Membrane vesicle delivery of a streptococcal M protein disrupts the blood-brain barrier by inducing autophagic endothelial cell death.

M family proteins are critical virulence determinants of Streptococci. Streptococcus equi subsp. zooepidemicus (SEZ) are Group C streptococci that cause meningitis in animals and humans. SzM, the M protein of SEZ, has been linked to SEZ brain invasion. Here, we demonstrate that SzM is important in SEZ disruption of the blood-brain barrier (BBB). SEZ release SzM-bound membrane vesicles (MVs), and endocytosis of these vesicles by human brain endothelial microvascular cells (hBMECs) results in SzM-dependent cytotoxicity. Furthermore, administration of SzM-bound MVs disrupted the murine BBB. A CRISPR screen revealed that SzM cytotoxicity in hBMECs depends on PTEN-related activation of autophagic cell death. Pharmacologic inhibition of PTEN activity prevented SEZ disruption of the murine BBB and delayed mortality. Our data show that MV delivery of SzM to host cells plays a key role in SEZ pathogenicity and suggests that MV delivery of streptococcal M family proteins is likely a common streptococcal virulence mechanism.

Establishment of a direct detection method for serum M-proteins without antibody enrichment based on MALDI-TOF MS technology / 中华检验医学杂志

Objective:To establish a matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) method for the direct detection of serum M protein without antibody enrichment, and to assess its detection performance.Methods:Method establishment. A total of 712 waste serum samples were collected from patients who applied for the M protein identification test in Beijing Chaoyang Hospital affiliated to Capital Medical University. The immunoglobulin light chain was obtained by reduction of IgG and IgA by TCEP, and the detection method was preliminarily determined. The waste serum samples from 20 healthy people were collected to determine the range of mass-to-charge ratios of κ and λ light chain ions. 8 parallel tubes and 8 batches were set up for intra-and inter-batch reproducibility evaluation. 10-fold, 100-fold and 200-fold diluted M protein from 23 positive samples were detected by established MALDI-TOF MS method, and its sensitivity was evaluated. 3 methods of IFE, SPE and MALDI-TOF MS were used to detect M protein simultaneously, and the coincidence rate between MALDI-TOF MS and IFE and SPE was calculated.Results:The repeatability within and between batches was 100%, respectively. The original, 10-, 100-and 200-fold dilutions of 23 M protein-positive samples were determined, and the detection limit of MALDI-TOF MS for M protein was 0.06-0.18 g/L. IFE as the gold standard, the overall coincidence rates of SPE and MALDI-TOF MS were 85.9% and 92.3%, respectively, and the positive coincidence rates of SPE and MALDI-TOF MS were 72.8% and 99.7%, respectively, of the 712 samples. Among the different types of M-proteins, MALDI-TOF-MS agreed 100% with IFE M-protein results for IgA, IgD, IgM, free light chain type and biclonal group, while the agreements of SPE for IgM, IgA and free light chain samples were only 66.7%, 58% and 19.5%, respectively. One positive sample in the IgG group was not detected by MALDI-TOF MS. 23 M-proteins positive samples were diluted by original, 10, 100 and 200 times to access the sensitivity of MALDI-TOF MS method. The coincidence rate of MALDI-TOF MS was 100% and IFE was 96% at 10-fold dilution. The coincidence rate of IFE was 28% and 23% of MALDI-TOF MS at 100-fold and 200-fold dilution, respectively.Conclusions:A MALDI-TOF MS method for the detection of serum M-proteins was successfully established. This method has the advantages of high detection throughput, fast speed, good sensitivity, specificity and coincidence rate.

Successful treatment of solitary bladder plasmacytoma: A case report.

BACKGROUND: Plasmacytoma is a rare neoplastic disorder that arises from B-lymphocytes. Solitary bladder plasmacytoma, a type of solitary extramedullary plasmacytoma, is even rarer. Treatments for solitary extramedullary plasmacytoma include surgery, chemotherapy, and radiation. However, there are no clinical trials or guidelines specifying which treatment might represent the gold standard. CASE SUMMARY: We herein report a case of a 51-year-old woman with solitary bladder plasmacytoma (SBP). There remains no consensus regarding the optimal treatment for SBP. However, we successfully treated her with transurethral resection of bladder tumor followed by postoperative radiotherapy (50 Gy/25 F). The patient remained free of tumor recurrence at a 7-mo follow-up. CONCLUSION: Radiation is the potential main treatment for SBP. However, surgery is also necessary.

