (OR = 3.36 [1.17-9.66]; P < 0.05) than the full dose PPI-users (OR = 2.15 [1.22-3.76]; P < 0.05) and the half dose PPI-users (OR = 1.64 [1.13-2.37]; P < 0.05). CONCLUSION: Our study reports evidence that the use of PPIs was associated with an increased risk of severe COVID-19 in older people.

Activated phosphoinositide 3-kinase δ syndrome: Update from the ESID Registry and comparison with other autoimmune-lymphoproliferative inborn errors of immunity.

BACKGROUND: Activated phosphoinositide-3-kinase δ syndrome (APDS) is an inborn error of immunity (IEI) with infection susceptibility and immune dysregulation, clinically overlapping with other conditions. Management depends on disease evolution, but predictors of severe disease are lacking. OBJECTIVES: This study sought to report the extended spectrum of disease manifestations in APDS1 versus APDS2; compare these to CTLA4 deficiency, NFKB1 deficiency, and STAT3 gain-of-function (GOF) disease; and identify predictors of severity in APDS. METHODS: Data was collected from the ESID (European Society for Immunodeficiencies)-APDS registry and was compared with published cohorts of the other IEIs. RESULTS: The analysis of 170 patients with APDS outlines high penetrance and early onset of APDS compared to the other IEIs. The large clinical heterogeneity even in individuals with the same PIK3CD variant E1021K illustrates how poorly the genotype predicts the disease phenotype and course. The high clinical overlap between APDS and the other investigated IEIs suggests relevant pathophysiological convergence of the affected pathways. Preferentially affected organ systems indicate specific pathophysiology: bronchiectasis is typical of APDS1; interstitial lung disease and enteropathy are more common in STAT3 GOF and CTLA4 deficiency. Endocrinopathies are most frequent in STAT3 GOF, but growth impairment is also common, particularly in APDS2. Early clinical presentation is a risk factor for severe disease in APDS. CONCLUSIONS: APDS illustrates how a single genetic variant can result in a diverse autoimmune-lymphoproliferative phenotype. Overlap with other IEIs is substantial. Some specific features distinguish APDS1 from APDS2. Early onset is a risk factor for severe disease course calling for specific treatment studies in younger patients.

Benralizumab for eosinophilic granulomatosis with polyangiitis.

BACKGROUND: Benralizumab is effective in the treatment of eosinophilic asthma and is being investigated for the treatment of other eosinophil-associated diseases. Reports on the use of benralizumab for the treatment of eosinophilic granulomatosis with polyangiitis (EGPA) are limited to case reports and small case series. METHODS: We conducted a multicentre, retrospective study including EGPA patients treated with off-label benralizumab. The primary endpoint was the rate of complete response defined as no disease activity (Birmingham Vasculitis Activity Score=0) and a prednisone dose ≤4 mg/day. Partial response was defined as no disease activity and a prednisone dose ≥4 mg/day. RESULTS: Sixty-eight patients were included, including 31 (46%) who had previously received mepolizumab. The use of benralizumab was warranted by uncontrolled asthma in 54 (81%), persistent ear, nose and throat (ENT) manifestations in 27 (40%) and persistent glucocorticoids (GCs) use in 48 (74%) patients. Median (IQR) follow-up after starting benralizumab was 23 (9-34) months. Thirty-three patients (49%) achieved a complete response, 24 (36%) achieved a partial response and 10 (15%) did not respond. Among the 57 patients who initially responded, 10 (18%) eventually required further line treatments. GCs were discontinued in 23 patients (38%). Prior mepolizumab use was associated with a higher rate of primary failure (26.7% vs 5.4%, p=0.034) and less frequent GCs discontinuation (14.8% vs 55.9%, p=0.001). Vasculitis flares occurred in 7 patients (11%) and were associated with histological evidence of vasculitis and/or antineutrophil cytoplasmic antibodies positivity at benralizumab initiation (p=0.004). CONCLUSIONS: Benralizumab appears to be an effective treatment for refractory asthma or ENT manifestations in EGPA and allows GC-sparing. However, its efficacy was lower after prior failure of mepolizumab.

