Increased HAS2-driven hyaluronic acid synthesis in shar-pei dogs with hereditary cutaneous hyaluronosis (mucinosis)

The Chinese shar-pei dog is known for its distinctive feature of wrinkled and thickened skin, defined as primary or hereditary cutaneous mucinosis. In a recent report, we identified the mucinous material deposited in the shar-pei skin as the polysaccharide hyaluronan (HA). In the present work, the molecular and cellular mechanisms underlying this phenotype have been identified in dermal fibroblasts isolated from shar-pei dogs. The production of HA, which appeared to be mainly associated with cell membrane protrusions and also intracellular, was higher in shar-pei fibroblasts than in control cells. The HA accumulation is related to a higher mRNA expression of the isoform HAS2 of the HA-synthesizing enzyme family, hyaluronan synthases (HAS). The higher expression of HAS2 in shar-pei fibroblasts was confirmed at the protein level. The other HAS isoenzymes, HAS1 and HAS3, and the HA-degrading enzymes, Hyal1 and Hyal2, were not differentially expressed in shar-pei fibroblasts compared with cells from control dogs. Fibroblasts from shar-pei dogs and from control dogs are morphologically different as observed by transmission electron microscopy. Scanning electron microscopy revealed a large number of cellular protrusions with associated globular deposits. Electron microscopy after labelling with biotinylated HA-binding protein confirmed an increased HA content in shar-pei fibroblasts, which could be localized in several subcellular structures. The authors propose the name hereditary cutaneous hyaluronosis (HCH) for affected dogs, because it better defines the cutaneous mucinosis of shar-pei dogs.     

Cutaneous mucinosis in shar-pei dogs is due to hyaluronic acid deposition and is associated with high levels of hyaluronic acid in serum

Cutaneous mucinosis affects primarily shar-pei dogs. Hyaluronic acid (HA) is considered to be the main component of mucin and CD44 is the major cell surface receptor of HA, necessary for its uptake and catabolism. The aims of this study were to identify the composition of the mucin in cutaneous mucinosis of shar-pei dogs, investigate the correlation between the deposition of HA and the expression of CD44, and determine whether shar-pei dogs with cutaneous mucinosis presented with elevated levels of serum HA. In skin biopsies, the mucinous material was stained intensely with Alcian blue and bound strongly by the hyaluronan-binding protein. No correlation was found between the degree of HA deposition in the dermis and the expression of CD44 in the skin of shar-pei dogs affected or unaffected by cutaneous mucinosis. A clear positive correlation was found between the existence of clinical mucinosis and the serum HA concentration. In control dogs, serum HA ranged from 155.53 to 301.62 microg L(-1) in shar-pei dogs; without mucinosis it ranged from 106.72 to 1251.76 microg L(-1) and in shar-pei dogs with severe mucinosis it ranged between 843.51 to 2330.03 microg L(-1). Altogether, the results reported here suggest that mucinosis of shar-pei dogs is probably the consequence of a genetic defect in the metabolism of HA.     

Serum and skin IgA concentrations in normal and atopic dogs

Objective To compare serum and skin surface IgA concentrations from atopic and normal dogs.
Procedure IgA concentrations in sera and skin washings of 20 clinically normal dogs that had no history of pruritus or skin disease were compared to those obtained in 20 dogs with a diagnosis of atopy determined by history, clinical examination and positive intradermal skin test.
Results There was no significant difference in the mean serum IgA concentration in normal dogs (252 ± 187 mg/L) versus atopic animals (314 ± 327). When skin washings from all sites in both groups were compared, atopic dogs had significantly greater concentrations of IgA in their skin washings than normal dogs as evaluated by an enzyme-linked immunoassay (P < 0.001). However, there was no significant difference between the individual sites of the skin washings of atopic and normal dogs.
Conclusion IgA concentrations of skin washings in atopic dogs were greater than in normal dogs. Further investigations need to determine if the greater concentrations were caused by nonspecific inflammation or by secretion of allergen-specific IgA onto the skin surface.     

