IgM Fractions Research Articles

Natural history of chronic idiopathic neutropenia of the adult

Chronic idiopathic neutropenia (CIN) is a rare benign condition caused by an immune attack against neutrophils, either primary or in the context of other autoimmune conditions, lymphoproliferative syndromes, and inborn errors of immunity. In this single-center prospective study, 131 adult CIN patients were enrolled (median age 55 years, range: 20–93). At baseline, 56% had anti-neutrophil autoantibodies and 31% had autoimmune comorbidities. Over a median 3-year follow-up, the rate of grade ≥ 2 infections was 42%, with 10% grade ≥ 3, irrespective of neutrophil counts, demographics, and anti-neutrophil antibodies positivity, and G-CSF was used in 6 patients only. No malignant evolution nor deaths were observed. Bone marrow evaluation showed a large granular lymphocyte (LGL) infiltrate in 52%, mostly polyclonal, and hypocellularity in 31% of cases. Immune-histochemistry highlighted deposits of IgG, IgM, and complement fractions C3 and C4d in most cases. Interestingly, 19% of tested patients displayed somatic mutations of myeloid genes with an association with age. In conclusion, adult CIN appears to be a benign condition without life-threatening infections, yet deserving an extensive hematologic evaluation including bone marrow assessment to inform the differential diagnosis.

Distinct patterns of auto-reactive antibodies associated with organ-specific immune-related adverse events.

ClinicalTrials.gov identifier: NCT03391869.

Intrathecal immunoglobin synthesis and its role in patients with neurosyphilis.

Intrathecal protein synthesis (ITS) occurs in various central nervous system disorders, but few quantitative studies have focused on ITS for neurosyphilis (NS) in southwestern China. We made a study to quantitatively assess the ITS in patients with NS and to investigate the association between ITS and the stages of NS. CSF-serum specimen pairs from 142 patients (66 NS and 76 non-NS/syphilis) were collected for routine CSF and serum tests. The NS group was divided into slight and severe subgroups according to the NS stages. Three formulas for the quantitative determination of the intrathecal synthesis were calculated to characterize the specimens, including the Ig index (QIg/Qalb), Ig extended index (Ig_EI), and intrathecally synthesized fraction (IgIF) using the hyperbolic function. The role of QTPPA/QIgG as an antibody index (AI = Q specific Ig/QIgG) was also explored. Sero_TRUST titres (1:16, 1:1-1:256), sero_TPPA titres (1:163840, 1:1280-1:1310720), total protein (MTP), and CSF_Igs (p < 0.05) were found to be significantly elevated in the NS group. Intrathecal Ig synthesis can be identified using all three formulas in the NS group. The pattern of Ig intrathecal synthesis was IgIF-G (48.62%) > IgIF-A = IgIF-M (p < 0.05), with the dominant intrathecal fraction being IgG (median, 48.62%), which was also verified by QIgG> Qalb> QIgM = QIgA. In the slight NS group, the intrathecal fractions of IgM (>0 in 4 out of 20 cases) and IgG (>0 in 16 out of 20) were lower than the intrathecal fractions of IgM (>0 in 19 out of 35 cases) and IgG (>0 in 33 out of 38) in the severe group (p < 0.05). The area under the curve (AUC) of the CSF_TPPA antibody index was 0.867 (0.792, 0.922), with an optimal cutoff point of 0.81, providing a sensitivity of 88.91% and specificity of 84.62%. Although the intrathecal synthesis pattern is IgG dominant in patients with NS, brain-derived IgM and IgA can also be found. Moreover, intrathecal IgM and IgG were associated with a parenchymatous type of neurosyphilis. Syphilis-specific antibodies are a new potential tool for NS diagnosis.

Auto-reactive antibodies as predictive markers for immune checkpoint–induced pneumonitis.

