Epidemiology of Mixed Connective Tissue Disease, 1985-2014: A Population-Based Study

A Case of Overlapping Autoimmune Syndrome

Overlapping autoimmune disorders are used to describe the coexistence of more than one autoimmune disease in the same patient. Mixed connective tissue disease (MCTD) and anti-synthetase syndrome (ASS) are autoimmune diseases that manifest with pulmonary involvement, presenting as persistent dyspnea. The coexistence of both conditions in the same patient is extremely rare. We herein report a case of a 44-year-old female who was diagnosed with MCTD with features of ASS (anti-Jo-1 antibody) in the setting of rheumatoid arthritis (anti-cyclic citrullinated peptide (anti-CCP) antibody), which shows temporary breathing improvement following treatment with corticosteroid and mycophenolate mofetil. However, after the completion of mycophenolate mofetil, she was found to be anti-Jo-1 antibody negative and anti-CCP antibody positive. Our case emphasizes the need to recognize overlapping autoimmune conditions in patients with complex clinical features and presentations with the immediate application of a comprehensive diagnostic approach and tailored treatment strategies. Early diagnosis and aggressive treatment are crucial for achieving remission and preventing organ damage.

Clinical presentation, course, and prognosis of patients with mixed connective tissue disease: A multicenter retrospective cohort

OBJECTIVES

The objective of this study is to better characterize the features and outcomes of a large population of patients with mixed connective tissue disease (MCTD).

METHODS

We performed an observational retrospective multicenter cohort study in France. Patients who fulfilled at least one diagnostic criterion set for MCTD and none of the criteria for other differentiated CTD (dCTD) were included.

RESULTS

Three hundred and thirty patients (88% females, median [interquartile range] age of 35 years [26-45]) were included. The diagnostic criteria of Sharp or Kasukawa were met by 97.3% and 93.3% of patients, respectively. None met other classification criteria without fulfilling Sharp or Kasukawa criteria. After a median follow-up of 8 (3-14) years, 149 (45.2%) patients achieved remission, 92 (27.9%) had interstitial lung disease, 25 (7.6%) had pulmonary hypertension, and 18 (5.6%) died. Eighty-five (25.8%) patients progressed to a dCTD, mainly systemic sclerosis (15.8%) or systemic lupus erythematosus (10.6%). Median duration between diagnosis and progression to a dCTD was 5 (2-11) years. The presence at MCTD diagnosis of an abnormal pattern on nailfold capillaroscopy (odds ratio [OR] = 2.44, 95% confidence interval [95%CI] [1.11-5.58]) and parotid swelling (OR = 3.86, 95%CI [1.31-11.4]) were statistically associated with progression to a dCTD. Patients who did not progress to a dCTD were more likely to achieve remission at the last follow-up (51.8% vs. 25.9%).

CONCLUSIONS

This study shows that MCTD is a distinct entity that can be classified using either Kasukawa or Sharp criteria, and that only 25.8% of patients progress to a dCTD during follow-up.

Raynaud's phenomenon associated with psoriatic arthritis

We report a case of Raynaud's phenomenon in a patient with psoriatic arthritis (PsA). A middle-aged right-handed housewife presented with complaints of severely painful hand discolouration for 1 week, which usually worsened with cold exposure. She was diagnosed with PsA 6 months earlier. Her PsA was well controlled with weekly methotrexate. Physical examination showed no features of scleroderma or skin necrosis of her right hand. Both radial pulses were strong and symmetrical. Her nailfolds were visibly normal. The extractable nuclear antigen panel and other blood investigations were negative for scleroderma and other possible causes of secondary Raynaud's phenomenon. Occupational or environmental factors were also excluded. Dermatoscope examination of the nailfolds revealed some areas of dilated capillary loops, areas of vascular sparing and proximal nail fold telangiectasia. The diagnosis of secondary Raynaud's phenomenon was made, and an oral calcium channel blocker was started. The patient had significant improvement in symptoms shortly afterwards.

Association between sinusitis and incident rheumatic diseases: a population-based study

OBJECTIVES

To determine whether antecedent sinusitis is associated with incident rheumatic disease.

METHODS

This population-based case-control study included all individuals meeting classification criteria for rheumatic diseases between 1995 and 2014. We matched three controls to each case on age, sex and length of prior electronic health record history. The primary exposure was presence of sinusitis, ascertained by diagnosis codes (positive predictive value 96%). We fit logistic regression models to estimate ORs for incident rheumatic diseases and disease groups, adjusted for confounders.

RESULTS

We identified 1729 incident rheumatic disease cases and 5187 matched controls (mean age 63, 67% women, median 14 years electronic health record history). After adjustment, preceding sinusitis was associated with increased risk of several rheumatic diseases, including antiphospholipid syndrome (OR 7.0, 95% CI 1.8 to 27), Sjögren's disease (OR 2.4, 95% CI 1.1 to 5.3), vasculitis (OR 1.4, 95% CI 1.1 to 1.9) and polymyalgia rheumatica (OR 1.4, 95% CI 1.0 to 2.0). Acute sinusitis was also associated with increased risk of seronegative rheumatoid arthritis (OR 1.8, 95% CI 1.1 to 3.1). Sinusitis was most associated with any rheumatic disease in the 5-10 years before disease onset (OR 1.7, 95% CI 1.3 to 2.3). Individuals with seven or more codes for sinusitis had the highest risk for rheumatic disease (OR 1.7, 95% CI 1.3 to 2.4). In addition, the association between sinusitis and incident rheumatic diseases showed the highest point estimates for never smokers (OR 1.7, 95% CI 1.3 to 2.2).

CONCLUSIONS

Preceding sinusitis is associated with increased incidence of rheumatic diseases, suggesting a possible role for sinus inflammation in their pathogenesis.

Mixed connective tissue disease-myositis overlap syndrome presenting as an allergic disease process to the emergency department: A case report

BACKGROUND

The "allergy epidemic" of the Western World, has led to an overwhelming number of emergency department presentations with allergic rhinitis, allergic conjunctivitis, atopic eczema, and asthma. Careful consideration should be given to screening for the typical signs and symptoms of Mixed connective tissue disease (MCTD) in patients presenting to the ED with what appears to be a simple allergic process. MCTD is a rare systemic rheumatic disease characterized by high levels of anti-U1RNP antibodies and various clinical signs and symptoms. The pathophysiology of MCTD is poorly understood. An association between allergen-mediated processes and MCTD has been reported in recent literature. Our case report involves a 40 year old African American female with initial outpatient presentation suggestive of atopic disease, with progressive worsening of symptoms while receiving allergen immunotherapy. The patient presented to the emergency department with bilateral leg cramping. The patient was found to have a CPK of 7000 unresponsive to fluids. The patient was evaluated by the Allergy and Rheumatology services. The patient was ultimately diagnosed with MCTD-Myositis Overlap Syndrome and started on steroids and IVIG with improvement in symptoms. While MCTD is not a diagnosis readily made in the ED, early identification and treatment of the disease is critical for prevention of long term complications.

