Primary complement and antibody deficiencies in autoimmune rheumatologic diseases with juvenile onset: a prospective study at two centers

Rheumatologic manifestations in children with underlying inborn errors of immunity

BACKGROUND AND OBJECTIVE

In recent years, many studies have been conducted on the possible link between rheumatologic diseases and inborn errors of immunity. Rheumatologic diseases may occur as manifestations of an underlying immunodeficiency disorder, and may appear before the more-common infectious manifestations more typically seen in immunodeficiency disorders. In this study, we have attempted to study such symptoms and uncover their relationship with inborn errors of immunity.

METHODOLOGY

In this retrospective descriptive-analytical study, 381 cases of IEIs in children that were referred to Mofid Children's Hospital clinic between 2015 and 2019 were evaluated for eligibility to be enrolled in the study. Of these patients, 20 that had confirmed rheumatologic diagnoses were entered into the study. Patients' demographic and medical data, including age at disease onset, age at diagnosis and type of diagnosed rheumatologic and immunodeficiency disorders, parental consanguinity rate, and relevant laboratory findings were retrieved for study and analyzed.

RESULTS

Among 20 eligible patients, half of which were female and half were male, the average age at disease onset, average age at diagnosis of the underlying immunodeficiency disease and average age at diagnosis of the rheumatologic disease were 2.98 ± 1.56, 5.26 ± 3.45 and 3.58 ± 2.97, respectively. JIA made up 10 of the observed rheumatic diseases ("the JIA group"); the remaining 10 patients included SLE (3), FMF (2), juvenile dermatomyositis (2), MCTD (1), GPA (1) and reactive arthritis (1) ("the non-JIA group"). As for the underlying immunodeficiency disorders, CID was seen in 8 patients, followed by CVID (5), XLA (4), SIgAD (2) and CGD (1). The average age at onset of the disease and the average age at diagnosis of the rheumatologic disease were significantly lower in the JIA group than in the non-JIA group (p < 0.05).

CONCLUSIONS

A plethora of rheumatologic manifestations may be observed in patients with IEIs; such manifestations should be actively sought out and treated in IEI patients.

CLINICAL TRIAL NUMBER

Not applicable.

Hypogammaglobulinemia in patients affected by limited cutaneous systemic sclerosis: Case series and review of the literature

Background

Hypogammaglobulinemia is a condition that can be related to both primary and secondary immunodeficiencies. While the role of primary immunodeficiency in immune-mediated diseases is well known, its occurrence in systemic sclerosis is not reported.

Objectives

This study aims to describe the clinical features associated with hypogammaglobulinemia in a cohort of limited cutaneous systemic sclerosis patients.

Methods

We retrospectively reviewed medical records of systemic sclerosis patients from two Italian referral centres (2010-2024). Included patients had limited cutaneous systemic sclerosis and presented reduced serum concentrations of one or more Ig isotypes (IgG < 700 mg/dL, IgA < 70 mg/dL or IgM < 50 mg/dL) in at least two separate measurements. Patients with secondary causes of hypogammaglobulinemia were excluded. Data collected included demographics, clinical features, Ig levels, infection history and comorbidities.

Results

We identified 30 systemic sclerosis patients (93% female, mean age 62 years) with limited cutaneous involvement and hypogammaglobulinemia. Most patients were positive for anti-centromere antibodies and received periodic intravenous infusions of prostaglandin analogues. No patient received immunosuppressive therapy. Median (interquartile range) serum IgG levels 519.5 (175) mg/dL, median IgA 65.5 (48) mg/dL and median IgM 71.5 (49) mg/dL. Four patients who met the European Society for Immunodeficiencies (ESID) criteria for common variable immunodeficiency experienced recurrent infections and had associated immune-mediated diseases. Five patients had selective IgA deficiency, with frequent immune-mediated comorbidities (thyroiditis, Sjögren's syndrome, arthritis, psoriasis). The other patients exhibited mild IgG deficiency without a significant infectious history.

