Transcriptome analysis of primary adult B-cell lineage acute lymphoblastic leukemia identifies pathogenic variants and gene fusions, and predicts subtypes for in depth molecular diagnosis.

BACKGROUND: B-cell acute lymphoblastic leukemia (B-ALL) is classified into subgroups based on known driver oncogenes and molecular lesions, including translocations and recurrent mutations. However, the current diagnostic tests do not identify subtypes or oncogenic lesions for all B-ALL samples, creating a heterogeneous B-ALL group of unknown subtypes. METHODS: We sorted primary adult B-ALL cells and performed transcriptome analysis by bulk RNA sequencing (RNA-seq). RESULTS: Transcriptomic analysis of an adult B-ALL cohort allowed the classification of four patient samples with subtypes that were not previously revealed by standard gene panels. The leukemia of two patients were of the DUX4 subtype and two were CRLF2+ Ph-like B-ALL. Furthermore, single nucleotide variant analysis detected the oncogenic NRAS-G12D, KRAS-G12D, and KRAS-G13D mutations in three of the patient samples, presenting targetable mutations. Additional oncogenic variants and gene fusions were uncovered, as well as multiple variants in the PDE4DIP gene across five of the patient samples. CONCLUSION: We demonstrate that RNA-seq is an effective tool for precision medicine in B-ALL by providing comprehensive molecular profiling of leukemia cells, identifying subtype and oncogenic lesions, and stratifying patients for appropriate therapy.

T-helper cell regulation of CD45 phosphatase activity by galectin-1 and CD43 governs chronic lymphocytic leukaemia proliferation.

Chronic lymphocytic leukaemia (CLL) is characterised by malignant mature-like B cells. Supportive to CLL cell survival is chronic B-cell receptor (BCR) signalling; however, emerging evidence demonstrates CLL cells proliferate in response to T-helper (Th) cells in a CD40L-dependent manner. We showed provision of Th stimulation via CD40L upregulated CD45 phosphatase activity and BCR signalling in non-malignant B cells. Consequently, we hypothesised Th cell upregulation of CLL cell CD45 activity may be an important regulator of CLL BCR signalling and proliferation. Using patient-derived CLL cells in a culture system with activated autologous Th cells, results revealed increases in both Th and CLL cell CD45 activity, which correlated with enhanced downstream antigen receptor signalling and proliferation. Concomitantly increased was the surface expression of Galectin-1, a CD45 ligand, and CD43, a CLL immunophenotypic marker. Galectin-1/CD43 double expression defined a proliferative CLL cell population with enhanced CD45 activity. Targeting either Galectin-1 or CD43 using silencing, pharmacology, or monoclonal antibody strategies dampened CD45 activity and CLL cell proliferation. These results highlight a mechanism where activated Th cells drive CLL cell BCR signalling and proliferation via Galectin-1 and CD43-mediated regulation of CD45 activity, identifying modulation of CD45 phosphatase activity as a potential therapeutic target in CLL.

Tetraspanin CD53 controls T cell immunity through regulation of CD45RO stability, mobility, and function.

T cells depend on the phosphatase CD45 to initiate T cell receptor signaling. Although the critical role of CD45 in T cells is established, the mechanisms controlling function and localization in the membrane are not well understood. Moreover, the regulation of specific CD45 isoforms in T cell signaling remains unresolved. By using unbiased mass spectrometry, we identify the tetraspanin CD53 as a partner of CD45 and show that CD53 controls CD45 function and T cell activation. CD53-negative T cells (Cd53-/-) exhibit substantial proliferation defects, and Cd53-/- mice show impaired tumor rejection and reduced IFNγ-producing T cells compared with wild-type mice. Investigation into the mechanism reveals that CD53 is required for CD45RO expression and mobility. In addition, CD53 is shown to stabilize CD45 on the membrane and is required for optimal phosphatase activity and subsequent Lck activation. Together, our findings reveal CD53 as a regulator of CD45 activity required for T cell immunity.

