Hypocomplementemia as a Risk Factor for Organ Damage Accrual in Patients with Systemic Lupus Erythematosus

The impact of normal serum complement levels on the disease classification and clinical characteristics in systemic lupus erythematosus

BACKGROUND

Some patients have normal levels of complement during the diagnosis of systemic lupus erythematosus (SLE), although decreased serum levels of complement are a hallmark of the active phase of the disease. This study investigated the clinical characteristics, impact on the classification of SLE, and the prognosis of patients with SLE who had normal serum complement levels at initial diagnosis (N-com).

METHODS

We evaluated 21 patients with N-com and 96 patients with hypocomplementemia at the initial diagnosis of SLE (H-com). The classification rates among the American College of Rheumatology (ACR) 1997, Systemic Lupus International Collaborating Clinics (SLICC) 2012, European League Against Rheumatism (EULAR)/ACR 2019 criteria, and clinical and immunological involvements were compared between SLE patients with N-com and H-com. Relapse and organ damage based on the SLICC/ACR damage index were also evaluated.

RESULTS

The classification rates of SLE were not significantly different in the ACR, SLICC, and EULAR/ACR criteria between the N-com and H-com groups. Patients with N-com had no significant differences in the classification rates among the three criteria, whereas patients with H-com had lower classification rates in the ACR criteria than in the SLICC criteria. A lower incidence of renal manifestation, less positivity for anti-dsDNA antibody, and a higher incidence of fever were observed in patients with N-com than in those with H-com. The occurrence of relapse and organ damage was not significantly different between patients with N-com and H-com.

CONCLUSION

Patients with N-com were less involved in renal manifestation and anti-dsDNA antibody positivity but had a higher incidence of fever than those with H-com, while having no disadvantage in SLE classification processes. Serum complement levels at the initial diagnosis of SLE may not predict prognosis.

The association between lupus serology and disease outcomes: A systematic literature review to inform the treat-to-target approach in systemic lupus erythematosus

INTRODUCTION

Serological markers such as anti-double stranded (ds)DNA antibodies and complement fractions C3/C4, are integral components of disease activity assessment in patients with systemic lupus erythematosus (SLE). However, it remains uncertain whether treatment should aim at restoration of serological abnormalities.

OBJECTIVES

To analyze and critically appraise the literature on the prognostic impact of active lupus serology despite clinical disease quiescence.

METHODS

A systematic literature review was performed in PubMed and EMBASE using the PICOT(S) (population, index, comparator, outcome(s), timing, setting) system to identify studies evaluating the association of serum anti-dsDNA, C3 and C4 levels assessed at the time of clinical remission or during the disease course, against the risk for impending flares and organ damage. Risk of bias was determined by the Quality in Prognosis Studies and ROB2 tools for observational and randomized controlled studies, respectively.

RESULTS

Fifty-three studies were eligible, the majority having moderate (70.6%) or high (11.8%) risk of bias and not adequately controlling for possible confounders. C3 hypocomplementemia during stable/inactive disease was associated with increased risk (2.0 to 3.8-fold) for subsequent flare in three out of seven relevant studies. Three out of four studies reported a significant effect of C4 hypocomplementemia on flare risk, including one study in lupus nephritis (likelihood ratio-positive 12.0). An increased incidence of flares (2.0 to 2.8-fold) was reported in 11 out of 16 studies assessing the prognostic effect of high anti-dsDNA, and similarly, the majority of studies yielded significant relationships with renal flares. Six studies examined the effect of combined (rather than individual) serological activity, confirming the increased risk (2.0 to 2.7-fold) for relapses. No consistent association was found with organ damage.

CONCLUSION

Notwithstanding the heterogeneity and risk of bias, existing evidence indicates a modest association between abnormal serology and risk for flare in patients with stable/inactive SLE. These findings provide limited support for inclusion of serology in the treat-to-target approach but rationalize to further investigate their prognostic implications especially in lupus nephritis.

Clinical significance of red blood cell distribution width in systemic lupus erythematosus patients

Background

Systemic lupus erythematosus (SLE) is a multi-organ autoimmune disorder with wide variety of clinical presentations. Recently, red blood cell distribution width (RDW) has been used as an inflammatory marker, similar to the erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) where systemic inflammation has been linked to increased RDW. Many researches have assessed independently selective different hematological markers that may reflect disease activity.

