Protein characterization using electrophoresis and immunofixation; a case-based review of dogs and cats

Serum protein electrophoresis in European mink (Mustela lutreola): reference intervals and comparison of agarose gel electrophoresis and capillary zone electrophoresis

BACKGROUND

Knowledge of reference intervals for blood analytes, including serum protein fractions, is of great importance for the identification of infectious and inflammatory diseases and is often lacking in wild animal species.

MATERIAL AND METHODS

Serum samples were obtained from European minks enrolled in the breeding program (n = 55). Agarose gel electrophoresis (AGE) and capillary zone electrophoresis (CZE) were used to separate and identify protein fractions. Albumin, α1, α2, β, and γ-globulins fractions were identified in all mink sera by both electrophoresis methods. Reference intervals (90% CI) were determined following the 2008 guidelines of the Clinical Laboratory Standard Institute. The methods were compared using Passing-Bablok regression, Bland-Altman analysis, and Lin's concordance correlation.

RESULTS

A significant bias was found between methods for α1, α2, and γ-globulin. Lin's concordance correlation was considered unacceptable for α1, α2, and β-globulins. Differences for gender between methods were found for albumin and α2-globuins, which were higher for males than females. γ-globulins were higher for adults than young minks using both methods; however, α1 and α2-globulins were lower.

CONCLUSION

Both methods are adequate for identifying serum protein disorders, but the AGE and CZE methods are not equivalent. Therefore, reference intervals for each technique are required.

Evaluation of serum protein electrophoresis and immunofixation in dogs seropositive for various vector-borne pathogens

BACKGROUND

Canine vector-borne diseases (VBDs) induce non-specific dysproteinemias, detectable by serum protein electrophoresis (SPE). VBDs have been reported to induce a monoclonal gammopathy pattern. Monoclonal gammopathies are commonly the result of paraprotein (M-protein) produced by an immunoglobulin-secreting neoplasm.

OBJECTIVES

The aims of this study were to characterize and compare SPE and immunofixation (IF) changes, evaluate the performance of previously identified SPE and IF interpretative criteria, and identify M-proteins in a cohort of dogs seropositive for a VBD and with an unknown history for an immunoglobulin-secreting neoplasm.

METHODS

A total of 143 serum samples from dogs that tested seropositive for different vector-borne pathogens were assessed by SPE. Cases with abnormal globulin fractions were further characterized by IF. Protein fraction and IF labeling results were evaluated using Kruskal-Wallis with Dunn's multiple comparisons and principal component analysis (PCA).

RESULTS

IF was performed in 112 VBD-seropositive samples with dysproteinemia evaluated by SPE. Most (84/112, 75%) had a polyclonal expansion. Only two dogs had findings suggestive of an M-protein when considering both SPE and immunofixation. PCA clustered E.canis/A.phagocytophilum and B.gibsoni/CM.haematoparvum groups with relatively more γ-globulins than albumin and α-globulins, and the B.gibsoni/CM.haematoparvum group with more prominent IgA and IgM labeling than IgG labeling. Additionally, D.immitis clustered with more prominent β-globulins than γ-globulins and more IgG4 than IgG-FC.

CONCLUSIONS

The previously derived interpretative criteria suggested an M-protein in very few VBD-seropositive dogs. PCA identified SPE and immunofixation pattern differences between dogs seropositive for different infectious agents.

Navigating the clinical landscape: Update on the diagnostic and prognostic biomarkers in multiple myeloma

Multiple myeloma, a complex hematologic malignancy, has devastating consequences for patients, including dramatic bone loss, severe bone pain, and pathological fractures that markedly decrease the quality of life and impact the survival of affected patients. This necessitates a refined understanding of biomarkers for accurate diagnosis and prognosis of such severe malignancy. Therefore, this article comprehensively covers current research, elucidating the diverse spectrum of biomarkers employed in clinical settings. From traditional serum markers to advanced molecular profiling techniques, the review provides a thorough examination of their utility and limitations. Through this scoping review, emphasis is placed on the evolving landscape of personalized medicine, where biomarkers play a pivotal role in tailoring therapeutic strategies. The integration of genomic, proteomic, next generation sequencing and flow cytometric data further enriches the discussion, unravelling the molecular intricacies underlying disease progression. The updated criteria allow for the treatment of people who clearly would benefit from therapy and might live longer if treated before significant organ damage occurs. Navigating through the evolving diagnostic and prognostic paradigms in multiple myeloma, this article equips clinicians and researchers with crucial insights for optimizing patient care and advancing future therapeutic approaches.

