Clinical, histologic, and immunologic signatures of Small Fiber Neuropathy in Systemic Lupus Erythematosus.

BACKGROUND AND OBJECTIVES: Systemic Lupus Erythematosus (SLE) often causes damage to small nerve fibers, leading to distressing painful and autonomic symptoms. Despite this, Small Fiber Neuropathy (SFN) remains an underrecognized complication for SLE patients. In this cross-sectional study, we aimed to assess SFN in patients with SLE and to explore its correlations with immunologic disease features and clinical manifestations. METHODS: We recruited 50 SLE patients (1 male to 12.5 females, aged 20-80 years) reporting painful disturbances. We conducted a comprehensive clinical and neurophysiological evaluation, using Nerve Conduction Studies and Quantitative Sensory Testing. Additionally, we carried out an extensive laboratory assessment of disease-related serological parameters. We also performed a thorough skin biopsy analysis, investigating somatic and autonomic innervation while detecting complement and inflammatory cell infiltrates within the skin. RESULTS: Out of 50 patients, 19 were diagnosed with SFN, primarily characterized by a non-length-dependent distribution; 7 had a mixed neuropathy, with both large and small fiber involvement. Patients with SFN were younger than patients with a mixed neuropathy (p = .0143); furthermore, they were more likely to have a history of hypocomplementemia (p = .0058) and to be treated with cyclosporine A (p = .0053) compared to patients without neuropathy. However, there were no significant differences in painful and autonomic symptoms between patients with and without SFN. DISCUSSION: This study highlights the relevant frequency of SFN with a non-length-dependent distribution among SLE patients experiencing painful symptoms. Indeed, SFN emerges as an early manifestation of SLE-related neuropathy and is closely associated with hypocomplementemia, suggesting a potential pathogenic role of the complement system. Moreover, SFN may be influenced by disease-modifying therapies. However, the precise role of SFN in shaping painful and autonomic symptoms in patients with SLE remains to be fully elucidated.

Pregnancy outcomes and risk factors analysis in patients with systemic lupus erythematous.

BACKGROUND: The management of systemic lupus erythematosus (SLE) during pregnancy remains a challenge currently. Identifying early predictors of adverse pregnancy outcomes in SLE patients can help to develop treatment plan and improve prognosis. The aim of this study is to explore the clinical and laboratory variables in the early pregnancy that can predict adverse neonatal and maternal outcomes, thereby facilitating the grading management of SLE. METHODS: A retrospective analysis was conducted on 126 pregnant women with SLE who were admitted to Zhongnan Hospital of Wuhan University between January 2017 and December 2022. All enrolled patients were diagnosed (including newly diagnosed and previously diagnosed) during first trimester of pregnancy and their clinical records, laboratory results and pregnancy outcomes were reviewed. The association between the clinical and laboratory characteristics of patients at 12 gestational age and the adverse neonatal (ANOs) as well as maternal outcomes (AMOs) were analyzed. RESULTS: A total of 117 live births (92.8%) were recorded in the study. ANOs occurred in 59 (46.8%) cases, including fetal loss in 9 cases (7.1%), preterm birth in 40 cases (31.7%), small for gestational (SGA) in 15 cases (11.9%), and complete heart block in 2 cases (1.5%). Univariate analysis showed that disease activity index (P < 0.0001), lupus nephritis (P = 0.0195), anti-SSB positivity (P = 0.0074) and hypocomplementemia (P = 0.0466) were related to ANOs. However, multivariate analysis showed that only disease activity during early pregnancy was an independent predictor for ANOs (OR = 7.053, 95% CI: 1.882 to 26.291, P = 0.004). In addition, 48 patients experienced AMOs during subsequent trimester, including 24 (19.0%) patients with disease flare and 23 (18.3%) patients with pre-eclampsia. Unplanned pregnancy (P = 0.010), active disease (P = 0.0004), new onset SLE (P = 0.0044) and lupus nephritis (P = 0.0009) were associated with AMOs in univariate analysis, while disease activity was identified as an independent risk factor for AMOs (OR = 2.553, 95% CI: 1.012-6.440, P = 0.047). CONCLUSION: Active disease in early pregnancy is associated with adverse pregnancy outcomes. For patients with high risk factor for ANOs and AMOs, more intensive treatment and follow-up should be a wise measure. Especially for those who suffer from active disease, they should be fully informed and given the option to terminate or continue their pregnancy.

