BACKGROUND: In vitro levels of complement C3 and C4 proteins are sensitive to storage conditions. To avoid in vitro complement activation when testing is delayed, serum should be frozen at -20degrees C within 2 hr of venipuncture. However, this is impractical in routine laboratory work. Therefore, we investigated alterations in C3 and C4 levels in refrigerated specimens over time and derived formulae to estimate initial levels of complement concentrations in delayed testing. METHODS: Ten fresh specimens were measured for C3 and C4 concentrations and were refrigerated at 4degrees C. We measured C3 and C4 levels in refrigerated samples daily for 4 days using an automated nephelometer (Beckman Coulter Inc., USA). RESULTS: C3 and C4 levels were significantly increased over time in refrigerated specimens (P<0.001, P<0.001, respectively). The increments in C3 and C4 levels were described by the equations: C3 (mg/dL)=3.55x+87.18 (r=0.9909), and C4 (mg/dL)=0.72x+22.3 (r=0.9395), where x=the number of days samples were refrigerated before testing. Increases in C3 and C4 concentrations were described on a percentage basis by the equations: DeltaC3 (%)=4.14x+1.07 (r=0.9903), and DeltaC4 (%)=3.57x+2.48 (r=0.9405). CONCLUSIONS: As the measured C3 and C4 concentrations increased by 3.55 mg/dL (4.1%) and 0.72 mg/dL (3.6%) per day in refrigerated specimens, the levels of C3 and C4 should be adjusted in delayed testing. We proposed that the formulae presented be used to back-calculate initial levels of C3 and C4 concentrations.
Complement Activation ; Complement C3* ; Complement C4 ; Complement System Proteins ; Phlebotomy

No abstract available.
Atypical Hemolytic Uremic Syndrome* ; Complement C3* ; Complement System Proteins*

OBJECTIVE: To investigate the effects of fecal microbiota transplantation (FMT) on intestinal microbiome and organism in patients with severe pneumonia during the convalescence period. METHODS: A prospective non-randomized controlled study was conducted. From December 2021 to May 2022, patients with severe pneumonia during the convalescence period who received FMT (FMT group) and patients with severe pneumonia during the convalescence period who did not receive FMT (non-FMT group) admitted to the First Affiliated Hospital of Guangzhou Medical University were enrolled. The differences of clinical indicators, gastrointestinal function and fecal traits between the two groups were compared 1 day before and 10 days after enrollment. The 16S rDNA gene sequencing technology was used to analyze the changes of intestinal flora diversity and different species in patients with FMT before and after enrollment, and metabolic pathways were analyzed and predicted by Kyoto Encyclopedia of Genes and Genomes database (KEGG). Pearson correlation method was used to analyze the correlation between intestinal flora and clinical indicators in FMT group. RESULTS: The level of triacylglycerol (TG) in FMT group was significantly decreased at 10 days after enrollment compared with before enrollment [mmol/L: 0.94 (0.71, 1.40) vs. 1.47 (0.78, 1.86), P < 0.05]. The level of high-density lipoprotein cholesterol (HDL-C) in non-FMT group was significantly decreased at 10 days after enrollment compared with before enrollment (mmol/L: 0.68±0.27 vs. 0.80±0.31, P < 0.05). There were no significant differences in other clinical indexes, gastrointestinal function or fecal character scores between the two groups. Diversity analysis showed that the α diversity indexes of intestinal flora in FMT group at 10 days after enrollment were significantly higher than those in non-FMT group, and β diversity was also significantly different from that in non-FMT group. Differential species analysis showed that the relative abundance of Proteobacteria at the level of intestinal flora in FMT group at 10 days after enrollment was significantly lower than that in non-FMT group [8.554% (5.977%, 12.159%) vs. 19.285% (8.054%, 33.207%), P < 0.05], while the relative abundance of Fusobacteria was significantly higher than that in non-FMT group [6.801% (1.373%, 20.586%) vs. 0.003% (0%, 9.324%), P < 0.05], and the relative abundance of Butyricimonas, Fusobacterium and Bifidobacterium at the genus level of the intestinal flora was significantly higher than that in non-FMT group [Butyricimonas: 1.634% (0.813%, 2.387%) vs. 0% (0%, 0.061%), Fusobacterium: 6.801% (1.373%, 20.586%) vs. 0.002% (0%, 9.324%), Bifidobacterium: 0.037% (0%, 0.153%) vs. 0% (0%, 0%), all P < 0.05]. KEGG metabolic pathway analysis showed that the intestinal flora of FMT group was changed in bisphenol degradation, mineral absorption, phosphonate and phosphinate metabolism, cardiac muscle contraction, Parkinson disease and other metabolic pathways and diseases. Correlation analysis showed that Actinobacteria and prealbumin (PA) in intestinal flora of FMT group were significantly positively correlated (r = 0.53, P = 0.043), Bacteroidetes was positively correlated with blood urea nitrogen (BUN; r = 0.56, P = 0.029) and complement C3 (r = 0.57, P = 0.027), Firmicutes was positively correlated with BUN (r = 0.56, P = 0.029) and complement C3 (r = 0.57, P = 0.027), Fusobacteria was significantly positively correlated with immunoglobulin M (IgM; r = 0.71, P = 0.003), Proteobacteria was significantly positively correlated with procalcitonin (PCT; r = 0.63, P = 0.012) and complement C4 (r = 0.56, P = 0.030). CONCLUSIONS FMT can reduce TG level, reconstruct intestinal microecological structure, change body metabolism and function, and alleviate inflammatory response by reducing the relative abundance of harmful bacteria in patients with severe pneumonia during the convalescence period.
Humans ; Fecal Microbiota Transplantation ; Complement C3 ; Convalescence ; Prospective Studies ; Feces

