Franciscus Kroese

Abatacept treatment reduces disease activity in early primary Sjögren's syndrome (open-label proof of concept ASAP study)

Objective To assess the efficacy and safety of abatacept in patients with early and active primary Sjögrens syndrome (pSS). Methods All 15 patients (12 women, three men) included in the open-label Active Sjögren Abatacept Pilot study met the revised American-European Consensus Group criteria for pSS and were biological disease-modifying antirheumatic drug-naive. Patients were treated with eight intravenous abatacept infusions on days 1, 15 and 29 and every 4u2005weeks thereafter. Follow-up was conducted at 4, 12, 24 (on treatment), 36 and 48u2005weeks (off treatment). Disease activity was assessed with European League Against Rheumatism (EULAR) Sjögrens Syndrome Disease Activity Index (ESSDAI) and EULAR Sjögrens Syndrome Patient Reported Index (ESSPRI). Several other functional, laboratory and subjective variables were analysed. Generalised estimating equations were used to analyse parameters over time. Results ESSDAI, ESSPRI, rheumatoid factor and IgG levels decreased significantly during abatacept treatment and increased post-treatment. Salivary and lacrimal gland function did not change during treatment. Fatigue and health-related quality of life (HR-QoL) improved significantly during treatment. No serious side effects or infections were seen. Conclusions In this open-label study, abatacept treatment is effective, safe and well tolerated, and results in improved disease activity, laboratory parameters, fatigue and HR-QoL in patients with early and active pSS. Trial registration number 2009-015558-40.

B Cell Reconstitution and T Helper Cell Balance After Rituximab Treatment of Active Primary Sjogren's Syndrome A Double- Blind, Placebo-Controlled Study

Objective n nTo assess the phenotype of reconstituting B cells after B cell depletion, and to assess the effect of reconstitution on the balance of Treg cells and effector T cells in patients with active primary Sjogrens syndrome (SS). n n n nMethods n nTwenty-eight patients with primary SS were treated on days 1 and 15 with either rituximab (n = 19) or placebo (n = 9). The frequencies and absolute numbers of circulating B cell subsets, Treg cells, and effector T cells were examined in fresh blood samples by 4-color flow cytometry at baseline and 5, 12, 24, 36, and 48 weeks after the first infusion. The results in rituximab-treated patients were compared with those in patients receiving placebo and with those in age- and sex-matched healthy controls (n = 10). n n n nResults n nAt baseline, patients with primary SS displayed several abnormalities in B cell homeostasis, including a significant reduction of CD27+ B cells and expansion of CD27– B cells, compared with healthy controls. At week 48 after rituximab treatment, the majority of emerging B cells exhibited a phenotype of transitional B cells. Although recovery of CD27+ memory B cells was delayed after rituximab treatment, a significant increase in Ig class–switched memory B cells within the memory pool was observed. In addition, percentages and absolute numbers of Treg cells and effector T cells, as well as ratios of effector T cells to Treg cells, did not change significantly after rituximab treatment. n n n nConclusion n nThe characteristics of reconstituted B cells in patients with primary SS following depletion by rituximab treatment showed dominance of transitional B cells during the early recovery phase, which corresponds to bone marrow–derived repopulation. The depletion of B cells did not influence the balance of peripheral Treg cells and effector T cells.

RT7-defined alloantigens in rats are part of the leucocyte common antigen family.

Haemopoietic cells carry a variety of cell‐surface molecules, some of which are known to have allotypic variation. In rats, the RT7 alloantigenic system has been well documented using alloantisera. We have produced the first mouse hybridomn cell line secreting an antibody. H1S41, which binds to leucocytes of rat strains carrying the RT7.2 but not the RT7.1 determinant. An lgG2b isotype switch variant (HIS4l.2b) of the original HIS41 (IgG1 isotype) was also made. HIS41 showed a clear and discrete binding in immunofluorescenl and histological experiments and has already been used in several studies on haemopoietic cell turnover and differentiation employing PVG rats congenic for RT7. The present study addresses the question of whether the RT7 gene products are members of the L‐CA family, which has been a matter of controversy over the last decade. When using HIS41 for the analysis of tissue distribution and molecular weight of RT7 gene products, a strong similarity was evident with the data reported for the L‐CA detected by MRC OX‐1 and MRC OX‐30. These two MoAb have been reported to bind to all members of the L‐CA family. All haemopoietic cells, excluding erythrocytes and the more mature stages of erythropoiesis, stained with HIS41. The molecular weights of HIS41 binding molecules on thymocytes and peripheral T cells were comparable to the L‐CA precipitated by MRC OX‐1. Capping and sequential immunoprecipitation studies indicated that HIS41 and MRC OX‐30‐ binding molecules were identical. MRC OX‐1. however, appeared to bind only a subset of these molecules. Thus, our study confirms the identity of RT7.2 gene products and L‐CA. lt also revealed a difference between MRC OX‐1 and MRC OX‐30 not noticed previously.