Occurrence of focal myositis during Behçet's disease: The identification of a specific vasculitis-associated focal myopathy.

AIMS: This study aimed to report the association of focal myositis (FM) and Behçet's disease (BD) and to analyse the main characteristics of such an association. METHODS: This is a retrospective multicentre study of patients with BD and FM (BD + FM+ group) and those without FM (BD - FM+ group). Clinical, laboratory, radiological, pathological, treatment and outcome data were analysed. RESULTS: The BD + FM+ group included 10 patients; the median [interquartile range] age at BD diagnosis was 25 [16-35] years, and at FM diagnosis, it was 30 [26-42] years. The diagnosis of BD preceded FM in the majority of cases (n = 8/10). FM occurrence was associated with BD flare-ups in three cases. The creatine kinase levels remained normal or slightly increased. Histological analyses identified relatively preserved muscle tissue, associated with vasculitis (n = 5/6). All patients required treatment; most patients relapsed (n = 9/10). The BD - FM+ group included 35 patients. A comparison of the groups identified a trend towards a younger median age at diagnosis of FM among those with BD (p = 0.063) and more frequent focal muscle swelling in the BD + FM+ group (p = 0.029). The pathological analysis identified significantly less frequent muscle alterations in the BD + FM+ group (muscle fibre size heterogeneity, p = 0.021; necrosis, p = 0.007; and fibrosis, p = 0.027). BD + FM+ patients had a higher frequency of relapse (p = 0.003) and systematic treatment (p = 0.042). CONCLUSIONS: FM occurring during BD appears to be part of the systemic vasculitis process and presents as a vasculitis-associated focal myopathy with a specific clinico-histological pattern. Patients with this association require long-term follow-up and adapted management. This case series also highlights the need for research on BD diagnostic criteria in cases of FM.

Immune thrombocytopenia with clinical significance in systemic lupus erythematosus: a retrospective cohort study of 90 patients.

OBJECTIVES: To describe the characteristics, treatment and outcome of patients with immune thrombocytopenia with clinical significance (ITPCS) associated with SLE. METHODS: This retrospective multicentre study included SLE patients who experienced ≥1 ITPCS (defined as ITP with attributable bleeding disorders and/or a platelet count <30×109/l). Other causes of secondary thrombocytopenia were excluded. Major bleeding event (MBG) was defined as Khellaf score >8 and/or WHO score >2. RESULTS: A total of 90 patients were included, the median (range) follow-up duration was 80 (6-446) months. ITP was diagnosed before SLE in 25 patients. They presented a high rate of autoimmune haemolytic anaemia (15%), antiphospholipid antibody (62%) and antiphospholipid syndrome (19%). The 25 (28%) patients who experienced MBG had significantly more bleedings at ITP diagnosis and higher bleeding scores, and serositis and thrombosis during follow-up. They required significantly more treatment lines, transfusions and hospitalizations. The 11 (12%) patients who experienced no bleeding event presented a significantly more restricted SLE phenotype (cutaneous and/or articular). Patients received a mean (range) of 4.2 (1-11) treatment lines. Corticosteroids and HCQ allowed ITPCS overall response in one-third of patients. The median relapse-free survival of rituximab (n = 34), AZA (n = 19), MMF (n = 8), thrombopoietin-receptor agonists (n = 16) and splenectomy (n = 19) were 53, 31.5, 61, 24.5 and 78 months, respectively. Four patients experienced thrombotic events after splenectomy and one occurred under thrombopoietin-receptor agonist treatment. CONCLUSION: SLE-ITCS patients displayed a high rate of haematological abnormalities and MBG patients exhibited higher morbidity. Management of thrombocytopenia was highly heterogeneous and many options seem viable.

Preemptive rituximab prevents long-term relapses in immune-mediated thrombotic thrombocytopenic purpura.