Immune-mediated vasculitis in a shar-pei with swollen hock syndrome

A castrated male shar-pei was presented for episodes of lethargy, swelling of the tarsal joints, and polydipsia with polyuria. Histological examination of biopsies from skin overlying the tarsi and direct immunoperoxidase immunohistochemical staining confirmed immune complex vasculitis, suggesting a role for immune complex deposition in the pathogenesis of shar-pei fever.     

Possible immunodeficiency in related rottweiler dogs

A litter of eight rottweiler pups is described in which two dogs died before the age of six months from systemic inflammatory disease, and two further pups developed inflammatory skin disease. All seven pups tested had a markedly low serum immunoglobulin A (IgA) concentration (< 0.1 mg/ml) and six of these dogs also had subnormal serum IgG (< 0.1 to 6.4 mg/ml). Tissues taken from three diseased pups were examined immunohistochemically using a number of lymphoid markers. Secondary lymphoid tissues had a paucity of CD3+ T lymphocytes, although T cells were found within some inflammatory foci. B-lymphocyte follicles were present within lymphoid tissues, but there were irregularities of plasma cell development and a lack of plasma cells of all classes within mucosal and cutaneous sites. Inflammatory lesions were dominated by macrophages expressing class II molecules of the major histocompatibility complex. Serum immunoglobulins were also investigated in eight related, clinically normal adult dogs. Five of these dogs, from two separate breeding lines, had subnormal serum IgA (< 0.1 to 0.15 mg/ml). The spectrum of disease within the affected litter may be consistent with an underlying inherited immunological defect, and the observed immunological abnormalities suggest a more complex disorder than simple IgA deficiency.     

Evaluation of systemic and secretory IgA concentrations and immunohistochemical stains for IgA-containing B cells in mucosal tissues of an Irish setter with selective IgA deficiency

Immunoglobulin A is the predominant secretory antibody at mucosal surfaces. In the dog, immunoglobulin A deficiency (IgAD) is characterized by low to absent serum IgA and normal to elevated serum immunoglobulin G (IgG) and immunoglobulin M (IgM) concentrations. However, studies comparing serum and secretory IgA in dogs have often documented a poor correlation, suggesting that serum concentrations should not be used to estimate mucosal secretion of this antibody. This report demonstrates the concurrent use of serum IgA, IgG, and IgM; secretory IgA (from bronchoalveolar lavage fluid); and immunohistochemical stains on bronchial and duodenal mucosa for IgA-containing B cells in a young Irish setter with recurrent respiratory and gastrointestinal signs.     

Dermatologic disorders of Chinese Shar Peis: 58 cases (1981-1989).

A retrospective study on the skin diseases of Chinese Shar Peis was conducted over a 9-year period. Skin disease was found in 58 (49.2%) of the 118 dogs studied. Folliculitis was the most common clinical finding (43 of 58 dogs). In 6 dogs, there was no apparent reason for the folliculitis; however, it was secondary to allergic dermatitis, demodicosis, IgA deficiency, or hypothyroidism in the other dogs. Approximately 20% of the dogs had more than one of these disorders. Serum IgA concentration was measured in 7 dogs and was low in all 7.     

Skin disease in dogs associated with zinc deficiency: a report of five cases

The literature on zinc deficiency is discussed. Five cases of skin disease in dogs associated with zinc deficiency are described. All the animals were Labrador Retrievers. Lesions in all cases were similar and consisted of a dry hair coat, mild generalized seborrhoea sicca and bilaterally symmetrical, focal, yellow crusts and scale over the distal parts of the limbs and the chin. These were accompanied by ceruminous otitis externa and superficial lymphomegaly. The serum and hair zinc concentrations were markedly subnormal in all cases. Treatment with oral zinc sulphate produced a rapid resolution of physical signs and restoration of serum zinc concentrations to the reference range. All dogs were fed on unsupplemented cereal-based diets. The clinical condition appeared to arise from dietary imbalances rather than an absolute deficiency of zinc, although there may have been accompanying inherent defects of zinc absorption in some cases.     

Cutaneous mucinosis and mastocytosis in a shar-pei

A 7-year-old shar-pei was presented because of a recurrent dermatologic condition. Skin biopsies revealed an idiopathic (primary) cutaneous mucinosis that initially responded to corticosteroids. The condition reappeared 2 years later and subsequent biopsies revealed a mast cell tumor in some of the skin sites previously diagnosed with mucinosis.     