Conclusions

This is the first study describing a cohort of patients with limited cutaneous systemic sclerosis and hypogammaglobulinemia. Our population presented a high prevalence of immune-mediated comorbidities but low infection rates. Further research is needed to explore the underlying mechanisms and clinical significance of hypogammaglobulinemia in these patients.

Secondary hypogammaglobulinemia: diagnosis and management of a pediatric condition of clinical importance

PURPOSE OF REVIEW

Secondary hypogammaglobulinemia, or low serum immunoglobulins, is associated with a variety of medications or medical conditions and may be symptomatic and lead to increased infectious risk. There is limited data regarding the study of acquired, or secondary, hypogammaglobulinemia (SHG) in pediatrics. The data to date has suffered from methodologic issues including retrospective study design, lack of baseline immunoglobulin measurements, and limited longitudinal follow-up.

RECENT FINDINGS

There is emerging research on the impact of B-cell depleting therapies, specifically rituximab and chimeric antigen T-cells, along with other autoimmune and malignant disease states, in the development of SHG in pediatric patients. This review will also summarize other relevant pediatric conditions related to SHG.

SUMMARY

The clinical relevance of SHG in pediatrics is increasingly appreciated. Improved understanding of the specific etiologies, risk factors, and natural history of SHG have informed screening and management recommendations.

The autoimmune rheumatological presentation of Common Variable Immunodeficiency Disorders with an overview of genetic testing

Primary immunodeficiency Disorders (PIDS) are rare, mostly monogenetic conditions which can present to a number of specialties. Although infections predominate in most PIDs, some individuals can manifest autoimmune or inflammatory sequelae as their initial clinical presentation. Identifying patients with PIDs can be challenging, as some can present later in life. This is often seen in patients with Common Variable Immunodeficiency Disorders (CVID), where symptoms can begin in the sixth or even seventh decades of life. Some patients with PIDs including CVID can initially present to rheumatologists with autoimmune musculoskeletal manifestations. It is imperative for these patients to be identified promptly as immunosuppression could lead to life-threatening opportunistic infections in these immunocompromised individuals. These risks could be mitigated by prior treatment with subcutaneous or intravenous (SCIG/IVIG) immunoglobulin replacement or prophylactic antibiotics. Importantly, many of these disorders have an underlying genetic defect. Individualized treatments may be available for the specific mutation, which may obviate or mitigate the need for hazardous broad-spectrum immunosuppression. Identification of the genetic defect has profound implications not only for the patient but also for affected family members, who may be at risk of symptomatic disease following an environmental trigger such as a viral infection. Finally, there may be clinical clues to the underlying PID, such as recurrent infections, the early presentation of severe or multiple autoimmune disorders, as well as a relevant family history. Early referral to a clinical immunologist will facilitate appropriate diagnostic evaluation and institution of treatment such as SCIG/IVIG immunoglobulin replacement. This review comprises three sections; an overview of PIDs, focusing on CVID, secondly genetic testing of PIDs and finally the clinical presentation of these disorders to rheumatologists.

Serum immunoglobulin A (IgA) levels in children affected with Juvenile Idiopathic Arthritis

BACKGROUND AND OBJECTIVE

Immunoglobulin A (IgA) is the most abundant antibody isotype in the human body, considering its presence on the mucosal surfaces, in addition to the amount circulating in the bloodstream. Serum IgA levels can be variably altered in several pathological settings. However, very few studies specifically investigated serum IgA in Juvenile Idiopathic Arthritis (JIA). In the present study, we specifically assessed serum IgA levels in our cohort of patients affected with JIA.

METHODS

In this cross-sectional study, serum IgA levels were measured in patients with JIA (and age-matched controls) and analyzed according to age class. The correlation of serum IgA levels with hematological, inflammatory, and disease activity parameters was assessed.