2554 Background: Certain immune-related adverse events (irAEs) that emerge with immune checkpoint blockade share clinical features of autoimmune conditions. Preexisting auto-reactive antibodies and their contribution to irAEs have not been well defined, and observations are limited. Methods: We longitudinally collected patient plasma samples from a clinical trial that combines immune checkpoint inhibitors, Ipilimumab, and Nivolumab (I+N) with subsequent radiation therapy (Lonestar, NCT03391869). Plasma samples were collected at baseline, after 12 weeks of I+N (induction), and at the time of Grade ≥ 2 pneumonitis (CTCAEv5.0). Auto reactive antibody profiles were analyzed using a fluorescence-based assay system that measures more than 130 antigens and is capable of assaying antibody reactivity for IgG and IgM fractions, including nuclear-cytosolic and tissue-specific antigens. Selected antibodies had a reportable result range, reference intervals, and reproducibility with quality controls. A paired t-test was used to compare the mean of longitudinally collected baseline and toxicity samples. An unpaired t-test was used to compare differences between groups. The False Discovery Rate was used to control the Type I error rate of multiple comparisons. Results: In the study cohort, G≥2 pneumonitis was observed in 11 patients out of 194 (5.6%). Serum was collected at baseline for all 11 patients, and 9 of the 11 patients had a serum sample collected at the time of pneumonitis event. Longitudinal serum samples (baseline and post-induction) collected from 32 patients without any irAEs were used as control. At baseline AChR3 and calmodulin antibodies were elevated in patients who developed pneumonitis, compared with baseline samples from controls (p≤0.05). At the time of pneumonitis IgM antibodies against AChR3, CXCL10, NSE, BAFF, CA242, Cytokeratin 19 were noted to be elevated in serum for pneumonitis cases compared with post induction samples from control (p≤0.005). Conclusions: We identified auto reactive antibodies associated with a higher risk of immunotherapy associated pneumonitis in patients treated with ipilimumab and nivolumab. These included auto reactive antibodies against proteins associated with lung injury (AChR3), lung inflammation (BAFF, CXCL10) and against alveolar epithelium (Cytokeratin 19). Future studies are warranted to determine if auto-reactive antibodies can be used as pre-treatment risk markers or to diagnose pneumonitis and may offer insights into to mechanisms that predispose toward pneumonitis.

Autoreactive antibodies control blood glucose by regulating insulin homeostasis

Homeostasis of metabolism by hormone production is crucial for maintaining physiological integrity, as disbalance can cause severe metabolic disorders such as diabetes mellitus. Here, we show that antibody-deficient mice and immunodeficiency patients have subphysiological blood glucose concentrations. Restoring blood glucose physiology required total IgG injections and insulin-specific IgG antibodies detected in total IgG preparations and in the serum of healthy individuals. In addition to the insulin-neutralizing anti-insulin IgG, we identified two fractions of anti-insulin IgM in the serum of healthy individuals. These autoreactive IgM fractions differ in their affinity to insulin. Interestingly, the low-affinity IgM fraction (anti-insulin IgMlow) neutralizes insulin and leads to increased blood glucose, whereas the high-affinity IgM fraction (anti-insulin IgMhigh) protects insulin from neutralization by anti-insulin IgG, thereby preventing blood glucose dysregulation. To demonstrate that anti-insulin IgMhigh acts as a protector of insulin and counteracts insulin neutralization by anti-insulin IgG, we expressed the variable regions of a high-affinity anti-insulin antibody as IgG and IgM. Remarkably, the recombinant anti-insulin IgMhigh normalized insulin function and prevented IgG-mediated insulin neutralization. These results suggest that autoreactive antibodies recognizing insulin are key regulators of blood glucose and metabolism, as they control the concentration of insulin in the blood. Moreover, our data suggest that preventing autoimmune damage and maintaining physiological homeostasis requires adaptive tolerance mechanisms generating high-affinity autoreactive IgM antibodies during memory responses.

Effectiveness of visible – Near infrared spectroscopy coupled with simulated annealing partial least squares analysis to predict immunoglobulins G, A, and M concentration in bovine colostrum

Visible - near infrared spectroscopy coupled with variable selection using simulated annealing PLS regression was tested to predict immunoglobulin fractions (g/L) of bovine colostrum, namely IgG, IgA and IgM. Immunoglobulins were quantified in 678 samples using the gold standard radial immunodiffusion. Samples were divided in calibration (50%) and validation (50%) datasets. Maximum number of selected variables were limited to 200 and root mean squared error in cross validation (RMSECV) was used as loss function. Performance of the final model developed using the calibration dataset was assessed on the validation dataset. Overall, simulated annealing PLS improved validation RMSECV compared to ordinary PLS regression by 3% to 17%. The present study demonstrated the effectiveness of the calibration model for accurate quantification of IgG, the most abundant immunoglobulin of bovine colostrum (RMSECV = 13.28 g/L; R2 = 0.83). These outcomes could be useful to assess colostrum quality intended for animal and human usage.

