Immunoglobulin A vasculitis (IgAV), also known as Henoch-Schönlein purpura, has complex etiology and pathogenesis which have not been fully clarified. The latest research shows that SARS-CoV-2 and related vaccines, human papilloma vaccine, and certain biological agents can also induce IgAV. Most studies believe that the formation of galactose-deficient IgA1 (Gd-IgA1) and Gd-IgA1-containing immune complex plays a crucial role in the pathogenesis of IgAV. It is hypothesized that the pathogenesis of IgAV is associated with the binding of IgA1 to anti-endothelial cell antibodies. In addition, genetics also constitutes a major focus of IgAV research. This article reviews the new advances in the etiology of IgAV and summarizes the role of Gd-IgA1, Gd-IgA1-containing immune complex, anti-endothelial antibody, IgA1 conjugates, T lymphocyte immunity, and genetic factors in the pathogenesis of IgAV.
Humans ; IgA Vasculitis ; Antigen-Antibody Complex ; Immunoglobulin A/genetics*

The C1q family is one of the subcomponents of the C1 complex that recognizes immune complexes and initiates the classical pathway of the complement system. In addition, as a pattern recognition receptor (PRR), the C1q family binds to a wide variety of ligands. As a member of the C1q family, the secretory C1q includes several subtypes. The main subtypes are cerebellin (Cbln) and C1q-like protein (C1ql). In the nervous system, secretory C1q is involved in the formation and regulation of various types of synapses, thus secretory C1q is closely related to diseases of the central nervous system. In this article, we review the role of secretory C1q in synapse formation and regulation, and its relationship with some diseases of the central nervous system.
Antigen-Antibody Complex ; Central Nervous System ; Complement C1q ; physiology ; Humans ; Synapses ; physiology

Anti–glomerular basement membrane (GBM) nephritis is characterized by circulating anti-GBM antibodies and crescentic glomerulonephritis (GN) with deposition of IgG along the GBM. In a limited number of cases, glomerular immune complexes have been identified in anti-GBM nephritis. A 38-year-old female presented azotemia, hematuria, and proteinuria without any pulmonary symptoms. A renal biopsy showed crescentic GN with linear IgG deposition along the GBM and mesangial IgA deposition. The patient was diagnosed as concurrent anti-GBM nephritis and IgA nephropathy. Therapies with pulse methylprednisolone and cyclophosphamide administration were effective. Concurrent cases of both anti-GBM nephritis and IgA nephropathy are rare among cases of anti-GBM diseases with deposition of immune complexes. This rare case of concurrent anti-GBM nephritis and IgA nephropathy with literature review is noteworthy.
Adult ; Anti-Glomerular Basement Membrane Disease ; Antibodies ; Antigen-Antibody Complex ; Azotemia ; Basement Membrane ; Biopsy ; Cyclophosphamide ; Female ; Glomerulonephritis ; Glomerulonephritis, IGA ; Hematuria ; Humans ; Immunoglobulin A ; Immunoglobulin G ; Methylprednisolone ; Nephritis ; Proteinuria

BACKGROUND/AIMS: Postoperative ileus (POI) is characterized by impaired propulsive function of the gastrointestinal tract after surgery. Although inflammation is considered to be an important pathogenesis of POI, significant data are lacking. We aim to correlate the recovery time of postoperative dysmotility with that of inflammation and mucosal permeability. METHODS: An experimental POI model of guinea pig was used. Contractile activity of the circular muscle of the stomach, jejunum, ileum, and proximal colon was measured through a tissue bath study. Inflammatory cells were counted, and the expression of calprotectin and tryptase were analyzed. The expression of protease-activated receptor 2 (PAR-2), claudin-1, and claudin-2 were analyzed with immunofluorescence. RESULTS: The small bowel and colon showed decreased contractile amplitude in the POI groups compared to control. In contrast to the colon, the contractile amplitude of the small bowel significantly recovered in the POI group at 6 hours after the operation compared to the control group. Inflammation was highly significant in the POI groups compared to the control and sham groups, especially in the colon. Immunofluorescence showed increased PAR-2 expression in the POI groups compared to sham. The decreased claudin-1 expression and increased claudin-2 expression may suggest increased mucosal permeability of the small bowel and colon in the POI groups. CONCLUSIONS: Increased inflammation and mucosal permeability may play an important role in the differential recovery stages in POI. These data may provide further insights into the pathophysiology and potential new therapeutic prospects of POI.
Animals ; Baths ; Claudin-1 ; Claudin-2 ; Colon ; Fluorescent Antibody Technique ; Gastrointestinal Tract ; Guinea Pigs ; Guinea ; Ileum ; Ileus ; Inflammation ; Jejunum ; Leukocyte L1 Antigen Complex ; Permeability ; Receptor, PAR-2 ; Stomach ; Tryptases