The prevalence of neutropenia and association with infections in patients with systemic lupus erythematosus: a Swedish single-center study conducted over 14 years.

Hematologic abnormalities are common manifestations of SLE, although neutropenia is observed less frequently and is not included in the classification criteria. Nonetheless, neutropenia is a risk factor for infections, especially those caused by bacteria or fungi. We aimed to evaluate the impact of neutropenia in SLE through a systematic investigation of all infections in a large cohort of well-characterized patients, focusing on neutropenia, lymphopenia, and hypocomplementemia. Longitudinal clinical and laboratory parameters obtained at visits to the Rheumatology Unit, Linköping University Hospital, and linked data on all forms of healthcare utilization for all the subjects included in our regional SLE register during 2008-2022 were assessed. Data regarding confirmed infections were retrieved from the medical records. Overall, 333 patients were included and monitored during 3,088 visits to a rheumatologist during the study period. In total, 918 infections were identified, and 94 occasions of neutropenia (ANC < 1.5 × 109/L) were detected in 40 subjects (12%). Thirty neutropenic episodes in 15 patients occurred in association with infections, of which 13 (43%) required in-hospital care, 4 (13%) needed intensive care, and 1 (3%) resulted in death. Bayesian analysis showed that patients with ≥ 1 occasion of neutropenia were more likely to experience one or more infections (OR = 2.05; probability of association [POA] = 96%). Both invasiveness (OR = 7.08; POA = 98%) and severity (OR = 2.85; POA = 96%) of the infections were significantly associated with the present neutropenia. Infections are common among Swedish SLE patients, 12% of whom show neutropenia over time. Importantly, neutropenia is linked to both the invasiveness and severity of infections. Awareness of the risks of severe infections in neutropenic patients is crucial to tailor therapies to prevent severe illness and death.

Impact of serological activity on flare following clinically inactive disease and remission in childhood-onset systemic lupus erythematosus.

OBJECTIVES: To assess the association between serological activity (SA) and clinical inactivity in SLE and to investigate whether SA predicts flare after clinically inactive disease (CID) and remission. METHODS: Longitudinal data of children from 3 paediatric rheumatology referral centres were retrospectively reviewed. CID was defined as clinical SLEDAI = 0 in patients with a prednisolone dose < 15 mg/day. A modified DORIS remission on treatment criteria was used to determine remission. RESULTS: Of the 124 patients included, 89.5% displayed SA at onset. Through follow-up, the rate of SA decreased to 43.3% at first CID and 12.1% at remission. Among patients with CID, 24 (20.7%) experienced a moderate to severe flare before the attainment ofremission. While previous proliferative lupus nephritis (OR : 10.2, p: 0.01) and autoimmune haemolytic anaemia (OR : 6.4, p: 0.02) were significantly associated with an increased odds of flare after CID, SA at CID was not associated with flare. In contrast, 21 (19.6%) patients experienced a flare in a median of 18 months after remission. Hypocomplementemia (OR : 9.8, p: 0.02) and a daily hydroxychloroquine dose < 5 mg/kg (OR : 5.8, p: 0.02) at remission significantly increased the odds of flare. CONCLUSION: SA increases the odds of flare at remission but not at CID. Suboptimal dosing of hydroxychloroquine should be avoided, especially in children with SA in remission to lower the risk of flares.

Significance of the weighted complement domain of the EULAR/ACR classification criteria in juvenile onset systemic lupus erythematosus.

