Acquired C1-inhibitor deficiency in a patient with systemic lupus erythematosus: a case report and review of the literature

Angioedema as a Rare Presentation of Systemic Lupus Erythematosus

Angioedema (AE) is an immune-mediated tissue swelling that can be life-threatening if it compromises the airway. This makes prompt diagnosis and management of the condition excruciatingly important. It can be hereditary or associated with infections, malignancies, and autoimmune diseases. There have been reported cases in the literature where Systemic lupus erythematosus (SLE) patients developed acquired angioedema raising suspicion of a possible association between the two conditions. We describe a case of a patient with no known medical issues, presenting with acute onset of her first episode of angioedema with airway compromise. Because of the rarity of awareness of the possible association of our conditions of interest, there was an inevitable delay in diagnosis and the patient was eventually diagnosed to have SLE and associated acquired angioedema as its first presentation.  This case report highlights the importance of maintaining high suspicion for SLE in patients with an isolated first episode of AE and discusses mechanisms involved in the disease process to shed light on available treatment modalities.

Epigenetic Mechanisms and Posttranslational Modifications in Systemic Lupus Erythematosus

The complex physiology of eukaryotic cells is regulated through numerous mechanisms, including epigenetic changes and posttranslational modifications. The wide-ranging diversity of these mechanisms constitutes a way of dynamic regulation of the functionality of proteins, their activity, and their subcellular localization as well as modulation of the differential expression of genes in response to external and internal stimuli that allow an organism to respond or adapt to accordingly. However, alterations in these mechanisms have been evidenced in several autoimmune diseases, including systemic lupus erythematosus (SLE). The present review aims to provide an approach to the current knowledge of the implications of these mechanisms in SLE pathophysiology.

Low Levels of IgM and IgA Recognizing Acetylated C1-Inhibitor Peptides Are Associated with Systemic Lupus Erythematosus in Taiwanese Women

The objective of this study was to identify novel acetylation (Ac) modifications of the C1-inhibitor (C1-INH) and explain the association of the levels of autoantibodies against acetylated C1-INH peptides with the risk of developing systemic lupus erythematosus (SLE). Ac modifications of the C1-INH were identified and validated through in-gel digestion, nano-liquid chromatography-tandem mass spectrometry, immunoprecipitation, and Western blotting by using serum protein samples obtained from patients with SLE and age-matched healthy controls (HCs). In addition, the levels of serum C1-INH, Ac-protein adducts, and autoantibodies against unmodified and acetylated C1-INH peptides were measured. C1-INH levels in patients with SLE were significantly lower than those in HCs by 1.53-fold (p = 0.0008); however, Ac-protein adduct concentrations in patients with SLE were significantly higher than those in HCs by 1.35-fold (p = 0.0009). Moreover, immunoglobulin M (IgM) anti-C1-INH^367-385 Ac and IgA anti-C1-INH^367-385 Ac levels in patients with SLE were significantly lower than those in HCs. The low levels of IgM anti-C1-INH^367-385 (odds ratio [OR] = 4.725, p < 0.001), IgM anti-C1-INH^367-385 Ac (OR = 4.089, p = 0.001), and IgA anti-C1-INH^367-385 Ac (OR = 5.566, p < 0.001) indicated increased risks for the development of SLE compared with HCs.

Acquired angioedema in juvenile systemic lupus erythematosus: case-based review

An acquired form of angioedema that is clinically similar but scarcer than the hereditary form may be caused, even more rarely, by the presence of an underlying autoimmune disease. We report a previously healthy 16-year-old girl with an acquired angioedema as a rare and initial presentation of systemic lupus erythematosus. The patient had no previous angioedema attack and no family history. She did not have any chronic diseases and did not use any medicine regularly. The patient was diagnosed with systemic lupus erythematosus with the presence of polyarthralgia, angioedema, leucopenia, and positivity of immunologic criteria. Her edema resolved with high-dose methylprednisolone and hydroxychloroquine slowly. In conclusion, new-onset angioedema in adolescent girls should be investigated to evaluate autoimmunity and the possibility of systemic lupus erythematosus. The related literature on acquired angioedema associated with systemic lupus erythematosus is also reviewed.