B cells play a role in graft rejection via several mechanisms. Specifically, B cells produce high-affinity antibodies to alloantigens including allogeneic major histocompatibility complex (MHC) with the help of follicular helper T cells. B cells also function as antigen-presenting cells for alloreactive T cells, resulting in the activation of alloreactive T cells. Conversely, the frequency of regulatory B cells increases under inflammatory conditions and suppresses the rejection process. Here, the differential roles of the major B cell subpopulations (B-1, follicular B, marginal zone B, and regulatory B cells) involved in transplantation rejection are discussed together with their interaction with T cells.
Antibodies ; Antibody Diversity ; Antigen-Presenting Cells ; B-Lymphocytes* ; B-Lymphocytes, Regulatory ; Graft Rejection* ; Isoantigens ; Major Histocompatibility Complex ; T-Lymphocytes ; T-Lymphocytes, Helper-Inducer

Systemic lupus erythematous (SLE) is a systemic autoimmune disease with multi-organ inflammation caused by the production of pathogenic autoantibodies and immune complexes reflecting a global loss of tolerance. Lupus nephritis (LN) is present in approximately 60% of SLE patients and is considered a major predictor of a poor prognosis. To date, many studies utilizing genomics, transcriptomics, epigenetics, metabolomics, and microbiome have been conducted on a range of animal models and lupus patients to understand the pathogenesis of SLE and LN. Collectively, these studies support the concept that LN is caused by increased cell death, which has not been properly dealt with; abnormal innate immunity; hyperactive adaptive immunity; and genetic variants triggered by a range of environmental factors. This review summarizes the results from studies that contributed strongly to elucidating the pathogenesis of SLE and LN, highlighting the immunological and non-immunological mechanisms.
Adaptive Immunity ; Allergy and Immunology ; Antigen-Antibody Complex ; Apoptosis ; Autoantibodies ; Autoimmune Diseases ; Cell Death ; Epigenomics ; Genomics ; Humans ; Immunity, Innate ; Inflammation ; Lupus Nephritis* ; Lymphocytes ; Metabolomics ; Microbiota ; Models, Animal ; Prognosis ; Wolves*

In addition to T cell-dependent (TD) Ab responses, T cells can also regulate T cell-independent (TI) B cell responses in the absence of a specific major histocompatibility complex (MHC) class II and antigenic peptide-based interaction between T and B cells. The elucidation of T cells capable of supporting TI Ab responses is important for understanding the cellular mechanism of different types of TI Ab responses. Natural killer T (NKT) cells represent 1 type of helper T cells involved in TI Ab responses and more candidate helper T cells responsible for TI Ab responses may also include γδ T cells and recently reported B-1 helper CD4⁺ T cells. Marginal zone (MZ) B and B-1 cells, 2 major innate-like B cell subsets considered to function independently of T cells, interact with innate-like T cells. Whereas MZ B and NKT cells interact mutually for a rapid response to blood-borne infection, peritoneal memory phenotype CD49d(high)CD4⁺ T cells support natural Ab secretion by B-1 cells. Here the role of innate-like T cells in the so-called TI Ab response is discussed. To accommodate the involvement of T cells in the TI Ab responses, we suggest an expanded classification of TD Ab responses that incorporate cognate and non-cognate B cell help by innate-like T cells.
Antibody Formation* ; Antigen-Antibody Reactions ; B-Lymphocyte Subsets ; B-Lymphocytes ; Classification ; Major Histocompatibility Complex ; Memory ; Natural Killer T-Cells ; Phenotype ; T-Lymphocytes* ; T-Lymphocytes, Helper-Inducer