Integration of T helper and BCR signals governs enhanced plasma cell differentiation of memory B cells by regulation of CD45 phosphatase activity.

Humoral immunity relies on the efficient differentiation of memory B cells (MBCs) into antibody-secreting cells (ASCs). T helper (Th) signals upregulate B cell receptor (BCR) signaling by potentiating Src family kinases through increasing CD45 phosphatase activity (CD45 PA). In this study, we show that high CD45 PA in MBCs enhances BCR signaling and is essential for their effective ASC differentiation. Mechanistically, Th signals upregulate CD45 PA through intensifying the surface binding of a CD45 ligand, Galectin-1. CD45 PA works as a sensor of T cell help and defines high-affinity germinal center (GC) plasma cell (PC) precursors characterized by IRF4 expression in vivo. Increasing T cell help in vitro results in an incremental CD45 PA increase and enhances ASC differentiation by facilitating effective induction of the transcription factors IRF4 and BLIMP1. This study connects Th signals with BCR signaling through Galectin-1-dependent regulation of CD45 PA and provides a mechanism for efficient ASC differentiation of MBCs.

Regular Exercise May Restore Certain Age-Related Alterations of Adaptive Immunity and Rebalance Immune Regulation.

Age-related changes of the immune system lead to an increased morbidity and mortality due to enhanced vulnerability to infectious diseases and malignancies. Recent studies revealed the important effects of physical activity on immune functions, which may largely depend on the type of exercise, its intensity and duration. However, limited information is available regarding the immunological effects of sport activities in older ages. The aim of our study was to examine the changes in a wide spectrum of lymphocyte subtypes after regular workout among healthy elderly individuals. We enrolled 29 elderly women with sedentary lifestyle (mean age: 67.03 ± 3.74 years) to take part in a 6-week long functional conditioning gymnastic exercise program. The percentages of peripheral natural killer (NK), NKT cells, T and B lymphocyte subtypes (early-/late-activated T, naïve and memory T, cytotoxic T (Tc), T-helper (Th)1, Th2, Th17, T regulatory type 1 (Tr1), CD4+CD127lo/-CD25bright Treg, as well as naïve and memory B cells) were determined by flow cytometry. Evaluation of the changes in functional capability of Treg cells was based on in vitro functional assays. At the end of exercise program, in parallel with improvements in body composition and physical performance, significant changes in naïve and memory lymphocyte ratios were observed. Importantly, levels of naïve Tc cells elevated, ratios of effector memory Tc cells decreased and distribution of memory B cells rearranged as well. Additionally, proportions of late-activated HLA-DR+ T cells increased, while percentages of anti-inflammatory interleukin (IL)-10 producing Tr1 cells, as well as immunosuppressive CD4+CD127lo/-CD25bright Treg cells decreased following the exercise workout. Changes observed after the regular exercise program indicate an improvement in the age-related redistribution of certain naïve and memory cell proportions and a retuned immune regulation in older ages.

The Imbalance of Circulating Follicular T Helper Cell Subsets in Primary Sjögren's Syndrome Associates With Serological Alterations and Abnormal B-Cell Distribution.

Since B-cell hyperactivity and pathologic antibody response are key features in the immunopathogenesis of primary Sjögren's syndrome (pSS), the role of follicular T helper (TFH) cells as efficient helpers in the survival and differentiation of B cells has emerged. Our aim was to investigate whether a change in the balance of circulating (c)TFH subsets and follicular regulatory T (TFR) cells could affect the distribution of B cells in pSS. Peripheral blood of 38 pSS patients and 27 healthy controls was assessed for the frequencies of cTFH cell subsets, TFR cells, and certain B cell subpopulations by multicolor flow cytometry. Serological parameters, including anti-SSA, anti-SSB autoantibodies, immunoglobulin, and immune complex titers were determined as part of the routine diagnostic evaluation. Patients with pSS showed a significant increase in activated cTFH cell proportions, which was associated with serological results. Frequencies of cTFH subsets were unchanged in pSS patients compared to healthy controls. The percentages and number of cTFR cells exhibited a significant increase in autoantibody positive patients compared to patients with seronegative pSS. The proportions of transitional and naïve B cells were significantly increased, whereas subsets of memory B cells were significantly decreased and correlated with autoantibody production. Functional analysis revealed that the simultaneous blockade of cTFH and B cell interaction with anti-IL-21 and anti-CD40 antibodies decreased the production of IgM and IgG. Imbalance in TFH subsets and TFR cells indicates an ongoing over-activated humoral immune response, which contributes to the characteristic serological manifestations and the pathogenesis of pSS.