Clinical and morphological characteristic of kidney damage in HIV/HCV co-infected patients who did not receive antiretroviral therapy

In the era of antiretroviral therapy (ART), the development of chronic kidney disease in HIV-infected patients is a significant complication not directly related to acquired immunodeficiency syndrome (AIDS), the risk of which is increased with co-infection with hepatitis C virus (HCV). The pathogenetic pathways of the development of kidney tissue damage and the formation of a morphological substrate for each of the viruses are different, but the immune-mediated mechanisms are a common link for the development of immune complex diseases. We studied renal necropsy samples in 20 patients with HIV/HCV co-infection who did not receive ART, and the dependence of the identified morphological substrate on the level of CD4+ in the blood, to assess and predict their morphogenesis. We observed predominantly segmental mesangial proliferation with an expansion of the mesangial matrix and glomerular involvement ≥50 % in 15 (75 %) cases and glomerular involvement &lt;50 % in 3 (15 %) cases. Endocapillary proliferation (E), infiltration of glomeruli with monocytes, neutrophil leukocytes, segmental macrophages were found in 2 (10 %) cases with the involvement of ≥ 50 % of glomeruli, which was regarded as an exudative component of the inflammatory response. In all cases, sclerosis of capillary loops was verified, which was mainly accompanied by their collapse, thickening of the capillary walls, namely the basement membranes of capillaries and segmental sclerosis of capillary loops of the glo­meruli of varying severity. Initial interstitial stromal fibrosis was found in 5 (25 %) cases, degenerative changes in the convoluted tubules — in 9 (45 %), mainly with the T0–T1 level. Positive expression of IgA, IgM, IgG, and C3 complement fractions in the form of linear and granular deposits along the capillary endothelium was detected with an intensity of “+” to “++”. We compared the verified morphological pattern and the level of CD4+ in the blood and found that patients with deeper immunosuppression show fewer changes, mainly characterized as sclerotic. Moreover, with an increase in the level of CD4+, the morphological substrate is enriched with a proliferative component. Expression of immunoglobulins and components of the complement system in immonohistochemical assay, in particular in areas of sclerotic changes, verifies the presence of prolonged immune complex associated lesions. To determine the detailed morphogenesis, it is advisable to perform a further correlation analysis of the data obtained with the control.

Direct Assessment of IgA and IgG Paraprotein By Hevylite Assay and Correlation to IMWG Response and Progression-Free Survival in Newly Diagnosed, Transplant-Eligible Multiple Myeloma Patients in the Prospective Phase III GMMG-MM5 Trial

Direct Assessment of IgA and IgG Paraprotein By Hevylite Assay and Correlation to IMWG Response and Progression-Free Survival in Newly Diagnosed, Transplant-Eligible Multiple Myeloma Patients in the Prospective Phase III GMMG-MM5 Trial

Autoantibodies stabilize neutrophil extracellular traps in COVID-19.