Our study aims to examine a number of hematological parameters that could reflect disease activity and to assess if there is a relationship between different hematological parameter (RDW, neutrophils and lymphocytes) to reflect SLE activity using Systemic Lupus Erythematosus Disease Activity Index (SLEDAI).

Results

The study comprised 60 SLE patients (52 females and 8 males) with a mean age of 34.53 years and mean disease duration was 4.085 years. The RDW values were significantly higher (p < 0.001) when comparing active patients (16.64 ± 4.7) versus inactive patients (13.16 ± 2.67) and controls (12.7 ± 1.13). Otherwise, insignificant differences were reported when comparing inactive SLE patients versus the control group (p = 0.242). There were no significant correlations (p > 0.05) between neutrophil count and lymphocyte count with C3, C4, SLEDAI score, 24 h urinary proteins, platelets count but significant only with hemoglobin level (p = 0.001).

Conclusion

Increased RDW is connected with active disease status of SLE patients. RDW could be used as a surrogate marker of the inflammation rather than neutrophil and lymphocyte count. It is a simple and easy testing included in CBC thus RDW could be used as a possible indicator to assess disease activity.

Complement activation in human autoimmune diseases and mouse models; employing a sandwich immunoassay specific for C3dg

In human autoimmune diseases, low plasma levels of complement factors C3 and C4 are commonly used as a proxy for complement activation. The measurements of C3 and C4 concentrations (the result of synthesis and consumption) however, show low sensitivity in patient follow-up. We find that the estimation of the C3dg fragment released during complement activation is a better parameter for complement activation. Available techniques for measuring the activation fragment C3dg, e.g. immune-electrophoresis or involving PEG-precipitation, are time-consuming and difficult to standardize. Here we examine the specificity and use of an antibody with mono-specificity for a neoepitope at the N-terminus of C3dg, which is only exposed after cleavage of C3. We present a stable, reproducible, and easy-to-use, time-resolved immunoassay with specificity for C3dg that can be used to directly evaluate ongoing complement activation. We demonstrate that the assay can be applied to clinical samples with a high specificity (95%) and a positive likelihood ratio of 10. It can also differentiate the complement related disease Systemic Lupus Erythematosus from controls and other immune-mediatedimmune mediated diseases like Rheumatoid Arthritis (86% specificity) and Spondyloarthritis (91% specificity). Further, we establish how the assay may also be used for experimental research in in vivo mouse models.

[Common variable immune deficiency in adult patients: analysis of 13 cases and literature review]

OBJECTIVE

To investigate the clinical and immunological characteristics, treatment and prognosis of common variable immune deficiency (CVID) in adult patients.

METHODS

We retrospectively analyzed the clinical data of 13 adult patients hospitalized in our hospital for CVID diagnosed according to the criteria in International Consensus Document (2016), and analyzed their clinical manifestations, laboratory test results, imaging findings, pathological examinations and treatments.

RESULTS

The mean age of onset was 24.46±16.82 years in these patients, who had a mean age of 32.54±14.86 years at diagnosis with a median diagnostic delay of 5 years (IQR: 2-15 years). The main manifestation of the patients was repeated infections, including repeated respiratory tract infection (10 cases; 76.9%) and repeated diarrhea (3 cases; 23.1%). Three (23.1%) of the patients had autoimmune disease and 10 (76.9%) had chronic pulmonary disease. IgG, IgA and IgM were decreased in all the patients. The proportion of CD4+T cells decreased in 10 patients (76.9%), CD8+T cells increased in 11 patients (84.6%), and CD4/ CD8 decreased in 10 patients (76.9%). Complement C3 decreased in 58.3% (7/12) and C4 decreased in 33.3% (4/12) of the patients. Twelve patients (92.3%) were treated with intravenous infusion of gamma globulin with symptomatic treatments. One patient died due to massive gastrointestinal hemorrhage, and the other patients showed improve ments after the treatments and were discharged.