Eight pillars of oncorheumatology: Crossroads between malignancies and musculoskeletal diseases.

ONCORHEUMATOLOGY: RELATIONSHIP BETWEEN MALIGNANCIES AND MUSCULOSKELETAL DISEASES: Oncorheumatology is the meeting point of tumor formation and rheumatic musculoskeletal diseases (RMD). Multiple interactions exist between these two medical specialties. One major field is the topic of malignancies associated with rheumatic diseases, while the other topic covers the development of musculoskeletal disease in cancer patients. Within the first group, secondary malignancies may be associated with rheumatic diseases. Mostly sustained inflammation is responsible for transition into cancer. Tumor-associated antigens (TAA) with adhesive properties are present on tumor cells. These molecules may also be expressed by inflammatory leukocytes and soluble TAA levels may be elevated in RMDs. There has been continuous debate with respect to the possible carcinogenicity of conventional and targeted antirheumatic drugs. Very recent data from registries suggest that neither biologics, nor JAK inhibitors increase cancer risk in arthritis patients. The issue of physiotherapy in rheumatic patients with recent or current cancer has also been controversial. Some modalities, primarily exercise, may be safely applied to patients with RMD and cancer. The second large topic includes paraneoplastic syndromes. Musculoskeletal paraneoplasias are triggered by tumor-derived mediators. These syndromes are sometimes slightly different from the classical RMDs. Various chemotherapies may also be associated with autoimmune side effects. Recently, these immune-related complications have also been observed in cancer patients treated with immune-checkpoint inhibitors. Sex hormone-deprivation therapies, such as aromatase inhibitors and anti-androgens are widely used for the treatment of breast and prostate cancer, respectively. These compounds may induce bone loss and lead to osteoporosis. Finally, primary and secondary malignancies of the musculoskeletal system may also interest rheumatologists. In this review, the clinical, practical aspects of these eight pillars of oncorheumatology will be discussed.

Oncorheumatology: relationship between malignancies and musculoskeletal diseases / Onkoreumatológia: a daganatos és mozgásszervi kórképek összefüggései

Oncorheumatology is the meeting point of tumour formation and rheumatic diseases. Multiple interactions exist between these two medical specialties. One major field is the topic of malignancies associated with rheumatic diseases, while the other topic covers the development of musculoskeletal disease in cancer patients. In the first group, secondary malignancies associated with rheumatic diseases, role of tumour-associated antigens in rheumatology, the possible carcinogenicity of conventional and targeted antirheumatic drugs and physical therapy of rheumatic patients with recent or current cancer will be discussed. The second large topic includes paraneoplastic syndromes, autoimmune-rheumatic side effects of oncotherapies (chemotherapy and immunotherapy), effects of hormone-deprivation therapies on bone and primary and secondary malignancies of the musculoskeletal system. Orv Hetil. 2020; 161(28): 1151-1165.

Ocular manifestations of rheumatic diseases.