Longitudinal follow-up of mixed connective tissue disease and overlapping autoimmune diseases of childhood onset in the Afro-descendant population of the French West Indies

INTRODUCTION

Overlap autoimmune syndromes (OAS) and mixed connective tissue disease (MCTD) are rare in children. We performed a retrospective, longitudinal and descriptive study of Afro-Caribbean patients from the French West Indies followed for MCTD and OAS to describe their characteristics and outcomes during childhood.

METHODS

Retrospective study from January 2000 to 2023. Listings of patients were obtained from multiple sources: computerized hospital archives and national hospital-based surveillance system, registry of pediatricians and adult specialists in internal medicine and the national registry for rare diseases. MCTD was defined according to Kasukawa's criteria. OAS was defined as overlapping features of systemic lupus erythematosus (SLE), systemic sclerosis (SSc), and dermatomyositis/autoimmune myositis (DM/AM).

RESULTS

Sixteen patients were included over a 23-year period (10 MCTD and 6 OAS). The incidence was 0.23 per 100,000 children-years. The mean age at diagnosis was 11.9 years old (2.4-17) with median follow up of 7.9 years (2.1-19.6). SLE phenotype was present in the highest, followed by SSc and DM/AM. Patients had an average of three flares during childhood (1-7). A quarter (25%) had symptomatic pulmonary arterial hypertension (PAH). Ninety-four percent received steroids during follow-up and 88% required a corticosteroid-sparing therapy. Three patients (19%) developed SLE after more than 10y of follow-up. There were no death and no chronic organ failure.

CONCLUSION

This is the largest pediatric cohort of MCTD and OAS in Afro-descendant patients treated in a country with a high standard of care. The clinical evolution did not differ between MCTD and OAS. The main complication was PAH, more frequent in our cohort.

Unusual non-infectious cause of meningitis

Meningitis, though commonly caused by various infectious agents, may also have non-infectious aetiologies. The clinical presentation, however may be identical to infectious meningitis. We present a case of a female in her 50s who presented with fever, headache, vomiting and neck rigidity. She had features of inflammatory polyarthritis, cold sensitivity, puffy digits, alopecia and easy fatigability. No evidence of infection was found, and serological features consistent with mixed connective tissue disease (MCTD) were revealed, which led to the diagnosis of MCTD-related aseptic meningitis.

Prevention of cardiovascular disease in young adults: Focus on gender differences. A collaborative review from the EAS Young Fellows

A steady rise in cardiovascular morbidity and mortality has been observed in young adults within the last decades. This trend corresponds to an increasing prevalence of traditional cardiovascular risk factors such as obesity and diabetes mellitus type 2 among young adults living in developed countries. Moreover, age-specific risk factors, such as substance abuse, contraceptive medication, and pregnancy-related diseases also correlate with an increased incidence of cardiovascular diseases. In this review, we discuss the available data for young adults on the epidemiology and the rationale for the causality of traditional and newly emerging risk factors of atherosclerotic cardiovascular diseases. We focus on gender-related differences in the exposure to these risk factors, investigate the recent data regarding screening and risk stratification in the young adult population, and describe the current state of the art on lifestyle and therapeutic intervention strategies in the primary prevention setting.

Pediatric mixed connective tissue disease versus other overlap syndromes: a retrospective multicenter cohort study

Pediatric mixed connective tissue disease (MCTD) is a subgroup of overlap syndromes. We aimed to compare the characteristics and outcomes in children with MCTD and other overlap syndromes. All MCTD patients met either Kasukawa or Alarcon-Segovia and Villareal criteria. The patients with other overlap syndromes had the features of ≥ 2 autoimmune rheumatic diseases but did not meet MCTD diagnostic criteria. Thirty MCTD (F/M = 28/2) and thirty (F/M = 29/1) overlap patients were included (disease onset < 18 years). The most prominent phenotype at disease onset and the last visit was systemic lupus erythematosus (SLE) in the MCTD group; juvenile idiopathic arthritis and dermatomyositis/polymyositis, respectively, in the overlap group. At the last visit, systemic sclerosis (SSc) phenotype was more frequent among MCTD than overlap patients (60% vs. 33.3%; p = 0.038). The frequency of the predominant SLE phenotype had decreased (60% to 36.7%), while predominant SSc phenotype had increased (13.3% to 33.3%) during follow-up in MCTD patients. Weight loss (36.7% vs. 13.3%), digital ulcers (20% vs. 0), swollen hands (60% vs. 20%), Raynaud phenomenon (86.7% vs. 46.7%), hematologic involvement (70% vs. 26.7%), and anti-Sm positivity (29% vs. 3.3%) were more common, while Gottron papules (16.7% vs. 40%) were less frequent among MCTD than overlap patients (p < 0.05). A higher percentage of overlap patients achieved complete remission than MCTD patients (51.7% vs. 24.1%; p = 0.047). The disease phenotype and outcome differ between pediatric MCTD and other overlap syndromes where MCTD may be regarded as a more severe disease. Analyzing these patients could pave the way for early and effective treatment.

Overlapping Autoimmune Diseases: A Case Report and Review of Eosinophilic Granulomatosis With Polyangiitis and Mixed Connective Tissue Disease

We describe a rare case of concurrent eosinophilic granulomatosis with polyangiitis and mixed connective tissue disease in a 27-year-old man who presented with pulmonary, renal, cardiac, and skin manifestations. We confirmed the diagnosis based on clinical, histopathological, and serological criteria. We treated the patient with corticosteroids, methotrexate, cyclophosphamide, and hydroxychloroquine, achieving early remission. The coexistence of both conditions in the same patient is extremely rare and has only been reported in a few cases worldwide. We also review the literature on these two rare autoimmune diseases' coexistence, pathogenesis, diagnosis, and management. Our case emphasizes recognizing overlapping autoimmune conditions in patients with complex clinical features and employing a comprehensive diagnostic approach and tailored treatment strategies. Further research is needed to understand these patients' epidemiology, prognosis, and optimal therapy. Early diagnosis and aggressive immunosuppression are crucial for achieving remission and preventing organ damage. We also identified the knowledge gaps and research needs in this field.

Population-based prevalence and incidence estimates of mixed connective tissue disease from the Manhattan Lupus Surveillance Program

OBJECTIVE

Epidemiological data for MCTD are limited. Leveraging data from the Manhattan Lupus Surveillance Program (MLSP), a racially/ethnically diverse population-based registry of cases with SLE and related diseases including MCTD, we provide estimates of the prevalence and incidence of MCTD.