Streptococcus pyogenes Forms Serotype- and Local Environment-Dependent Interspecies Protein Complexes.

Streptococcus pyogenes is known to cause both mucosal and systemic infections in humans. In this study, we used a combination of quantitative and structural mass spectrometry techniques to determine the composition and structure of the interaction network formed between human plasma proteins and the surfaces of different S. pyogenes serotypes. Quantitative network analysis revealed that S. pyogenes forms serotype-specific interaction networks that are highly dependent on the domain arrangement of the surface-attached M protein. Subsequent structural mass spectrometry analysis and computational modeling of one of the M proteins, M28, revealed that the network structure changes across different host microenvironments. We report that M28 binds secretory IgA via two separate binding sites with high affinity in saliva. During vascular leakage mimicked by increasing plasma concentrations in saliva, the binding of secretory IgA was replaced by the binding of monomeric IgA and C4b-binding protein (C4BP). This indicates that an upsurge of C4BP in the local microenvironment due to damage to the mucosal membrane drives the binding of C4BP and monomeric IgA to M28. These results suggest that S. pyogenes has evolved to form microenvironment-dependent host-pathogen protein complexes to combat human immune surveillance during both mucosal and systemic infections. IMPORTANCE Streptococcus pyogenes (group A Streptococcus [GAS]), is a human-specific Gram-positive bacterium. Each year, the bacterium affects 700 million people globally, leading to 160,000 deaths. The clinical manifestations of S. pyogenes are diverse, ranging from mild and common infections like tonsillitis and impetigo to life-threatening systemic conditions such as sepsis and necrotizing fasciitis. S. pyogenes expresses multiple virulence factors on its surface to localize and initiate infections in humans. Among all these expressed virulence factors, the M protein is the most important antigen. In this study, we perform an in-depth characterization of the human protein interactions formed around one of the foremost human pathogens. This strategy allowed us to decipher the protein interaction networks around different S. pyogenes strains on a global scale and to compare and visualize how such interactions are mediated by M proteins.

Small Structural Proteins E and M Render the SARS-CoV-2 Pseudovirus More Infectious and Reveal the Phenotype of Natural Viral Variants.

The SARS-CoV-2 pseudovirus is a commonly used strategy that mimics certain biological functions of the authentic virus by relying on biological legitimacy at the molecular level. Despite the fact that spike (S), envelope (E), and membrane (M) proteins together wrap up the SARS-CoV-2 virion, most of the reported pseudotype viruses consist of only the S protein. Here, we report that the presence of E and M increased the virion infectivity by promoting the S protein priming. The S, E, and M (SEM)-coated pseudovirion is spherical, containing crown-like spikes on the surface. Both S and SEM pseudoviruses packaged the same amounts of viral RNA, but the SEM virus bound more efficiently to cells stably expressing the viral receptor human angiotensin-converting enzyme II (hACE2) and became more infectious. Using this SEM pseudovirus, we examined the infectivity and antigenic properties of the natural SARS-CoV-2 variants. We showed that some variants have higher infectivity than the original virus and that some render the neutralizing plasma with lower potency. These studies thus revealed possible mechanisms of the dissemination advantage of these variants. Hence, the SEM pseudovirion provides a useful tool to evaluate the viral infectivity and capability of convalescent sera in neutralizing specific SARS-CoV-2 S dominant variants.

Reporting Apparent Biclonal Immunoglobulin-A Monoclonal Proteins with Identical Light Chains.

It is generally not well appreciated that Immunoglobulin A (IgA) can present as apparent biclonal monoclonal protein (M-protein) comprising monomers and polymers, despite the fact that Kyle pointed this out in 1999. In this clinical communication, we report on 3 patients with Ig-A multiple myeloma (MM) who displayed this phenomenon. Of these 3 patients, 2 had identical kappa light chains suggesting biclonality, while the other had 2 lambda light chains. Because the Ig-A M-proteins are clustered in the beta-area, accurate densitometric quantification is made difficult. Hence, we suggest assaying Ig-A levels and free light chains in concert with the M-protein levels to monitor these patients on therapy. In conclusion, when encountering biclonal Ig-A M-proteins with identical light chains, the laboratorian should add the 2 values and present one composite number to the clinician.