In vitro gastrointestinal simulated digestion of three plant proteins: determination of digestion rate, free amino acids and peptide contents

Cassava protein (CP), barley protein (BP) and yellow pea protein (YPP) are important nutrient and integral constituent of staple in pet foods. It is known that the digestion of proteins directly influences their absorption and utilisation. In the present work, we performed in vitro simulated gastrointestinal digestion of three plant proteins as a staple for dog and cat food. The digestion rate of CP, BP and YPP in dog food was 56.33 ± 0.90%, 48.53 ± 0.91%, and 66.96 ± 0.37%, respectively, whereas the digestion rate of CP, BP, and YPP in cat food was 66.25 ± 0.72%, 43.42 ± 0.83%, and 58.05 ± 0.85%, respectively. Using SDS-polyacrylamide gel electrophoresis to determine the molecular weight (MW) of each protein and the products of their digestion, it was revealed that MW of digestion samples decreased, and MW during the small intestine phase was lower than that during the gastric phase. Peptide sequences of digested products were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS), and it was found that the total number of peptides in the small intestine digestion samples was higher than that in the gastric phase samples. The MW of peptides obtained from CP was within the range of 1000-1500 Da, while MW of peptides derived from BP and YPP was within the range of 400-2000 Da. In addition, free amino acids were mainly produced in the small intestine phase. Furthermore, the percentage of essential amino acids in the small intestine phase (63 ~ 82%) was higher than that in the gastric phase (37 ~ 63%). Taken together, these findings contribute to the current understanding of the utilisation of plant proteins in dog and cat foods and provide important insights into the selection and application of plant proteins as a staple in dog and cat foods.

Comparison of agarose gel and capillary zone electrophoresis methods with preliminary reference interval generation using capillary zone electrophoresis in bald eagles (Haliaeetus leucocephalus)

BACKGROUND

Electrophoresis can be used to aid in the diagnosis of different diseases in avian species. Capillary zone electrophoresis (CZE) is an automated method that is proposed to be superior to the dye methods used in agarose gel electrophoresis (AGE). However, reference intervals (RIs) for CZE in avian species and comparison studies between electrophoretic methods are lacking.

OBJECTIVES

The goals of the current study were to compare AGE and CZE methods and determine reference intervals for CZE using plasma from bald eagles (Haliaeetus leucocephalus).

METHODS

Heparinized plasma samples from 44 bald eagles (mean age 18.7 years) under managed care were examined by AGE and CZE. Method comparison analyses were completed, as well as the generation of preliminary RIs using the CZE method and ASVCP guidelines.

RESULTS

Passing-Bablok regression and Bland-Altman plots demonstrate that these methods are not equivalent. All fractions were significantly correlated between the methods except for alpha 1 globulin. Inter-assay and intra-assay CVs for CZE were lower or comparable to AGE and ranged from 2.4% to 15.4%, and 0.8% to 8.3%, respectively. CZE resolved more fractions than AGE with two fractions observed in the beta and gamma region vs one for AGE in each region.

CONCLUSIONS

CZE provided improved resolution and reproducibility for the quantitation of protein fractions in the bald eagle. Although most fraction results correlated with AGE, these methods were judged as not equivalent, necessitating method-specific Rls. Reference intervals generated from a limited number of mostly aged individuals under managed care should be considered preliminary; additional studies will aid in the production of more robust intervals.

Waldenström's Macroglobulinemia in a Normoproteinemic Dog with Atypical Bimorphic Plasmacytoid Differentiation and Monoclonal Gammopathy