Drug-induced immune hemolytic anemia (DIIHA) is a rare side effect of drugs. DIIHA may cause a systemic inflammatory response that results in acute multi-organ failure and death. Ceftizoxime belongs to the class of third generation cephalosporins, which are the most common drugs associated with DIIHA. Herein, we present a case of a 66-year-old man who developed fatal DIIHA after receiving a second dose of ceftizoxime. He was admitted to receive photodynamic therapy. He had a history of a single parenteral dose of ceftizoxime 3 months prior to admission. On the day of the procedure — shortly after the infusion of ceftizoxime — the patient's mental status was altered. The blood test results revealed hemolysis. Oliguric acute kidney injury developed, and continuous renal replacement therapy had to be applied. On the suspicion of DIIHA, the patient underwent plasmapheresis. Diagnosis was confirmed by a detection of drug-dependent antibody with immune complex formation. Although his hemolysis improved, his liver failure did not improve. He was eventually discharged to palliative care, and subsequently died.
Acute Kidney Injury ; Aged ; Anemia, Hemolytic* ; Antigen-Antibody Complex ; Ceftizoxime ; Cephalosporins ; Diagnosis ; Hematologic Tests ; Hemolysis ; Humans ; Liver Failure ; Palliative Care ; Photochemotherapy ; Plasmapheresis ; Renal Replacement Therapy

Membranous nephropathy is the most common pathologic lesion in adult patients with nephrotic syndrome. The cause is idiopathic, and the pathogenesis is believed to involve the deposition of immune complexes in the subepithelial tissue of the glomerular capillaries. After a period of 5 to 10 years, one-third of patients with membranous nephropathy will develop spontaneous remission, one-third will develop sustained proteinuria, and one-third will experience progression to chronic renal disease. Proteinuria may recur in patients who are in complete remission; this has been reported in approximately 26% of patients during an average of 89 months. To date, however, recurrence of membranous nephropathy has not been reported in patients who have been in complete remission for ≥ 20 years. We report herein such a case. Membranous nephropathy may recur in adult patients who are currently in the remission stage. Ongoing follow-up is therefore required, even after several years of complete remission.
Adult ; Antigen-Antibody Complex ; Capillaries ; Follow-Up Studies ; Glomerulonephritis ; Glomerulonephritis, Membranous* ; Humans ; Nephrotic Syndrome ; Proteinuria ; Recurrence ; Remission, Spontaneous ; Renal Insufficiency, Chronic

Drug-induced immune hemolytic anemia (DIIHA) is a rare side effect of drugs. DIIHA may cause a systemic inflammatory response that results in acute multi-organ failure and death. Ceftizoxime belongs to the class of third generation cephalosporins, which are the most common drugs associated with DIIHA. Herein, we present a case of a 66-year-old man who developed fatal DIIHA after receiving a second dose of ceftizoxime. He was admitted to receive photodynamic therapy. He had a history of a single parenteral dose of ceftizoxime 3 months prior to admission. On the day of the procedure — shortly after the infusion of ceftizoxime — the patient's mental status was altered. The blood test results revealed hemolysis. Oliguric acute kidney injury developed, and continuous renal replacement therapy had to be applied. On the suspicion of DIIHA, the patient underwent plasmapheresis. Diagnosis was confirmed by a detection of drug-dependent antibody with immune complex formation. Although his hemolysis improved, his liver failure did not improve. He was eventually discharged to palliative care, and subsequently died.
Acute Kidney Injury ; Aged ; Anemia, Hemolytic ; Antigen-Antibody Complex ; Ceftizoxime ; Cephalosporins ; Diagnosis ; Hematologic Tests ; Hemolysis ; Humans ; Liver Failure ; Palliative Care ; Photochemotherapy ; Plasmapheresis ; Renal Replacement Therapy