PURPOSE: Our aim was to summarize key aspects of the pathomechanism and the ocular involvements of rheumatic and systemic autoimmune diseases. METHODS: Apart from a paper in French (Morax V, Ann Oculist 109:368-370, 1893), all papers referred to in this article were published in English. All the materials were peer-reviewed full-text papers, letters, reviews, or book chapters obtained through a literature search of the PubMed database using the keywords ocular manifestations; pathogenesis; systemic inflammatory rheumatic diseases; rheumatoid arthritis; osteoarthritis; fibromyalgia; systemic lupus erythematosus; seronegative spondyloarthritis; ankylosing spondylitis; reactive arthritis; enteropathic arthritis; psoriatic arthritis; systemic sclerosis; polymyalgia rheumatica and covering all years available. Some statements articulated in this paper reflect the clinical experience of the authors in their tertiary-referral center. RESULTS: Ophthalmic disorders are categorized by anatomical subgroups in all rheumatic diseases. The most common ocular manifestations are diverse types of inflammations of different tissues and dry eye disease (DED). CONCLUSION: The eye could be a responsive marker for the onset or aggravation of an immune reactivation in many rheumatic diseases, furthermore, ocular findings can antedate the diagnosis of the underlying rheumatic disease. By recognizing ocular manifestations of systemic rheumatic diseases it might be possible to avoid or at least delay many long term sequelae.

Corneal Manifestations of Inflammatory Bowel Disease.

Purpose: To evaluate detailed corneal parameters of inflammatory bowel disease (IBD) patients, including Crohn's disease (CD) and ulcerative colitis (UC) patients, and to assess associations between anterior segment values and other clinical variables.Methods: This prospective cross-sectional case-control study at a tertiary referral center included 30 CD patients, 36 UC patients and 80 age- and gender-matched controls with no ocular symptoms or ocular surface disorders. All study participants underwent a comprehensive ophthalmological evaluation with special interest in dry eye disease (DED). Corneal parameters were evaluated by Pentacam.Results: The mean age of CD patients, UC patients, and controls was 45.80 ± 11.55 years, 52.00 ± 16.05, and 50.68 ± 14.62, respectively. The average disease duration was 12.72 ± 5.83 years for CD patients and 15.94 ± 10.09 years for UC patients. All pachymetric (center, apex and thinnest) and corneal volume (CV) measurements were significantly decreased, while anterior chamber angle width (ACA) values were significantly increased on both sides in all IBD patients compared to those in controls (p < .05). In addition, several anterior segment parameters were altered unilaterally in CD or UC patients. Negative correlations were found between corneal parameters and Schirmer I test values.Conclusions: Our investigations suggest that IBD patients have thinner corneas compared to that of controls. The coexistence of reduced tear quantity seems to have an additional impact on the thinning of the cornea in IBD patients. Early recognition of corneal impairments, a possible extraintestinal manifestation of IBD, should be included in the disease checkup to reduce vision-threatening developments.

Hematopoietic stem cell transplantation in autoimmune disorders: From immune-regulatory processes to clinical implications.

Autoimmune diseases are characterized by the development of autoreactive T- and B-cells targeting self-antigens, which eventually can result in chronic and persistent organ damage. The autologous hematopoietic stem cell transplantation (AHSCT) opened new avenues in the treatment of patients with severe, treatment-resistant autoimmune diseases. This paper reviews the immune-regulatory mechanisms behind AHSCT, and also summarizes the experiences of clinical practice related to the therapy in organ-specific and systemic autoimmune diseases. It seems that the intricate interplay of various immune competent cells with regulatory capacity control in a synergistic manner the repopulated immune system after AHSCT, which potentially leads to a significant clinical improvement in certain autoimmune diseases. However, the widespread use of AHSCT was intrinsically limited, due to the serious side-effects of conditioning treatment and relatively high treatment-related mortality; moreover, the development of new effective and safe therapeutic approaches and the dawn of biological agents further limited its indications in the last decade. Nevertheless, with an appropriate patient selection and increased experience of transplant centres, the risks can be minimized, and AHSCT remained still a reasonable choice in multiple sclerosis and systemic sclerosis when the conventional therapy failed and further progression of disease is inevitable.

Dyslipidemia in systemic lupus erythematosus.