The release of neutrophil extracellular traps (NETs) by hyperactive neutrophils is recognized to play an important role in the thromboinflammatory milieu inherent to severe presentations of COVID-19. At the same time, a variety of functional autoantibodies have been observed in individuals with severe COVID-19, where they likely contribute to immunopathology. Here, we aimed to determine the extent to which autoantibodies might target NETs in COVID-19 and, if detected, to elucidate their potential functions and clinical associations. We measured anti-NET antibodies in 328 individuals hospitalized with COVID-19 alongside 48 healthy controls. We found high anti-NET activity in the IgG and IgM fractions of 27% and 60% of patients, respectively. There was a strong correlation between anti–NET IgG and anti–NET IgM. Both anti–NET IgG and anti–NET IgM tracked with high levels of circulating NETs, impaired oxygenation efficiency, and high circulating D-dimer. Furthermore, patients who required mechanical ventilation had a greater burden of anti-NET antibodies than did those not requiring oxygen supplementation. Levels of anti–NET IgG (and, to a lesser extent, anti–NET IgM) demonstrated an inverse correlation with the efficiency of NET degradation by COVID-19 sera. Furthermore, purified IgG from COVID-19 sera with high levels of anti-NET antibodies impaired the ability of healthy control serum to degrade NETs. In summary, many individuals hospitalized with COVID-19 have anti-NET antibodies, which likely impair NET clearance and may potentiate SARS-CoV-2–mediated thromboinflammation.

Role of Immunoglobulin M and A Antibodies in the Neutralization of Severe Acute Respiratory Syndrome Coronavirus 2.

BackgroundSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected millions of people globally. Virus infection requires the receptor-binding domain (RBD) of the spike protein. Although studies have demonstrated anti-spike and -RBD antibodies to be protective in animal models, and convalescent plasma as a promising therapeutic option, little is known about immunoglobulin isotypes capable of blocking infection.MethodsWe studied spike- and RBD-specific immunoglobulin isotypes in convalescent and acute plasma/serum samples using a multiplex bead assay. We also determined virus neutralization activities in plasma and serum samples, and purified immunoglobulin fractions using a vesicular stomatitis pseudovirus assay.ResultsSpike- and RBD-specific immunoglobulin (Ig) M, IgG1, and IgA1 were produced by all or nearly all subjects at variable levels and detected early after infection. All samples displayed neutralizing activity. Regression analyses revealed that IgM and IgG1 contributed most to neutralization, consistent with IgM and IgG fractions’ neutralization potency. IgA also exhibited neutralizing activity, but with lower potency.ConclusionIgG, IgM, and IgA are critical components of convalescent plasma used for treatment of coronavirus disease 2019 (COVID-19).

Modified Widal test using 2-mercaptoethanol for detecting anti-salmonella IgM in febrile patients

Introduction: Despite limitations, the Widal test is widely used in resource-constrained settings because it is fast, inexpensive and user-friendly. Therefore, efforts continue to improve its diagnostic utility. Aims: Using 2-mercaptoethanol (2-ME) to detect the IgM fraction of total agglutinins detected by the Widal test in the serum of febrile patients. Materials and Methods: Single serum specimens were collected from 333 patients presenting to our hospital with fever. One aliquot of serum was tested by standard Widal test; a positive result was defined as simultaneous elevation of ‘O’ and 'H' titres to 1:80 or above. A second aliquot was simultaneously tested by a modified Widal test in which serum was diluted in isotonic saline with added 2-ME (0.12M) instead of in plain isotonic saline. Differences in titre between the two versions of Widal test were noted. A four-fold or greater reduction in titre upon testing with 2-ME, was considered evidence of specific IgM. Results: Standard Widal test was positive in 55 (16.5%) out of 333 patients. A ?4-fold reduction of ‘O’ titre in modified Widal test was found in 38 (69.1%) out of 55 cases, indicating the presence of specific IgM. A similar reduction of 'H' titre was seen in only 6 (11%) out of 55 cases. Conclusion: Simultaneous use of standard Widal test and modified Widal test with 2-ME allows the detection of specific IgM at a low cost. This can increase the diagnostic utility of the Widal test. Keywords: Acute febrile illness, Typhoid fever, Serology, IgM, Laboratory diagnosis.

Evaluation of the Classification Accuracy of the Kidney Biopsy Direct Immunofluorescence through Convolutional Neural Networks.