RESULTS

No significant difference in the frequency of low IgA levels (according to the definition of complete and partial IgA deficiency) was observed between JIA patients and controls, overall. This pediatric study population showed a progressive increase of total serum IgA concentrations with age, as expected; however, in JIA patients aged 10-17 years, total IgA serum levels resulted to be significantly higher than in age-matched control subjects. No clear correlation between IgA levels and the examined inflammatory, hematological, and disease activity parameters was observed in JIA patients, except for the erythrocyte sedimentation rate (ESR) in oligoarticular JIA patients: here, serum IgA levels showed a positive and moderate covariation with ESR, which was also observed for disease activity (JADAS-10) in selected oJIA patients without biological therapy.

CONCLUSIONS

In our cohort of JIA patients, total serum IgA levels were not reduced and were actually increased in adolescents compared to controls. Larger studies are needed to confirm this finding, which cannot be certainly explained based on the available data in this study, even though JIA disease control and/or chronic inflammation may be implicated to some extent.

Practical guidance for the diagnosis and management of secondary hypogammaglobulinemia: A Work Group Report of the AAAAI Primary Immunodeficiency and Altered Immune Response Committees

Secondary hypogammaglobulinemia (SHG) is characterized by reduced immunoglobulin levels due to acquired causes of decreased antibody production or increased antibody loss. Clarification regarding whether the hypogammaglobulinemia is secondary or primary is important because this has implications for evaluation and management. Prior receipt of immunosuppressive medications and/or presence of conditions associated with SHG development, including protein loss syndromes, are histories that raise suspicion for SHG. In patients with these histories, a thorough investigation of potential etiologies of SHG reviewed in this report is needed to devise an effective treatment plan focused on removal of iatrogenic causes (eg, discontinuation of an offending drug) or treatment of the underlying condition (eg, management of nephrotic syndrome). When iatrogenic causes cannot be removed or underlying conditions cannot be reversed, therapeutic options are not clearly delineated but include heightened monitoring for clinical infections, supportive antimicrobials, and in some cases, immunoglobulin replacement therapy. This report serves to summarize the existing literature regarding immunosuppressive medications and populations (autoimmune, neurologic, hematologic/oncologic, pulmonary, posttransplant, protein-losing) associated with SHG and highlights key areas for future investigation.

IgA deficiency and autoimmune comorbidities in Juvenile Idiopathic Arthritis

OBJECTIVES

(1) To describe the prevalence of IgA deficiency (IgAD), uveitis, coeliac disease (CD) and thyroid disorders in a multicentric cohort of patients diagnosed with JIA and, (2) to evaluate whether patients with JIA and IgAD present other autoimmune diseases more frequently than patients with normal serum levels of IgA.

METHODS

Retrospective chart review of a cohort of patients diagnosed with JIA followed at the paediatric rheumatology units of two hospitals in Madrid, Spain.

RESULTS

A total of 193 patients were included. Of them, 123 were females (64%). Median age at disease onset was 5.6 years (IQR 2.5-9.7) and the median time of follow-up was 5.1 years (IQR 2.2-8.1). The three most common ILAR categories were oligoarticular (53%), polyarticular RF negative (20%) and enthesitis related arthritis (10%). Serum IgA levels were available in 172/193 (89%); 25/172 (15%) had selective (<7mg/dl, n=8) or partial (7-69mg/dl, n=17) IgAD. All the patients had periodic eye exams. Eighteen children (9%) had anterior uveitis, 15/18 chronic and 3/18 acute. Serum anti transglutaminase IgA, or IgG in IgAD were obtained in 135/193 (70%). Four children (3%) were diagnosed with CD either by intestinal biopsy (n=3) or by the combination of characteristic clinical, serological and genetic features (n=1); two of them had IgAD (p=0.12; OR=6.4; 95% CI 0.9-47.6). Only 1/153 (0.7%) patient had hyperthyrotropinemia with positive anti-thyroid antibodies and required replacement therapy.

