Transcobalamin receptor antibodies in autoimmune vitamin B12 central deficiency.

Vitamin B12 is critical for hematopoiesis and myelination. Deficiency can cause neurologic deficits including loss of coordination and cognitive decline. However, diagnosis relies on measurement of vitamin B12 in the blood, which may not accurately reflect the concentration in the brain. Using programmable phage display, we identified an autoantibody targeting the transcobalamin receptor (CD320) in a patient with progressive tremor, ataxia, and scanning speech. Anti-CD320 impaired cellular uptake of cobalamin (B12) in vitro by depleting its target from the cell surface. Despite a normal serum concentration, B12 was nearly undetectable in her cerebrospinal fluid (CSF). Immunosuppressive treatment and high-dose systemic B12 supplementation were associated with increased B12 in the CSF and clinical improvement. Optofluidic screening enabled isolation of a patient-derived monoclonal antibody that impaired B12 transport across an in vitro model of the blood-brain barrier (BBB). Autoantibodies targeting the same epitope of CD320 were identified in seven other patients with neurologic deficits of unknown etiology, 6% of healthy controls, and 21.4% of a cohort of patients with neuropsychiatric lupus. In 132 paired serum and CSF samples, detection of anti-CD320 in the blood predicted B12 deficiency in the brain. However, these individuals did not display any hematologic signs of B12 deficiency despite systemic CD320 impairment. Using a genome-wide CRISPR screen, we found that the low-density lipoprotein receptor serves as an alternative B12 uptake pathway in hematopoietic cells. These findings dissect the tissue specificity of B12 transport and elucidate an autoimmune neurologic condition that may be amenable to immunomodulatory treatment and nutritional supplementation.

Effect of Ruxolitinib on Lung Function after Allogeneic Stem Cell Transplantation.

Ruxolitinib, a selective Janus kinase (JAK)1/2 inhibitor, has recently been proposed for steroid-refractory chronic graft-versus host disease (cGVHD) after allogeneic hematopoietic stem cell transplantation (HSCT), particularly in severe skin cGVHD. Lung function impairment is common in severe skin cGVHD through concomitant bronchiolitis obliterans syndrome (BOS) or restrictive lung disease (RLD) from skin sclerosis. To date, no treatment has shown a benefit on lung function in this context. We retrospectively assessed the effect of ruxolitinib on lung function in a cohort of 70 patients diagnosed with sclerotic-type skin cGVHD between March 2015 and April 2018. Among these patients, 36 received ruxolitinib. To handle confounding by indication bias, exposure groups were matched on the propensity score to receive ruxolitinib, incorporating age, myeloablative conditioning, total body irradiation, BOS, forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and tobacco use at the time of cohort entry, as well as the time from transplantation. The 1:1 matching used a greedy-matching algorithm with replacement, with a caliper of 0.10. FVC and FEV1 trajectories during follow-up were compared in the matched samples, using linear mixed-effects models. The median duration of follow-up of the 46 matched patients was 58 months (interquartile range, 32 to 84 months). Ten patients had an RLD (6 exposed, 4 unexposed), and 13 patients were diagnosed with BOS (8 exposed, 5 unexposed). FEV1 decreased significantly over time independent of exposure to ruxolitinib (P < .0001). The FEV1 trajectory was similar in the exposed patients and the unexposed patients (P = .11). In conclusion, ruxolitinib administration did not demonstrate any improvement in the course of respiratory function in allogeneic HSCT recipients with sclerotic-type skin cGVHD.

A dysbiotic microbiome triggers TH17 cells to mediate oral mucosal immunopathology in mice and humans.

Periodontitis is one of the most common human inflammatory diseases, yet the mechanisms that drive immunopathology and could be therapeutically targeted are not well defined. Here, we demonstrate an expansion of resident memory T helper 17 (TH17) cells in human periodontitis. Phenocopying humans, TH17 cells expanded in murine experimental periodontitis through local proliferation. Unlike homeostatic oral TH17 cells, which accumulate in a commensal-independent and interleukin-6 (IL-6)-dependent manner, periodontitis-associated expansion of TH17 cells was dependent on the local dysbiotic microbiome and required both IL-6 and IL-23. TH17 cells and associated neutrophil accumulation were necessary for inflammatory tissue destruction in experimental periodontitis. Genetic or pharmacological inhibition of TH17 cell differentiation conferred protection from immunopathology. Studies in a unique patient population with a genetic defect in TH17 cell differentiation established human relevance for our murine experimental studies. In the oral cavity, human TH17 cell defects were associated with diminished periodontal inflammation and bone loss, despite increased prevalence of recurrent oral fungal infections. Our study highlights distinct functions of TH17 cells in oral immunity and inflammation and paves the way to a new targeted therapeutic approach for the treatment of periodontitis.