A 2-year-old neutered female Small Munsterlander dog was presented for an insect bite. Physical examination revealed a poor body condition, a peripheral lymphadenomegaly, and suspected splenomegaly. A complete blood count (Sysmex XN-V) revealed marked leukocytosis with lymphocytosis and abnormal dot plots. An abnormal monomorphic lymphoid population and marked rouleaux formation were noted on the blood smear. Lymph node aspirates contained an atypical bimorphic population of lymphocytes, either with a plasmacytoid or a blastic appearance. This double population was also found in the spleen, liver, bone marrow, tonsils, and other tissues. Peripheral blood and lymph node clonality assays revealed clonal BCR gene rearrangement. Flow cytometry revealed a mixed population of small-sized B-cells (CD79a+ CD21+ MHCII+) and medium-sized B-cells (CD79a+ CD21- MHCII-) in lymph nodes and a dominant population of small-sized mature B-cells (CD21+ MHCII+) in peripheral blood. Though normoproteinemic, serum protein electrophoresis revealed an increased α2-globulin fraction with an atypical restricted peak, identified as monoclonal IgM by immunofixation. Urine protein immunofixation revealed a Bence-Jones proteinuria. A diagnosis of Waldenström's macroglobulinemia was made. Chemotherapy was initiated, but the dog was euthanized 12 months after the initial presentation due to marked clinical degradation.

Spurious capillary zone electrophoresis pattern in hypercholesterolemic dogs

Capillary zone electrophoresis (CZE) is a relatively new serum protein electrophoresis method with higher resolution than other electrophoretic techniques. Hypercholesterolemic dogs exhibit a peculiar CZE pattern. Specifically, they have a shoulder or peak immediately next to the albumin peak. We investigated the prevalence of this spurious peak in hypercholesterolemic dogs and its correlation with the serum cholesterol concentration. Moreover, possible discrepancies between the CZE and spectrophotometric (bromocresol green [BCG] method) albumin concentrations in those animals were evaluated, as well as the accuracy in measuring albumin by a different CZE fractionation system. We retrospectively enrolled 500 hypercholesterolemic and normotriglyceridemic dogs. Each electrophoretic curve was inspected visually to identify a spurious peak (prevalence of 68.8%). We chose 120 dogs to further investigate the albumin concentration; CZE albumin was significantly higher than measured using the BCG method. A weak but significant correlation (r = 0.412; p <0.0001) was observed between the magnitude of the spurious peak and the serum cholesterol concentration. Finally, the significant difference between CZE and BCG albumin measurement disappeared (p = 0.92) when the spurious peak was considered as α1-globulins instead of albumin.

Anaemia in Sheep Caused by Babesia and Theileria Haemoparasites

Piroplasmoses in sheep are caused by vector-borne apicomplexan protozoa, Babesia and Theileria. Different species are responsible for the disease; some species are more pathogenic than others and have a worldwide distribution. In this sense, these causative agents can cause anaemia in flocks. In general, these vector-borne diseases infect small ruminants and cause host-mediated pathology. In the case of Babesia species, a combination of different mechanisms is involved: red blood cell lysis due to intracellular parasite multiplication, activation of biogenic amines and the coagulation system with the possibility of disseminated intravascular coagulation. By contrast, less information is available on the different immunopathogenic mechanisms involved in the development of anaemia in sheep with theileriosis. However, the mechanisms of pathogenic action in theileriosis are similar to those studied in babesiosis. Diagnosis is based on compatible clinical signs, laboratory findings, specific diagnostic tests and the presence of the tick vector. Some of these tests detect the causative agent itself, such as direct identification by light microscopy and molecular analysis. In contrast, other tests detect the sheep's immune response to the organism by serology. Both diseases pose a significant diagnostic challenge for veterinary practitioners around the world. This review presents the most frequent clinical signs, pathogenesis and clinicopathological findings, diagnosis.

Urinary phoretograms performed by capillary electrophoresis in dogs with chronic disease with or without Leishmania infantum infection

INTRODUCTION

The study of early markers to detect kidney malfunction has increased in recent years since serum markers, such as creatinine increase when there is a 75% loss of renal mass. Urinary capillary electrophoresis (UCE) is an available laboratory technique that provides an easily interpretable electrophoretic pattern. This pattern in our study has been divided into five fractions as it is done in serum: fraction 1 migrating in the albumin zone, fraction 2 in the alpha₁-globulins zone, fraction 3 in the alpha₂-globulins zone, fraction 4 in the beta-globulins zone, and fraction 5 in the gamma globulins zone. UCE can be useful in the early diagnosis of renal disease.

MATERIAL AND METHODS

In this study, UCE was performed in dogs with azotemia and proteinuria due to chronic kidney disease (CKD) not related to Leishmania infantum (L. infantum) infection (G₁, n = 11) and dogs with CKD related to L. infantum infection (G₂, n = 17) and compared with reference intervals from healthy dogs (G₀, n = 123), with the aim of comparing their phoretograms and assessing changes in the fractions of the phoretograms based on the health status of individuals.