CONCLUSION

Patients with JIA frequently present autoimmune comorbidities. IgAD does not seem to increase their prevalence, with the possible exception of CD.

Serum immunoglobulin levels, complement components 3 and 4, HLA-B27 allele and spondyloarthropathy in patients with non-infectious anterior uveites

OBJECTIVE

To identify the relationship between serum immunoglobulin levels, complement components 3 and 4, the presence of the HLA-B27 allele and diagnosis of spondyloarthropathies in patients with non-infectious anterior uveitis.

MATERIALS AND METHODS

The participants were 197 patients with a non-infectious anterior uveitis. The concentrations of serum immunoglobulins, C3 and C4 proteins of the complement were determined by turbidimetry. The personal history of suspected immunodeficiency, ophthalmological complications, arthralgia, family history of spondyloarthropathies and the presence of the HLA-B27 allele were collected.

RESULTS

A family history of spondyloarthropathy, axial arthralgias, and ophthalmological complications were more frequent in HLA-B27 positive patients (P=.0005, P≤.0001, P≤.0001 respectively) and in patients with spondyloarthropathy diagnoses (P≤.0001, P≤.0001, P≤.0001 respectively). A personal history of recurrent sepsis, and gastrointestinal abnormalities was associated with the presence of the HLA-B27 allele (P≤.0001, P=.0240 respectively) and with the diagnosis of spondyloarthropathy (P=.0492, P=.0017 respectively). IgG decrease was observed (χ²=18.5, OR=5.03, 95% CI=2.32-10.89, P=.0001) and M (OR=7.13, 95% CI=1.40-36.4; P=.0128) in patients positive for the HLA-B27 allele and in patients with a diagnosis of SpA (P=.0364 and P=.0028 respectively). The decrease of C3 proteins (OR=4.82; CI 95%=1.35-17.11; P=.0328) and C4 (OR=9.09; CI 95%=2.13-38.88; P=.0074) were associated with a spondyloarthropathies diagnosis.

CONCLUSIONS

Patients with non-infectious anterior uveitis, positive for the HLA-B27 allele and diagnosed with spondyloarthropathies have alterations in serum immunoglobulin levels and complement components 3 and 4, which could contribute to the perpetuation and worse clinical course of this disease.

Lupus manifestations in children with primary immunodeficiency diseases: Comprehensive phenotypic and genetic features and outcome

OBJECTIVES

To report the phenotypic, genetic findings and outcome of children with lupus manifestations associated with primary immunodeficiency diseases (PIDs).

METHODS

Data are retrospectively collected on patients with lupus manifestations and PIDs seen between 1998 and 2019. Data comprised the clinical findings and genetic testing, the response to treatment and the accrual damage related to SLE.

RESULTS

A total of 39 patients (22 female) were reviewed. Thirty-four patients had lupus manifestations and six patients with SLE-like manifestations. Genetic analysis was performed in 25 patients. Complement deficiency was the most frequent PIDs; 26 patients were C1q deficient, three patients had C3 deficiency, two patients had C4 deficiency and one patient with heterozygous C8b variant. The other seven patients had different PIDs genetic defects that include SCID caused by PNP deficiency, CGD, CVID (PIK3CD), IL-2RB mutation, DNase II deficiency, STAT1 mutation, ISG15 mutation and Griscelli syndrome type 3. Mucocutaneous lesions, arthritis and lung involvement were the main clinical features. 84.1% experienced recurrent infections. The mean accrual damage was 2.7 ± 2.2. There were five deaths because of infection.

CONCLUSION

This study suggests that patients with lupus manifestations and early onset disease, family history of SLE or recurrent infections should undergo immunological work-up and genetic testing to rule out PIDs.