OBJECTIVE: To investigate the significance of detecting serum complement C3 and C4 in patients with multiple myeloma (MM) and to explore its correlation with myeloma bone disease (MBD). METHODS: The levels of serum complement C3 and C4 in 69 MM patients and 30 healthy people were examined by scatter nephelometry. The bone density of L1-4 vertebral body, bilateral femoral neck and bilateral hip joints were measured by dual energy bone density meter (DXA). RESULTS: The levels of serum complement C3 and C4 in MM patients significantly increased in comparison with that in healthy people (P＜0.01). The patients in advanced clinical stage exhibited a higher levels of C3 and C4 than those in stable stage (P＜0.01). In addition, the patients with grade C of MBD had a higher levels of serum complement C3 and C4 than those in patients with grade A and B of MBD (P＜0.01). The levels of serum complement C3 and C4 in MM patients negatively correlated with bone density in L1-4 vertebral body, bilateral femoral necks and hip joints. The correlation coefficients were r=-0.938, r=-0.659, r=-0.745, r=-0.748, r=-0.596 in complement C3 and r=-0.908, r=-0.623, r=-0.710, r=-0.714, r=-0.595 in complement C4, respectively. CONCLUSION The levels of complement C3 and C4 positively correlate with the severity of bone disease and bone density in MM patients, which suggests that complement C3 and C4 plays important roles in the development of MBD. The levels of serum C3 and C4 may be the sensitive biomarkers of MBD.
Biomarkers ; Complement C3 ; metabolism ; Complement C4 ; metabolism ; Femur Neck ; Humans ; Multiple Myeloma

