IgM and IgA rheumatoid factors in canine polyarthritis

Prevalence of antinuclear antibodies and rheumatoid factor titers in dogs with arthritis secondary to leishmaniosis (Leishmania infantum)

Dogs with infectious arthritis may occasionally exhibit positive serum antinuclear antibody (ANA) and rheumatoid factor (RF) titers; however, relevant data are sparse for arthritis secondary to canine leishmaniosis (CanL) caused by Leishmania infantum. We determined the prevalence of positive serum ANA and RF titers in dogs with arthritis secondary to CanL. Blood samples from adult, client-owned dogs with purulent arthritis secondary to CanL, without any comorbidities, were collected for diagnostic purposes. Serum ANA titers were measured by immunoperoxidase test and RF titers by the Rose-Waaler latex test. Twelve of 23 dogs enrolled prospectively in our study had clinical arthritis, and 11 of 23 had subclinical arthritis. Based on LeishVet clinical staging, 7 dogs had clinical stage II disease, 11 had clinical stage III disease, and 5 had stage IV. None of the 23 dogs was seropositive for ANA; 3 of 23 were positive for RF. ANA and/or RF seropositivity, in dogs with CanL-associated arthritis, appears to be weak, if present at all. Based on our results, positive serum ANA and RF titers should not be expected in dogs with arthritis secondary to CanL.

Point prevalence and clinical course of proteinuria in dogs with idiopathic non-erosive immune-mediated polyarthritis

Objectives

To describe the point prevalence and clinical course of proteinuria in dogs diagnosed with idiopathic non‐erosive immune‐mediated polyarthritis.

Materials and Methods

Cases presenting to a single referral centre with a diagnosis of idiopathic non‐erosive immune‐mediated polyarthritis were retrospectively recruited from January 2009 to August 2018. Data including signalment, urinalysis, clinicopathological results, cytology from arthrocentesis, treatment and long‐term follow‐up were analysed. Dogs were defined as: non‐proteinuric (UPC <0.2), borderline proteinuric (UPC 0.2‐0.5) or overtly proteinuric (UPC >0.5).

Results

Fifty‐eight dogs met the inclusion criteria. Twenty‐two dogs were overtly proteinuric (38%), eight dogs were borderline proteinuric (14%) and 28 dogs were non‐proteinuric (48%). Repeated urinalysis was performed in nine of 12 dogs with UPC greater than 2.0. The UPC decreased in all nine dogs, with the UPC decreasing to less than 0.5 in 44% of dogs. A greater than 50% decrease in UPC was noted in 44% of dogs, despite seven of nine (77%) receiving prednisolone as either monotherapy or in conjunction with an adjunctive immunosuppressive medication.

Clinical Significance

Proteinuria was common in this cohort of dogs diagnosed with primary idiopathic non‐erosive immune‐mediated polyarthritis. The use of prednisolone does not appear to be contraindicated in proteinuric dogs with idiopathic non‐erosive immune‐mediated polyarthritis.

Characterization of canine anti-mouse antibodies highlights that multiple strategies are needed to combat immunoassay interference

Immunoassays are widely used for detection and quantification of analytes in biological samples, but are vulnerable to analytical errors caused by interfering sample substances. Of particular interest are endogenous anti-animal antibodies that may bind to the immunoassay antibodies and cause erroneous test results. This phenomenon is a hazard to patient safety in both human and veterinary medicine. Here, we demonstrate that anti-mouse antibodies in dogs bind selectively to different regions of the murine IgG molecule, cross-react with IgG from different species, and consist of all major antibody classes present in canine serum (IgA, IgG and IgM). The antibody characteristics varied among individuals and their prevalence differed between two dog breeds. The selective binding to different IgG regions suggests that the antibodies might not originate from immunization through exposure to mice or other species. These findings show that canine anti-mouse antibodies are highly heterogeneous in nature and therefore require a combination of strategies to be counteracted.

Detection of IgM-rheumatoid factor and anti-citrullinated protein antibodies in healthy horses and their comparison

Rheumatoid factor (RF) is used in human and veterinary medicine in the form of IgM RF traditionally to support the diagnosis of rheumatoid arthritis (RA). In the latest diagnostic criteria, presence of anti - citrullinated protein antibodies (ACPA) was added to the grading system for the diagnosis of RA in humans. A change which is not integrated or routinely used in veterinary medicine. The criteria changed partly because of RF's diagnostic shortcomings, which include its increased titer detection in humans with non-rheumatoid diseases, inability to predict the disease and increased titers over the limit in the older population. Clinical signs similar to human RA were reported in horses in a condition known as idiopathic polysynovitis. Similarities in the clinical presentation to RA raised a question to the usability of RF and ACPA in horses. In our study, sixty clinically healthy horses, ranging from 3 days to 30 years of age, were evaluated for their serum levels of IgM RF. 55 of these horses were tested for ACPA, using methods of ELISA measuring Anti - CFG (Anti citrullinated fibrinogen antibody). The results of the study demonstrated the existence of an age-dependent increase in the level of IgM RF up to the age of about 9 years and ACPA's independence of the horse's age as well as both markers independence of the horse sex.