Alterations of Total Serum Immunoglobulin Concentrations in Pemphigus and Pemphigoid: Selected IgG2 Deficiency in Bullous Pemphigoid

Pemphigus and pemphigoid diseases are organ-specific autoimmune diseases of the skin and/or mucous membranes, which are caused by autoantibodies targeting structural proteins of the skin. In other autoimmune diseases, a high prevalence of primary antibody deficiencies was noted. Conversely, a high prevalence of autoimmune diseases is reported in patients with primary antibody deficiencies. With the exception of one study, pointing toward a decrease of IgG in pemphigus patients, with a relative enrichment of IgG4, serum immunoglobulin (Ig) concentrations had not been studied in pemphigus and pemphigoid. Hence, we here aimed to investigate serum concentrations of IgM, IgA, IgG, and IgG1-4 in pemphigus and pemphigoid patients, as well as in healthy controls. Serum Ig concentrations were determined by ELISA in 105 healthy controls, 100 pemphigus vulgaris (PV), 100 pemphigus foliaceus, 99 bullous pemphigoid (BP), and 55 linear IgA bullous dermatosis (LAD) patients. In healthy controls, age had a significant impact on Ig serum concentrations: In controls at ages of 69 years or older, IgM and IgG were decreased, while all other Ig, except IgA and IgG4, were increased. When stratified by sex, lower IgM concentrations were observed in males. When corrected for age and/or sex, and compared to controls, an increase in serum IgA was noted in LAD. In almost all patient cohorts, an increase in IgG1 and IgG4 was observed, while a decrease in IgG2 or IgG3 was seen in BP or PV patients. This points toward a possible association of BP with IgG2 deficiency and warrants evaluation of IgG2 in BP patients prior to immunosuppressive therapy.

The Epidemiology and Clinical Manifestations of Autoimmunity in Selective IgA Deficiency

Selective immunoglobulin A deficiency (SIgAD) is the most common primary immunodeficiency, defined as an isolated deficiency of IgA (less than 0.07 g/L). Although the majority of people born with IgA deficiency lead normal lives without significant pathology, there is nonetheless a significant association of IgA deficiency with mucosal infection, increased risks of atopic disease, and a higher prevalence of autoimmune disease. To explain these phenomena, we have performed an extensive literature review to define the geoepidemiology of IgA deficiency and particularly the relative risks for developing systemic lupus erythematosus, hyperthyroidism, hypothyroidism, type 1 diabetes mellitus, Crohn's disease, ulcerative colitis, rheumatoid arthritis, juvenile idiopathic arthritis, ankylosing spondylitis, and vitiligo; these diseases have strong data to support an association. We also note weaker associations with scleroderma, celiac disease, autoimmune hepatitis, immune thrombocytopenic purpura, and autoimmune hemolytic anemia. Minimal if any associations are noted with myasthenia gravis, lichen planus, and multiple sclerosis. Finally, more recent data provide clues on the possible immunologic mechanisms that lead to the association of IgA deficiency and autoimmunity; these lessons are important for understanding the etiology of autoimmune disease.

Serum Immunoglobulin Levels, Complement Components 3 and 4, HLA-B27 Allele and Spondyloarthropathy in Patients with Non-Infectious Anterior Uveites

OBJECTIVE

To identify the relationship between serum immunoglobulin levels, complement components 3 and 4, the presence of the HLA-B27 allele and diagnosis of spondyloarthropathies in patients with non-infectious anterior uveitis.

MATERIALS AND METHODS

The participants were 197 patients with a non-infectious anterior uveitis. The concentrations of serum immunoglobulins, and C3 and C4 proteins of the complement were determined by turbidimetry. The personal history of suspected immunodeficiency, ophthalmological complications, arthralgia, family history of spondyloarthropathies and the presence of the HLA-B27 allele were collected.