OBJECTIVE: We aimed to compare the clinical and laboratory characteristics of patients with SLE according to the weighted complement status of the EULAR/ACR criteria and investigate whether different weighting of the complement status at disease onset is associated with outcomes. METHODS: Patients diagnosed with juvenile onset SLE who fulfilled the 2019 EULAR/ACR classification criteria were retrospectively analyzed. RESULTS: Among 43 patients included, hypocomplementemia was observed in 37 (86%), mostly with a low level of both complement C3 (C3) and complement C4 (C4) (53.5%). In patients with low levels of both C3 and C4, more common cutaneous (65.2% vs 28.6%, p: 0.045), musculoskeletal involvement (78.3% vs 42.9%, p: 0.039), autoimmune hemolytic anemia (52.2% vs 14.3%, p: 0.035), positive anti-dsDNA (65.2% vs 21.4%, p: 0.017) and anti-Sm antibodies (60.9% vs 21.4%, p: 0.04) were observed. In addition these patients had higher scores from the 2019 EULAR/ACR classification criteria (26 vs 15.5, p: < 0.0001). Remission and flare rates, and SLE associated damage were not differed according to the complement status in patients with hypocomplementemia. CONCLUSION: Observation of more frequent clinical and serological activity with higher total scores from the EULAR/ACR classification criteria supported the higher scoring of patients with low C3 and C4 in the weighted criteria. However, since significant number of patients did not exhibit low complement C4, and the frequency of kidney involvement did not differ according to the weighted complement status, complement C3 might be suggested as a more important diagnostic tool in patients with juvenile onset SLE. Also, weighted complement status at onset did not seem to affect the disease outcomes.

ANCA-associated vasculitis with protein-losing enteropathy is characterized by hypocomplementemia.

Protein-losing enteropathy (PLE) has been reported to be associated with various systemic autoimmune diseases. However, reports regarding PLE in ANCA-associated vasculitis (AAV) patients are limited. We herein aimed to describe the clinical characteristics of AAV with PLE. We conducted a retrospective chart review of patients who were diagnosed with AAV and who began treatment at the University of Tokyo Hospital between June 2003 and June 2020. Among 68 AAV patients, there were four patients (5.9%) with PLE, consisting of two patients with MPA, one patient with GPA, and one patient with EGPA. Clinical courses were described, and their data were compared with AAV patients without PLE. Demographic characteristics, disease activity, and the pattern of organ involvement were similar between patients with PLE and without PLE. Patients with PLE had hypocomplementemia more frequently than the patients without PLE (CH50 75.0% vs 1.8%, p < 0.001, C3 50.0% vs 1.8%, p = 0.01, C4 75.0% vs 3.5%, p = 0.001). Although hypoalbuminemia improved with immunosuppressive therapy for AAV, the improvement in hypoalbuminemia was slow in most cases. We also performed a systematic review on PLE associated with vasculitis. Thirteen reports were included, and Henoch-Schonlein Purpura patients with PLE also tended to have hypocomplementemia. In conclusion, PLE is a rare complication of AAV and complement system may associate with the mechanism of PLE.

Maternal disease activity and serological activity as predictors of adverse pregnancy outcomes in women with systemic lupus erythematosus: a retrospective chart review.