Preemptive rituximab infusions prevent relapses in immune thrombotic thrombocytopenic purpura (iTTP) by maintaining normal ADAMTS13 activity. However, the long-term outcome of these patients and the potential adverse events of this strategy need to be determined. We report the long-term outcome of 92 patients with iTTP in clinical remission who received preemptive rituximab after identification of severe ADAMTS13 deficiency (activity <10%) during the follow-up. Thirty-seven patients had >1 iTTP episode, and the median cumulative relapse incidence before preemptive rituximab was 0.33 episode per year (interquartile range [IQR], 0.23-0.66). After preemptive rituximab, the median cumulative relapse incidence in the whole population decreased to 0 episodes per year (IQR, 0-1.32; P < .001). After preemptive rituximab, ADAMTS13 activity recovery was sustained in 34 patients (37%) during a follow-up of 31.5 months (IQR, 18-65), and severe ADAMTS13 deficiency recurred in 45 patients (49%) after the initial improvement. ADAMTS13 activity usually improved with additional courses of preemptive rituximab. In 13 patients (14%), ADAMTS13 activity remained undetectable after the first rituximab course, but retreatment was efficient in 6 of 10 cases. In total, 14 patients (15%) clinically relapsed, and 19 patients (20.7%) experienced benign adverse effects. Preemptive rituximab treatment was associated with a change in ADAMTS13 conformation in respondent patients. Finally, in the group of 23 historical patients with iTTP and persistently undetectable ADAMTS13 activity, 74% clinically relapsed after a 7-year follow-up (IQR, 5-11). In conclusion, persistently undetectable ADAMTS13 activity in iTTP during remission is associated with a higher relapse rate. Preemptive rituximab reduces clinical relapses by maintaining a detectable ADAMTS13 activity with an advantageous risk-benefit balance.

Clinical and biological features in PIEZO1-hereditary xerocytosis and Gardos channelopathy: a retrospective series of 126 patients.

We describe the clinical, hematologic and genetic characteristics of a retrospective series of 126 subjects from 64 families with hereditary xerocytosis. Twelve patients from six families carried a KCNN4 mutation, five had the recurrent p.Arg352His mutation and one had a new deletion at the exon 7-intron 7 junction. Forty-nine families carried a PIEZO1 mutation, which was a known recurrent mutation in only one-third of the cases and private sequence variation in others; 12 new probably pathogenic missense mutations were identified. The two dominant features leading to diagnosis were hemolysis that persisted after splenectomy and hyperferritinemia, with an inconstant correlation with liver iron content assessed by magnetic resonance imaging. PIEZO1-hereditary xerocytosis was characterized by compensated hemolysis in most cases, perinatal edema of heterogeneous severity in more than 20% of families and a major risk of post-splenectomy thrombotic events, including a high frequency of portal thrombosis. In KCNN4-related disease, the main symptoms were more severe anemia, hemolysis and iron overload, with no clear sign of red cell dehydration; therefore, this disorder would be better described as a 'Gardos channelopathy'. These data on the largest series to date indicate that PIEZO1-hereditary xerocytosis and Gardos channelopathy are not the same disease although they share hemolysis, a high rate of iron overload and inefficient splenectomy. They demonstrate the high variability in clinical expression as well as genetic bases of PIEZO1-hereditary xerocytosis. These results will help to improve the diagnosis of hereditary xerocytosis and to provide recommendations on the clinical management in terms of splenectomy, iron overload and pregnancy follow-up.

Muscle Damage Due to Fusidic Acid-Statin Interaction: Review of 75 Cases From the French Pharmacovigilance Database and Literature Reports.