RESULTS

A family history of spondyloarthropathy, axial arthralgias, and ophthalmological complications were more frequent in HLA-B27 positive patients (P=.0005, P≤.0001, and P≤.0001, respectively) and in patients with spondyloarthropathy diagnoses (P≤.0001, P≤.0001, and P≤.0001, respectively). A personal history of recurrent sepsis, and gastrointestinal abnormalities was associated with the presence of the HLA-B27 allele (P≤.0001, and P=.0240, respectively) and with the diagnosis of spondyloarthropathy (P=.0492, and P=.0017, respectively). IgG decrease was observed (χ2=18.5, OR 5.03, 95% CI 2.32-10.89; P=.0001) and IgM (OR 7.13, 95% CI 1.40-36.4; P=.0128) in patients positive for the HLA-B27 allele and in patients with a diagnosis of spondyloarthropathies (P=.0364 and P=.0028, respectively). The decrease of C3 proteins (OR 4.82; CI 95% 1.35-17.11; P=.0328) and C4 (OR 9.09; CI 95% 2.13-38.88; P=.0074) were associated with a spondyloarthropathies diagnosis.

CONCLUSIONS

Patients with non-infectious anterior uveitis, positive for the HLA-B27 allele and diagnosed with spondyloarthropathies have alterations in serum immunoglobulin levels and complement components 3 and 4, which could contribute to the perpetuation and worse clinical course of this disease.

Evaluation of screening for coeliac disease in children with juvenile idiopathic arthritis

AIM

To study the prevalence of coeliac disease (CD) in children with Juvenile idiopathic arthritis (JIA), by screening a population-based cohort of children with JIA using autoantibodies against tissue transglutaminase (anti-TG2).

METHODS

All children diagnosed with JIA in three Swedish counties, with disease onset between 2007 and 2014, were included prospectively. Serum levels of IgA anti-TG2 antibodies, IgG anti-TG2 antibodies, and total IgA were analysed. Children with positive levels of IgA anti-TG2 antibodies and children with IgA deficiency in combination with positive levels of IgG anti-TG2 antibodies were referred to the paediatric gastroenterology unit for gastroscopy and small intestine biopsy.

RESULTS

A total of 216 children were included, and analysis of IgA and IgG anti-TG2 antibodies was performed in 213 children. Three children were diagnosed with CD prior to the diagnosis of JIA, and three additional children were found through screening, resulting in a CD point prevalence of 2.8% (95% CI 0.6-5.0%).

CONCLUSION

We found a point prevalence of CD close to previous described prevalence in the general population of Swedish children. Therefore, general screening for CD in children with JIA is not supported by our data. However, this study shows that asymptomatic CD in children with JIA may be found by screening.

Primary immunodeficiency and autoimmunity: A comprehensive review

The primary immunodeficiency diseases (PIDs) include many genetic disorders that affect different components of the innate and adaptive responses. The number of distinct genetic PIDs has increased exponentially with improved methods of detection and advanced laboratory methodology. Patients with PIDs have an increased susceptibility to infectious diseases and non-infectious complications including allergies, malignancies and autoimmune diseases (ADs), the latter being the first manifestation of PIDs in several cases. There are two types of PIDS. Monogenic immunodeficiencies due to mutations in genes involved in immunological tolerance that increase the predisposition to develop autoimmunity including polyautoimmunity, and polygenic immunodeficiencies characterized by a heterogeneous clinical presentation that can be explained by a complex pathophysiology and which may have a multifactorial etiology. The high prevalence of ADs in PIDs demonstrates the intricate relationships between the mechanisms of these two conditions. Defects in central and peripheral tolerance, including mutations in AIRE and T regulatory cells respectively, are thought to be crucial in the development of ADs in these patients. In fact, pathology that leads to PID often also impacts the Treg/Th17 balance that may ease the appearance of a proinflammatory environment, increasing the odds for the development of autoimmunity. Furthermore, the influence of chronic and recurrent infections through molecular mimicry, bystander activation and super antigens activation are supposed to be pivotal for the development of autoimmunity. These multiple mechanisms are associated with diverse clinical subphenotypes that hinders an accurate diagnosis in clinical settings, and in some cases, may delay the selection of suitable pharmacological therapies. Herein, a comprehensively appraisal of the common mechanisms among these conditions, together with clinical pearls for treatment and diagnosis is presented.