PURPOSE: To evaluate the association between disease activity, serological activity, and adverse pregnancy outcomes (APOs) in women with systemic lupus erythematosus (SLE) and determine the cut-off values of complements to predict APOs in live birth cases. METHODS: This retrospective chart review included pregnant women with SLE who had singleton live births after 22 weeks between 2006 and 2020. First trimester maternal disease activity was assessed for SLE onset during pregnancy, antiphospholipid syndrome, SLE pregnancy disease activity index (SLEPDAI), disease flare-ups, lupus nephritis, pancytopenia, and daily prednisolone dosage. Serological activity was assessed for autoantibodies and complements. APOs included preterm birth (PTB), low birth weight infants, small-for-gestational age infants, preterm premature rupture of membranes, and preeclampsia (PE). Chi-square and Fisher's exact tests were used to compare categorical variables; a receiver-operating characteristic analysis was performed to calculate the cut-off values of complements to predict APOs. RESULTS: Fifty-two participants met the inclusion criteria. The incidence of PTB and PE was associated with a high SLEPDAI (p < 0.001, p = 0.001), disease flare-ups (p = 0.007, p < 0.001), lupus nephritis (p = 0.020, p = 0.012), anti-dsDNA antibodies (p = 0.047, p = 0.016), anti-SSA antibodies (p = 0.003, p = 0.004), low CH 50 (p < 0.001, p < 0.001), low C3 (p < 0.001, p < 0.001), and low C4 (p < 0.001, p = 0.001), respectively. The cut-off values of C4 to predict PTB and PE were 13.0 mg/dL (higher than the normal lowest limit). CONCLUSION: High maternal disease activity and high serological activity in the first trimester in women with SLE are significantly associated with APOs. Proper disease control and close management for hypocomplementemia are required for better perinatal outcomes.

Hypocomplementemia is related to elevated serum levels of IgG subclasses other than IgG4 in IgG4-related kidney disease.

OBJECTIVES: This study investigated the clinical features of IgG4-RKD patients with hypocomplementemia compared with those without it, so as to clarify the factors related to hypocomplementemia. METHODS: In this single-center retrospective study, we analyzed the clinical features of 25 patients with IgG4-RKD according to the presence/absence of hypocomplementemia. Additionally, we validated the results of a single-center study in a separate large multicenter cohort of 328 patients with IgG4-RD, and searched for factors related to hypocomplementemia. RESULTS: Serum IgG levels (p < .001), non-IgG4 IgG levels, calculated as the total IgG minus IgG4 (p < .001), serum IgG1 levels (p = .017), and the number of involved organs (p = .018) were significantly higher in the hypocomplementemia group. At relapse of renal lesions in four patients, all had serum IgG4 re-elevation, with the three with hypocomplementemia presenting worsening of hypocomplementemia and re-elevation of non-IgG4 IgG levels. In a validation cohort of 328 patients with IgG4-RD, multivariate logistic regression analysis indicated elevation of non-IgG4 IgG levels to be an independent factor related to hypocomplementemia in the patients with IgG4-RKD. CONCLUSION: The present study suggests that hypocomplementemia is associated with elevation of IgG subclasses other than IgG4 including IgG1 in IgG4-RKD.

Complement depletion and Coombs positivity in pneumococcal hemolytic uremic syndrome (pnHUS). Case series and plea to revisit an old pathogenetic concept.

Hemolytic uremic syndrome is a rare complication of invasive pneumococcal infection (pnHUS). Its pathogenesis is poorly understood, and treatment remains controversial. The emerging role of complement in various forms of HUS warrants a new look at this "old" disease. We performed a retrospective analysis of clinical and laboratory features of three sequential cases of pnHUS since 2008 associated with pneumonia/pleural empyema, two due to Streptococcus pneumoniae serotype 19 A. Profound depletion of complement C3 (and less of C4) was observed in two patients. One patient was Coombs test positive. Her red blood cells (RBCs) strongly agglutinated with blood group compatible donor serum at 0 °C, but not at 37 °C. All three patients were treated with hemodialysis, concentrated RBCs, and platelets. Patient 2 received frozen plasma for hepatic failure with coagulation factor depletion. Intravenous immunoglobulin infusion, intended to neutralize pneumococcal neuraminidase in patient 3, was associated with rapid normalization of platelets and cessation of hemolysis. Two patients recovered without sequelae or disease recurrence. Patient 2 died within 2½ days of admission due to complicating Pseudomonas aeruginosa sepsis and multiorgan failure. Our observations suggest that pnHUS can be associated with dramatic, transient complement consumption early in the course of the disease, probably via the alternative pathway. A critical review of the literature and the reported cases argue against the postulated pathological role of preformed antibodies against the neuraminidase-exposed Thomsen-Friedenreich neoantigen (T antigen) in pnHUS. The improved understanding of complement regulation and bacterial strategies of complement evasion allows to propose a testable, new pathogenetic model of pnHUS. This model shifts emphasis from the action of natural anti-T antibodies toward impaired Complement Factor H (CFH) binding and function on desialylated membranes. Removal of neuraminic acid residues converts (protected) self to non-self surfaces that supports membrane attack complex (MAC) assembly. Complement activation is potentially exacerbated by decreased CFH availability following tight CFH binding to pneumococcal evasion proteins and/or by the presence of genetic variants of complement regulator proteins. Detailed clinical and experimental investigations are warranted to better understand the role of unregulated complement activation in pnHUS. Instead of avoidance of plasma, a new, integrated model is evolving, which may include short-term therapeutic complement blockade, particularly where genetic or functional APC dysregulation is suspected, in addition to bacterial elimination and, potentially, neuraminidase neutralization.