BACKGROUND/AREA OF UNCERTAINTY: Statins, which reduce cardiovascular risk in both primary and secondary prevention, are one of the most widely prescribed therapeutic classes in the world. Usually well-tolerated, statin-associated muscle symptoms are a well-known adverse effect. Fusidic acid (FA) is a bacteriostatic antibiotic of interest in the treatment of methicillin-resistant Staphylococcus aureus infections. Cases of rhabdomyolysis, sometimes fatal, have been reported after coprescription of FA and a statin. DATA SOURCES/AREA OF UNCERTAINTY: We studied 75 cases of muscle damage related to interaction between FA and a statin reported in the French national pharmacovigilance database (43 cases) and from a literature review (32 cases). RESULTS: Cases were mostly men (72.5%), often overweight (mean body mass index: 29.4). The most commonly reported statins were atorvastatin (60%), simvastatin (22.7%), and rosuvastatin (8.0%). Muscle disorders appeared on average 30 days after initiation of FA. Symptoms were muscle weakness (82%), dark urine (71%), and myalgia (61%). Mean creatine kinase level at diagnosis was 43,890 UI/mL, and acute renal injury occurred more than half of the cases. Outcome was fatal in 22% of cases and 28% kept sequelae at the end of the follow-up (54 days). CONCLUSIONS: Muscle damage induced by interaction between FA and statin is a potentially life-threatening complication, leading to contraindication of this association in France. This is to be reminded especially because FA is about to get FDA approval and should soon be available in the United States.

What attitude towards a patient with somatoform disorder? / Quelle attitude face à un patient ayant un trouble somatoforme ?

The diagnosis of a somatic symptom disorder must be based on both a negative approach - eliminating another psychiatric or non-psychiatric disorder that would better explain the symptoms - and a positive one, which is, based on the search for characteristic thoughts, emotions or behaviours as well as biological or psychological factors that may promote, trigger or sustain the disorder. Additional tests and specialized medical consultations should not be prescribed solely to reassure the patient; they may actually worsen the condition. The management will move away from the outdated notion of "medically unexplained symptoms" to rely on: the acknowledgment of the painful, debilitating and involuntary nature of the symptoms; the proposal of a positive diagnosis acceptable by the patient and an explanatory model compatible with his or her representations, aimed at putting an end to dysfunctional health care utilization; the proposal of therapeutic objectives aimed at functional rather than symptomatic recovery; the negotiation of pharmacological (selective or mixed serotonin reuptake inhibitor if necessary) and non-pharmacological interventions, especially when it comes to limiting the factors that sustain the disorder; the coordination of the various healthcare professionals.

Le diagnostic de trouble somatoforme doit reposer sur une démarche tout autant négative ­ éliminer un autre trouble psychiatrique ou non psychiatrique qui expliquerait mieux les symptômes ­ que positive, c'est-à-dire fondée sur la recherche de pensées, d'émotions ou de comportements caractéristiques et de facteurs biologiques ou psychologiques pouvant favoriser, déclencher ou pérenniser le trouble. Examens complémentaires et avis médicaux spécialisés ne doivent pas avoir pour seul but de rassurer le patient ; ils peuvent en effet s'avérer iatrogènes. La prise en charge doit se détourner de la notion désuète de « symptômes médicalement inexpliqués ¼ pour s'appuyer sur : la reconnaissance du caractère pénible, invalidant et non volontaire des symptômes ; la proposition d'un diagnostic positif acceptable et d'un modèle explicatif compatible avec les représentations du patient, visant à mettre un terme à l'errance diagnostique ; la proposition d'objectifs thérapeutiques visant un rétablissement fonctionnel plus que symptomatique ; la négociation des moyens pharmacologiques (inhibiteur sélectif ou mixte de recapture de la sérotonine si nécessaire) et non pharmacologiques, en particulier la lutte contre les facteurs d'entretien du trouble ; la coordination des soins entre les divers intervenants

Efficacy and safety of biologics in relapsing polychondritis: a French national multicentre study.