METHODS

MLSP cases were identified from rheumatologists, hospitals and population databases using a variety of International Classification of Diseases, Ninth Revision codes. MCTD was defined as one of the following: fulfilment of our modified Alarcon-Segovia and Kahn criteria, which required a positive RNP antibody and the presence of synovitis, myositis and RP; a diagnosis of MCTD and no other diagnosis of another CTD; and a diagnosis of MCTD regardless of another CTD diagnosis.

RESULTS

Overall, 258 (7.7%) cases met a definition of MCTD. Using our modified Alarcon-Segovia and Kahn criteria for MCTD, the age-adjusted prevalence was 1.28 (95% CI 0.72, 2.09) per 100 000. Using our definition of a diagnosis of MCTD and no other diagnosis of another CTD yielded an age-adjusted prevalence and incidence of MCTD of 2.98 (95% CI 2.10, 4.11) per 100 000 and 0.39 (95% CI 0.22, 0.64) per 100 000, respectively. The age-adjusted prevalence and incidence were highest using a diagnosis of MCTD regardless of other CTD diagnoses and were 16.22 (95% CI 14.00, 18.43) per 100 000 and 1.90 (95% CI 1.49, 2.39) per 100 000, respectively.

CONCLUSIONS

The MLSP provided estimates for the prevalence and incidence of MCTD in a diverse population. The variation in estimates using different case definitions is reflective of the challenge of defining MCTD in epidemiologic studies.

Towards Early Diagnosis of Mixed Connective Tissue Disease: Updated Perspectives

Mixed Connective Tissue Disease (MCTD) is an autoimmune disease first described by Sharp et al in 1972, characterized by the presence of anti-Ribonucleoprotein antibodies directed against the U1 complex (anti-U1RNP). The condition shares clinical characteristics with Systemic Lupus Erythematosus, Rheumatoid Arthritis, and Systemic Sclerosis. Diagnosis is quite difficult due to its rarity, the lack of validated classification criteria, and its heterogeneous clinical presentation. While in the early stages its nuanced clinical features might lead to it being incorrectly classified as other Connective Tissue Diseases (CTDs) or even not recognized, in cases of longstanding disease its classification as a CTD is clear but challenging to discriminate from overlap syndromes. MCTD should be considered a distinct entity due to the presence of a specific genetic substrate and the presence of the high titer of a specific autoantibody, anti-U1RNP, present in all the commercial kits for Extractable Nuclear Antigens, and almost always associated with Antinuclear Antibody positivity with a coarse speckled pattern. Except for anti-U1RNP, no specific biomarkers are available to guide clinicians to a correct classification of MCTD, which is arrived at by the association of clinical, serological and instrumental evaluation. In the first stages, the disease is mainly characterized by Raynaud's phenomenon, inflammatory arthritis, puffy fingers, myalgia and/or myositis, and rarely, trigeminal neuropathy. Longstanding disease is generally associated with the development of Pulmonary Hypertension and Interstitial Lung Disease, which are the two main causes of mortality in MCTD. The aim of this review is to summarize current knowledge on the early recognition of MCTD.

Incidence and prevalence of systemic sclerosis in Thailand in year 2017-2020: a database from the Ministry of Public Health

BACKGROUND

A better understanding of the epidemiological profile of systemic sclerosis (SSc) in Thais could improve care, human resource deployment, and public health budgeting.

OBJECTIVES

We aimed to determine the incidence and prevalence of SSc in Thailand between 2017 and 2020.

METHODS

A descriptive epidemiological study was performed using the Information and Communication Technology Center, Ministry of Public Health database, comprising all types of healthcare providers during the study period. Demographic data of patients having a primary diagnosis of M34 systemic sclerosis and over 18 years of age between 2017 and 2020 were reviewed. The incidence and prevalence of SSc were calculated as well as their respective 95% confidence intervals (CIs).

RESULTS

The number of SSc cases in 2017 was 15,920 from a total Thai population of 65,204,797. The prevalence of SSc in 2017 was 24.4 per 100,000 populations (95% CI 24.0-24.8). The prevalence of SSc among women was 2 times greater than among men (32.7 vs. 15.8 per 100,000). The incidence of SSc was stable from 2018 to 2019 but dropped slightly in 2020 (7.2, 7.6, and 6.8 per 100,000 person-years, respectively). Most SSc cases were in northeastern Thailand (11.6, 12.1, and 11.1 per 100,000 person-years from 2018 to 2020, respectively) and the peak was between 60 and 69 years of age (24.6, 23.8, and 20.9 per 100,000 person-years from 2018 to 2020, respectively).

CONCLUSION

SSc is a rare disease among Thais. The disease was commonly revealed in late middle-aged women with a peak at age 60-69 years, mainly from the northeast regions. The incidence remained stable during the study period, albeit during the emergence of the coronavirus pandemic a slight decline was recorded. Key Points • The incidence and prevalence of systemic sclerosis (SSc) vary across ethnic populations. • There is a lack of epidemiology research of SSc since the 2013 ACR/EULAR Classification Criteria for Scleroderma was adopted among Thais included Asia-Pacific population as the population has some different clinical features than those reported among Caucasians. • SSc is a rare connective disease among Thais and commonly presents in late middle-aged group of both genders, mainly in Thailand's northern and northeastern regions. • When compare to the epidemiology of SSc in Asia-Pacific, the prevalence of SSc in Thais was higher than among East Asians and the Indian population and the incidence of SSc among Thais was greater than the other Asia-Pacific population including Australian.

Secondary cardiac amyloidosis in a patient with mixed connective tissue disease: A case report

We report the case of a 62-year-old man who presented with shortness of breath, cough, bilateral lower limbs' swelling, and blackish discoloration of multiple fingertips over the past 2 months. Anti-Ribonucleoprotein antibodies were found to be present, and gadolinium-based cardiac MRI showed non-vascular subendocardial enhancement with diffuse symmetrical thickening of the left ventricular wall. A diagnosis of Mixed connective tissue disease with secondary cardiac amyloidosis was thus made, and the patient was successfully managed with intravenous cyclophosphamide, corticosteroids, and other supportive measures. Although extremely rare, this case shows that secondary cardiac amyloidosis should be considered while managing patients with MCTD.

Basophils beyond allergic and parasitic diseases

Basophils bind IgE via FcεRI-αβγ2, which they uniquely share only with mast cells. In doing so, they can rapidly release mediators that are hallmark of allergic disease. This fundamental similarity, along with some morphological features shared by the two cell types, has long brought into question the biological significance that basophils mediate beyond that of mast cells. Unlike mast cells, which mature and reside in tissues, basophils are released into circulation from the bone marrow (constituting 1% of leukocytes), only to infiltrate tissues under specific inflammatory conditions. Evidence is emerging that basophils mediate non-redundant roles in allergic disease and, unsuspectingly, are implicated in a variety of other pathologies [e.g., myocardial infarction, autoimmunity, chronic obstructive pulmonary disease, fibrosis, cancer, etc.]. Recent findings strengthen the notion that these cells mediate protection from parasitic infections, whereas related studies implicate basophils promoting wound healing. Central to these functions is the substantial evidence that human and mouse basophils are increasingly implicated as important sources of IL-4 and IL-13. Nonetheless, much remains unclear regarding the role of basophils in pathology vs. homeostasis. In this review, we discuss the dichotomous (protective and/or harmful) roles of basophils in a wide spectrum of non-allergic disorders.