Eruption of lymphocyte recovery with atypical lymphocytes mimicking a primary cutaneous T-cell lymphoma: a series of 12 patients.

Eruption of lymphocyte recovery (ELR) may occur during bone marrow aplasia after chemotherapies. We reviewed the clinical and pathologic features of 12 patients (male-female ratio, 7:5; median age, 61 years) with an atypical ELR histologically mimicking a primary cutaneous T-cell lymphoma such as Sézary syndrome or CD30+ T-cell lymphoproliferative disorder. All the patients displayed an erythematous maculopapular eruption on the trunk and the limbs associated with fever. All but one had received a polychemotherapy for an acute myeloid leukemia (n=10) or a urothelial carcinoma (n=1) before the occurrence of the skin eruption. One had an autoimmune lymphoproliferative syndrome causing chronic agranulocytosis requiring granulocyte colony-stimulating factor injection. In all patients, the skin eruption was associated with a slight increase of white blood cell count followed by bone marrow recovery within the next weeks. All skin biopsies showed a dermal perivascular lymphocytic infiltrate containing atypical medium- to large-sized CD3+, CD4+ and CD8+, CD25+, ICOS+, PD1- lymphocytes with a strong CD30 expression in most instances (n=10), suggesting the recruitment of strongly activated T cells in the skin. In 6 patients, a diagnosis of CD30+ lymphoproliferative disorder or Sézary syndrome was proposed or suspected histopathologically, and only the clinical context allowed the diagnosis of ELR with a peculiar presentation with atypical lymphocytes. We describe a series of patients with an unusual form of ELR characterized by the presence of atypical activated T cells in the skin. On a practical ground, pathologists should be aware of this distinctive and misleading presentation.

Usefulness of KIR3DL2 to Diagnose, Follow-Up, and Manage the Treatment of Patients with Sézary Syndrome.

Purpose: KIR3DL2 is a recently discovered marker of the malignant clonal cell population in Sézary syndrome. We intended to evaluate the expression of KIR3DL2 on blood T cells as a diagnostic, prognostic, and follow-up marker of Sézary syndrome.Experimental Design: Sixty-four patients diagnosed with Sézary syndrome were included in this monocentric study. We collected the percentage of KIR3DL2+ cells among CD3+ T cells, obtained by flow cytometry, and other classical diagnostic criteria for Sézary syndrome at diagnosis and during the follow-up.Results: Compared with the classical diagnostic factors, KIR3DL2 was the most sensitive diagnostic factor for Sézary syndrome. Univariate and multivariate analyses established that an eosinophil cell count >700/mm3 and a percentage of KIR3DL2+ cells within the CD3+ T cells >85% at diagnosis were associated with a significantly reduced disease-specific survival. Moreover, KIR3DL2 immunostaining allowed the assessment of treatment efficiency and specificity toward tumor cells, the detection of the residual disease following treatment, and the occurrence of relapse, even though patients clinically experienced complete remission and/or undetectable circulating Sézary cells by cytomorphologic analysis.Conclusions: We show that KIR3DL2 expression is the most sensitive diagnostic criterion of Sézary syndrome when compared with all other available biological criteria. It also represents the best independent prognostic factor for Sézary syndrome-specific death and the most relevant feature for the follow-up of Sézary syndrome, showing the invasion of the functional lymphocytes pool by Sézary cells. KIR3DL2 therefore represents a valuable tool for routine use as a clinical parameter at diagnosis, for prognosis and during patient follow-up. Clin Cancer Res; 23(14); 3619-27. ©2017 AACR.

Mechanisms Underpinning Increased Plasma Creatinine Levels in Patients Receiving Vemurafenib for Advanced Melanoma.