Cryoglobulinemic Glomerulonephritis Associated With Nodal and Renal Infiltration by T-Cell Lymphoma of T-Follicular Helper Phenotype: A Case Report.

We present a unique case of cryoglobulinemic glomerulonephritis associated with nodal and renal infiltration by T-cell lymphoma of T-follicular helper phenotype. The patient presented with transient neurologic symptoms, severe nephritic syndrome with nephrotic-range proteinuria, and acute kidney injury. He had elevated double-stranded DNA levels, low complement levels, detectable cryoglobulin, and detectable immunoglobulin M (IgM) paraprotein. The kidney biopsy showed cryoglobulinemic glomerulonephritis with a membranoproliferative pattern and diffuse interstitial infiltrates on light microscopy; IgM, C3 but weak IgG, C1q, and negative C4d staining on immunofluorescence; and deposits with organized substructures on electron microscopy. Positron emission tomography showed diffuse uptake in bilaterally enlarged kidneys and a localized group of lymph nodes. Subsequent lymph node biopsy revealed Epstein-Barr virus-negative nodal T-cell lymphoma, which was also proven in renal tissue. The association between T-cell lymphoma, autoantibodies, and cryoglobulinemia may represent a paraneoplastic phenomenon. His renal prognosis has been excellent, but overall prognosis and survival is dictated by the clinical course of T-cell lymphoma.

Progressive reduction of serum complement levels: a risk factor for relapse in patients with hypocomplementemia in systemic lupus erythematosus.

OBJECTIVE: Serologically active clinically quiescent (SACQ)-SLE is a subtype of systemic lupus erythematosus (SLE); most SACQ-SLE patients relapse. Although complement and/or anti-dsDNA level fluctuations during SACQ status are reportedly not useful for predicting relapse, they might be useful in specific clinical settings. We aimed to assess the correlation between future relapse and progressive reductions in serum complement levels following remission in patients with hypocomplementemia . METHODS: We retrospectively reviewed patients aged ≥15 years who were treated with ≥20 mg/day of prednisolone for remission induction. After achieving remission, the patients treated with prednisolone tapered to ≤15 mg/day without relapse and followed by hypocomplementemia (first hypocomplementemia point) were analyzed. The primary outcome was the relapse during the first 24 months. RESULTS: Seventy-six patients were enrolled; 31 (40.8%) relapsed. A ≥10% reduction after the first hypocomplementemia point in serum C3, C4, and CH50 levels was found in 10, 21, and 16 patients, respectively. Hazard ratios (95% confidence intervals) for relapse were 2.32 (0.92-5.12) for serum C3 levels and 2.46 (1.18-5.01) for serum C4 levels. Progressive reductions in serum C3 and C4 levels had relatively high specificity (93.3% and 82.2%) but limited sensitivity (22.6% and 41.9%) for predicting relapse. However, simultaneous progressive reduction in C3 levels and increase in anti-dsDNA antibody levels had the highest specificity (97.8%), and simultaneous progressive reduction in C4 levels or increase in anti-dsDNA antibody levels had the highest sensitivity (71.0%). CONCLUSION: Simultaneous progressive reductions in complement levels and increases in anti-dsDNA antibody levels may indicate future relapse SACQ-SLE patients.