A Case of Mixed Connective Tissue Disease That Transformed Into Systemic Lupus Erythematosus After a Long Clinical Course

Mixed connective tissue disease (MCTD), a multisystem autoimmune disease that was first proposed in 1972, has overlapping features with other autoimmune diseases. In recent studies, mixed connective tissue disease has been reported to change into other connective tissue diseases (CTD; such as systemic lupus erythematosus [SLE], polymyositis, and systemic sclerosis [SSc]) in the long term. We report the case of a 58-year-old Japanese man diagnosed with mixed connective tissue disease 15 years ago. During his clinical course, he developed discoid lupus erythematosus, pancytopenia, a low complement titer, proteinuria, and hematuria. He also turned positive for the anti-double-stranded deoxyribonucleic acid (dsDNA) antibody. A kidney biopsy revealed lupus nephritis (LN) class IV. Therefore, we considered this to be a shift from mixed connective tissue disease to systemic lupus erythematosus. We changed his treatment to lupus nephritis, after which he remained in remission. Our case suggests that mixed connective tissue disease may shift to other connective tissue diseases over a long period; therefore, it is necessary to identify whether patients with mixed connective tissue disease fulfill the diagnostic criteria for other connective tissue diseases when new manifestations appear.

[Consensus guideline on the interdisciplinary diagnosis of interstitial lung diseases]

The evaluation of a patient with interstitial lung disease (ILD) includes assessment of clinical, radiological, and often histopathological data. As there were no specific recommendations to guide the evaluation of patients under the suspicion of an ILD within the German practice landscape, this position statement from an interdisciplinary panel of ILD experts provides guidance related to the diagnostic modalities which should be used in the evaluation of ILD. This includes clinical assessment rheumatological evaluation, radiological examinations, histopathologic sampling and the need for a final discussion in a multidisciplinary team.

Interstitial Lung Disease in Mixed Connective Tissue Disease: An Advanced Search

The spectrum of pulmonary manifestations associated with mixed connective tissue disease ranges from pulmonary hypertension and interstitial lung disease to pleural effusions, alveolar hemorrhage, and complications from the thromboembolic disease. Interstitial lung disease in mixed connective tissue disease is a frequently occurring entity, although in most cases it tends to be self-limited or slowly progressive. Despite this, a significant percentage of patients may present a progressive fibrosing phenotype, thus posing a great challenge regarding its therapeutic approach, given the scarcity of clinical studies that compare the efficacy of immunosuppressants available to date. Due to this, many recommendations are extrapolated from other diseases with similar characteristics such as systemic sclerosis and systemic lupus erythematosus. That is why it is proposed to carry out an advanced search of the literature in order to clarify its clinical, radiological, and therapeutic characteristics to achieve its evaluation from a holistic point of view.

Acute Peritonitis Is Not Always a Surgical Fix: A Rare Case of Mixed Connective Tissue Disease Presenting as Polyserositis

Mixed connective tissue disease (MCTD) is a complex rheumatologic condition whose diagnosis often presents a challenge to even specialists in the field. Many cases are therefore underrecognized or misdiagnosed due to the heterogeneity of the presentation and manifestations. This report highlights the intricacies of diagnosing a case of MCTD when the presenting symptom is atypical. Herein, we present a case of a young girl who had severe abdominal pain, initially concerning for acute peritonitis from cholecystitis, and was found to have polyserositis affecting the pleural space, pericardium, peritoneum and pelvis secondary to mixed connective tissue disease and adrenal insufficiency.

Associations between nailfold capillary aberrations and autoantibodies in children and adults with Raynaud's phenomenon

OBJECTIVE

To characterise associations between individual nailfold capillary aberrations with autoantibodies in a cross-sectional study on children and adults with Raynaud's phenomenon (RP).

METHODS

Consecutive children and adults with RP and without previously known connective tissue disease (CTD) systemically underwent nailfold capillaroscopy and laboratory tests for the presence of antinuclear antibodies (ANA). The prevalence of individual nailfold capillary aberrations and ANA was assessed, and the associations between individual nailfold capillary aberrations and ANA were analysed separately in children and adolescents.

RESULTS

In total, 113 children (median age 15 years) and 2858 adults (median age 48 years) with RP and without previously known CTD were assessed. At least one nailfold capillary aberration was detected in 72 (64%) of included children and in 2154 (75%) of included adults with RP (children vs adults p<0.05). An ANA titre ≥1:80, ≥1:160 or≥1:320 was observed in 29%, 21% or 16% of included children, and in 37%, 27% or 24% of screened adults, respectively. While the occurrence of individual nailfold capillary aberrations was related to the presence of an ANA titre of ≥1:80 in adults (reduced capillary density, avascular fields, haemorrhages, oedema, ramifications, dilations and giant capillaries: each p<0.001), no comparable association between nailfold capillary aberrations and ANA was observed in children with RP without previously known CTD.

CONCLUSION

In contrast to adults, the association between nailfold capillary aberrations and ANA might be less pronounced in children. Further studies are warranted to validate these observations in children with RP.

Anti-MDA5 antibody dermatomyositis-associated rapidly progressive interstitial lung disease patient complicated with mixed connective tissue disease: A case report

Anti-MDA5 antibody dermatomyositis (DM) is a special type of myositis, which can potentially cause rapidly progressive interstitial lung disease (RP-ILD). Mixed connective tissue disease (MCTD) is a complex disease with different characteristics of autoimmune connective tissue disease, associated with ILD. Both are rare diseases, and few patients with both diseases have been reported. A 71-year-old woman complained of palpitations, with a 2 months history of rash around her hands, extensor surface of right elbow, and the nape of her neck. Subsequently, the patient had acute exacerbation of dyspnea and tachypnea. Anti-Ro52, U1 RNP and MDA5 antibodies were positive; the presenting evidence was suggestive of anti-MDA5⁺ DM-RP-ILD complicated with MCTD. Our patient deteriorated rapidly and had a fatal outcome, despite "triple therapy" for RP-ILD. This case illustrates that patients with coexisting anti-MDA5⁺ DM and MCTD have the former's typical clinical manifestations, and may develop ILD quickly rather than slowly as in MCTD, especially with the coexistence of anti-Ro52 antibodies.

X marks the spot in autoimmunity

INTRODUCTION

Autoimmune diseases mostly affect females. Besides hormones, several factors related to chromosome X have been called in action to explain this sex predominance.