Angioedema as the presenting feature of systemic lupus erythematosus

A young female in her early 20s presented with low-grade fever for 1 month, puffiness of face and abdominal distension for 15 days. Evaluation revealed pancytopenia with normocellular marrow, hypocomplementaemia and Coomb's positive haemolytic anaemia. She had angioedema with laryngospasm and worsening facial oedema which had dramatic response to steroids. Further workup lead to a diagnosis of systemic lupus erythematosus with neuropsychiatric involvement. Treatment with pulse steroids and cyclophosphamide resulted in dramatic improvement of her symptoms with no recurrence of angioedema during her follow-up visits.

Acquired C1 Inhibitor Deficiency

Acquired angioedema due to C1-INH deficiency (C1-INH-AAE) can occur when there are acquired (not inherited) deficiencies of C1-INH. A quantitative or functional C1-INH deficiency with negative family history and low C1q is diagnostic of C1-INH-AAE. The most common conditions associated with C1-INH-AAE are autoimmunity and B-cell lymphoproliferative disorders. A diagnosis of C1-INH-AAE can precede a diagnosis of lymphoproliferative disease and confers an increased risk for developing non-Hodgkin lymphoma. Treatment focuses on symptom control with therapies that regulate bradykinin activity (C1-INH concentrate, icatibant, ecallantide, tranexamic acid, androgens) and treatment of any underlying conditions.

Facial angioedema and systemic lupus erythematosus: case report

Non-medication-related acquired deficiencies of C1 esterase inhibitor (C1-INH) can cause the facial acquired angioedema (AAE) seen in systemic lupus erythematosus (SLE). The defect can originate from a lymphoproliferative disease (LPD) that catabolizes C1-INH or from circulating antibodies that inactivate C1-INH. This report describes a third and rare variety of facial AAE originating in SLE in which there was no LPD or circulating antibodies to impede C1-INH activity.

Serpins, immunity and autoimmunity: old molecules, new functions

Serine protease inhibitors (serpins) are evolutionary old, structurally conserved molecules which encompass nearly all branches of life. More than 1,000 serpins were characterized to date which are subdivided into 16 subgroups (A-P) according to their common ancestry; among them, 37 are found in humans. Serpins were termed after their capability to inhibit serine proteases, but mounting evidence suggests that they may achieve a greater deal of functions, ranging from embryological growth to synaptic plasticity, development of both myeloid and lymphoid immune cells, and modulation of apoptosis. Serpins are mainly extracellular molecules, although some of them (namely, ov-serpins or clade B serpins) mostly act inside the cells, being either ubiquitously or tissue-specifically expressed. Among newly characterized serpin functions, regulation of cellular proliferation through apoptosis modulation and proteasome disturbance seems to play a major role. Accordingly, several serpins were found to be hyperexpressed in tumor cells. Indeed, apoptosis dysregulation is likely to be a cornerstone in both tumorigenesis and autoimmunity, since uncontrolled cellular viability results in tumor proliferation, while inefficient disposal of apoptotic debris may favor the rescue of autoreactive immune cells. Such a process was widely documented in systemic lupus erythematosus (SLE). Interestingly, alterations in the expression of some serpins, e.g., the ov-serpin SERPINB3, are being unraveled in patients affected with SLE and other autoimmune disorders, suggesting that a failure in serpin function might affect immune homeostasis and self-tolerance, thereby contributing to autoimmunity. Here, we provide an overview of serpin origin, function, and dysfunction, focusing on human serpins and ov-serpins, with a hub on SERPINB3.

Evidence that abnormally large seasonal declines in vitamin D status may trigger SLE flare in non-African Americans