Cardiovascular disease is one of the major causes of morbidity and mortality in patients with systemic lupus erythematosus (SLE). Accelerated atherosclerosis is related to traditional (age, hypertension, diabetes mellitus, dyslipidemia, obesity, smoking, and positive family history) and non-traditional, disease-related factors. Traditional risk factors are still more prominent in patients with lupus, as both hypertension and hypercholesterinemia were independently associated with premature atherosclerosis in several SLE cohorts. In this work, the authors summarize the epidemiology of dyslipidemia in lupus patients and review the latest results in the pathogenesis of lipid abnormalities. The prevalence of dyslipidemia, with elevations in total cholesterol (TC), low-density lipoprotein (LDL), triglyceride (TG), and apolipoprotein B (ApoB), and a reduction in low-density lipoprotein (LDL) levels are about 30% at the diagnosis of SLE rising to 60% after 3 years. Multiple pathogenetic mechanism is included, C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) can suppress HDL and increase TG, auto-antibodies can cause the injury of the endothelium, lipoprotein lipase (LPL) activity can be reduced by circulating inflammatory mediators and antibodies, and increased oxidative stress may trigger a wide range of pro-atherogenic lipid modifications. As a major risk factor, dyslipidemia should be treated aggressively to minimize the risk of atherosclerosis and cardiovascular events. Randomized controlled trials with statins are controversial in the detention of atherosclerosis progression, but can be favorable by inhibiting immune activation that is the arterial wall and by decreasing lupus activity.

The assessment of immune-regulatory effects of extracorporeal photopheresis in systemic sclerosis: a long-term follow-up study.

The therapeutic options in systemic sclerosis (SSc) are limited mainly to the management of complications, and decelerating fibrosis and preventing disease progression are still great challenges. Extracorporeal photopheresis (ECP) is one of the promising therapeutic strategies in SSc; nevertheless, there is no consensus on the ideal timing and frequency of treatment cycles. In the present study, we evaluated the long-term effects of consecutive ECP treatments, and the stability of clinical and laboratory improvements. We enrolled nine patients with diffuse cutaneous SSc and performed 12 ECP cycles (24 ECP treatments) per patient in total. ECP cycles were carried out once in every 6 weeks, and each cycle consisted of two procedures. Sixteen healthy individuals served as controls for laboratory assessment. Following the sixth ECP cycle, we observed further improvement in skin score, which was confirmed by high-resolution ultrasonography as well. After the second ECP cycle, values of Tr1 and CD4+CD25(bright) Treg cells increased; however, Tr1 cells remained under control values until the 10th cycle. Suppressor activity of CD4+CD25+ Treg cells improved, while percentages of Th17 cells decreased. At the end of 12-month follow-up, we did not observe significant deterioration in skin involvement; however, improvement in laboratory parameters diminished after 12 months. If the first six ECP cycles are effective, uninterrupted continuation of treatment should be considered, which may lead to the normalization of Tr1 cell values along with further clinical improvement. Our laboratory observations indicate that immunomodulatory effect of ECP treatments lasts for 1 year only.

Vascular Endothelial Growth Factor in Tear Samples of Patients with Systemic Sclerosis.

BACKGROUND: Systemic sclerosis is an autoimmune disease, characterized by widespread small vessel vasculopathy, immune dysregulation with production of autoantibodies, and progressive fibrosis. Changes in levels of proangiogenic cytokines had already been determined largely in serum. Our aim was to assess the levels of VEGF in human tears of patients with SSC. PATIENTS AND METHODS: Forty-three patients (40 female and 3 men, mean (SD) age 61 (48-74) years) with SSc and 27 healthy controls were enrolled in this study. Basal tear sample collection and tear velocity investigations were carried out followed by an ophthalmological examination. Total protein concentrations and VEGF levels were determined in tear samples. RESULTS: The average collected tear fluid volume developed 10.4 µL (1.6-31.2) in patients and 15.63 µL (3.68-34.5) in control subjects. The average total protein level was 6.9 µg/µL (1.8-12.3) in tears of patients and control tears contained an average of 4.132 µg/µL (0.1-14.1) protein. In patients with SSc the average concentration of VEGF was 4.9 pg/µL (3.5-8.1) and 6.15 pg/µL (3.84-12.3) in healthy samples. CONCLUSIONS: Total protein production was increased because of the smaller tear volume. Decreased VEGF in tear of SSc patients can be explained also by the decreased tear secretion of patients.