AREAS COVERED

This paper provides an overview on the role of chromosome X (chrX) in explaining why females have higher susceptibility to autoimmunity. The work outlines some essential concepts regarding chrX inactivation, escape from chrX inactivation and the evolutionary history of chrX. In addition, we will discuss the concept of gene escape in immune cells, with examples related to specific X-linked genes and autoimmune diseases.

EXPERT OPINION

There is growing evidence that many genes present on chrX escape inactivation, and some of them have significant immune-mediated functions. In immune cells of female individuals the escape of these genes is not constant, but the knowledge of the mechanisms controlling this plasticity are not completely understood. Future studies aimed at the characterization of these modifications at single-cell resolution, together with conformational 3D studies of the inactive X chromosome, will hopefully help to fill this gap of knowledge.

Urinary abnormality in mixed connective tissue disease predicts development of other connective tissue diseases and decrease in renal function

OBJECTIVE

To clarify the clinical significance of development of urinary abnormality in mixed connective tissue disease (MCTD).

METHODS

Forty-one patients with an initial diagnosis of MCTD, followed at five hospitals between April 1, 2000 and December 31, 2013, were included. The relationship between urinary abnormality and various clinical parameters were retrospectively analyzed. Urinary abnormality was defined as proteinuria and/or hematuria detected by urinalysis. Development of other connective tissue diseases (CTDs) was defined as satisfaction of the criteria of each respective disease.

RESULTS

Of 41 patients (34 females, 7 males, mean age at diagnosis 42.2 ± 15.2 years), 16 developed urinary abnormality (UrA(+) patients). The total incidences of development of other CTDs were higher in the UrA(+) patients than UrA(-) (62.5% versus 16.0%, p = .01). In the comparison between UrA(+) and UrA(-) patients, there were no significant differences in follow-up duration or last determined estimated glomerular filtration rate (eGFR), although eGFR decreased more significantly in the UrA(+) patients than UrA(-). (-20.2 ± 17.2 vs -6.1 ± 13.8 ml/min/1.73m2, p = .01; -21.0 ± 18.9 vs -6.7 ± 14.1%, p = .03).

CONCLUSION

Urinary abnormality during the clinical course in MCTD is predictive of a higher incidence of developing other CTDs. Furthermore, it might also predict long-term renal prognosis in patients with an initial diagnosis of MCTD.

Incidence and Clinical Pattern of Mixed Connective Tissue Disease in Sudanese Patients at Omdurman Military Hospital: Hospital-Based Study

Background

Mixed connective tissue disease (MCTD) is a rare autoimmune disease, characterized by the production of specific autoantibody anti-RNP, which presents with varied overlapping symptoms of different connective tissue disorders. The aim of this study is to identify the frequency and patterns of MCTD.

Methods

This is a descriptive cross-sectional hospital-based study conducted at the rheumatology clinic at Omdurman Military Hospital between February 2019 and July 2019. The study included 30 patients and data were collected using a designated questionnaire.

Results

The study showed that the majority of patients (96.7%) were females and only 3.3% was male. About 30% of the patients aged between 30 and 39 years were the most affected. As a first diagnosis, 10% of the patients had a MCTD fulfilling the Alarcon-Segovia criteria. The remaining 90% of the patients were diagnosed with other diseases before evolving into MCTD. The most common clinical presentation was arthralgia in 100% of the patients, 90% were symmetrically followed by myositis in 70% of the patients, arthritis in 63.3% of the patients, puffy fingers in 63.3% of the patients, and hand swelling in 60% as major musculoskeletal symptoms. Regarding the initial results in immunological profile, the most common positive autoantibodies among the patients were anti-RNP titer in 96.7% of the patients, ANA in 90%, anti-Sm in 50%, RF in 50%, anti-Ds DNA in 46.7%, and anti-Ro in 43.3%.

Conclusion

This study showed that MCTD is more common in females, only 10% of patients presented with a fulfilling criteria of the disease at diagnosis, and the rest of the patients presented with other rheumatologic diseases before evolving into MCTD.

Post Ambulatory Swollen Hands (POTASH): An Autobiographical Case Report

Post ambulatory swollen hands (POTASH) is a rarely described etiology for hand swelling; to the best of my knowledge, it has only been reported in the medical literature a decade ago in a prospective study evaluating its development in walkers who were either dog owners (who walked or did not walk their dogs) in comparison to non-dog owners. In addition to swelling after initiating ambulation by participating in an activity such as hiking, running, or walking, there are also several other causes of swollen hands; a positive fist sign has only been described in a limited number of conditions observed in individuals with hand swelling. A fist is created when there is clenching of the fingers and the fingertips are in direct contact with the palm of the hand with the thumb lying on top of the fingers between the proximal and distal interphalangeal joints. A positive fist sign is demonstrated by the inability to clench the fingers tightly into a fist; indeed, it is a common--yet not frequently reported--manifestation observed in individuals with a swollen hand. In contrast, a negative fist sign occurs when the patient can form a fist of tightly clenched fingers. The author, a 62-year-old physician and long-distance runner since high school, developed recurrent episodes of POTASH beginning five years ago. He noticed asymptomatic, bilateral, and symmetric swelling of his dorsal and palmar hands--with a positive fist sign--beginning after approximately one hour of running; the degree of swelling was proportional to the duration of time he ran. His hand swelling would completely resolve spontaneously--and his fist sign would be negative--within two hours after he stopped running. Recommendations for hikers and walkers to potentially eliminate or limit the degree of POTASH have been suggested; for dog owners who walked their dog, POTASH was less likely to occur if they regularly walked the dog. Several etiologies for POTASH have been proposed; however, the definitive pathogenesis for hand swelling related to either hiking, running, or walking remains to be determined. Therefore, research to gain additional insight and possibly establish the cause of ambulatory-associated swollen hands is warranted.

The dilemma: scleroderma renal crisis vs lupus nephritis in a patient with mixed connective tissue disorder

Introduction

Mixed connective tissue disorder (MCTD) is a rare connective tissue disorder characterized by features of systemic lupus erythematosus, dermatomyositis, systemic sclerosis, and rheumatoid arthritis. MCTD is associated with an elevated antibody titer to U1 small nuclear ribonucleoprotein.

Case description

A 49-year-old man presented to the emergency department for evaluation of worsening shortness of breath with associated for bilateral hand pain and swelling associated with morning stiffness which was initially thought to be related to systemic lupus erythematous (SLE). He was also found to have a positive autoantibody, and he was later diagnosed with MCTD complicated by scleroderma renal crisis.

Conclusion

MCTD is a rare connective tissue disorder with overlapping features of SLE, dermatomyositis, systemic sclerosis, and rheumatoid arthritis. The diagnosis of MCTD requires a high index of suspicion and careful workup. Immunosuppressive therapy is the mainstay of treatment that improves patient outcomes.