CONTEXT: Serum creatinine has been reported to increase in patients receiving Vemurafenib, yet neither the prevalence nor the mechanism of this adverse event are known. OBJECTIVE: We aimed to evaluate the frequency and the mechanisms of increases in plasma creatinine level in patients receiving Vemurafenib for advanced melanoma. METHODS: We performed a retrospective monocentric study including consecutive patients treated with Vemurafenib for an advanced melanoma. We collected clinical and biological data concerning renal function before introduction of Vemurafenib and in the course of monthly follow-up visits from March 2013 to December 2014. Cystatin C-derived glomerular filtration rate was evaluated before and after Vemurafenib initiation, as increase in serum cystatin C is specific to a decrease in the glomerular filtration rate. We also performed thorough renal explorations in 3 patients, with measurement of tubular secretion of creatinine before and after Vemurafenib initiation and a renal biopsy in 2 patients. RESULTS: 70 patients were included: 97% of them displayed an immediate, and thereafter stable, increase in creatinine (+22.8%) after Vemurafenib initiation. In 44/52 patients in whom Vemurafenib was discontinued, creatinine levels returned to baseline. Serum cystatin C increased, although proportionally less than serum creatinine, showing that creatinine increase under vemurafenib was indeed partly due to a renal function impairment. In addition, renal explorations demonstrated that Vemurafenib induced an inhibition of creatinine tubular secretion. CONCLUSION: Thus, Vemurafenib induces a dual mechanism of increase in plasma creatinine with both an inhibition of creatinine tubular secretion and slight renal function impairment. However, this side effect is mostly reversible when Vemurafenib is discontinued, and should not lead physicians to discontinue the treatment if it is effective.

Certolizumab pegol - A new therapeutic option for refractory disseminated pyoderma gangrenosum associated with Crohn's disease.

Systemic steroids, in association or not with cyclosporin, are indicated for the treatment of large or widespread Pyoderma gangrenosum (PG). We report the case of a 27-year-old woman with a 15-year history of severe Crohn's disease, who developed a severe and disseminated PG, refractory to multiple lines of treatment. Infliximab and adalimumab were contraindicated, either because of allergy or of ineffectiveness on Crohn's disease. The addition of certolizumab pegol to the baseline treatment, associating systemic steroids and tacrolimus, finally allowed the complete healing of PG. Oral prednisone was stopped and tacrolimus was decreased, without any cutaneous or digestive relapse. Certolizumab pegol could be an alternative therapy in the treatment of PG in case of intolerance or ineffectiveness of the other anti-tumor necrosis factor (anti-TNF) therapies.

Skin Telangiectasia and the Identification of a Subset of Systemic Sclerosis Patients With Severe Vascular Disease.

OBJECTIVE: Cutaneous telangiectasia (CT) are common in systemic sclerosis (SSc) patients, but their ability to stratify patients by risk is poorly known. We aimed to determine whether the number and size of CT were associated with the pattern of microvascular lesions assessed by nailfold videocapillaroscopy (NVC) and markers reflecting the severity of SSc-related vasculopathy. METHODS: We performed a cross-sectional study, including consecutive SSc patients over a 6-month period. We also considered 3 predefined subsets of patients according to the number of hand or face CT: absence, ≤10, or >10 hand or face CT (profuse CT). Pseudotumoral CT were defined as CT with >5 mm diameter. RESULTS: A total of 87 patients were included, of whom 75 (86%) had CT (27 with profuse and 19 with pseudotumoral CT). Profuse and pseudotumoral CT were both associated with capillary loss (P < 0.001 and P = 0.002, respectively) and severe neoangiogenesis (P = 0.015 and P = 0.041, respectively), 2 hallmarks of the late NVC pattern. In multivariate analysis, profuse CT were independently associated with past or current digital ulcers (odds ratio [OR] 2.95 [95% confidence interval (95% CI) 1.09-19.63]), and pseudotumoral CT were independently associated with the late NVC pattern (OR 4.84 [95% CI 1.32-26.19]) and with precapillary pulmonary hypertension (OR 12.60 [95% CI 1.68-94.53]). CONCLUSION: We demonstrate that the number and size of CT are associated with the most severe NVC pattern. In addition, profuse and pseudotumoral CT identify a subset of patients with a more severe vascular phenotype. Further prospective studies should determine whether CT number and size could serve as an early clinical biomarker for the development of severe vascular disease.