In Rheumatoid Arthritis, Synovitis at Different Inflammatory Sites Is Dominated by Shared but Patient-Specific T Cell Clones.

Genetic and immunological evidence clearly points to a role for T cells in the pathogenesis of rheumatoid arthritis (RA). Selective targeting of such disease-associated T cell clones might be highly effective while having few side effects. However, such selective targeting may only be feasible if the same T cell clones dominate the immune response at different sites of inflammation. We leveraged high-throughput technology to quantitatively assess whether different T cell clones dominate the inflammatory infiltrate at various sites of inflammation in this prototypic autoimmune disease. In 13 RA patients, we performed quantitative next-generation sequencing-based human TCRß repertoire analysis in simultaneously obtained samples from inflamed synovial tissue (ST) from distinct locations within one joint, from multiple joints, and from synovial fluid (SF) and peripheral blood (PB). Identical TCRß clones dominate inflammatory responses in ST samples taken from different locations within a single joint and when sampled in different joints. Although overall ST-SF overlap was comparable to higher ST-ST values, the overlap in dominant TCRß clones in ST-SF comparisons was much lower than ST-ST and comparable to the low ST-PB overlap. In individual RA patients, a limited number of TCRß clones dominate the immune response in the inflamed ST regardless of the location within a joint and which joint undergoes biopsy; in contrast, there is limited overlap of ST with SF or PB TCR repertoires. This limited breadth of the T cell response in ST of the individual RA patient indicates that development of immunotherapies that selectively modulate dominant T cell responses might be feasible.

Acquisition of N-Glycosylation Sites in Immunoglobulin Heavy Chain Genes During Local Expansion in Parotid Salivary Glands of Primary Sjögren Patients.

Previous studies revealed high incidence of acquired N-glycosylation sites acquired N-glycosylation sites in RNA transcripts encoding immunoglobulin heavy variable region (IGHV) 3 genes from parotid glands of primary Sjögren's syndrome (pSS) patients. In this study, next generation sequencing was used to study the extent of ac-Nglycs among clonally expanded cells from all IGVH families in the salivary glands of pSS patients. RNA was isolated from parotid gland biopsies of five pSS patients and five non-pSS sicca controls. IGHV sequences covering all functional IGHV genes were amplified, sequenced, and analyzed. Each biopsy recovered 1,800-4,000 unique IGHV sequences. No difference in IGHV gene usage was observed between pSS and non-pSS sequences. Clonally related sequences with more than 0.3% of the total number of sequences per patient were referred to as dominant clone. Overall, 70 dominant clones were found in pSS biopsies, compared to 15 in non-pSS. No difference in percentage mutation in dominant clone-derived IGHV sequences was seen between pSS and non-pSS. In pSS, no evidence for antigen-driven selection in dominant clones was found. We observed a significantly higher amount of ac-Nglycs among pSS dominant clone-derived sequences compared to non-pSS. Ac-Nglycs were, however, not restricted to dominant clones or IGHV gene. Most ac-Nglycs were detected in the framework 3 region. No stereotypic rheumatoid factor rearrangements were found in dominant clones. Lineage tree analysis showed in four pSS patients, but not in non-pSS, the presence of the germline sequence from a dominant clone. Presence of germline sequence and mutated IGHV sequences in the same dominant clone provide evidence that this clone originated from a naïve B-cell recruited into the parotid gland to expand and differentiate locally into plasma cells. The increased presence of ac-Nglycs in IGHV sequences, due to somatic hypermutation, might provide B-cells an escape mechanism to survive during immune response. We speculate that glycosylation of the B-cell receptor makes the cell sensitive to environmental lectin signals to contribute to aberrant B-cell selection in pSS parotid glands.

IgG4-Associated Cholangitis in Patients Resected for Presumed Perihilar Cholangiocarcinoma: a 30-Year Tertiary Care Experience.