A Rare Case of Fatal Hemorrhagic Stroke in a Young Female with Early Mixed Connective Tissue Disease

Mixed connective tissue disease (MCTD) often presents as a slow progressive illness with low morbidity and mortality. Serious central nervous system disease is uncommon, and fatal outcomes are rarely seen. Here, we report a rare case of fatal hemorrhagic stroke in a 43-year-old female with a rapidly progressive MCTD. She presented to primary care with a history of headaches, visual disturbances, and unprovoked lower extremity swelling and pain. A rheumatological workup showed positive antinuclear (ANA) and ribonucleoprotein (RNP) antibodies. Magnetic resonance imaging (MRI) found a 12 mm hemorrhage along a cortical sulcus of the right frontal lobe, and a follow-up magnetic resonance angiography (MRA) and ophthalmological exam showed no definitive signs of vasculitis. Over the course of her workup, she developed swollen hands, Raynaud's syndrome, myalgias, and synovitis characteristic of evolving MCTD. The patient then began to experience severe headaches over one month. Repeat MRI was ordered, but never completed, and the patient presented to the emergency department (ED) with a severe, right-sided headache, and left-sided visual disturbance. In the ED, she began to display evidence of delirium and seizure activity and became unresponsive. A computerized tomography scan (CT) of the brain showed a right parietal lobe intraparenchymal hemorrhage approximately 5 × 3 × 5 cm in size with secondary mass effect including mid- and hind-brain herniation. Computerized tomography angiography (CTA) of the brain showed signs of large vessel vasculitis. A craniectomy was performed; however, the patient never regained consciousness and died several days later. Vasculitis, while rare in connective tissue diseases, should be aggressively assessed for and managed in patients with any early signs and symptoms of cerebrovascular involvement to prevent fatal outcomes.

Interstitial Lung Disease in Connective Tissue Diseases: Survival Patterns in a Population-Based Cohort

Objectives: Interstitial lung disease (ILD) is associated with impaired survival among patients with connective tissue diseases (CTDs), but population-based data on the frequency of ILD and pulmonary hypertension (PH) in different CTD subtypes and the impact on survival are sparse. Methods: We included patients with a first-time ICD-10 diagnosis of systemic sclerosis (SSc), mixed connective tissue disease (MCTD), myositis, systemic lupus erythematosus (SLE), or Sjögren’s disease registered in the Danish National Patient Registry between 2000 and 2015. Among these, we identified patients with ILD and PH. Using Kaplan–Meier analysis, we assessed survival for the five subtypes of CTD ± ILD and compared survival among CTD patients overall ± ILD with survival in the general population ± ILD. Results: We identified 11,731 patients with a diagnosis of CTD; 637 (5.4%) had a diagnosis of ILD. The proportion of patients with ILD was higher in SSc (13.4%) and MCTD (9.1%) than in myositis (6.0%), SLE (4.1%), and Sjögren (2.8%). Fifty-one percent were diagnosed with ILD in their fifties and sixties. PH was more frequent in SSc (7.5%) and MCTD (4.1%). Five-year survival was 73.3% (66.7–80.6) in SSc-ILD, 81.0% (69.0–95.1) in MCTD-ILD, 84.7% (77.3–92.9) in myositis-ILD, 83.5% (76.2–91.5) in SLE-ILD, and 84.7 (78.4–91.6) in Sjögren-associated ILD. Survival in CTD-ILD overall was impaired for all age groups compared with CTD alone. Age-stratified survival was comparable between CTD-ILD and ILD in the general population. The survival gap between ILD and non-ILD increased with age. Conclusion: Survival was comparable between different CTD-ILD subtypes and comparable to survival in non-CTD-ILD.

Chronic neutropenia: how best to assess severity and approach management?

INTRODUCTION

Neutropenia is a relatively common finding in medical practice and the medical approach requires a gradual and pertinent diagnostic procedure as well as adapted management.

AREAS COVERED

The area of chronic neutropenia remains fragmented between diverse diseases or situations. Here physicians involved in different aspects of chronic neutropenia gather both the data from medical literature till the end of May 2021 and their experience to offer a global approach for the diagnosis of chronic neutropenia as well as their medical care.

EXPERT OPINION

In most cases, the neutropenia is transient, frequently related to a viral infection, and not harmful. However, neutropenia can be chronic (i.e. >3 months) and related to a number of etiologies, some clinically benign, such as so-called 'ethnic' neutropenia. Autoimmune neutropenia is the common form in young children, whereas idiopathic/immune neutropenia is a frequent etiology in young females. Inherited neutropenia (or congenital neutropenia) is exceptional, with approximately 30 new cases per 10⁶ births and 30 known subtypes. Such patients have a high risk of invasive bacterial infections, and oral infections. Supportive therapy, which is primarily based on daily administration of an antibiotic prophylaxis and/or treatment with granulocyte-colony stimulating factor (G-CSF), contributes to avoiding recurrent infections.

Application of NGS Technology in Understanding the Pathology of Autoimmune Diseases

NGS technologies have transformed clinical diagnostics and broadly used from neonatal emergencies to adult conditions where the diagnosis cannot be made based on clinical symptoms. Autoimmune diseases reveal complicate molecular background and traditional methods could not fully capture them. Certainly, NGS technologies meet the needs of modern exploratory research, diagnostic and pharmacotherapy. Therefore, the main purpose of this review was to briefly present the application of NGS technology used in recent years in the understanding of autoimmune diseases paying particular attention to autoimmune connective tissue diseases. The main issues are presented in four parts: (a) panels, whole-genome and -exome sequencing (WGS and WES) in diagnostic, (b) Human leukocyte antigens (HLA) as a diagnostic tool, (c) RNAseq, (d) microRNA and (f) microbiome. Although all these areas of research are extensive, it seems that epigenetic impact on the development of systemic autoimmune diseases will set trends for future studies on this area.

Detection and Management of Interstitial Lung Diseases Associated With Connective Tissue Diseases

Interstitial lung disease (ILD) is a common manifestation of connective tissue diseases (CTDs). A proportion of patients with CTD-ILDs develop progressive fibrosing ILD, which is characterized by worsening fibrotic abnormalities on high-resolution computed tomography scan, decline in lung function, worsening symptoms, and early mortality. Here, we review the impact of ILD in patients with CTDs, the importance of prompt diagnosis and close monitoring, and the evidence available to guide the management of CTD-ILDs. Management of patients with CTD-ILDs should be individualized and involve close collaboration between rheumatologists and pulmonologists. Immunosuppression is the mainstay of therapy for CTDs, but evidence for its effectiveness in slowing the progression of ILD is limited. Recently, nintedanib has been approved to slow decline in lung function in patients with systemic sclerosis-associated ILD and chronic fibrosing ILDs with a progressive phenotype. The results of ongoing clinical trials will help clinicians take a more evidence-based approach to the treatment of CTD-ILDs.