RESULTS

Fraction 2 was statistically augmented in dogs with CKD (G₁) when compared with the healthy population (G₀) and dogs infected by L. infantum (G₂). Fraction 3 was statistically increased in dogs with CKD (G₁) and dogs infected by L. infantum (G₂) compared with G_0. Fraction 4 was found to be statistically decreased in dogs with CKD (G₁) and dogs infected by L. infantum (G₂) compared with G_0. Fraction 5 was statistically higher in dogs with L. infantum (G₂) compared with G₀ and dogs with CKD (G₁). No statistical relationship was found between the protein to creatinine ratio and different fractions from the urinary phoretogram in the study population. No statistical relationship was found between serum and urine fractions in the study population.

DISCUSSION

The results of the present study suggest that UCE is a promising non-invasive technique that might be used as a part of the diagnostic and follow-up in dogs with kidney disease due to different pathologies.

Relationship between Serum Protein Electrophoresis, Endoscopic and Histopathological Scores in 99 Cats with Chronic Enteropathy

Simple Summary

Serum protein electrophoresis (SPE) is a laboratory test used to separate different protein fractions. It is used to investigate animals with hyperglobulinemia and to distinguish between monoclonal and polyclonal gammopathies. SPE can also highlight acute or chronic inflammation patterns which are useful in disease monitoring. SPE is effective in humans with intestinal bowel disease (IBD) and chronic liver diseases. In addition, hypergammaglobulinemia is a marker of extraintestinal manifestations in human IBD patients, which often includes hepatic and pancreatic disease. Concurrent pancreatic and/or hepatic diseases in cats with chronic enteropathy (CE) have often been found, which may contribute to SPE alterations. The present study investigated the relationship between SPE and endoscopy, histopathology, and hepatic and pancreatic ultrasonographic findings in ninety-nine cats diagnosed with CE. No significant differences were observed between SPE and endoscopic and histopathological severity scores. Cats with concurrent pancreatic and/or hepatic ultrasonographic alterations showed lower albumin, lower α-globulin, and higher γ-globulin levels than cats diagnosed with enteropathy alone. This study suggests that hepatic and/or pancreatic alterations may influence SPE fractions in cats with CE, and should form the basis for further prospective studies on cats with diaditis and triaditis.

Abstract

Few studies have investigated total protein (TP) and serum protein electrophoresis (SPE) in cats with chronic enteropathy (CE). Cats diagnosed with CE were evaluated to investigate the relationships between TP, SPE and endoscopy, histopathology, and extraintestinal involvement. Medical records were searched for cats with a history of chronic gastrointestinal signs and a final diagnosis of CE. Information on signalment, TP, SPE, endoscopic score, histopathological diagnosis and score, and concurrent hepatic or pancreatic ultrasonographic alterations was collected. Relationships between protein profiles and other variables were investigated. Ninety-nine cats were included in the study, 63 diagnosed with various degrees of bowel inflammation and 36 with small-cell alimentary lymphoma. The most common TP alteration was hypoproteinemia (24%). No significant differences were observed between protein profiles and endoscopic and histopathological severity scores. Forty-five cats showing concurrent pancreatic and/or hepatic ultrasonographic alterations, had significantly lower albumin, lower α-globulin, and higher γ-globulin levels than cats not showing concurrent alterations. Disease severity scores did not seem to influence the protein profile in cats with CE. Extraintestinal involvement may be suspected in cats with lower albumin and α-globulins and higher γ-globulins.

ASSESSMENT OF CAPILLARY ZONE ELECTROPHORESIS AND SERUM AMYLOID A QUANTITATION IN CLINICALLY NORMAL AND ABNORMAL SOUTHERN WHITE RHINOCEROS (CERATOTHERIUM SIMUM SIMUM) AND SOUTHERN BLACK RHINOCEROS (DICEROS BICORNIS MINOR)

Capillary zone electrophoresis (CZE) and an immunoassay for serum amyloid A (SAA) were used to examine serum samples from clinically normal and abnormal southern white rhinoceros (Ceratotherium simum simum) and southern black rhinoceros (Diceros bicornis minor) under managed care. CZE resolved seven fractions as well as subfractions for α1 globulins. Reference intervals were calculated for white rhinoceros (n = 33) and found to have some differences over previously reported intervals generated using agarose gel electrophoresis (AGE) methods in sera from free-ranging animals. In addition, the coefficient of variation related to fraction quantitation was found to be overlapping or superior to that reported for AGE. No significant differences were observed in CZE measurands and total protein between clinically normal and abnormal rhinoceros. In contrast to CZE, significant differences in SAA levels (P < 0.001) were observed in samples from the white rhinoceros between clinically normal and abnormal animals. In addition, in limited sample sets with repeated measures, SAA provided prognostic value. Future studies should generate more robust reference intervals and delineate the application of both SAA quantitation and CZE in routine health assessments and in prognostication.