Cutaneous vasculitis in systemic lupus erythematosus patients: potential key players and implications.

OBJECTIVES: The aim of the present work was to study the clinical characteristics of cutaneous vasculitis (CV) in systemic lupus erythematosus (SLE) patients and find possible potential key players in its development and implicated associations with the disease manifestations. PATIENTS AND METHODS: Fifty adult female SLE patients underwent full history taking, thorough clinical examination and laboratory investigations. The SLE Disease Activity Index (SLEDAI) and accumulated damage using the Systemic Lupus International Collaborative Clinics/American College of Rheumatology Damage Index (SLICC/ACR DI) were assessed. RESULTS: The mean age of the patients was 29.1 ± 6.1 years and was significantly lower in those with CV (p = 0.018). The disease duration was 4.9 ± 3.7 years. CV was present in 30% of the patients. Musculoskeletal manifestations and hypocomplementemia were present in all patients with CV. The SLEDAI and SLICC/ACR DI tended to be higher in those with CV. Complement (C3 and C4) was significantly consumed in CV patients (p < 0.0001). Antiphospholipids were comparable between those with and without CV. Lupus nephritis, cardiovascular manifestations and Sjögren syndrome were significantly linked to the development of CV (p = 0.025, p = 0.023 and p < 0.0001, respectively). Both C3 and C4 showed a high sensitivity (93.3% and 86.7%) to detect CV in SLE at cut-off values below 81.4 mg/dl and 16.8 mg/dl, respectively. CONCLUSION: CV is closely related to hypocomplementemia but not to antiphospholipids and is associated with lupus nephritis, musculoskeletal manifestations and Sjögren syndrome.

Invasive meningococcal disease due to a non-capsulated Neisseria meningitidis strain in a patient with IgG4-related disease.

BACKGROUND: Invasive Meningococcal Disease (IMD) is a rare and critical disease in Japan. Most of these cases are caused by capsulated Neisseria meningitidis strains. Non-capsulated (non-typable) strains are considered relatively low-pathogenic and can colonize in the nasopharynx of healthy children and young adults. As far as could be ascertained, only twelve IMD cases due to non-capsulated strains have been reported in the literature. No clear risk factors could be identified in a literature review (unknown or immunocompetent, seven cases; C6 deficiency, three cases). CASE PRESENTATION: We report a Japanese male taxi driver with bacteremia and meningitis due to non-capsulated N. meningitidis. He had a fever and shaking chills. Ceftriaxone was administered, and the patient finally recovered. During the clinical course, relative adrenal insufficiency occurred and was treated with hydrocortisone. A hidden co-morbidity, immunoglobulin G4 (IgG4)-related disease, was revealed in the past surgical history (a resection of bilateral orbital tumors), which included symptoms (swelling lachrymal glands and lymph nodes), elevated IgG4, immunoglobulin E, and hypocomplementemia. He recovered finally and no recurrence was observed. CONCLUSIONS: Our IMD case is the first reported in Japan, where IMD is not considered pandemic. The patient had a history of IgG4-related disease, although we could not establish a clear relationship between the patient's IMD and co-morbidity. A collection of further clinical cases might establish the risk factors and characteristics of IMD that could be caused by this neglected pathogen, non-capsulated N. meningitidis.

Systemic involvement in primary Sjogren's syndrome evaluated by the EULAR-SS disease activity index: analysis of 921 Spanish patients (GEAS-SS Registry).