Complement in autoimmune diseases

The complement system is an ancient and evolutionary conserved element of the innate immune mechanism. It comprises of more than 20 serum proteins most of which are synthesized in the liver. These proteins are synthesized as inactive precursor proteins which are activated by appropriate stimuli. The activated forms of these proteins act as proteases and cleave other components successively in amplification pathways leading to exponential generation of final effectors. Three major pathways of complement pathways have been described, namely the classical, alternative and lectin pathways which are activated by different stimuli. However, all the 3 pathways converge on Complement C3. Cleavage of C3 and C5 successively leads to the production of the membrane attack complex which is final common effector. Excessive and uncontrolled activation of the complement has been implicated in the host of autoimmune diseases. But the complement has also been bemusedly described as the proverbial "double edged sword". On one hand, complement is the final effector of tissue injury in autoimmune diseases and on the other, deficiencies of some components of the complement can result in autoimmune diseases. Currently available tools such as enzyme based immunoassays for functional assessment of complement pathways, flow cytometry, next generation sequencing and proteomics-based approaches provide an exciting opportunity to study this ancient yet mysterious element of innate immunity.

Clinical features and long-term outcomes of systemic lupus erythematosus: comparative data of childhood, adult and late-onset disease in a national register

Systemic lupus erythematosus (SLE) affects predominantly women at reproductive age but may present at any age. Age at disease onset has a modulating effect on presentation and course of disease, but controversies persist regarding its impact on long-term outcome. Our aims were to characterize clinical features, co-morbidities and cumulative damage in childhood-onset, adult-onset and late-onset SLE. Patients with childhood-onset SLE fulfilling ACR 1997 criteria were identified in a nationwide register-Reuma.pt/SLE (N = 89) and compared with adult-onset and late-onset counterparts matched 1:1:1 for disease duration. 267 SLE patients with mean disease duration of 11.9 ± 9.3 years were analyzed. Skin (62 %), kidney (58 %), neurological (11 %) and hematologic involvement (76 %) were significantly more common in childhood-onset SLE and disease activity was higher in this subset than in adult- and late-onset disease (SLEDAI-2K 3.4 ± 3.8 vs. 2.2 ± 2.7 vs. 1.6 ± 2.8, respectively; p = 0.004). Also, more childhood-onset patients received cyclophosphamide (10 %) and mycophenolate mofetil (34 %). A greater proportion of women (96 %), prevalence of arthritis (89 %) and anti-SSA antibodies (34 %) were noted in the adult-onset group. There was a significant delay in the diagnosis of SLE in older ages. Co-morbidities such as hypertension, diabetes and thyroid disease were significantly more frequent in late-onset SLE, as well as the presence of irreversible damage evaluated by the SLICC/ACR damage index (20 vs. 26 vs. 40 %; p < 0.001). Greater organ involvement as well as the frequent need for immunosuppressants supports the concept of childhood-onset being a more severe disease. In contrast, disease onset is more indolent but co-morbidity burden and irreversible damage are greater in late-onset SLE, which may have implications for patients' management.

Rheumatologic manifestations of primary immunodeficiency diseases

In the last 5 years, several hundred articles have been published concerning the link between primary immunodeficiency disease (PID) and rheumatologic diseases. Although rheumatologic complications were originally thought to be at the opposite ends of the spectrum of immunopathologic manifestations, they are now all being considered secondary manifestations of a causative primary "immune derangement." For the rheumatologist, it is important to be able to identify patients who may present with typical rheumatologic findings but who have an underlying PID. In a systematic manner, this overview addresses both the systemic and organ-based rheumatologic diseases which have known associations with primary immunodeficiencies, and explores how immunodeficiency may actually cause these clinical manifestations.