Protein electrophoresis of non-traditional species: A review

EPH has been demonstrated to be a useful tool in companion animals while providing an opportunity to characterize globulinemias, including paraproteinemia. In EPH of non-traditional species, these same applications are important, but the primary use is to gauge the acute-phase and humoral immune responses. This includes the valid quantitation of albumin as well as the examination of fractions reflective of increases in acute-phase reactants and immunoglobulins. Agarose gel EPH and, more recently, capillary zone EPH have been applied to samples from these species. Performing these analyses provides special challenges in the placement of fraction delimits, generation of RIs, and interpretation of results. Recommended as part of routine bloodwork, EPH can also provide key results that are helpful in clinical and field-based health assessments as well as in prognostication.

Method comparison for serum protein electrophoretic M-protein quantification: Agarose gel electrophoresis and capillary zone electrophoresis in canine and feline sera

BACKGROUND

Densitometric quantification of myeloma paraproteins (M-proteins) is used to monitor secretory myeloma related disorders in humans and dogs. The previous work in dogs used agarose gel electrophoresis (AGE) but did not establish if other methods of serum protein electrophoresis, such as capillary zone electrophoresis (CZE), were comparable.

OBJECTIVES

We aimed to determine if the densitometric quantification of M-proteins using CZE would yield results comparable to AGE methods.

METHODS

Fifty-one serum samples from 22 dogs and 18 cats with confirmed monoclonal gammopathies and previously performed AGE were evaluated using CZE on a Sebia Minicap system. Samples were run in duplicate, and their M-proteins were densitometrically measured using the corrected perpendicular drop method previously described. Human-based quality control samples were used to determine the inter-run coefficient of variation (CV). Patient samples were used to calculate the intra-run CV. Method comparison was performed using simple linear regression, Passing-Bablok regression, and Bland-Altman analyses, and Medx evaluations.

RESULTS

Inter-run and intra-run CVs for CZE were 3.71%-7.65% and 2.89%-4.74%, respectively. Simple linear regression demonstrated an excellent correlation (r > 0.98). Passing-Bablok regression was compatible with the presence of proportional bias in the entire population, and Bland-Altman plots revealed a proportional bias in the feline cases. The Medx evaluation suggested that the two methods did not perform similarly in clinical samples with poor performance at a decision limit of 0.5 gm/dL.

CONCLUSIONS

Capillary zone electrophoresis is an acceptable method for M-protein densitometric quantification in canine and feline sera but cannot be used interchangeably with AGE-based evaluations.

Acute-phase protein synthesis: a key feature of innate immune functions of the liver

The expression of acute-phase proteins (APP's) maintains homeostasis and tissue repair, but also represents a central component of the organism's defense strategy, especially in the context of innate immunity. Accordingly, an inflammatory response is accompanied by significant changes in the serum protein composition, an aspect that is also used diagnostically. As the main site of APP synthesis the liver is constantly exposed to antigens or pathogens via blood flow, but also to systemic inflammatory signals originating either from the splanchnic area or from the circulation. Under both homeostatic and acute-phase response (APR) conditions the composition of APP's is determined by the pattern of regulatory mediators derived from the systemic circulation or from local cell populations, especially liver macrophages. The key regulators mentioned here most frequently are IL-1β, IL-6 and TNF-α. In addition to a variety of molecular mediators described mainly on the basis of in vitro studies, recent data emphasize the in vivo relevance of cellular key effectors as well as molecular key mediators and protein modifications for the regulation and function of APP's. These are aspects, on which the present review is primarily focused.

Diagnosis, treatment, and outcome in a dog with systemic Mycoleptodiscus indicus infection

Objective

Describe the diagnosis, clinical course, and management of a dog with systemic Mycoleptodiscus indicus infection.