Case of rare association of peripheral neuropathy with mixed connective tissue disorder

Chronic inflammatory demyelinating polyneuropathy (CIDP) is probably the best-recognised progressive immune-mediated peripheral neuropathy. It presents with symmetrical, motor predominant peripheral neuropathy that produces both distal and proximal weakness. Here we report a case of a 38-year-old man who presented with chronic additive large and small joint inflammatory polyarthritis, associated with morning stiffness, anasarca associated with frothy urine and progressive episodic, relapsing and remitting, sensorimotor lower motor neuron type quadriparesis without any bladder and bowel involvement. He was diagnosed as a case of CIDP, and the aetiology was found out to be mixed connective tissue disorder, which is a rare association with CIDP. The patient responded dramatically to glucocorticoid.

[Atypical arthritis of the hands : Collagenosis-part 2]

BACKGROUND

Progressive systemic scleroderma (PSS) and mixed connective tissue disease (MCTD) represent vasculitic autoimmune diseases from the group of collagenoses with manifestations in various organ systems such as the skin, the internal organs and the joints.

OBJECTIVE

To present the atypical arthritis patterns of the hands in PSS and MCTD that differ from those in rheumatoid arthritis (RA) and psoriatic arthritis (PsA) in the context of clinical and serologic findings and in consideration of the classification of PSS and MCTD.

MATERIALS AND METHODS

Narrative review based on the current literature on the subject from the radiological and rheumatological point of view.

RESULTS

In PSS, combinations of acral soft tissue atrophy, nonreactive acro-osteolysis, and interstitial calcifications can be visualized by projection radiography, which in the final stage can lead to a scleroderma claw hand. Digital pharmacoangiography of the hands can be used to reliably diagnose manifest vascular occlusions of the digital arteries. MCTD is characterized by various overlapping symptoms of at least two systemic autoimmune diseases and most frequently presents in the hand with symmetrical involvement of the PIP (proximal interphalangeal), MCP (metacarpophalangeal) and wrist joints with the manifestation of so-called "puffy fingers".

CONCLUSIONS

The presented morphological atypical arthritis patterns of the hands in PSS and MCTD differ considerably from the typical patterns in the hands in RA and PsA. MRI is useful to diagnose early stages and pharmacoangiography can be used to differentiate between temporary and manifest digital vascular occlusions.

Basophils and IgE contribute to mixed connective tissue disease development

BACKGROUND

Mixed connective tissue disease (MCTD) is a rare and complex autoimmune disease that presents mixed features with other connective tissue diseases, such as systemic lupus erythematosus, systemic sclerosis, and myositis. It is characterized by high levels of anti-U1 small nuclear ribonucleoprotein 70k autoantibodies and a high incidence of life-threatening pulmonary involvement. The pathophysiology of MCTD is not well understood, and no specific treatment is yet available for the patients. Basophils and IgE play a role in the development of systemic lupus erythematosus and thus represent new therapeutic targets for systemic lupus erythematosus and other diseases involving basophils and IgE in their pathogenesis.

OBJECTIVE

We sought to investigate the role of basophils and IgE in the pathophysiology of MCTD.

METHODS

Basophil activation status and the presence of autoreactive IgE were assessed in peripheral blood of a cohort of patients with MCTD and in an MCTD-like mouse model. Basophil depletion and IgE-deficient animals were used to investigate the contribution of basophils and IgE in the lung pathology development of this mouse model.

RESULTS

Patients with MCTD have a peripheral basopenia and activated blood basophils overexpressing C-C chemokine receptor 3. Autoreactive IgE raised against the main MCTD autoantigen U1 small nuclear ribonucleoprotein 70k were found in nearly 80% of the patients from the cohort. Basophil activation and IgE anti-U1 small nuclear ribonucleoprotein 70k were also observed in the MCTD-like mouse model along with basophil accumulation in lymph nodes and lungs. Basophil depletion dampened lung pathology, and IgE deficiency prevented its development.

CONCLUSIONS

Basophils and IgE contribute to MCTD pathophysiology and represent new candidate therapeutic targets for patients with MCTD.

Connective Tissue Disease Related Interstitial Lung Disease

Patients with connective tissue diseases may have pulmonary involvement, including interstitial lung disease. Various patterns of interstitial lung disease have been classically described in certain connective tissue diseases. It is now recognized that there is significant overlap between patterns of interstitial lung disease observed in the various connective tissue diseases. Differentiating idiopathic from connective tissue disease-related interstitial lung disease is challenging but of clinical importance. New concepts in the diagnosis of connective tissue disease related interstitial lung disease may prove useful in making the diagnosis.

"Mixed connective tissue disease": a condition in search of an identity

Mixed connective tissue disease was first described as a new autoimmune rheumatic disease in 1972 based on the claim of a distinct clinical picture associated with anti-RNP antibody positivity. Subsequently, this new entity has divided opinions in the rheumatology community. We have reviewed recent cohort studies with more than 100 patients, comparing the clinical and immunological features, treatment, prognosis and evolution to well-defined autoimmune rheumatic diseases. We also reviewed clinical features of undifferentiated autoimmune rheumatic diseases based on the most recent studies. After gathering and reviewing these data, we discuss whether the designation “mixed connective tissue disease” should be maintained.

A 21-Year-Old Woman with Joint Pain and Skin Ulceration

The illness started with pain and stiffness in her bilateral hands and wrists four months prior, with progression to bilateral elbows, knees, and ankles. The pain and stiffness were worse in the morning and limited her ability to use her hands or walk comfortably. She also noted swelling of her hands, knees, and ankles. The pain and swelling improved slightly with ibuprofen. She also noted increased fatigue, alopecia, decreased appetite, and nausea. She went to urgent care one month earlier and a physician prescribed ibuprofen and obtained initial serologies.

Epigenome-Wide Comparative Study Reveals Key Differences Between Mixed Connective Tissue Disease and Related Systemic Autoimmune Diseases

Mixed Connective Tissue Disease (MCTD) is a rare complex systemic autoimmune disease (SAD) characterized by the presence of increased levels of anti-U1 ribonucleoprotein autoantibodies and signs and symptoms that resemble other SADs such as systemic sclerosis (SSc), rheumatoid arthritis (RA), and systemic lupus erythematosus (SLE). Due to its low prevalence, this disease has been very poorly studied at the molecular level. We performed for the first time an epigenome-wide association study interrogating DNA methylation data obtained with the Infinium MethylationEPIC array from whole blood samples in 31 patients diagnosed with MCTD and 255 healthy subjects. We observed a pervasive hypomethylation involving 170 genes enriched for immune-related function such as those involved in type I interferon signaling pathways or in negative regulation of viral genome replication. We mostly identified epigenetic signals at genes previously implicated in other SADs, for example MX1, PARP9, DDX60, or IFI44L, for which we also observed that MCTD patients exhibit higher DNA methylation variability compared with controls, suggesting that these sites might be involved in plastic immune responses that are relevant to the disease. Through methylation quantitative trait locus (meQTL) analysis we identified widespread local genetic effects influencing DNA methylation variability at MCTD-associated sites. Interestingly, for IRF7, IFI44 genes, and the HLA region we have evidence that they could be exerting a genetic risk on MCTD mediated through DNA methylation changes. Comparison of MCTD-associated epigenome with patients diagnosed with SLE, or Sjögren's Syndrome, reveals a common interferon-related epigenetic signature, however we find substantial epigenetic differences when compared with patients diagnosed with rheumatoid arthritis and systemic sclerosis. Furthermore, we show that MCTD-associated CpGs are potential epigenetic biomarkers with high diagnostic value. Our study serves to reveal new genes and pathways involved in MCTD, to illustrate the important role of epigenetic modifications in MCTD pathology, in mediating the interaction between different genetic and environmental MCTD risk factors, and as potential biomarkers of SADs.