Clinical features and pathological joint changes in dogs with erosive immune-mediated polyarthritis: 13 cases (2004-2012)

OBJECTIVE To evaluate the clinical features and pathological joint changes in dogs with erosive immune-mediated polyarthritis (IMPA). DESIGN Retrospective case series. ANIMALS 13 dogs with erosive IMPA and 66 dogs with nonerosive IMPA. PROCEDURES The medical record database of a veterinary teaching hospital was reviewed to identify dogs with IMPA that were examined between October 2004 and December 2012. For each IMPA-affected dog, information extracted from the medical record included signalment, diagnostic test results, radiographic findings, and treatments administered. Dogs were classified as having erosive IMPA if review of radiographs revealed the presence of bone lysis in multiple joints, and descriptive data were generated for those dogs. All available direct smears of synovial fluid samples underwent cytologic evaluation. The synovial fluid total nucleated cell count and WBC differential count were estimated and compared between dogs with erosive IMPA and dogs with nonerosive IMPA. RESULTS 13 of 79 (16%) dogs had erosive IMPA. Dogs with erosive IMPA had a mean ± SD age of 7.1 ± 2.4 years and body weight of 8.3 ± 3.4 kg (18.3 ± 7.5 lb). All 13 dogs had erosive lesions in their carpal joints. The estimated median synovial fluid lymphocyte count for dogs with erosive IMPA was significantly greater than that for dogs with nonerosive IMPA. All dogs received immunosuppressive therapy with leflunomide (n = 9), prednisone (3), or prednisone-azathioprine (1). CONCLUSIONS AND CLINICAL RELEVANCE Results indicated erosive IMPA most commonly affected the carpal joints of middle-aged small-breed dogs. Further genetic analyses and analysis of lymphocyte-subsets are warranted for dogs with erosive IMPA.

Anti-leishmania antibodies in cerebrospinal fluid from dogs with visceral leishmaniasis

Visceral leishmaniasis in Brazil is caused by Leishmania (Leishmania) chagasi and the dog is its most important reservoir. The clinical features in dogs include loss of weight, lymphadenopathy, renal failure, skin lesions, fever, hypergammaglobulinemia, hepatosplenomegaly, anemia, and, rarely, neurological symptoms. Most infected animals develop active disease, characterized by high anti-leishmania antibody titers and depressed lymphoproliferative ability. Antibody production is not primarily important for protection but might be involved in the pathogenesis of tissue lesions. An ELISA test was used to determine if there is an association between neurological symptoms and the presence of anti-L. chagasi antibodies in cerebrospinal fluid (CSF). Thirty serum and CSF samples from symptomatic mixed breed dogs (three with neurological symptoms) from a region of high incidence of visceral leishmaniasis in Brazil were examined for antibody using total parasite antigen and anti-dog IgG peroxidase conjugate. A high level of L. chagasi antibodies was observed in sera (mean absorbance SD, 1.939 0.405; negative control, N = 20, 0.154 0.074) and CSF (1.571 0.532; negative control, N = 10, 0.0195 0.040) from all animals studied. This observation suggests that L. chagasi can cause breakdown of filtration barriers and the transfer of antibodies and antigens from the blood to the CSF compartment. No correlation was observed between antibody titer in CSF and neurological symptoms.

A review of immunologic diseases of the dog

The following review is based on notes used in the teaching of clinical immunology to veterinary students. Immune diseases of the dog are placed into six different categories: (1) type I or allergic conditions; (2) type II or auto- and allo-antibody diseases; (3) type III or immune complex disorders; (4) type IV or cell-mediated immune diseases; (5) type V conditions or gammopathies; and (6) type VI or immunodeficiency disorders. Separate discussions of transplantation immunology and the use of drugs to regulate unwanted immune responses are also included.

The production of arthritis in beagles by an immunological reaction to bovine serum albumin

Arthritis was produced in beagles by the immunological reaction to bovine serum albumin (BSA). Dogs immunized with BSA showed the development of delayed type-hypersensitivity response to BSA and the significant increase in the titer of serum anti-BSA antibodies. The development of arthritis and the increase in a number of nucleated cells in synovial fluid were observed by the injection with BSA into the knee joints of immunized dogs. The synovial membrane of BSA-injected joints revealed a remarkable villous hyperplasia of membrane, and an infiltration of lymphocytes and plasma cells around vessels, resulting in a lymphoid nodule-like formation. The depositions of IgG and C3 on the surface of the synovial membrane were also observed in BSA-injected joints. Histopathological and immunopathological findings indicated that the immune response to BSA in the knee joints could induce a rheumatoid arthritis like chronic synovitis in dogs.