Development of a fecal sample collection strategy for extraction and quantification of fecal immunoglobulin A in dogs

OBJECTIVE: To develop a fecal sample collection strategy and quantification method for measurement of fecal IgA concentrations in dogs. SAMPLE POPULATION: Fecal samples from 23 healthy pet dogs of various breeds. PROCEDURES: Immunoglobulin A was extracted from fecal samples. An ELISA for the measurement of fecal IgA concentrations was established and analytically validated. Intraindividual variation of fecal IgA was determined by calculation of coefficients of variation. A sample collection strategy was developed on the basis of results of intraindividual variation of fecal IgA concentrations. A reference range for fecal IgA concentrations was determined. RESULTS: The method for extraction and quantification of fecal IgA was determined to be sufficiently sensitive, reproducible, accurate, and precise. On the basis of the intraindividual variability of our results, the determined fecal sample collection strategy required analysis of a total of 4 fecal samples/dog, with each fecal sample collected on 2 consecutive days with 28 days between sample collection periods (ie, days 1 and 2 followed by days 28 and 29). Reference range values for fecal IgA concentration were 0.22 to 3.24 mg/g of feces. CONCLUSIONS AND CLINICAL RELEVANCE: Methods of fecal IgA extraction and quantification used in our study allow for identification of dogs with consistently low fecal IgA concentrations. Use of these techniques will enable future investigations into possible associations between low fecal IgA concentrations and signs of gastrointestinal disease in dogs.     

Relative deficiency in IgA production by duodenal explants from German shepherd dogs with small intestinal disease

Matched samples of serum, saliva and tears were collected from four groups of dogs; two of the groups were German shepherd dogs (GSDs) either with (Group 1) or without (Group 4) a variety of small intestinal disorders; the remaining two groups were dogs of other breeds, again with (Group 2) or without (Group 3) small intestinal disease. Capture ELISAs were used to measure IgG, IgM, IgA and albumin concentrations within these samples; intestinal humoral immune status of clinical cases was assessed by quantifying immunoglobulin production from duodenal explant cultures.There were no significant differences in IgG, IgM or IgA concentrations in serum, saliva or tears between the different groups of dog. Moreover, no significant differences were noted between groups for IgG, IgM and IgA salivary and tear secretory indices. IgA production by 24-h explant cultures was significantly lower in GSDs compared with non-GSDs with small intestinal disease (groups 1 and 2, respectively), but the numbers of lamina propria IgA(+) plasma cells in duodenal biopsies were not different between groups. These results suggest that there may be a relative deficiency in local IgA secretion in GSDs with small intestinal enteropathies, which is not reflected in either serum IgA concentrations, or in secretion at unaffected mucosal sites. It remains to be determined whether such a deficiency is a breed-related primary defect, or whether it arises secondary to the pathological processes within the intestinal mucosa.     

Hyperadrenocorticism in 10 dogs with skin lesions as the only presenting clinical signs

Ten dogs that had skin lesions as the only presenting signs of hyperadrenocorticism (HAC) and as the owners' primary complaint are described. Dogs were included if the initial examination was for skin disease, there were no signs of systemic illness on initial presentation and there was a confirmed diagnosis of HAC by specific screening tests. Dogs were excluded if they had a severe disease that might interfere with screening tests for HAC or if the screening tests were not diagnostic. There were five males and five females; six dogs were intact. Nine dogs were diagnosed at ≥7 years. Eight dogs weighed ≤10 kg. Alopecia was present in nine dogs. Eight dogs had bacterial pyoderma, five had hyperpigmentation, and four had thin skin. One dog had unresolved dermatophytosis. Skin lesions resolved after treatment in eight dogs. One dog was not treated and one was lost to follow-up. This study showed that skin lesions may be the only clinical signs of HAC. The presence of the more common clinical signs of HAC, such as a non-pruritic, truncal alopecia and/or thin skin, without any systemic signs of HAC and/or the presence of poorly responsive skin infections warrant screening for this disease.     

Agammaglobulinemia in a horse.