Contribution of pulmonary function tests (PFTs) to the diagnosis and follow up of connective tissue diseases

Introduction

Connective Tissue Diseases (CTDs) are systemic autoimmune conditions characterized by frequent lung involvement. This usually takes the form of Interstitial Lung Disease (ILD), but Obstructive Lung Disease (OLD) and Pulmonary Artery Hypertension (PAH) can also occur. Lung involvement is often severe, representing the first cause of death in CTD. The aim of this study is to highlight the role of Pulmonary Function Tests (PFTs) in the diagnosis and follow up of CTD patients.

Main body

Rheumatoid Arthritis (RA) showed mainly an ILD with a Usual Interstitial Pneumonia (UIP) pattern in High-Resolution Chest Tomography (HRCT). PFTs are able to highlight a RA-ILD before its clinical onset and to drive follow up of patients with Forced Vital Capacity (FVC) and Carbon Monoxide Diffusing Capacity (DL_CO). In the course of Scleroderma Spectrum Disorders (SSDs) and Idiopathic Inflammatory Myopathies (IIMs), DL_CO appears to be more sensitive than FVC in highlighting an ILD, but it can be compromised by the presence of PAH. A restrictive respiratory pattern can be present in IIMs and Systemic Lupus Erythematosus due to the inflammatory involvement of respiratory muscles, the presence of fatigue or diaphragm distress.

Conclusions

The lung should be carefully studied during CTDs. PFTs can represent an important prognostic tool for diagnosis and follow up of RA-ILD, but, on their own, lack sufficient specificity or sensitivity to describe lung involvement in SSDs and IIMs. Several composite indexes potentially able to describe the evolution of lung damage and response to treatment in SSDs are under investigation. Considering the potential severity of these conditions, an HRCT jointly with PFTs should be performed in all new diagnoses of SSDs and IIMs. Moreover, follow up PFTs should be interpreted in the light of the risk factor for respiratory disease related to each disease.

Relationships among Antibodies against Extractable Nuclear Antigens, Antinuclear Antibodies, and Autoimmune Diseases in a Brazilian Public Hospital

One characteristic of autoimmune diseases (ADs) is the production of autoantibodies for extractable nuclear autoantigens, which may aid in the discrimination of the different types of autoimmune diseases and is related to different antinuclear antibody (ANA) patterns. The present study verified the profile of patient samples tested for extractable nuclear antigens (ENA) antibodies in a public hospital and correlated the ENA results with ANA patterns and patient diagnoses. The study reviewed data in the medical records of patients who underwent anti-ENA tests at a public hospital in the West of the State of Paraná from February 2011 to January 2017. Patients were classified according to age, ethnicity, gender, anti-ENA test results, ANA results, and the presence or absence of AD. Thirty-six (20.9%) samples of the 172 anti-ENA tests were positive, seven (4.1%) samples were undetermined, and 129 (75%) exhibited negative results. The ANA reagent was found in 84.3% of the anti-ENA-positive samples. The anti-SSA/Ro autoantibody exhibited the highest frequency in the group, 41.7% (15/36). The most common pattern was nuclear fine speckled, which was found in 24.3% of the samples. The association results indicated a significant relationship between ANA titer and diagnosis in the anti-ENA- and ANA-positive patients. The anti-ENA-negative patients were diagnosed with an AD in 35% (45/129) of the cases, and 75% (27/36) of the anti-ENA-positive patients were diagnosed with an AD. Systemic lupus erythematosus and scleroderma were the most common pathologies in the antigen-positive patients. The anti-ENA test is a good marker to aid in the complex clinical diagnosis of patients with autoimmune diseases.

Could Lymphocyte Profiling be Useful to Diagnose Systemic Autoimmune Diseases?

Considering the implications of B, T, and natural killer (NK) cells in the pathophysiology of systemic autoimmune diseases, the assessment of their distribution in the blood could be helpful for physicians in the complex process of determining a precise diagnosis. In primary Sjögren's syndrome, transitional and active naive B cells are increased and memory B cells are decreased compared to healthy controls and other systemic diseases. However, their utility to improve the accuracy of classification criteria has not been proven. In early untreated rheumatoid arthritis, proportions of regulatory T cells are constantly reduced, but other patterns are difficult to determine given the heterogeneity of published studies. In systemic lupus erythematosus, the lack of studies using large cohorts of patients and the diversity of the possible pathological mechanisms involved are also important impediments. Nevertheless, transitional B cell and plasma cell proportions are increased in most of the studies, the CD4/CD8 ratio is decreased, and the number of NK cells is reduced. Despite the low number of studies, anomalies of lymphocyte subset distribution was also described in ANCA-associated vasculitis, systemic scleroderma, and myositis. For now, flow cytometric analysis of lymphocyte subsets has focused mainly on specific subpopulations and is more useful for basic and translational research than for diagnostics in clinical practice. However, new modern methods such as mass cytometry and bioinformatics analyses may offer the possibility to simultaneously account for the relative proportions of multiple lymphocyte subsets and define a global profile in homogeneous groups of patients. The years to come will certainly incorporate such global lymphocyte profiling in reclassification of systemic autoimmune diseases.

Emergence of Smoldering ANCA-associated Glomerulonephritis during the Clinical Course of Mixed Connective Tissue Disease and Sjögren's Syndrome

A 67-year-old woman presented with hematuria and proteinuria 16 and 11 months ago, respectively. She had been followed up as mixed connective tissue disease and Sjögren's syndrome for over 19 years. Blood chemistry showed no elevated serum creatinine or C-reactive protein but did reveal myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA) of 300 U/dL. A kidney biopsy showed pauci-immune focal necrotizing glomerulonephritis. She was treated with prednisolone and rituximab, resulting in normal urinalysis and decreased MPO-ANCA. The complication of ANCA-associated glomerulonephritis should not be overlooked when abnormal urinalysis findings appear in the course of connective tissue disease, irrespective of the presence of rapidly progressive glomerulonephritis.