BACKGROUND: Distinguishing perihilar cholangiocarcinoma (PHC) from benign forms of sclerosing cholangitis affecting the hilar bile ducts is challenging, since histological confirmation of PHC is difficult to obtain and accurate non-invasive diagnostic tests are not available. IgG4-associated cholangitis (IAC), an imitator of PHC, may present with clinical and radiographical signs of PHC. IAC can be accurately diagnosed with a novel qPCR test. The aim of this study was to investigate the incidence and long-term activity of IAC in patients resected for PHC in a single tertiary center over a period of 30 years. METHODS: All patients with benign disease who underwent surgery for presumed PHC in our institute between 1984 and 2015 were identified. Benign liver and bile duct specimens were re-evaluated by a pathologist and scored according to international consensus pathology criteria for IgG4-related disease (IgG4-RD). Patients with benign disease still alive were followed-up and a clinical diagnosis of IAC was made using a combination of the HISORt group C (response to steroids) criteria and elevated serum IgG4 levels and/or the novel IgG4/IgG RNA ratio. Also, recurrent symptomatic disease at any time after surgery requiring immunosuppression was assessed. RESULTS: Out of 323 patients who underwent surgery for presumed PHC, 50 patients (15%) had benign disease. In 42% (n = 21/50) of these patients a histological (n = 17) or clinical (n = 4) diagnosis of IAC was established. The remaining patients were diagnosed with unclassified sclerosing inflammation, cystadenoma, or sclerosing hemangioma. Nine out of 12 IAC patients who were followed-up showed episodes of recurrent disease requiring immunosuppressive treatment. CONCLUSIONS: Liver and bile duct resections for PHC during three decades disclosed in 15% benign biliary disorders mimicking PHC of which 42% were definitely diagnosed as IAC. IgG4-RD remains active in the majority of patients with IAC years after surgery. Novel diagnostic tests for IAC might reduce misdiagnosis, unnecessary surgery, and life-threatening complications.

Immunoglobulin G4(+) B-cell receptor clones distinguish immunoglobulin G 4-related disease from primary sclerosing cholangitis and biliary/pancreatic malignancies.

UNLABELLED: Immunoglobulin G4 (IgG4)-related disease (IgG4-RD) of the biliary tree and pancreas is difficult to distinguish from sclerosing cholangitis and biliary/pancreatic malignancies (CA). An accurate noninvasive test for diagnosis and monitoring of disease activity is lacking. We demonstrate that dominant IgG4(+) B-cell receptor (BCR) clones determined by next-generation sequencing accurately distinguish patients with IgG4-associated cholangitis/autoimmune pancreatitis (n = 34) from those with primary sclerosing cholangitis (n = 17) and CA (n = 17). A novel, more affordable, and widely applicable quantitative polymerase chain reaction (qPCR) protocol analyzing the IgG4/IgG RNA ratio in blood also achieves excellent diagnostic accuracy (n = 125). Moreover, this qPCR test performed better than serum IgG4 levels in sensitivity (94% vs. 86%) and specificity (99% vs. 73%) and correlates with treatment response (n = 20). CONCLUSIONS: IgG4(+) BCR clones and IgG4/IgG RNA ratio markedly improve delineation, early diagnosis, and monitoring of IgG4-RD of the biliary tree and pancreas. (Hepatology 2016;64:501-507).

Clonal evolution of CD8+ T cell responses against latent viruses: relationship among phenotype, localization, and function.