Automation and validation of a MALDI-TOF MS (Mass-Fix) replacement of immunofixation electrophoresis in the clinical lab.

Objectives: A matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) method (Mass-Fix) as a replacement for gel-based immunofixation (IFE) has been recently described. To utilize Mass-Fix clinically, a validated automated method was required. Our aim was to automate the pre-analytical processing, improve positive specimen identification and ergonomics, reduce paper data storage and increase resource utilization without increasing turnaround time. Methods: Serum samples were batched and loaded onto a liquid handler along with reagents and a barcoded sample plate. The pre-analytical steps included: (1) Plating immunopurification beads. (2) Adding 10 µl of serum. (3) Bead washing. (4) Eluting the immunoglobulins (Igs), and reducing to separate the heavy and light Ig chains. The resulting plate was transferred to a second low-volume liquid handler for MALDI plate spotting. MALDI-TOF mass spectra were collected. Integrated in-house developed software was utilized for sample tracking, driving data acquisition, data analysis, history tracking, and result reporting. A total of 1,029 residual serum samples were run using the automated system and results were compared to prior electrophoretic results. Results: The automated Mass-Fix method was capable of meeting the validation requirements of concordance with IFE, limit of detection (LOD), sample stability and reproducibility with a low repeat rate. Automation and integrated software allowed a single user to process 320 samples in an 8 h shift. Software display facilitated identification of monoclonal proteins. Additionally, the process maintains positive specimen identification, reduces manual pipetting, allows for paper free tracking, and does not significantly impact turnaround time (TAT). Conclusions: Mass-Fix is ready for implementation in a high-throughput clinical laboratory.

Structure-based group A streptococcal vaccine design: Helical wheel homology predicts antibody cross-reactivity among streptococcal M protein-derived peptides.

Group A streptococcus (Strep A) surface M protein, an α-helical coiled-coil dimer, is a vaccine target and a major determinant of streptococcal virulence. The sequence-variable N-terminal region of the M protein defines the M type and also contains epitopes that promote opsonophagocytic killing of streptococci. Recent reports have reported considerable cross-reactivity among different M types, suggesting the prospect of identifying cross-protective epitopes that would constitute a broadly protective multivalent vaccine against Strep A isolates. Here, we have used a combination of immunological assays, structural biology, and cheminformatics to construct a recombinant M protein-based vaccine that included six Strep A M peptides that were predicted to elicit antisera that would cross-react with an additional 15 nonvaccine M types of Strep A. Rabbit antisera against this recombinant vaccine cross-reacted with 10 of the 15 nonvaccine M peptides. Two of the five nonvaccine M peptides that did not cross-react shared high sequence identity (≥50%) with the vaccine peptides, implying that high sequence identity alone was insufficient for cross-reactivity among the M peptides. Additional structural analyses revealed that the sequence identity at corresponding polar helical-wheel heptad sites between vaccine and nonvaccine peptides accurately distinguishes cross-reactive from non-cross-reactive peptides. On the basis of these observations, we developed a scoring algorithm based on the sequence identity at polar heptad sites. When applied to all epidemiologically important M types, this algorithm should enable the selection of a minimal number of M peptide-based vaccine candidates that elicit broadly protective immunity against Strep A.

Association of Monoclonal Gammopathy with Progression to ESKD among US Veterans.