Case Summary

A 5‐year‐old male neutered Giant Schnauzer presented with left eye anterior uveitis, peripheral lymphadenopathy, hyperglobulinemia, anemia, and thrombocytopenia. A diagnosis of M. indicus infection was made based on histopathology and PCR. Treatment with itraconazole and terbinafine resulted in resolution of the hyperglobulinemia, anemia, thrombocytopenia, and peripheral lymphadenopathy. No evidence of fungal organisms was identified on lymph node, liver, or ocular histopathology after 7 months of treatment.

New or Unique Information Provided

This case is the first report of a systemic M. indicus infection in an apparently immunocompetent dog. Clinical resolution was achieved with systemic itraconazole and terbinafine.

Diagnostic performance of routine electrophoresis and immunofixation for the detection of immunoglobulin paraproteins (M-Proteins) in dogs with multiple myeloma and related disorders: Part 2-Toward improved diagnostic performance

BACKGROUND

The diagnostic performance of routine electrophoresis (agarose gel electrophoresis [AGE] and capillary zone electrophoresis [CZE]) and species-specific immunofixation (IF) for the detection of immunoglobulin paraproteins (M-proteins) and diagnosis of secretory myeloma-related disorders (sMRD) can be improved. Available canine IF targets were IgG-FC, IgA, IgM, light chain (LC), IgG4, and free LC (fLC) antibodies.

OBJECTIVE

We aimed to review specific features associated with the presence of M-proteins in canine serum samples and the common features causing inaccurate reporting of M-proteins to improve the diagnostic performance of routine electrophoresis and IF for the detection of M-proteins.

METHODS

Features found in AGE, CZE, routine IF, IgG4 IF, and fLC IF of 100 canine serum samples from Part 1 of this study were evaluated by simple and multivariate logistic regression to identify factors associated with the presence of M-proteins. Cases falsely called negative or positive for M-proteins were reviewed to identify the common features that could be used to increase the diagnostic performance of SPE and IF for M-protein detection.

RESULTS

The presence of hypogammaglobulinemia or any peak taller than albumin was associated with an M-protein. Total protein concentrations, globulin concentrations, or peaks wider than albumin were not associated with an M-protein. Free LC sMRD cases were not diagnosed by SPE and routine IF. Cases with infectious and inflammatory etiologies had a restricted polyclonal gammopathy with multiple γ-globulin restrictions resulting in some false-positive results. SPE combined with all available IF results and the specific features identified in this study had an estimated sensitivity of 95.1% and specificity of 81.4%.

CONCLUSIONS

The identified criteria of this study increase the diagnostic performance of the electrophoretic evaluation for M-proteins.

Diagnostic performance of routine electrophoresis and immunofixation for the detection of immunoglobulin paraproteins (M-Proteins) in dogs with multiple myeloma and related disorders: Part 1 - Current performance

BACKGROUND

Routine electrophoresis [agarose gel electrophoresis (AGE) and capillary zone electrophoresis (CZE)] and species-specific immunofixation (IF) can be used alone or in combination to detect immunoglobulin paraprotein (M-protein) and diagnose secretory myeloma-related disorders (sMRD).

OBJECTIVE

We aimed to evaluate the performance of AGE, CZE, CZE plus IF (CZE-IF), and AGE plus IF (AGE-IF) for detecting canine serum M-proteins.

METHODS

One hundred canine cases that had AGE, CZE, and routine IF performed on serum, and where B-cell lineage neoplasia (such as B-cell lymphoma and plasma cell tumors) had been diagnosed or excluded, were evaluated. Routine IF protocols targeted IgG-FC, IgA, and IgM heavy chains and light chains. IgG4 IF and free light chain IF were also performed. B-cell lineage neoplasms with an M-protein detected, using any available method, were classified as sMRD. Datasets from AGE, CZE, IF, CZE-IF, and AGE-IF (electrophoretograms, gel images, and fraction concentrations) were composed and reviewed. The sensitivity, specificity, and Youden's index for M-protein detection were determined for each dataset.

RESULTS

The combination of AGE-IF or CZE-IF was more sensitive (82.9%) than CZE alone (72.0%) or AGE alone (64.6%) and more specific (66.1%, 48.3%, 51.7%, respectively). Immunofixation could be used alone to detect M-proteins (sensitivity 82.9%, specificity 61.9%), but there were technical challenges that complicated the performance and evaluation of the test. Myeloma with free light chains only was found in 5/41 cases of sMRD.