Immunohistopathology is an essential technique in the diagnostic workflow of a kidney biopsy. Deep learning is an effective tool in the elaboration of medical imaging. We wanted to evaluate the role of a convolutional neural network as a support tool for kidney immunofluorescence reporting. High-magnification (×400) immunofluorescence images of kidney biopsies performed from the year 2001 to 2018 were collected. The report, adopted at the Division of Nephrology of the AOU Policlinico di Modena, describes the specimen in terms of "appearance," "distribution," "location," and "intensity" of the glomerular deposits identified with fluorescent antibodies against IgG, IgA, IgM, C1q and C3 complement fractions, fibrinogen, and κ- and λ-light chains. The report was used as ground truth for the training of the convolutional neural networks. In total, 12,259 immunofluorescence images of 2542 subjects undergoing kidney biopsy were collected. The test set analysis showed accuracy values between 0.79 ("irregular capillary wall" feature) and 0.94 ("fine granular" feature). The agreement test of the results obtained by the convolutional neural networks with respect to the ground truth showed similar values to three pathologists of our center. Convolutional neural networks were 117 times faster than human evaluators in analyzing 180 test images. A web platform, where it is possible to upload digitized images of immunofluorescence specimens, is available to evaluate the potential of our approach. The data showed that the accuracy of convolutional neural networks is comparable with that of pathologists experienced in the field.

The Accumulation of Tau-Immunoreactive Hippocampal Granules and Corpora Amylacea Implicates Reactive Glia in Tau Pathogenesis during Aging.

SummaryThe microtubule-associated tau protein forms pathological inclusions that accumulate in an age-dependent manner in tauopathies including Alzheimer's disease (AD). Since age is the major risk factor for AD, we examined endogenous tau species that evolve during aging in physiological and diseased conditions. In aged mouse brain, we found tau-immunoreactive clusters embedded within structures that are reminiscent of periodic acid-Schiff (PAS) granules. We showed that PAS granules harbor distinct tau species that are more prominent in 3xTg-AD mice. Epitope profiling revealed hypo-phosphorylated rather than hyper-phosphorylated tau commonly observed in tauopathies. High-resolution imaging and 3D reconstruction suggest a link between tau clusters, reactive astrocytes, and microglia, indicating that early tau accumulation may promote neuroinflammation during aging. Using postmortem human brain, we identified tau as a component of corpora amylacea (CA), age-related structures that are functionally analogous to PAS granules. Overall, our study supports neuroimmune dysfunction as a precipitating event in tau pathogenesis.

Antibody Responses against Enterovirus Proteases are Potential Markers for an Acute Infection.

Background: Enteroviruses are a group of common non-enveloped RNA viruses that cause symptoms ranging from mild respiratory infections to paralysis. Due to the abundance of enterovirus infections it is hard to distinguish between on-going and previous infections using immunological assays unless the IgM fraction is studied. Methods: In this study we show using Indirect ELISA and capture IgM ELISA that an IgG antibody response against the nonstructural enteroviral proteins 2A and 3C can be used to distinguish between IgM positive (n = 22) and IgM negative (n = 20) human patients with 83% accuracy and a diagnostic odds ratio of 30. Using a mouse model, we establish that the antibody response to the proteases is short-lived compared to the antibody response to the structural proteins in. As such, the protease antibody response serves as a potential marker for an acute infection. Conclusions: Antibody responses against enterovirus proteases are shorter-lived than against structural proteins and can differentiate between IgM positive and negative patients, and therefore they are a potential marker for acute infections.

Purified human anti-Tn and anti-T antibodies specifically recognize carcinoma tissues

Described in several epithelial cancer cells, Tn- (GalNAcα1-O-Ser/Thr) and T- (Galβ3GalNAcα1-O-Ser/Thr) antigens are examples of tumor-associated antigens. Increased expression of Tn- and T-antigens is associated with tumor invasion and metastasis, and patients with high concentration of anti-Tn and anti-T antibodies have a more benign evolution of pathology. Asialofetuin (ASF) and ovine submaxillary mucin (OSM) are two glycoproteins that expose T- and Tn-antigen, respectively. In this work, using ASF or OSM we affinity-purified anti-T and anti-Tn antibodies from normal human plasma and tested their ability to specifically recognize tumor human tissues. Whereas purified anti-T antibodies (purity degree increase of 127-fold, and 22% recovery) were mainly IgG, for purified anti-Tn antibodies (purity degree enhancement of 125-fold, and 26% yield) the IgM fraction was predominant over the IgG one. IgG2 subclass was significantly enriched in both purified antibody samples. Purified antibodies did not bind normal human tissue (0/42), although recognized malignant tissues from different origin such as colon carcinoma (11/77 by anti-Tn; 7/79 by anti-T), breast carcinoma (10/23 by anti-Tn; 7/23 by anti-T), and kidney carcinoma (45/51 by anti-Tn; 42/51 by anti-T). Our results suggest that purified human anti-Tn and anti-T antibodies have a potential as anti-tumor therapeutic agents; restoring their levels in human sera could positively affect the evolution of patients with epithelial tumor pathologies.