BACKGROUND AND OBJECTIVES: Whether patients with monoclonal protein are at a higher risk for progression of kidney disease is not known. The goal of this study was to measure the association of monoclonal protein with progression to ESKD. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This was a retrospective cohort study of 2,156,317 patients who underwent serum creatinine testing between October 1, 2000 and September 30, 2001 at a Department of Veterans Affairs medical center, among whom 21,898 had paraprotein testing within 1 year before or after cohort entry. Progression to ESKD was measured using linked data from the US Renal Data System. RESULTS: Overall, 1,741,707 cohort members had an eGFR≥60 ml/min per 1.73 m2, 283,988 had an eGFR of 45-59 ml/min per 1.73 m2, 103,123 had an eGFR of 30-44 ml/min per 1.73 m2 and 27,499 had an eGFR of 15-29 ml/min per 1.73 m2. The crude incidence of ESKD ranged from 0.7 to 80 per 1000 person-years from the highest to lowest eGFR category. Patients with low versus preserved eGFR were more likely to be tested for monoclonal protein but no more likely to have a positive test result. In adjusted analyses, a positive versus negative test result was associated with a higher risk of ESKD among patients with an eGFR≥60 ml/min per 1.73 m2 (hazard ratio, 1.67; 95% confidence interval, 1.22 to 2.29) and those with an eGFR of 15-29 ml/min per 1.73 m2 (hazard ratio, 1.38; 95% confidence interval, 1.07 to 1.77), but not among those with an eGFR of 30-59 ml/min per 1.73 m2. Progression to ESKD was attributed to a monoclonal process in 21 out of 76 versus seven out of 174 patients with monoclonal protein and preserved versus severely reduced eGFR at cohort entry. CONCLUSIONS: The detection of monoclonal protein provides little information on ESKD risk for most patients with a low eGFR. Further study is required to better understand factors contributing to a positive association of monoclonal protein with ESKD risk in patients with preserved and severely reduced levels of eGFR.

POEMS syndrome presentation with progressive weakness in upper and lower limbs: A case report.

Polyneuropathy, organomegaly, endocrinopathy, M proteins, and skin changes (POEMS) syndrome is a rare variant of plasma cell disorders with multiple systemic manifestations. A 50-year-old female patient presented with progressive weakness in her upper and lower limbs; tingling, numbness and burning in her feet; polyneuropathy (demyelinating in the majority of cases of POEMS syndrome); monoclonal plasma cell disorder (typicallyλ-restricted in cases of POEMS syndrome); sclerotic lesions on the spine and pelvis; organomegaly, including hepatomegaly, splenomegaly and lymphadenopathy; edema; pleural effusion; adrenal, thyroidal, pituitary, gonadal and pancreatic endocrinopathy; skin changes, including hyperpigmentation, dry skin and hypertrichosis; thrombocytosis; pulmonary hypertension; low vitamin B12 and weight loss. Following the diagnosis of POEMS syndrome, the patient was treated only with pain-alleviating corticosteroids. Respiratory failure-induced mortality occurred 24 months after the patient first experienced difficulty walking and numbness in her lower extremities. The present study suggests that abnormal symptoms in cases of POEMS syndrome should be further evaluated during the diagnosis and treatment.

Paraprotein-Related Kidney Disease: Attack of the Killer M Proteins.

Paraproteins are monoclonal Igs or their components (light or heavy chains) that are produced by a clonal population of mature B cells, most commonly plasma cells. These paraproteins or monoclonal proteins are secreted into the blood and subsequently filtered by the glomerulus before entering into urine, where they can cause various types of kidney disease, including both glomerular and tubulointerstitial injuries. Furthermore, a monoclonal protein that causes a specific glomerular or tubulointerstitial lesion in a human can reproducibly cause the same pathology when injected into an animal, supporting unique paraprotein characteristics. This Moving Points in Nephrology will provide an update for the Clinical Journal of the American Society of Nephrology readership on some of the clinically relevant kidney lesions associated with monoclonal paraprotein production and the pathophysiology underlying these kidney lesions.

Paraprotein-Related Kidney Disease: Kidney Injury from Paraproteins-What Determines the Site of Injury?

Disorders of plasma and B cells leading to paraproteinemias are associated with a variety of renal diseases. Understanding the mechanisms of injury and associated nephropathies provides a framework that aids clinicians in prompt diagnosis and appropriate adjunctive treatment of these disorders. Glomerular diseases that may be associated with paraproteinemias include amyloid deposition, monoclonal Ig deposition disease, proliferative GN with monoclonal Ig deposits, C3 glomerulopathy caused by alterations in the complement pathway, immunotactoid glomerulopathy, fibrillary GN, and cryoglobulinemia. Tubular lesions include the classic Fanconi syndrome, light-chain proximal tubulopathy, interstitial fibrosis, and cast nephropathy. These paraproteinemic renal diseases are distinct in their pathogenesis as well as their urinary and kidney biopsy findings. Renal pathology is usually initiated by deposition and direct involvement of the intact monoclonal Ig or Ig fragments with resident cells of the nephron. Our review summarizes current insights into the underlying molecular pathogenesis of these interesting kidney lesions.