CONCLUSIONS

Adding routine IF to routine electrophoresis increases the ability to accurately identify M-proteins; however, there is still room for further diagnostic performance improvements.

Serum protein profiles and C-reactive protein in natural canine filariasis

Background and Aim:

Canine filariasis is caused by several species of filarial worms. The pathophysiological response to infection is mainly due to the filaria lifecycle. Laboratory detection methods to assess the pathological alterations characteristic of filariasis are needed urgently. Serum protein profiles and C-reactive protein (CRP) levels are used widely to diagnose several animal diseases. This study aimed to determine the serum protein profiles and CRP levels in dogs infected with Dirofilaria immitis or Brugia pahangi or both parasites.

Materials and Methods:

Blood samples were collected from 980 dogs presenting at animal hospitals and veterinary clinics in Bangkok and its vicinity. The presence of microfilaria in samples was determined using a buffy coat smear and staining with Wright–Giemsa. The sheathed and unsheathed microfilaria species were identified by acid phosphatase staining. Forty positive samples were tested. The serum protein profiles were identified by agarose gel electrophoresis. The CRP concentration was measured using a fluorescent immunoassay.

Results:

Albumin levels and albumin-to-globulin ratios were significantly lower, and total protein, β2 globulin, and γ globulin levels were significantly elevated in dogs infected with D. immitis and B. pahangi compared with reference values in normal dogs. The average CRP concentrations in dogs infected with D. immitis or B. pahangi were 69.9 and 12.9 mg/L, respectively.

Conclusion:

The total protein and γ globulin levels increased in canine filariasis compared with the normal reference range. The CRP concentration in dogs infected with D. immitis was extremely high, whereas that in dog infected with B. pahangi was normal.

Retrospective evaluation of the use of the International Myeloma Working Group response criteria in dogs with secretory multiple myeloma

BACKGROUND

Current recommendations for monitoring disease progression and response to treatment in humans with multiple myeloma include evaluation of serum paraprotein (M-protein) concentration. Densitometry, species-specific radial immunodiffusion (RID) and ELISA methods can be used to quantify M-proteins.

OBJECTIVE

Retrospectively evaluate use of the International Myeloma Working Group (IMWG) response criteria for humans in dogs with multiple myeloma.

ANIMALS

Sixteen dogs with a diagnosis of multiple myeloma, M-protein documented by serum protein electrophoresis (SPE) and immunofixation (IF) in an initial sample and subsequent electrophoretic evaluation of serial samples.

METHODS

Retrospectively, densitometric M-proteins, RID and globulins were measured and characterized according to IMWG criteria. Available clinical history was reviewed. Overall survival time (OST) was calculated from initial electrophoretic evaluation to death or last contact.

RESULTS

All cases received some form of nonstandardized chemotherapy. Complete response (CR), a lack of detectable M-protein by SPE and IF, was documented in 1 case. Median survival was longer for dogs that attained ≥90% densitometric M-protein reduction (630 days) than for those that did not attain at least 50% reduction in densitometric M-protein (284 days; log rank P = .006). Five dogs were defined as having progressive disease (M-protein increase of >25% and at least 0.5 g/dL from nadir), which correlated with concurrent or subsequent clinical deterioration. Response criteria categorized by serum globulins or RID was not correlated with OST or clinical findings.

CONCLUSIONS AND CLINICAL IMPORTANCE

Densitometric M-protein characterized using IMWG response criteria correlated with OST and clinical findings. Densitometric M-protein detection should be used to monitor dogs with multiple myeloma.

Polyclonal B-cell lymphocytosis in English bulldogs

Background

English bulldogs disproportionally develop an expansion of small B‐cells, which has been interpreted as B‐cell chronic lymphocytic leukemia (BCLL). However, clonality testing in these cases has often not been supportive of neoplasia.

Hypothesis

English bulldogs have a syndrome of nonneoplastic B‐cell expansion.

Animals

Eighty‐four English bulldogs with small‐sized CD21+ B‐cell lymphocytosis in the blood as determined by flow cytometry.