IgM specific to lipopolysaccharide of Vibrio cholerae is a surrogate antibody isotype responsible for serum vibriocidal activity.

Serum vibriocidal antibody assays have long been used to evaluate the immunogenicity of cholera vaccines formulated with killed whole-cell Vibrio cholerae. However, the antibody isotypes responsible for the serum vibriocidal activity are not fully characterized. In this study, we examined 20 clinical serum samples obtained from human subjects who had been vaccinated with a killed, whole-cell cholera vaccine and a positive control, human convalescent sera with high vibriocidal activity, to determine which isotype antibody is associated with the vibriocidal activity. Antibody isotypes from pooled convalescent sera were fractionated by size-exclusion column chromatography, and the major vibriocidal activity was detected in the IgM fraction. Depletion of IgM antibodies in the convalescent sera produced a significant (P<0.05) decrease in vibriocidal activity (16-fold decrease), whereas only a small change was observed with depletion of IgG or IgA. In addition, anti-LPS IgM antibody showed the highest correlation with vibriocidal activity (Spearman correlation coefficient r = 0.846) among antibody isotypes against heat-killed V. cholerae, lipopolysaccharide (LPS), or major outer membrane protein (Omp U), while total IgG, IgA, or IgM antibody level was not correlated with vibriocidal activity in the 20 human clinical serum samples. Furthermore, human convalescent sera significantly (P<0.001) inhibited the attachment of V. cholerae to HT-29, a human intestinal epithelial cell in vitro. Interestingly, IgM-depleted convalescent sera could not effectively inhibit bacterial adherence compared with non-depleted sera (P<0.05). Finally, bacterial adhesion was significantly inhibited by sera with high vibriocidal titer compared with low-titer sera (P = 0.014). Collectively, we demonstrated that anti-V. cholerae LPS IgM is highly correlated with serum vibriocidal activity and it could be a surrogate antibody isotype representing protective antibodies against V. cholerae.

Human brucellosis in Rio Grande do Norte, Brazil

Background: Brucellosis or Malta fever is a zoonotic disease caused by intracellular cocobacilli gram negative aerobic of the genus Brucella. Although it being transmitted to humans since 1859, the correct diagnosis and treatment are challenging. Brucellosis is prevalent in males, farmers and laboratories professionals. The human Brucellosis is most commonly transmitted by the consumption of raw dairy products, aerosol inhalation or direct contact with infected animal. Methods: Data were obtained through medical records review, physical examination findings and laboratory results. Case: A 64-year-old male farmer presented to the infectious disease department with a 30-day history of moderate fever, asthenia and appetite loss. Previously diagnosed with rheumatoid arthritis, he was in chronic use of prednisone (10 mg/day). In addition, he was using glibenclamide and losartan for diabetes mellitus and hypertension, respectively. Posterior to hospital admission, he had been unsuccessfully treated with empirical intravenous antibiotics (ceftriaxone, metronidazole, gentamicin, oxacillin). After three weeks of hospitalization, the patient reported dry cough and abdominal pain in the right upper quadrant. The clinical investigation turned to the suspicion of brucellosis when the patient detailed his daily cow's milk consumption and direct contact with goats. Therefore, serology revealed the presence of high level of antibody against Brucella, being positive for the IgM fraction. He initiated treatment with rifampicin and ciprofloxacin in the following 6 weeks. As his condition improved, he was discharged and referred to an outpatient clinic, remaining asymptomatic. Results: There are few academic publications focused in brucellosis in the medical field. Considered an occupational disease, human Brucellosis remains a common disease in rural areas. Due to the lack of specific symptoms, its diagnostic requires extensive knowledge in infectious diseases and epidemiology. Conclusion: This case highlights the importance of brucellosis serology, as well as preventive programs and educational interventions. The provision of diagnostic tests in endemic regions might enhance the probability of diagnosis and facilitate the effective treatment of human brucellosis worldwide.