UNLABELLED: Human cytomegalovirus (hCMV) infection is characterized by a vast expansion of resting effector-type virus-specific T cells in the circulation. In mice, interleukin-7 receptor α (IL-7Rα)-expressing cells contain the precursors for long-lived antigen-experienced CD8(+) T cells, but it is unclear if similar mechanisms operate to maintain these pools in humans. Here, we studied whether IL-7Rα-expressing cells obtained from peripheral blood (PB) or lymph nodes (LNs) sustain the circulating effector-type hCMV-specific pool. Using flow cytometry and functional assays, we found that the IL-7Rα(+) hCMV-specific T cell population comprises cells that have a memory phenotype and lack effector features. We used next-generation sequencing of the T cell receptor to compare the clonal repertoires of IL-7Rα(+) and IL-7Rα(-) subsets. We observed limited overlap of clones between these subsets during acute infection and after 1 year. When we compared the hCMV-specific repertoire between PB and paired LNs, we found many identical clones but also clones that were exclusively found in either compartment. New clones that were found in PB during antigenic recall were only rarely identical to the unique LN clones. Thus, although PB IL-7Rα-expressing and LN hCMV-specific CD8(+) T cells show typical traits of memory-type cells, these populations do not seem to contain the precursors for the novel hCMV-specific CD8(+) T cell pool during latency or upon antigen recall. IL-7Rα(+) PB and LN hCMV-specific memory cells form separate virus-specific compartments, and precursors for these novel PB hCMV-specific CD8(+) effector-type T cells are possibly located in other secondary lymphoid tissues or are being recruited from the naive CD8(+) T cell pool. IMPORTANCE: Insight into the self-renewal properties of long-lived memory CD8(+) T cells and their location is crucial for the development of both passive and active vaccination strategies. Human CMV infection is characterized by a vast expansion of resting effector-type cells. It is, however, not known how this population is maintained. We here investigated two possible compartments for effector-type cell precursors: circulating acute-phase IL-7Rα-expressing hCMV-specific CD8(+) T cells and lymph node (LN)-residing hCMV-specific (central) memory cells. We show that new clones that appear after primary hCMV infection or during hCMV reactivation seldom originate from either compartment. Thus, although identical clones may be maintained by either memory population, the precursors of the novel clones are probably located in other (secondary) lymphoid tissues or are recruited from the naive CD8(+) T cell pool.

IgG4-associated cholangitis: a comprehensive review.

IgG4-associated cholangitis (IAC) is a major manifestation of immunoglobulin G4-related disease (IgG4-RD), an inflammatory multiorgan disorder of unknown cause. IAC and autoimmune pancreatitis (AIP) may mimic sclerosing cholangitis, cholangiocarcinoma, or pancreatic carcinoma. Typically, elderly male patients present with abdominal discomfort, weight loss, jaundice, and itch. At present, no accurate diagnostic test for IAC and IgG4-RD is at hand, often causing significant diagnostic delay. Serum IgG4 is only diagnostic when markedly raised (>4× ULN). Imaging in IAC discloses mass-forming lesions and/or strictures in the biliary tract. Histology may show tissue infiltration of IgG4-expressing plasma cells. Diagnostic criteria for histologic and imaging findings, serum tests, organ manifestation pattern, and response to immunosuppressive therapy (HISORt) criteria are used for the diagnosis of IgG4-RD. Still, considering the difficulty in diagnosing IAC and AIP, unnecessary hepatic or pancreatic resections for presumed malignancies occur. The good response to corticosteroid therapy in IAC and other manifestations of IgG4-RD suggests an immune-mediated inflammatory disease. Maintenance immunosuppression after induction of remission is needed in the majority of patients to avoid relapse. The pathogenesis of IAC and IgG4-RD remains poorly understood. Unresolved questions include: (i) Does IgG4 have a pro- or anti-inflammatory role in IAC? (ii) Is IAC a B cell- and/or T cell-mediated disease? (iii) Which are the molecular targets attacked by the immune system in IgG4-RD? Here, we review the diagnostic and therapeutic management of the disease and discuss recent pathophysiological findings, which might help to better understand the molecular mechanisms contributing to IAC and other manifestations of IgG4-RD.

[IgG4-related disease]. / IgG4-gerelateerde ziekte.

The diagnosis IgG4-related disease (IgG4-RD) is often difficult to make. The clinical spectrum is diverse, with a variety of organ systems that may be affected simultaneously or sequentially. Patients often present with symptoms that mimic a malignant disease, for example, symptoms compatible with a pancreatic tumour. The lack of reliable tests often prolongs the diagnostic process. Limited insight into the causative disease mechanisms has confined the therapeutic options to the empirical use of immunosuppression. During the past year, the first papers on the fundamental aspects of the disease have resulted in the emergence of a new disease model for IgG4-RD. Recently published clinical and experimental findings support the hypothesis that antigenic stimulation plays a pivotal role in the aetiology of IgG4-RD. These new insights may pave the way for more sensitive diagnostic tests and more evidence-based strategies to cope with the many manifestations of IgG4-related disease.