Methods

This is a retrospective study. We characterized this syndrome by assessing B‐cell clonality, clinical presentation, flow cytometric features, and immunoglobulin gammopathy patterns. We identified 84 cases with CD21+ lymphocytosis among 195 English bulldogs with blood samples submitted to the Colorado State University‐Clinical Immunology laboratory for immunophenotyping between 2010 and 2019. Flow cytometry features were compared to normal B‐cells and BCLL cases. PCR for antigen receptor rearrangements (PARR) by multiple immunoglobulin primers was performed to assess B‐cell clonality. A subset of cases with gammopathy were examined by protein electrophoresis, immunofixation, and immunoglobulin subclass ELISA quantification.

Results

Seventy percent (58/83) of cases had polyclonal or restricted polyclonal immunoglobulin gene rearrangements, suggesting nonmalignant B‐cell expansion. The median age of all dogs in the study was 6.8 years and 74% were male. The median (range) lymphocyte count was 22 400/μL (2000‐384 400/μL) and B‐cells had low expression of class II MHC and CD25. Splenomegaly or splenic masses were detected in 57% (26/46) of cases and lymphadenopathy in 11% (7/61). Seventy‐one percent (52/73) of cases had hyperglobulinemia and 77% (23/30) with globulin characterization had IgA ± IgM polyclonal or restricted polyclonal gammopathy patterns.

Conclusions and Clinical Importance

Polyclonal B‐cell lymphocytosis in English bulldogs is characterized by low B‐cell class II MHC and CD25 expression, splenomegaly and hyperglobulinemia consisting of increased IgA ± IgM. We hypothesize that this syndrome has a genetic basis.

The Electrophoretic Pattern of Serum Proteins in Sheep with Naturally Acquired Gastrointestinal Nematode Infections

The objective of this study was to describe the serum protein pattern in sheep with naturally acquired gastrointestinal parasitosis and to compare the distribution of protein fractions with the results obtained in animals with negative fecal examination results. Fecal and blood samples were taken from twenty-nine sheep positive for nematode eggs and twenty-four animals with negative results of fecal examination. Between the evaluated groups of sheep significant differences were noted in the relative mean values for all protein fractions and for albumin/globulin ratio (p<0.01 and p<0.001). The concentrations of total proteins showed no significant differences between both groups of sheep. The absolute mean values of albumin, α2-globulins and A/G ratio were significantly lower, the mean concentrations of α1-, β-, γ1- and γ2-globulins significantly higher in the nematode positive group of sheep (p<0.01 and p<0.001). In the nematode positive group the protein electrophoretic pattern showed a double α2-zone in three sheep and the γ-globulin zones were characterized by a diffuse higher broad and wide peaks. The presented results indicate that the gastrointestinal parasitic infections in sheep alter the distribution of serum proteins, and suggest their usefulness in animals with unchanged serum protein concentrations. The study brings new findings and extends the knowledge about the metabolic responses and consequences of gastrointestinal parasitic infections in sheep, particularly with regard to alterations in protein metabolism.

Identification of canine IgG and its subclasses, IgG1, IgG2, IgG3 and IgG4, by immunofixation and commercially available antisera

Immunofixation is a diagnostic and research tool used for characterizing the electrophoretic location of immunoglobulin fractions in serum and urine. Commercially available polyclonal antisera which discriminate two IgG subclasses (IgG1 and IgG2) are available and commonly used. More recently, four IgG subclasses have been defined in the dog based on cDNA data. Archived serum from 16 dogs with naturally occurring monoclonal or biclonal gammopathies were characterized using routine serum protein electrophoresis, routine immunofixation and LCMS/MS as 3 IgA, 3 IgM, 2 IgG2, 7 IgG3 and 2 IgG4 heavy chain predominant cases. Immunofixation reactivity of a panel of commercially available antisera to these cases was characterized. The anti-human IgG antisera was the only tested antisera which bound all canine IgG restricted bands without also labelling IgA or IgM heavy chains or light chains. The tested polyclonal antisera labeled as reacting with canine IgG2 bound canine IgG2, IgG3, IgA and IgM and may label IgG1. The tested polyclonal antisera labeled as reacting with canine IgG1 bound the canine IgG4 bands but not those identified as IgA, IgM, IgG2 or IgG3 and likely did not bind IgG1. This data suggests that commercially available polyclonal IgG1 antisera (Bethyl A40 - 120A and Bio-Rad AHP947) can be used to positively but possibly not selectively identify canine IgG4 by immunofixation.