Paraprotein-Related Kidney Disease: Evaluation and Treatment of Myeloma Cast Nephropathy.

Nearly 50% of patients with multiple myeloma develop renal disease, most commonly from AKI caused by cast nephropathy. Development of AKI is associated with poor 1-year survival and reduces the therapeutic options available to patients. There is a great need for more effective therapies. Cast nephropathy is caused by the interaction and aggregation of filtered free light chains and Tamm-Horsfall protein causing intratubular obstruction and damage. The key to treating cast nephropathy is rapid lowering of free light chains, because this correlates with renal recovery. Newer chemotherapy agents rapidly lower free light chains and have been referred to as renoprotective. There is additional great interest in using extracorporeal therapies to remove serum free light chains. Small trials initially showed benefit of therapeutic plasma exchange to improve renal outcomes in cast nephropathy, but a large randomized trial of therapeutic plasma exchange failed to show benefit. A newer technique is extended high-cutoff hemodialysis. This modality uses a high molecular weight cutoff filter to remove free light chains. To date, trials of high-cutoff hemodialysis use in patients with cast nephropathy have been encouraging. However, there are no randomized trials showing the benefit of high-cutoff hemodialysis when used in addition to newer chemotherapeutic regimens. Until these studies are available, high-cutoff hemodialysis cannot be recommended as standard of care.

Bridging the Divide: An Onco-Nephrologic Approach to the Monoclonal Gammopathies of Renal Significance.

The monoclonal gammopathies of renal significance (MGRS) are a group of disorders characterized by monoclonal Ig deposition in the kidney, but are not associated with systemic lymphoma or overt multiple myeloma. The prevailing hypothesis is that the pathogenic paraproteins in MGRS are produced by underlying B cell or plasma cell clones. However, in the MGRS literature, the yield of detecting a clone has been variable, and progression to ESRD is common. Here, we present an "onco-nephrologic" approach to the MGRS disorders by highlighting recent advances in lymphoma and multiple myeloma that can be used in the evaluation and management of these patients.

An improved SELEX technique for selection of DNA aptamers binding to M-type 11 of Streptococcus pyogenes.

Streptococcus pyogenes is a clinically important pathogen consisting of various serotypes determined by different M proteins expressed on the cell surface. The M type is therefore a useful marker to monitor the spread of invasive S. pyogenes in a population. Serotyping and nucleic acid amplification/sequencing methods for the identification of M types are laborious, inconsistent, and usually confined to reference laboratories. The primary objective of this work is to develop a technique that enables generation of aptamers binding to specific M-types of S. pyogenes. We describe here an in vitro technique that directly used live bacterial cells and the Systematic Evolution of Ligands by Exponential Enrichment (SELEX) strategy. Live S. pyogenes cells were incubated with DNA libraries consisting of 40-nucleotides randomized sequences. Those sequences that bound to the cells were separated, amplified using polymerase chain reaction (PCR), purified using gel electrophoresis, and served as the input DNA pool for the next round of SELEX selection. A specially designed forward primer containing extended polyA20/5Sp9 facilitated gel electrophoresis purification of ssDNA after PCR amplification. A counter-selection step using non-target cells was introduced to improve selectivity. DNA libraries of different starting sequence diversity (10(16) and 10(14)) were compared. Aptamer pools from each round of selection were tested for their binding to the target and non-target cells using flow cytometry. Selected aptamer pools were then cloned and sequenced. Individual aptamer sequences were screened on the basis of their binding to the 10 M-types that were used as targets. Aptamer pools obtained from SELEX rounds 5-8 showed high affinity to the target S. pyogenes cells. Tests against non-target Streptococcus bovis, Streptococcus pneumoniae, and Enterococcus species demonstrated selectivity of these aptamers for binding to S. pyogenes. Several aptamer sequences were found to bind preferentially to the M11 M-type of S. pyogenes. Estimated binding dissociation constants (Kd) were in the low nanomolar range for the M11 specific sequences; for example, sequence E-CA20 had a Kd of 7±1 nM. These affinities are comparable to those of a monoclonal antibody. The improved bacterial cell-SELEX technique is successful in generating aptamers selective for S. pyogenes and some of its M-types. These aptamers are potentially useful for detecting S. pyogenes, achieving binding profiles of the various M-types, and developing new M-typing technologies for non-specialized laboratories or point-of-care testing.