Cross-sectional studies have shown that low vitamin D (25-hydroxyvitamin D (25(OH)D)) is associated with increased systemic lupus erythematosus (SLE) activity. This study is the first to assess the temporal relationship between 25(OH)D levels and onset of SLE flare. This assessment was made possible because of the specimen bank and database of the Ohio SLE Study (OSS), a longitudinal study of frequently relapsing SLE that involved regular bimonthly patient follow-up. We identified for this study 82 flares from 46 patients that were separated by at least 8 months from previous flares. Serum 25(OH)D levels were measured at 4 and 2 months before flare, and at the time of flare (a flare interval). We found that for flares occurring during low daylight months (LDM, Oct-Mar), 25(OH)D levels were decreased at the time of flare, but only in non-African American (non-AA) patients (32% decrease at flare, compared to 4 months prior, p < 0.001). To control for seasonal effects, we also measured 25(OH)D levels in the LDM "no-flare" intervals, which were intervals that matched to the same calendar months of the patients' LDM flare intervals, but that didn't end in flare (n = 24). For these matches, a significant decrease occurred in 25(OH)D levels during the flare intervals (18.1% decrease, p < 0.001), but not during the matching no-flare intervals (6.2% decrease, p = 0.411). For flares occurring during high daylight months (HDM), 25(OH)D levels changed only in non-AA patients, increasing slightly (5.6%, p = 0.010). Analysis of flare rates for the entire OSS cohort (n = 201 flares) revealed a tendency for higher flare rates during LDM compared to HDM, but again only in non-AA patients (p = 0.060). Flare rates were lower during HDM for non-AA patients compared to AA patients (p = 0.028). In conclusion, in non-AA SLE patients, unusually large declines in 25(OH)D during LDM may be mechanistically related to SLE flare, whereas relatively high 25(OH)D levels during HDM may protect against flare.

Acquired angioedema with C1 inhibitor deficiency associated with anticardiolipin antibodies

Acquired angioedema (AAE) with C1 inhibitor deficiency is often associated to B cell lymphoproliferative disorders or autoimmune diseases. We report a case of AAE associated with IgM anti-cardiolipin antibodies, with frequent edematous attacks, that disappeared completely after a slight immunosuppression and danazol therapy.

Acquired angioedema

Acquired angioedema (AAE) is characterized by acquired deficiency of C1 inhibitor (C1-INH), hyperactivation of the classical pathway of human complement and angioedema symptoms mediated by bradykinin released by inappropriate activation of the contact-kinin system. Angioedema recurs at unpredictable intervals, lasts from two to five days and presents with edema of the skin (face, limbs, genitals), severe abdominal pain with edema of the gastrointestinal mucosa, life-threateing edema of the upper respiratory tract and edema of the oral mucosa and of the tongue. AAE recurs in association with various conditions and particularly with different forms of lymphoproliferative disorders. Neutralizing autoantibodies to C1-INH are present in the majority of patients. The therapeutic approach to a patient with AAE should first be aimed to avoid fatalities due to angioedema and then to avoid the disability caused be angioedema recurrences. Acute attacks can be treated with plasma-derived C1-INH, but some patients become non-responsive and in these patients the kallikrein inhibitor ecallantide and the bradykinin receptor antagonist icatibant can be effective. Angioedema prophylaxis is performed using antifibrinolytic agents and attenuated androgens with antifibrinolytic agents providing somewhat better results. Treatment of the associated disease can resolve AAE in some patients.

Incidence and risk factors of infection in a single cohort of 110 adults with systemic lupus erythematosus

Infection is a major cause of mortality in patients with systemic lupus erythematosus (SLE). This study describes infectious complications in SLE patients and analyzes the risk factors for infection at the time of SLE diagnosis and during the course of SLE in a case-control study. Of 110 patients enrolled, 42 (38%) had at least 1 episode of infectious disease. The incidence of infectious disease was 4.4/100 patient-years (py) with a total follow-up duration of 954 y. In multivariate analysis, independent predictors of infection at the time of SLE diagnosis were an SLE disease activity index (SLEDAI) > 12 (p = 0.01), C3 levels < 90 mg/dl (p = 0.01) and positive anti-ds DNA antibodies (p < 0.01). Frequent flare-ups (p = 0.04) and follow-up duration > or =8 y (p = 0.023) were also significant risk factors for infectious diseases. It is mandatory to closely observe SLE patients with risk factors for developing infectious diseases.

Complement deficiencies in humans and animals: links to autoimmunity

Complement is involved in the pathogenesis of systemic lupus erythematosus (SLE) in multiple ways and may act as both friend and foe. Inherited homozygous deficiency of one of the earliest components of the classical pathway is strongly associated with susceptibility to the development of SLE. However, complement is also implicated in the effector inflammatory phase of the autoimmune response that characterizes the disease. A further paradox in the links between complement and SLE is the observation that autoantibodies to some complement proteins, especially to C1q, develop as part of the autoantibody response. In this chapter, the role of the complement system in SLE is reviewed and hypotheses advanced to explain the complex relationships between complement and lupus.