Immunologic deficiency was suspected in an 18-month-old Standardbred horse with persistent fever, multifocal bacterial infection, and neutropenia with a large number of immature neutrophils. Serum protein electrophoresis revealed marked depression of the gamma-globulin fraction (0.2 g/100 ml). Immunologic testing and histologic examination of lymphoid tissues identified the immune deficit as agammaglobulinemia. Serum concentrations of immunoglobulin (Ig)G and IgG(T) were initially low and declined with time; IgM and IgA were not detectable. The horse failed to produce antibodies when inoculated with foreign antigens but had a positive cell-mediated skin reaction to intradermal phytolectin injection, and lymphocytes responded normally to in vitro stimulation by mitogens. Histologic examination of lymphoid tissues revealed absence of germinal centers and plasma cells.     

Selective IgM deficiency and abnormal B-cell response in a foal.

Selective IgM deficiency was diagnosed in a 3-month-old Standardbred colt that was referred for chronic respiratory tract disease. Immunoglobulin quantification revealed normal IgG and IgA concentrations, but undetectable IgM concentration. Stimulation of blood lymphocytes with the T-cell mitogens concanavalin A and phytohemagglutinin yielded results within the normal range. However, stimulation with the B-cell mitogen lipopolysaccharide produced no response. A B-cell defect similar to that associated with several immunodeficiency disorders in people was suggested as the cause of the IgM deficiency in this colt.     

Maple syrup urine disease as a cause of spongiform encephalopathy in calves

Estimates of branched chain amino acid concentrations in plasma and, or, serum, urine, cerebrospinal fluid, formalin-fixed cerebral tissue and the associated formalin, provided evidence for a diagnosis of branched chain keto acid decarboxylase deficiency in five polled Hereford calves. The similarity of the clinical signs of dullness, recumbency and opisthotonos, and the observation of severe status spongiosus within the central nervous system, indicated that this condition had probably affected seven other newborn calves. It is suggested that this condition is analogous to branched chain keto acid decarboxylase deficiency or maple syrup urine disease of children.     

Serum cobalamin, urine methylmalonic acid, and plasma total homocysteine concentrations in Border Collies and dogs of other breeds

Objective-To determine reference ranges for serum cobalamin (Cbl), urine methylmalonic acid (uMMA), and plasma total homocysteine (tHcys) concentrations and to compare values for healthy control dogs with values for Border Collies (BCs), a breed in which hereditary cobalamin deficiency has been identified. Animals-113 BCs, 35 healthy control dogs fed a typical diet, and 12 healthy dogs fed a bone and raw food diet exclusively. Procedures-Urine and blood samples were obtained from each dog and Cbl, uMMA, and tHcys concentrations were determined. Results-Reference ranges for Cbl (261 to 1,001 ng/L), uMMA (0 to 4.2 mmol/mol of creatinine), and tHcys (4.3 to 18.4 μmol/L) concentrations were determined. Four BCs had a Cbl concentration lower than the assay detection limit (150 ng/L); median uMMA and tHcys concentrations in these dogs were 4,064 mmol/mol of creatinine and 51.5 μmol/L, respectively. Clinical abnormalities included stunted growth, lethargy, anemia, and proteinuria. Abnormalities improved after administration of cobalamin. Of the 109 healthy BCs with Cbl and tHcys concentrations within reference ranges, 41 (37.6%) had a high uMMA concentration (range, 5 to 360 mmol/mol). Results for dogs fed raw food were similar to those for control dogs. Conclusions and Clinical Relevance-Hereditary cobalamin deficiency is a rare disease with various clinical signs. The finding of methylmalonic aciduria in healthy eucobalaminemic BCs and BCs with clinical signs of Cbl deficiency was surprising and indicated these dogs may have defects in intracellular processing of Cbl or intestinal Cbl malabsorption, respectively. Studies investigating Cbl absorption and metabolic pathways are warranted.     