CONCLUSIONS

The clinical manifestations of CVID are diverse, and recurrent respiratory tract infection is the most common manifestation. Decreased IgG often accompanied by lowered IgA and IgM levels is a common finding in laboratory tests. The treatment of CVID currently relies on gamma globulin with symptomatic treatments for the complications.

Utility of the AVISE Connective Tissue Disease test in predicting lupus diagnosis and progression

Background

The AVISE Connective Tissue Disease (CTD) test uses autoantibody, erythrocyte-bound C4d (EC4d) and B-cell-bound C4d (BC4d) levels to aid in diagnoses of SLE, other CTDs and fibromyalgia. We evaluated the utility of the AVISE CTD test in predicting SLE disease development and damage progression.

Methods

Patients who had undergone AVISE CTD testing were assessed for SLE diagnosis by the Systemic Lupus International Collaborating Clinics (SLICC) and American College of Rheumatology criteria and for SLE damage by the Systemic Lupus International Collaborating Clinics Damage Index (SDI) at the time of AVISE testing (t=0) and 2 years later (t=2).

Results

Among 117 patients without a previous diagnosis of SLE, 65% of patients who tested positive developed SLE at t=2, compared with 10.3% of patients who tested non-positive (p<0.0001). AVISE-positive patients fulfilled significantly more SLICC diagnostic criteria than AVISE-non-positive patients at both t=0 (3.8±2.1 vs 1.9±1.1, p=0.001) and t=2 (4.5±2.2 vs 2.1±1.2, p<0.0001). AVISE-positive patients also had had significantly higher SDI at t=2 (1.9±1.3 vs 1.03±1.3, p=0.01). BC4d levels correlated with the number of SLICC criteria at t=0 (r=0.33, p<0.0001) and t=2 (r=0.34, p<0.0001), as well as SDI at t=0 (r=0.25, p=0.003) and t=2 (r=0.26, p=0.002).

Conclusions

The AVISE CTD test can aid in SLE evaluation by predicting SLE disease development and future damage progression.

Longitudinal anti-nuclear antibody (ANA) seroconversion in systemic lupus erythematosus: a prospective study of Swedish cases with recent-onset disease

Serum immunoglobulin (Ig)G anti-nuclear antibodies (ANA) detected by indirect immunofluorescence (IF) microscopy remains a hallmark of systemic lupus erythematosus (SLE). Whether or not IF-ANA status varies over time is controversial. We therefore designed a prospective study with longitudinal follow-up of patients with recent-onset SLE. The study population consisted of 54 recently diagnosed SLE cases, all meeting the 1982 American College of Rheumatology (ACR) and/or the 2012 Systemic Lupus International Collaborating Clinics (SLICC) criteria. Clinical follow-up data, including disease activity, organ damage and sera, were collected from clinical onset of SLE and onwards, in most cases yearly (0-96 months). IF-ANA was analysed on human epithelial cells-2 (HEp-2) cells and categorized regarding staining patterns. Using an addressable laser bead assay (FIDIS™ Connective profile), we measured IgG-ANA fine specificities against Ro52/SSA, Ro60/SSA, Sjögren's syndrome type B antigen (La/SSB), Smith antigen (Sm), Smith antigen/ribonucleoprotein (Sm/RNP), U1 RNP (U1RNP), dsDNA, ribosomal-P protein and histone. At baseline, all patients were judged ANA-positive at an abnormal titre corresponding to the 95th percentile of healthy blood donors, but seven of 54 patients (13%) lost ANA-positivity over time. Homogeneous (AC-1; 46%) and speckled (AC-4 or 5; 31%) were the most frequently observed patterns at inclusion, whereas 7% switched pattern at least once during follow-up. Established associations between ANA fine specificities and clinical data were confirmed. Levels of anti-Sm/RNP, but not of anti-dsDNA, correlated with clinical disease activity [modified SLE disease activity 2000 (mSLEDAI-2K)]. Our data indicate that a considerable proportion of Swedish patients with SLE lose ANA-positivity over time, whereas consistent staining patterns were frequent. The clinical and mechanistic relevance of ANA seroconversion remains uncertain. Further prospective evaluations in larger SLE populations with more diverse ethnicities are warranted.