Potential role of plasmapheresis in severe cytomegalovirus infection with ongoing immunemediated hemolysis and low complement level

Symptomatic cytomegalovirus (CMV) infections are rare in patients with no previous history of immunosuppressive therapy or condition. A 33-year-old woman with type-2 diabetes, endstage renal disease (ESRD) and unexplained lower extremity weakness was admitted with failure to thrive, ongoing hemolysis, low haptoglobin and C3 levels and suppressed IgM and IgG globulin fractions. Multiple cultures and serologic workup for autoimmune disorders remained negative. CMV viral titer by serum polymerase chain reaction (PCR) revealed massive elevation at 9.2 million copies/mL. Initial CMV IgG titer was positive, IgM titer remained consistently negative and CMV was recovered from cerebrospinal fluid, as well. She received treatment with I.V. ganciclovir, CMV immune globulin (CytoGam) and three sessions of plasmapheresis (PLEX). The extreme viremia without neutropenia, lack of IgM antibody reconversion and CMV-mediated hemolysis with a low complement level were all very unusual features. Timely initiation of PLEX may have contributed to recovery

Multiple sclerosis: Presence of serum antibodies to lipids and predominance of cholesterol recognition.

A lot of available data on lipid immunology in multiple sclerosis (MS) have been derived from studies using synthetic lipids, therefore the role of lipids in the immunopathogenesis of MS remains poorly defined. The present study on the lipid response in MS was performed on native lipids from autopsied brain tissue. For this, lipid fractions (n = 9) were prepared from MS (n = 3) and control (n = 2) white matter according to the Folch procedure and were characterized depending on their solubility in chloroform/methanol. TLC showed that, in brain from MS cases, neutral lipids were rich in cholesterol and cholesterol esters while lipids from control brains displayed a predominance of phospholipids. MS serum IgG and IgM were found to bind to MS brain lipid fractions with a higher efficacy (p < 0.05) than the control serum. F(ab)2 fractionation revealed that MS serum IgG binding depended on a specific antibody-type of recognition. Pre-adsorption of serum with cholesterol, galactocerebrosides, sulfitides, and phosphatidylinositol prior to ELISA with MS brain lipids, showed that cholesterol diminished IgG and IgM binding up to 70%. Experiments with synthetic lipids confirmed the predominance of cholesterol binding by MS serum. Our results demonstrate that IgG and IgM fractions from MS serum specifically and predominantly recognize native cholesterol and cholesterol esters isolated from the brain tissue of patients with MS. © 2017 Wiley Periodicals, Inc.

Phosphocholine-Specific Antibodies Improve T-Dependent Antibody Responses against OVA Encapsulated into Phosphatidylcholine-Containing Liposomes.

Liposomes containing phosphatidylcholine have been widely used as adjuvants. Recently, we demonstrated that B-1 cells produce dipalmitoyl-phosphatidylcholine (DPPC)-specific IgM upon immunization of BALB/c mice with DPPC-liposomes encapsulating ovalbumin (OVA). Although this preparation enhanced the OVA-specific humoral response, the contribution of anti-DPPC antibodies to this effect was unclear. Here, we demonstrate that these antibodies are secreted by B-1 cells independently of the presence of OVA in the formulation. We also confirm that these antibodies are specific for phosphocholine. The anti-OVA humoral response was partially restored in B-1 cells-deficient BALB/xid mice by immunization with the liposomes opsonized with the serum total immunoglobulin (Ig) fraction containing anti-phosphocholine antibodies, generated in wild-type animals. This result could be related to the increased phagocytosis by peritoneal macrophages of the particles opsonized with the serum total Ig or IgM fractions, both containing anti-phosphocholine antibodies. In conclusion, in the present work, it has been demonstrated that phosphocholine-specific antibodies improve T-dependent antibody responses against OVA carried by DPPC-liposomes.