Influence of parental serum immunoglobulins on morbidity and mortality of beagles and their offspring

Serum IgA, IgG, and IgM concentrations were determined for Beagle sires and dams of 717 matings to assess the relationship of parental immunoglobulins with the morbidity and mortality of their pups. A significant relationship was not found between parental immunoglobulins and pup mortality. Pups born to dams with low serum IgA (P less than 0.001) and IgM (P less than 0.02) concentrations, however, were found to have an increased incidence of sneezing, coughing, nasal discharge, and conjunctivitis. Thirty-eight percent of pups born to dams with IgA less than or equal to 40 mg/dl developed these same conditions during the first 18 weeks of life, compared with 32% of pups of dams with IgA of 41 to 65 mg/dl and 27% of pups of dams with IgA greater than 65 mg/dl. Similarly, 41% of pups born to dams with low IgM (less than or equal to 135 mg/dl) developed abnormal respiratory tract signs, compared with 34% and 30% of pups born to dams with medium (136 to 175 mg/dl) and high (greater than 175 mg/dl) IgM, respectively. Serum IgA concentrations of the sires were also associated with abnormal respiratory tract signs in pups, but this influence was evident only at 10 to 18 weeks of age. To determine biologic variability of serum IgA, 60 Beagle dams were selected from 3 serum IgA categories, low (10 to 21 mg/dl), medium (60 to 80 mg/dl), and high (125 to 210 mg/dl). A second serum IgA was determined from a sample taken 2 years later.(ABSTRACT TRUNCATED AT 250 WORDS)     

Systemic and secretory antibody responses to sequential bovine respiratory syncytial virus infections in vaccinated and nonvaccinated calves

To investigate the influence of humoral immunity on the severity of disease caused by infection with bovine respiratory syncytial virus (BRSV), an experimentally induced infection study was performed on vaccinated and nonvaccinated calves. Fifteen weanling calves were allotted to 3 groups: 1 group of 6 calves was exposed to 2 live virus aerosols, 35 days apart; another group of 6 calves was vaccinated prior to the same aerosol exposures; and the remaining 3 calves served as controls. Clinical signs of infection were converted to a numerical score for evaluating disease severity. For 14 days after each virus exposure, BRSV-specific IgG and IgM concentrations in serum and BRSV-specific IgA concentration in nasopharyngeal exudate and lung lavage fluid were measured by ELISA. Serum BRSV-specific IgG and IgM and secretory BRSV-specific IgA concentrations did not correlate with disease sign expression. There was a strong correlation between viral isolation and disease scores. Vaccination prior to virus exposure appeared to have little or no effect on severity of the disease, but it did appear to affect disease persistence. Findings indicate that the immunoglobulins evaluated may be primarily protective in nature and do not contribute to disease severity.     

Immunoglobulin concentrations in serum and nasal secretions of calves at the onset of pneumonia

Immunoglobulin (Ig) concentrations in serum and in nasal secretions were correlated with pneumonia and diarrhea during the first 12 weeks of life in 56 calves. The peak onset of pneumonia occurred between 2 and 4 weeks of age when the calves' serum IgG1, IgG2, and IgA concentrations were lowest. As IgG2 concentrations increased, fewer calves developed pneumonia. Peak onset of pneumonia was also correlated with the lowest IgG and IgA concentrations in the calves' nasal secretions. Most calves developed pneumonia when serum concentrations of IgG1 were less than 1.5 g/dl, IgG2 less than 0.3 g/dl, IgA less than 0.1 g/dl, and IgM less than 0.2 g/dl and when the combined IgG and IgA values in nasal secretions were less than 0.2 mg of Ig/mg of protein. In study A, diarrhea preceded pneumonia in 63% of 56 calves. In study B, 38% of 23 calves had diarrhea and/or hemorrhagic feces before pneumonia. Seemingly, there was a relationship between diarrhea and pneumonia. Furthermore, pneumonia occurred at or just after the time when IgG1, IgG2, and IgA concentrations in serum and the combined IgG and IgA concentrations in nasal secretions were lowest. Pneumonia is a common disease of calves between 1 and 5 months of age, a period coinciding with the usual low point in serum immunoglobulin (Ig) concentrations due to catabolism of passively acquired antibodies. Calves that absorb less than adequate amounts of Ig may be susceptible to pneumonia at approximately 2 months of age, when serum Ig concentrations would be lowest.(ABSTRACT TRUNCATED AT 250 WORDS)