OBJECTIVE: To evaluate systemic involvement in primary SS in a large cohort of Spanish patients using the EULAR-SS disease activity index (ESSDAI) definitions. METHODS: Systemic involvement was characterized using ESSDAI definitions for the 10 clinical domains (constitutional, lymphadenopathy, glandular, articular, cutaneous, pulmonary, renal, peripheral nervous system, central nervous system and muscular). ESSDAI scores at diagnosis, during follow-up and cumulated at the last visit were calculated. RESULTS: The cohort consisted of 921 patients. After a mean follow-up of 75 months, 77 (8%) patients still had an ESSDAI score of zero at the last visit. Organ by organ, the percentage of patients who developed activity during the follow-up (ESSDAI score ≥ 1 at any time) ranged between 1.4% and 56%, with articular, pulmonary and peripheral neurological involvement being the most common. Logistic multivariate regression analysis showed the following features at diagnosis and had the closest association with systemic activity (statistically significant independent variables in at least two domains): cryoglobulinaemia in five domains; anaemia, lymphopenia and low C3 levels in three domains each and age <35 years in two domains. Sicca features, ANA and RF at diagnosis were not associated with a higher cumulated activity score in any clinical domain. CONCLUSION: Primary SS is undeniably a systemic disease, with the joints, lungs, skin and peripheral nerves being the most frequently involved organs. Cytopenias, hypocomplementaemia and cryoglobulinaemia at diagnosis strongly correlated with higher cumulated ESSDAI scores in the clinical domains. Clinically the ESSDAI provides a reliable picture of systemic involvement in primary SS.

Evaluation of the significance of complement-related genes mutations in atypical postinfectious glomerulonephritis: a pilot study.

BACKGROUND: Postinfectious glomerulonephritis with C3-dominant glomerular deposition (C3-PIGN) involves C3-dominant glomerular deposition without immunoglobulin. Atypical C3-PIGN involves persistent hypocomplementemia. We investigated the clinical features and explored complement-related gene mutations in atypical PIGN patients. METHODS: We enrolled atypical C3-PIGN patients and collected data regarding the clinical presentation and pathological characteristics and follow-up data. We measured the levels of complement associated antibodies and performed whole-exome sequencing (WES) to detect mutations in complement-related genes. RESULTS: The analysis included six atypical C3-PIGN patients. All patients were antistreptolysin-O (ASO) positive. All patients had varying degrees of hematuria, and four patients had proteinuria. None of the patients were positive for complement-related antibodies. All patients possessed mutations of genes related to the complement pathway, including alternative complement pathway genes-CFI, CFH, CFHR3, CFHR5; the lectin pathway gene-MASP2; and the common complement pathway gene-C8A. The rare variant of CFHR3 has been reported in C3 glomerulonephritis. During 56-73 months of follow-up, the levels of urine markers in three patients recovered within 6 months, and the remaining patients had abnormal urine test results over 12 months. Patients who received glucocorticoid therapy recovered faster. CONCLUSIONS: Our study suggested that complement-related gene mutations may be an important cause of persistent hypocomplementemia in atypical C3-PIGN patients. In addition to variations in alternate pathway-related genes, we also found variations in lectin pathway-related genes, especially MASP2 genes. Although the overall prognosis was good, atypical C3-PIGN patients exhibited a longer period for recovery. Our results suggested that atypical C3-PIGN patients should receive more medical attention and need testing for mutations in complement-related genes.

Multiple Myeloma as a Potential Cause of Low Complements in Patients With Acute Kidney Injury.

Multiple myeloma (MM) is a plasma cell malignancy belonging to the class of monoclonal gammopathies that leads to end-organ damage myeloma events that encompass anemia, the presence of lytic bone lesions, hypercalcemia, and renal insufficiency. However, there are very few reported cases of patients with low complements in the context of MM and renal failure. Traditionally, low complements in glomerular disease are associated with conditions such as membranoproliferative glomerulonephritis, cryoglobulinemia, systemic lupus erythematous, and post-infectious glomerulonephritis. Despite its rarity, physicians should maintain a high degree of suspicion and consider MM as a potential cause of low complements in patients with renal injury. In this case report, we present a patient with a history of MM associated with acute kidney injury with hypocomplementemia, an atypical presentation of myeloma in MM.