Immunologic pathomechanism of Hodgkin's lymphoma.

Hodgkin's lymphoma is a lymphoid malignancy of the immune system. The pathognomonic Hodgkin and Reed-Sternberg cells (HRS) are derived mainly from monoclonal, preapoptotic B cells, and they carry rearranged, somatically mutated immunoglobulin heavy chains. In an appropriate microenvironment, HRS cells escape from apoptosis by several mechanisms, including single mutations, aberrant signaling pathways. Eventually, weakened immune surveillance leads to uncontrolled, disproportional B cell proliferation. This review summarizes the latest findings on the pathogenesis of Hodgkin lymphoma, with a special emphasis on immunologic processes, and depicts current and future immunotherapeutic regimens, which improve treatment outcomes and reduce late toxicities.

Clinical course, prognosis, and causes of death in mixed connective tissue disease.

OBJECTIVE: To study the survival rate and prognostic indicators of mixed connective tissue disease (MCTD) in a Hungarian population. METHODS: Two hundred eighty patients with MCTD diagnosed between 1979 and 2011 were followed prospectively. Clinical features, autoantibodies, and mortality data were assessed. Prognostic factors for survival were investigated and survival was calculated from the time of the diagnosis by Kaplan-Meier method. RESULTS: A total of 22 of 280 patients died: the causes of death were pulmonary arterial hypertension (PAH) in 9 patients, thrombotic thrombocytopenic purpura in 3, infections in 3, and cardiovascular events in 7. The 5, 10, and 15-year survival rates after the diagnosis was established were 98%, 96%, and 88%, respectively. The deceased patients were younger at the diagnosis of MCTD compared to patients who survived (35.5 ± 10.4 vs 41.8 ± 10.7 yrs; p < 0.03), while there was no difference in the duration of the disease (p = 0.835). Our cohort study showed that the presence of cardiovascular events (p < 0.0001), esophageal hypomotility (p = 0.04), serositis (p < 0.001), secondary antiphospholipid syndrome (p = 0.039), and malignancy (p < 0.001) was significantly higher in the deceased patients with MCTD. The presence of anticardiolipin (p = 0.019), anti-ß2-glycoprotein I (p = 0.002), and antiendothelial cell antibodies (p = 0.002) increased the risk of mortality. CONCLUSION: Overall, PAH remained the leading cause of death in patients with MCTD. The prevalence of cardiovascular morbidity and mortality, malignancy, and thrombotic events increased during the disease course of MCTD. The presence of antiphospholipid antibodies raised the risk of mortality.

Assessment of intracellular cytokines and regulatory cells in patients with autoimmune diseases and primary immunodeficiencies - novel tool for diagnostics and patient follow-up.

Serum and intracytoplasmic cytokines are mandatory in host defense against microbes, but also play a pivotal role in the pathogenesis of autoimmune diseases by initiating and perpetuating various cellular and humoral autoimmune processes. The intricate interplay and fine balance of pro- and anti-inflammatory processes drive, whether inflammation and eventually organ damage will occur, or the inflammatory cascade quenches. In the early and late, as well as inactive and active stages of autoimmune diseases, different cellular and molecular patterns can dominate in these patients. However, the simultaneous assessment of pro- and anti-inflammatory biomarkers aids to define the immunological state of a patient. A group of the most useful inflammatory biomarkers are cytokines, and with increasing knowledge during the last decade their role have been well-defined in patients with autoimmune diseases and immunodeficiencies. Multiple pathological processes drive the development of autoimmunity and immunodeficiencies, most of which involve quantitative and qualitative disturbances in regulatory cells, cytokine synthesis and signaling pathways. The assessment of these biomarkers does not aid only in the mechanistic description of autoimmune diseases and immunodeficiencies, but further helps to subcategorize diseases and to evaluate therapy responses. Here, we provide an overview, how monitoring of cytokines and regulatory cells aid in the diagnosis and follow-up of patients with autoimmune diseases and immunodeficiencies furthermore, we pinpoint novel cellular and molecular diagnostic possibilities in these diseases.