B-cell hyperactivity in primary Sjögren's syndrome

Primary Sjögrens syndrome (pSS) is characterized by mononuclear inflammatory infiltrates and IgG plasma cells in salivary and lacrimal glands which lead to irreversible destruction of the glandular tissue and is accompanied by sensation of dryness of mouth and eyes. B cells play a central role in the immunopathogenesis and exhibit signs of hyperactivity. Hyperactivity of B cells is the consequence of the coordinated and integrated action of stimulation of the B-cell receptor, CD40 and toll-like receptors in the presence of appropriate cytokines. As discussed, overexpression of type I IFN and BAFF on one hand and IL-6 and IL-21 on the other hand are critically involved in the enhanced plasma cell formation in pSS patients. Hyperactivity of B cells results in secretion of autoantibodies and production of various cytokines. These insights in the role of B cells in the pathogenetic process of pSS offer ample targets for successful therapeutical intervention in pSS.

Toward new classification criteria for Sjögren's syndrome?

Sjögren’s syndrome (SS) is an autoimmune inflammatory disorder of the exocrine glands. SS particularly affects the salivary and lacrimal glands. Patients most frequently present with dry mouth and dry eyes, which are often accompanied by nonspecific symptoms such as malaise and fatigue. Extraglandular manifestations include vasculitis, polyneuropathy, and arthritis, and these signs can present early, even at the time of diagnosis. Lymphoma develops in 5–10% of patients with SS. There is a need for early recognition and diagnosis of SS, because the health-related quality of life worsens as SS progresses. In addition, treatment using the currently available biologic agents is most effective in patients with primary SS who have high levels of disease activity and a relatively short duration of related symptoms (1). In this issue of Arthritis & Rheumatism, Cornec et al (2) propose adding salivary gland ultrasonography (SGUS) to the consensus criteria of the American– European Consensus Group (AECG) (3). As discussed by the authors, SGUS might be of value in classifying primary SS, but it is also a promising tool for earlier detection (possibly replacing the invasive salivary gland biopsy) and for monitoring disease progression. In this editorial, the term “primary” SS is used when referring to studies that were performed specifically in patients with a diagnosis of primary SS according to the AECG criteria (3). The AECG classification criteria are the most widely applied criteria for SS, but several modifications to these criteria have been suggested (2,4–6). These modifications include adding SGUS to the AECG criteria (2), limiting the classification criteria to include only objective tests (4), and replacing sialography (5) and sialoscintigraphy (6) with SGUS. Importantly, classification criteria help to define homogeneous study groups but are not intended for diagnostic purposes. Classification criteria usually have high specificity but lower sensitivity; for diagnostic purposes, sensitivity must also be high (7). In addition, diagnostic tests must be easy to perform and should not cause too much distress to the patient, especially when such tests need to be performed repeatedly, as in patients in whom the suspicion for SS is high but who have not yet fulfilled the classification criteria. SGUS might be such a test, because it is noninvasive, thus allowing repeated monitoring of the salivary glands over time. When criteria are revised, a criterion can be added to an existing criteria set or replaced by another more specific and/or sensitive criterion within that criteria set, or the whole set of criteria can be replaced by one with better properties. Both SGUS and saliva tests are very promising in the context of classification but also for diagnosis and monitoring (2,5,6,8–12). Cornec et al (and previously also Takagi et al [5] and Milic et al [6]) propose adding SGUS to the AECG criteria, because SGUS proved valuable for assessing major salivary gland involvement in primary SS and seemed to exhibit good diagnostic properties. Cornec and colleagues showed that adding SGUS to the AECG criteria increased the sensitivity of the AECG criteria for primary SS from 78% to 87% while retaining the specificity of these criteria. Scintigraphy and sialography, 2 “objective salivary gland tests” in the AECG criteria, are now considered inappropriate; it would be of great benefit if SGUS could replace these tests in the criteria set, but these studies did not address this possibility. In the study by Cornec et al, the mean SD disease duration of the included patients with primary SS was 7.1 7.5 years, which can be considered a limitation of their study. Our group (10) showed that in the early stages of SS, the function of the parotid gland H. Bootsma, MD, PhD, F. K. L. Spijkervet, DMD, PhD, F. G. M. Kroese, PhD, A. Vissink, MD, DMD, PhD: University of Groningen and University Medical Center Groningen, Groningen, The Netherlands. Address correspondence to H. Bootsma, MD, PhD, Department of Rheumatology and Clinical Immunology, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands. E-mail: h.bootsma@umcg.nl. Submitted for publication May 21, 2012; accepted in revised form September 4, 2012.

Monoclonal Antibodies to Rat B Lymphocyte (Sub-)Populations

The study of B lymphocyte differentiation is greatly facilitated by the use of suitable monoclonal antibodies (MAb’s). For mice and men a variety of MAb’s binding to cell surface determinants of B lineage cells has been described (1). However, as yet almost no B lineage specific MAb’s have been described for the rat. Since this animal appears very appropiate for studies of early phases of B lymphocyte differentiation (2) as well as late phases, in particular with respect to marginal zone cells (3), we produced MAb’s against surface antigens of rat B lineage cells.