OBJECTIVE: Stress and depression have been known to be associated with impairment in immune function. This study was designed to elucidate the abnormalities of humoral immune function in patients with depressive illness. METHOD: The author compared seam immunoglobulin IgG, IgA, IgM, and complements C3, C4, checked with rate Nephelometry, between hospitalized depressed patients and healthy normal controls. The depressive symptoms were rated with the Hamilton Depression Rating Scale and the current life events were evaluated with the Social Readjustment Rating Scale. RESULTS: 1) Serum levels of immunoglobulin and complements of depressed patients as well as those of normal controls were generally within normal range. 2) The levels of the immunoglobulin IgM were found to be significantly increased in depressed patients compared to healthy normal controls. 3) The levels of complement C3, C4 tended to be slightly increased in depressed patients compared to healthy normal controls, but with no statistical significance. 4) Serum immunglobulin and complement levels were not significantly correlated with age, severity of depression and life events in depressed patients. CONCLUSION: These findings expand previously reported evidence of immune abnormalities in depressive illness and provide a partial explanation for some of these findings and suggest that depressive illness is associated with an acute phase immune response. However, the seam immunoglobulin and complement levels were not correlated with the severity of depression and life events in depressive illness. So, it is difficult to consider the serum immunoglobulin and complement levels as specific markers of depressive illness. Further research on the interaction between hormones and immunity in depression is warranted.
Complement C3 ; Complement System Proteins ; Depression* ; Humans ; Immunoglobulin A ; Immunoglobulin G ; Immunoglobulin M ; Immunoglobulins ; Nephelometry and Turbidimetry ; Reference Values

The immune system contributes to body defence mechanism, but sometimes show unfavorable immune disease. Cerebral vasospasm is a major problem in aneurysmal subarachnoid hemorrhage(SAH), but the pathogenesis is poorly understood. Some authors suggest cerebral vasospasm is one type of autoimmune vasculitis. In 35 patients(male 20, female 15) with aneurysmal SAH. the levels of serum immunoglobulin(Ig) G, A, M, E and complement C3(C3) were determined to analyze the relation among Igs, C3, cerebral vasospasm and clinical grade. The results were as follows : 1) Highly significant correlation presented between C3 level and cerebral vasospasm(p<0.001). 2) Highly significant correlation presented between IgA level and cerebral vasospasm(p<0.001). 3) Significant correlation showed IgA with admission grade(p<0.001) and outcome(p<0.01). 4) Significant correlation showed C3 with admission grade(p<0.05) and outcome(p<0.01). 5) Among the 4 groups(SAH without vasospasm, SAH within vasospasm, hypertensive intracranial hematoma(HICH), herniated intervertebral disc(HIVD)), significant statistical difference at the level of IgA and C3 with others is observed in the group 2. 6) In serial determination of C3 levels performed in 8 patients(group 1 and group 2), correlative alteration between C3 level and cerebral vasospasm was observed. From the above results, these findings suggest that IgA and C3 levels not only might be reflected the severity of the neurological insult but also provide the usefulness as a predictable marker of cerebral vasospasm in aneurysmal SAH.
Aneurysm* ; Complement C3* ; Complement System Proteins* ; Female ; Humans ; Immune System ; Immune System Diseases ; Immunoglobulin A ; Immunoglobulins* ; Subarachnoid Hemorrhage* ; Vasculitis ; Vasospasm, Intracranial*

A 72-year-old woman presented with generalized edema and proteinuria. Renal biopsy disclosed highly organized fibrillary deposits in subendothelial area by electron microscopy. The microfibrils were 14 nm in diameter and randomly arranged. They did not have a microtubular appearance. These materials were negative for Congo red staining. Cryoglobulinemia or paraproteinemia including light chains was not found. So we can diagnose her as fibrillary glomerulonephritis (GN). In fibrillary GN serum complement levels are usually normal except in rare cases with systemic disease. Here we present a rare case of fibrillary GN with unusual hypocomplementemia.
Aged ; Biopsy ; Complement C3 ; Complement System Proteins ; Congo Red ; Cryoglobulinemia ; Edema ; Female ; Glomerulonephritis ; Humans ; Light ; Microfibrils ; Microscopy, Electron ; Paraproteinemias ; Proteinuria