The effects of extracorporeal photochemotherapy on T cell activation and regulatory mechanisms in patients with systemic sclerosis.

In the study, we investigated the influence of extracorporeal photochemotherapy (ECP) on lymphocyte activation and cell death by determining CD95, Annexin V, CD69 and human leukocyte antigen (HLA)-DR expression on circulating T and B cells in systemic sclerosis (SSc) patients and assessed their changes after ECP therapies. Moreover, we evaluated the relationship between lymphocyte activation and the observed changes in immunoregulatory functions following ECP treatments. We enrolled 19 SSc patients, who received 12 ECP treatments in total. Blood samples were taken prior to the first therapy and 6 weeks after each cycle. Samples were also obtained from 16 healthy controls. Lymphocyte subgroups were quantified by flow cytometry. Initially, patients had higher numbers and percentages of peripheral CD95(+) T cells, but not CD95(+) B cells, compared to control values. After ECP treatments, values of CD95(+) T cells decreased and became similar to controls. Annexin V expression on T and B cells did not change during the therapy. We observed a significant negative correlation between the changes in percentages of peripheral CD95(+) T cells and CD4(+)CD25(+) Treg cells. Although neither early-activated (CD69(+)) nor late-activated (HLA-DR+) T lymphocytes showed significant changes after ECP, clear negative correlations developed between them and the functional ability of CD4(+)CD25(+) Treg cells after the last treatment. Our results indicate that the initial increase of CD95(+) expression in SSc presumably reflects a physiological response to the pronounced autoimmune processes, which can be effectively attenuated by the restoration of regulative T cell numbers and functions as the result of ECP therapy.

Sex steroids in Sjögren's syndrome.

The purpose of the review is to consider pathomechanisms of Sjögren's syndrome (SS), which could explain the female dominance (9:1), the most common age of onset (40-50 years) and targeting of the exocrine glands. Estrogens seem to specifically protect secretory glandular acinar cells against apoptosis whereas lack of estrogens during menopause and climacterium specifically leads to increased apoptosis of the exocrine secretory cells. Male gonads produce testosterone and convert it in exocrine glands to dihydrotesterosterone (DHT), which is anti-apoptotic and protects against acinar cell apoptosis. Estrogen-deficient women need to produce dehydroepiandrosterone (DHEA) in the adrenal glands and convert it to DHT in exocrine glands in a complex and branching reaction network in which individual enzymatic reactions are catalyzed in forward and backward directions by a myriad of different isoforms of steroidogenic enzymes. Tailoring DHT in peripheral tissues is much more complex and vulnerable in women than in men. In SS the intracrine steroidogenic enzyme machinery is deranged. These endo-/intracrine changes impair acinar remodeling due to impaired integrin α1ß1 and integrin α2ß1 expression so that the intercalated duct progenitor cells are unable to migrate to the acinar space, to differentiate to secretory acinar cells upon contact with laminin-111 and laminin-211 specifically found in the acinar basement membrane. The disarranged endo-/intracrine estrogen/androgen balance induces acinar cells to release microparticles and apoptotic bodies and to undergo apoptotis and/or anoikis. Membrane particles contain potential autoantigens recognized by T- (TCRs) and B-cell receptors (BCRs) and danger-associated molecular patterns (DAMPs) recognized by Toll-like receptors (TLRs). In membrane particles (or carrier-complexes) antigen/adjuvant complexes could stimulate professional antigen capturing, processing and presenting cells, which can initiate auto-inflammatory and autoimmune cascades, break the self-tolerance and finally lead to SS.