DNA-hydrolysing activity of IgG antibodies from the sera of patients with schizophrenia

Abstract

It is believed that damage to the membranes of brain cells of schizophrenia (SCZ) patients induces the formation of autoantigens and autoantibodies. Nevertheless, the importance of immunological changes leading to the loss of tolerance to self-antigens in the genesis of SCZ has not been established. The MALDI mass spectra of the IgG light chains of 20 healthy donors were relatively homogeneous and characterized by one peak with only one maximum. In contrast to the healthy donors, the MALDI mass spectra of IgG light chains corresponding to 20 SCZ patients demonstrated, similarly to 20 autoimmune systemic lupus erythematosus (SLE) patients, two maxima of a comparable intensity. In addition, the MALDI spectra of the IgG light chains of five SLE and four SCZ patients contained a small additional brightly pronounced peak with remarkably lower molecular mass compared with the main one. DNase autoantibodies (abzymes) can be found in the blood of patients with several autoimmune diseases, while the blood of healthy donors or patients with diseases without a significant disturbance of the immune status does not contain DNase abzymes. Here, we present the first analysis of anti-DNA antibodies and DNase abzymes in the sera of SCZ patients. Several strict criteria have been applied to show that the DNase activity is an intrinsic property of IgGs from the sera of SCZ patients. The sera of approximately 30% of SCZ patients displayed a higher content of antibodies (compared with 37% of SLE) interacting with single- and double-stranded DNA compared with healthy donors. Antibodies with DNase activity were revealed in 80% of the patients. These data indicate that some SCZ patients may show signs of typical autoimmune processes to a certain extent.

Hydrolysis by catalytic IgGs of microRNA specific for patients with schizophrenia

“…Electrophoretically homogeneous IgGs from sera of SCZ patients and healthy donors were purified by affinity chromatography of serum proteins on protein G‐Sepharose and then by FPLC gel filtration under “acid shock” conditions as in . To analyze the “average” RNase activity of IgGs, we have prepared a mixture of equal amounts of 35 electrophoretically homogeneous IgGs of SCZ patients (scz‐IgG mix ) and 20 healthy donors (healt‐IgG mix ).…”

“…FPLC gel‐filtration of scz‐IgG mix under conditions of “acidic shock” (pH 2.6) and its affinity chromatography on Sepharose bearing immobilized mouse Abs against human IgGs were carried out as in Refs. .…”

“…It has been recently shown that similar to systemic lupus erythematosus (SLE) and multiple sclerosis (MS) , DNA and myelin basic protein (MBP)‐hydrolyzing Abs, which can play an important harmful role in MS and SLE pathogenesis (for review see Refs. ) are detected in sera of SCZ patients . In addition, the MALDI mass spectra of the light chains of IgGs of 20 healthy donors characterized by one peak with only one maximum .…”

Rapid detection of alteration of serum IgG in patients with schizophrenia after risperidone treatment by matrix‐assisted laser desorption ionization/time‐of‐flight mass spectrometry

“…In 2015, Ermakov et al reported DNA‐hydrolyzing activity of IgG antibodies in schizophrenic patients. Their results showed that the IgG antibodies with DNase activity were seen in 80% of patients with schizophrenia . Liu et al also studied serum immunoinflammation‐related protein complex changes in psychosis, and their major finding was that total serum amounts of IgG, IgA, and IgM were significantly lower in patients with schizophrenia .…”

Acquired Factor XII Deficiency in a Patient with Schizophrenia

“…According to the previous studies, immune dysfunction may contribute to the pathogenesis of psychiatric diseases such as schizophrenia in the field of Neuroimmunology [6]. Overall, two general reasons can consider for positive lupus anticoagulant in the schizophrenia patients, firstly, brain inflammation as well as damage to the membrane of brain cells that can induce autoantibodies production [7], secondly, drug-induced lupus anticoagulant can be resulted from long term use of certain medications, such as phenothiazines. These findings trigger questions regarding what disorders can be result following the schizophrenia-induced autoimmunity.…”