EULAR Sjögren's Syndrome Disease Activity Index (ESSDAI) is sensitive to show efficacy of rituximab treatment in a randomised controlled trial

Rituximab therapy is a promising treatment for primary Sjogrens syndrome (pSS).1 ,2 So far, treatment studies performed in patients with pSS lacked the use of a uniform outcome measure to monitor disease activity.nnRecently, the European League Against Rheumatism (EULAR) developed the EULAR Sjogrens Syndrome Disease Activity Index (ESSDAI).3 ESSDAI was shown to be able to monitor disease activity in patient profile and open-label studies.4 ,5 To further study the utility of ESSDAI for clinical studies, we assessed the responsiveness of ESSDAI after rituximab treatment in a randomised controlled trial (RCT) of patients with pSS.6 nnAs the principal investigator (HB) was involved in the development of ESSDAI, the database of a single-centre, randomised, double-blind, placebo-controlled trial (see ref. 6 for details) was prospectively completed with regard to all ESSDAI domains, namely the cutaneous, respiratory, renal, articular, muscular, peripheral and central nervous system, haematological, glandular, constitutional, …

Predominantly proinflammatory cytokines decrease after B cell depletion therapy in patients with primary Sjögren's syndrome

Cytokines are critical in initiating and perpetuating the chronic inflammatory response in primary Sjogrens syndrome (pSS).1 Rituximab has beneficial effects on disease activity in pSS patients2 and results in a rise in B cell activating factor (BAFF) levels.3 Whether (elevated) levels of other (proinflammatory) cytokines are affected was addressed in this study. This information is important for understanding of the effect of rituximab in pSS.nnTwenty-eight patients with early-onset pSS2 treated with rituximab (n=18) or placebo (n=10), and 10 age-matched and sex-matched healthy controls (HCs) were assessed for presence of cytokines/chemokines in serum, using a multiplex-25 bead array assay (Invitrogen, Breda, The Netherlands). The following cytokines and chemokines were analysed: GM-CSF, IL-1β, IL-1Ra, IL-2, IL-2R, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12p40/p70, IL-13, IL-15, IL-17, IFN-α, IFN-γ, TNF-α, MCP-1/CCL2, MIP-1α/CCL3; MIP-1β/CCL4, RANTES/CCL5, Eotaxin/CCL11, MIG/CXCL9 and IP-10/CXCL10.nnAt baseline, levels for nearly all cytokines/chemokines were significantly higher in pSS patients than …

Systems analysis of primary Sjögren's syndrome pathogenesis in salivary glands identifies shared pathways in human and a mouse model

IntroductionPrimary Sjögrens syndrome (pSS) is a chronic autoimmune disease with complex etiopathogenesis. Despite extensive studies to understand the disease process utilizing human and mouse models, the intersection between these species remains elusive. To address this gap, we utilized a novel systems biology approach to identify disease-related gene modules and signaling pathways that overlap between humans and mice.MethodsParotid gland tissues were harvested from 24 pSS and 16 non-pSS sicca patients and 25 controls. For mouse studies, salivary glands were harvested from C57BL/6.NOD-Aec1Aec2 mice at various times during development of pSS-like disease. RNA was analyzed with Affymetrix HG U133+2.0 arrays for human samples and with MOE430+2.0 arrays for mouse samples. The images were processed with Affymetrix software. Weighted-gene co-expression network analysis was used to identify disease-related and functional pathways.ResultsNineteen co-expression modules were identified in human parotid tissue, of which four were significantly upregulated and three were downregulated in pSS patients compared with non-pSS sicca patients and controls. Notably, one of the human disease-related modules was highly preserved in the mouse model, and was enriched with genes involved in immune and inflammatory responses. Further comparison between these two species led to the identification of genes associated with leukocyte recruitment and germinal center formation.ConclusionOur systems biology analysis of genome-wide expression data from salivary gland tissue of pSS patients and from a pSS mouse model identified common dysregulated biological pathways and molecular targets underlying critical molecular alterations in pSS pathogenesis.

The microbiome–systemic diseases connection

The human microbiome consists of all microorganisms occupying the skin, mucous membranes and intestinal tract of the human body. The contact of the mucosal immune system with the human microbiome is a balanced interplay between defence mechanisms of the immune system and symbiotic or pathogenic microbial factors, such as microbial antigens and metabolites. In systemic autoimmune diseases (SADs) such as rheumatoid arthritis, systemic lupus erythematosus and Sjögrens syndrome, the immune system is deranged to a chronic inflammatory state and autoantibodies are an important hallmark. Specific bacteria and/or a dysbiosis in the human microbiome can lead to local mucosal inflammation and increased intestinal permeability. Proinflammatory lymphocytes and cytokines can spread to the systemic circulation and increase the risk of inflammation at distant anatomical sites, such as the joints or salivary glands. Increased intestinal permeability increases antigen exposure and the risk of autoantibody production. If the human microbiome indeed plays such a critical role in SADs, this finding holds a great promise for new therapeutic strategies, such as diet interventions and probiotics and prebiotics. This review provides a background on the human microbiome and mucosal immunity in the gut and oral cavity and gives a summary of the current knowledge on the microbiome-SADs connection.