Evaluation of neutralization patterns of the five unique Argentine equine arteritis virus field strains reported / Evaluación de los patrones de neutralización de las únicas cinco cepas argentinas descritas de arteritis viral equina

Equine viral arteritis (EVA) is a contagious viral disease that frequently causes mild or subclinical infections in adult horses. Only one EAV serotype has been described. However, there are differences in antigenicity, pathogenicity and neutralization characteristics of virus field strains. The interaction of two viral proteins, GP5 and M, is critical for infectivity and amino acid changes in the GP5 sequences have an effect on the neutralizing phenotype, regardless the effects of other viral proteins. The objective of the present study was to evaluate the neutralization phenotypes of the 5 unique Argentine EAV strains reported and to compare them with the neutralization phenotypes of the EAV-UCD reference strain, with special emphasis on the analysis of M and GP5 proteins. The strains had a similar neutralization phenotype pattern when anti-EAV serum, derived from EAV seropositive horses, was used in the analysis. Meanwhile, low titers were observed when equine polyclonal anti-EAV reference sera were used in the assay. Argentine strains have almost the same amino acid substitutions, with the exception of LP01 strain, that mainly involves the first variable region V1, especially in neutralization sites B and C. However, they are fairly different from the EAV-UCD strain. Nevertheless, the nucleotide and amino acid differences observed among the Argentine strains LP02/R, LP02/C, LP02/P and LP-LT-ARG did not show any variations in the neutralization phenotype.

La arteritis viral equina (AVE) ocasiona infecciones, en su mayoría subclínicas, pero puede causar abortos y enfermedad respiratoria. Si bien se ha descrito un solo serotipo de AVE, existen diferencias en cuanto a la antigenicidad, patogenicidad y patrones de neutralización en las cepas de campo. Los ORF5 y ORF6 del virus codifican las proteínas de envoltura GP5 y M; la interacción entre estas proteínas es crítica para la infectividad. Los cambios en las secuencias de aminoácidos en la proteína GP5, especialmente en la región V1, afectan el fenotipo neutralizante, sin tener en cuenta variaciones aminoacídicas de otras proteínas virales. En este estudio evaluamos los fenotipos neutralizantes de las 5 únicas cepas de arteritis viral equina aisladas en Argentina y los comparamos con los de la cepa de referencia EAV-UCD por virus neutralización cruzada y análisis de secuencias aminoacídicas de las proteínas M y GP5. Las cepas argentinas presentaron un patrón de neutralización similar cuando se utilizaron sueros positivos del banco de sueros, mientras que fueron neutralizadas en menor medida por los sueros policlonales de referencia anti-AVE. A excepción de la cepa LP01, las cepas argentinas tienen casi las mismas sustituciones aminoacídicas en la primera región variable V1 de la proteína GP5, específicamente en los sitios neutralizantes B y C, pero difieren en gran medida respecto de la cepa de referencia EAV-UCD. Las diferencias encontradas en los aislamientos LP02/R, LP02/C, LP02/P y LT-LP-ARG no se reflejaron en variaciones en el fenotipo neutralizante.

Significance of immunofixation electrophoresis in the identification of M proteins / 第三军医大学学报

Objective To study the application of immunofixation electrophoresis(IFE) in typing M proteins. Methods Serum M proteins were detected in 43 patients and 20 normal controls by agarose gel IFE and rate nephelometery. Results Of 43 patients, 29 were affirmed to have M proteins, including 20 cases of IgG ?, 5 IgG ?, 2 IgM ?, 1 IgA ? and 1 ?. Conclusion The technology of IFE, characterized by easy differentiation of electrophoretic bands, simple operation and rapidity, has great value in typing M proteins.

An overview of monoclonal gammapathies.

The neoplastic proliferation of single clones of plasma cells causes synthesis of very large amount of monoclonal immunoglobulins consisting of only one type of heavy either the gamma, alpha, mu, delta or epsilon chain or only kappa or lambda light chains. Each monoclonal immunolobulin differs idiotypically from each other. These monoclonal immunoglobulins are also called paraproteins and are frequently associated with a broad heterogeneous group of plasma cell dyscrasias. Occasionally their presence is observed in a few benign conditions and in old age. In the present review a detailed account of different types of monoclonal gammapathies are described.