Genome-wide association study and gene expression analysis identifies CD84 as a predictor of response to etanercept therapy in rheumatoid arthritis.

Anti-tumor necrosis factor alpha (anti-TNF) biologic therapy is a widely used treatment for rheumatoid arthritis (RA). It is unknown why some RA patients fail to respond adequately to anti-TNF therapy, which limits the development of clinical biomarkers to predict response or new drugs to target refractory cases. To understand the biological basis of response to anti-TNF therapy, we conducted a genome-wide association study (GWAS) meta-analysis of more than 2 million common variants in 2,706 RA patients from 13 different collections. Patients were treated with one of three anti-TNF medications: etanercept (n = 733), infliximab (n = 894), or adalimumab (n = 1,071). We identified a SNP (rs6427528) at the 1q23 locus that was associated with change in disease activity score (ΔDAS) in the etanercept subset of patients (P = 8 × 10(-8)), but not in the infliximab or adalimumab subsets (P>0.05). The SNP is predicted to disrupt transcription factor binding site motifs in the 3' UTR of an immune-related gene, CD84, and the allele associated with better response to etanercept was associated with higher CD84 gene expression in peripheral blood mononuclear cells (P = 1 × 10(-11) in 228 non-RA patients and P = 0.004 in 132 RA patients). Consistent with the genetic findings, higher CD84 gene expression correlated with lower cross-sectional DAS (P = 0.02, n = 210) and showed a non-significant trend for better ΔDAS in a subset of RA patients with gene expression data (n = 31, etanercept-treated). A small, multi-ethnic replication showed a non-significant trend towards an association among etanercept-treated RA patients of Portuguese ancestry (n = 139, P = 0.4), but no association among patients of Japanese ancestry (n = 151, P = 0.8). Our study demonstrates that an allele associated with response to etanercept therapy is also associated with CD84 gene expression, and further that CD84 expression correlates with disease activity. These findings support a model in which CD84 genotypes and/or expression may serve as a useful biomarker for response to etanercept treatment in RA patients of European ancestry.

Increased numbers of CD5+ B lymphocytes with a regulatory phenotype in spondylarthritis.

OBJECTIVE: Whether and how B lymphocytes contribute to the pathogenesis of spondylarthritis (SpA), a seronegative arthritis associated with gut inflammation, remains unknown. Because innate-like CD5+ B lymphocytes with regulatory functions have been identified in colitis models, we undertook the present study to analyze the presence and function of CD5+ B cells in human SpA. METHODS: Peripheral blood B cells from patients with SpA, patients with rheumatoid arthritis (RA), and healthy controls were analyzed by flow cytometry. Synovial biopsy samples were evaluated by immunohistochemistry analysis. Sorted CD5+ and CD5- B cells were analyzed for somatic hypermutation, expression of costimulatory molecules, and cytokine production. RESULTS: The naive, marginal zone-like, and to a lesser extent memory B cell compartments in patients with SpA exhibited a clear and specific increase of CD5+ B cells, which was not found in patients with RA. This increase was not due to either B cell activation or preferential migration of CD5- B cells to the inflamed synovium. Consistent with their phenotype and the low-affinity polyreactive immunoglobulins produced by their murine counterpart cells, CD5+ B cells from patients with SpA showed low levels of somatic hypermutation. With regard to antigen presentation, CD5+ B cells expressed slightly increased HLA-DR levels but low CD80 and CD86 levels. In vitro activation failed to up-regulate these costimulatory molecules but induced significant production of interleukin-10 and interleukin-6 by CD5+ B cells. CONCLUSION: CD5+ B cells are specifically increased in SpA. Analysis of somatic hypermutation, expression of antigen-presenting and costimulatory molecules, and cytokine production indicates that this B cell subset has regulatory capacities. Further investigation of the potential role of CD5+ cells in SpA is warranted.