PURPOSE: This study analyzed protein alterations between the normal vitreous and the vitreous with proliferative diabetic retinopathy by proteomics to find the proteins which may elicit diabetic retinopathy. METHODS: Two-dimensional electrophoresis was used to make the protein map. Image analysis between the spots on each gels by a proteomics based approach were used to reveal vitreous protein alterations which may elicit proliferative diabetic retinopathy. MALDI-TOF/ESI-TOF mass spectrometry also was used to identify altered protein spots on the gel. RESULTS: Of the 110 different spots on each gels, 36 different proteins were identified and among them 23 proteins were altered in the vitreous with proliferative diabetic retinopathy compared with normal vitreous. Nineteen proteins including alpha-1-antitrypsin, Ig G and A, and complement C3 and C4 were increased in the vitreous with proliferative diabetic retinopathy and 4 proteins includng pigment epithelium derived factor were decreased compared to the normal vitreous. CONCLUSIONS: The authors found that pigment epithelium derived factor may be the key protein that induces the neovascularization in the vitreous with proliferative diabetic retinopathy. Increased levels of Ig G and A and C3 and C4 is thought to be related to the autoimmune inflammation in early diabetic microangiopathy. Furthermore, proteins such as alpha-1-antitrypsin may contribute to protective functions of the ischemic retinal cells.
Complement C3 ; Diabetic Angiopathies ; Diabetic Retinopathy* ; Electrophoresis ; Epithelium ; Gels ; Inflammation ; Mass Spectrometry ; Proteomics ; Retinaldehyde

OBJECTIVETo investigate the value of serum IgA/C3 ratio in the diagnosis of IgA nephropathy and explore its relationship with the clinicopathological features of the patients.

METHODSSixty-six patients with IgA nephropathy, 111 with other glomerular diseases, and 40 healthy control subjects without kidney disease were tested for serum IgA and C3 levels using CRM470 adjusted standardized immune turbidimetric method, and the IgA/C3 ratio was calculated. According to Oxford and Lee's classification criteria, we analyzed the pathological grades of the renal biopsy samples from patients with IgA nephropathy. The ROC curve was used to assess the value of serum IgA and IgA/C3 ratio in predicting IgA nephropathy.

RESULTSPatients with IgA nephropathy had an elevated serum IgA/C3 ratio than those with other glomerular diseases and the control subjects, with an area under the ROC curve of 0.776. An elevated serum IgA/C3 ratio was not found to significantly correlate with the pathological grade of renal biopsy samples in patients with IgA nephropathy.

CONCLUSIONIn the absence of renal biopsy findings, serum IgA/C3 ratio can help in the diagnosis of IgA nephropathy.

Biopsy ; Case-Control Studies ; Complement C3 ; analysis ; Glomerulonephritis, IGA ; blood ; diagnosis ; Humans ; Immunoglobulin A ; blood ; Kidney ; pathology

Epilepsy is a brain condition characterized by the recurrence of unprovoked seizures. Recent studies have shown that complement component 3 (C3) aggravate the neuronal injury in epilepsy. And our previous studies revealed that TRPV1 (transient receptor potential vanilloid type 1) is involved in epilepsy. Whether complement C3 regulation of neuronal injury is related to the activation of TRPV1 during epilepsy is not fully understood. We found that in a mouse model of status epilepticus (SE), complement C3 derived from astrocytes was increased and aggravated neuronal injury, and that TRPV1-knockout rescued neurons from the injury induced by complement C3. Circular RNAs are abundant in the brain, and the reduction of circRad52 caused by complement C3 promoted the expression of TRPV1 and exacerbated neuronal injury. Mechanistically, disorders of neuron-glia interaction mediated by the C3-TRPV1 signaling pathway may be important for the induction of neuronal injury. This study provides support for the hypothesis that the C3-TRPV1 pathway is involved in the prevention and treatment of neuronal injury and cognitive disorders.
Animals ; Astrocytes/metabolism* ; Complement C3/metabolism* ; Epilepsy ; Mice ; Neurons/pathology* ; Status Epilepticus ; TRPV Cation Channels/metabolism*