OBJECTIVES: To assess the efficacy and the safety of biologics in a cohort of patients with relapsing polychondritis (RP). METHODS: We conducted a French multicentre retrospective cohort study including patients treated with biologics for RP. Efficacy outcomes were clinical response (partial or complete) and complete response during the first 6 months of exposure, plus daily corticosteroid dose at 6 months. Other outcomes were adverse drug reactions (ADRs), persistence of biologics and factors associated with a response. RESULTS: This study included 41 patients exposed to 105 biologics (tumour-necrosis factor (TNF) inhibitors, n=60; tocilizumab, n=17; anakinra, n=15; rituximab, n=7; abatacept, n=6). Overall response rate during the first 6 months of exposure was 62.9%. Complete response rate was 19.0%. Reduced corticosteroid doses were highly variable among patients. ADRs were mostly infections (n=42). Reasons for biologic withdrawal (73.3%) were insufficient efficacy (34.3%; ranging from 23.5% for tocilizumab to 72.7% for etanercept), loss of efficacy (18.1%) and ADRs (20.9%; mostly for anakinra: 46.7%). Persistence was comparable among biologic classes. Among TNF inhibitors, the highest persistence was observed with adalimumab. Differences in clinical response rates were observed depending on biologics and organ involvement. There were trends towards a lower response rate in cases with associated myelodysplastic syndrome and for a higher response rate for nasal/auricular chondritis, sternal chondritis and concomitant exposure to non-biologic disease-modifying antirheumatic drugs. CONCLUSIONS: This study describes the efficacy of biologics for refractory RP. However, the number of complete responses was low and there were concerns about the risk of ADRs, particularly infections.

Systemic inflammatory and autoimmune manifestations associated with myelodysplastic syndromes and chronic myelomonocytic leukaemia: a French multicentre retrospective study.

OBJECTIVE: We describe myelodysplastic syndrome (MDS)-associated systemic inflammatory and autoimmune diseases (SIADs), their treatments and outcomes and the impact of SIADs on overall survival in a French multicentre retrospective study. METHODS: In this study, 123 patients with MDS and SIADs were analysed. RESULTS: Mean age was 70 years (s.d. 13) and the male:female ratio was 2. The SIADs were systemic vasculitis in 39 (32%) cases, CTD in 31 (25%) cases, inflammatory arthritis in 28 (23%) cases, a neutrophilic disorder in 12 (10%) cases and unclassified in 13 cases (11%). The SIADs fulfilled the usual classification criteria in 75 (66%) cases, while complete criteria were not reached in 21 (19%) cases. A significant association was shown between chronic myelomonocytic leukaemia (CMML) and systemic vasculitis (P = 0.0024). One hundred and eighteen (96%) SIAD patients were treated (91% with steroids), with an 83% response to first-line treatment, including 80% for steroids alone. A second-line treatment for SIADs was required for steroid dependence or relapse in 48% of cases. The effect of MDS treatment on SIADs could be assessed in 11 patients treated with azacytidine and SIAD response was achieved in 9/11 (80%) and 6/11 (55%) patients at 3 and 6 months, respectively. Compared with 665 MDS/CMML patients without SIADs, MDS/CMML patients with SIADs were younger (P < 0.01), male (P = 0.03), less often had refractory anaemia with ring sideroblasts (P < 0.01), more often had a poor karyotype (16% vs 11%, P = 0.04) and less frequently belonged to low and intermediate-1 International Prognostic Scoring System categories, but no survival difference was seen between patients with MDS-associated SIADs and without SIADs (P = 0.5). CONCLUSION: The spectrum of SIADs associated to MDS is heterogeneous, steroid sensitive, but often steroid dependent.

Aplastic anemia as a feature of systemic lupus erythematosus: a case report and literature review.

Peripheral cytopenias are common in systemic lupus erythematosus, but bone marrow involvement is rarely reported. Aplastic anemia is the result of immune-mediated destruction of hematopoietic stem cells causing pancytopenia and characterized by an empty bone marrow. This rare but serious disease has been described as an unusual manifestation of systemic lupus erythematosus. We reviewed the 25 cases published in the English language literature and discuss the clinical presentation, outcome, treatment, and pathophysiology of aplastic anemia as a complication of systemic lupus erythematosus. We report here the first case of aplastic anemia associated with systemic lupus erythematosus treated with an allogeneic hematopoietic stem cell transplant. Over one half of patients received concomitantly the diagnoses of systemic lupus erythematosus and aplastic anemia. No clinical or histological features can distinguish primary aplastic anemia from aplastic anemia occurring in systemic lupus erythematosus patients. The overall mortality is about 15% and corticosteroid-based therapy alone or in combination with other immunomodulatory drugs can restore bone marrow function. Systemic lupus erythematosus may be complicated by bone marrow involvement. The diagnosis of peripheral cytopenias should be confirmed by bone marrow aspiration. All these patients should receive cortisone as a first treatment. Plasma exchanges seem to have some efficacy. Other different immunomodulatory therapies were used with variable results.

Immune deficiency-related enteropathy-lymphocytopenia-alopecia syndrome results from tetratricopeptide repeat domain 7A deficiency.

BACKGROUND: Inflammatory bowel disease (IBD) is one of the most common chronic gastrointestinal diseases, but the underlying molecular mechanisms remain largely unknown. Studies of monogenic diseases can provide insight into the pathogenesis of IBD. OBJECTIVE: We thought to determine the underlying molecular causes of IBD occurring in 2 unrelated families in association with an immune deficiency. METHODS: We performed genetic linkage analysis and candidate gene sequencing on 13 patients from a large consanguineous family affected by early-onset IBD, progressive immune deficiency, and, in some cases, autoimmunity and alopecia, a condition we named enteropathy-lymphocytopenia-alopecia. The candidate gene was also sequenced in an unrelated patient with a similar phenotype. We performed histologic analysis of patients' intestinal biopsy specimens and carried out functional assays on PBMCs. Gut organoids derived from a patient's biopsy specimen were analyzed. RESULTS: We identified biallelic missense mutations in tetratricopeptide repeat domain 7A (TTC7A) in all patients from both families. The resulting TTC7A depletion modified the proliferation, adhesion, and migratory capacities of lymphocytes through inappropriate activation of the RhoA signaling pathway. Normal function was restored by wild-type TTC7A expression or addition of a RhoA kinase inhibitor. The growth and polarity of gut epithelial organoids were also found to be dependent on the RhoA signaling pathway. CONCLUSIONS: We show that TTC7A regulates the actin cytoskeleton dynamics in lymphocytes through the RhoA signaling pathway and is required in both lymphocytes and epithelial cells for maintaining equilibrium between cell proliferation, migration, polarization, and cell death. Our study highlights variability in the phenotypic expression resulting from TTC7A deficiency and outlines that impairment of both epithelial cells and lymphocytes cooperatively causes IBD.

Gastrointestinal manifestations in mastocytosis: a study of 83 patients.

BACKGROUND: Mastocytosis is a heterogeneous disease characterized by mast cell accumulation in 1 or more organs. Gastrointestinal manifestations of systemic mastocytosis have been previously studied in small cohorts of patients, and no specific histologic description is available. OBJECTIVE: We sought to assess the clinical and pathologic features of gastrointestinal manifestations in patients with mastocytosis. METHODS: Medical history and gastrointestinal symptoms of patients with mastocytosis (n = 83) were compared with those of matched healthy subjects (n = 83) by means of patient questionnaire. Data were analyzed for epidemiologic, clinical, biological, and genetic factors associated with gastrointestinal symptoms for patients with mastocytosis. A comparative analysis of gastrointestinal histology from patients with mastocytosis (n = 23), control subjects with inflammatory bowel disease (n = 17), and healthy subjects (n = 19) was performed. RESULTS: The following gastrointestinal symptoms occurred more frequently and were more severe in patients with mastocytosis than in healthy subjects: bloating (33% vs 7.2%, P < .0001), abdominal pain (27.3% vs 4.8%, P < .0001), nausea (23% vs 8.4%, P = .02), and diarrhea (33.85% vs 1.2%, P < .0001). Patients with mastocytosis had a significantly higher incidence of personal history of duodenal ulcer (P = .02). Wild-type (WT) c-Kit was associated with diarrhea (P = .03). Specific histologic lesions were present in patients with mastocytosis but were not correlated with clinical symptoms. CONCLUSION: Gastrointestinal manifestations in patients with mastocytosis are highly prevalent and often severe. Clinical symptoms do not correspond to histologic findings, are nonspecific, and can simulate irritable bowel syndrome.