Immunosuppression in horses refers to a state where the horse's immune system is weakened or functioning less effectively. This condition can arise due to various factors, including disease, stress, medications, or environmental influences. Immunosuppression can impact a horse's ability to respond to infections, heal from injuries, and recover from illnesses. Research in this area explores the mechanisms underlying immunosuppression, its effects on equine health, and strategies for management and prevention. This page aggregates peer-reviewed research studies and scholarly articles that investigate the causes, effects, and clinical implications of immunosuppression in horses.
Melo UP, Ferreira C, Barreto SWM.Respiratory diseases considerably affect equine athletes, being the second most common cause of poor performance. Among these diseases, fungal pneumonia in horses, caused specifically by Aspergillus spp., is relatively rare but potentially fatal. Fungal pneumonia typically affects horses exposed to fungal elements due to environmental factors, immunosuppression, or previous debilitating illnesses. Treatment is complex, with minimal success due to late diagnosis and serious concomitant underlying diseases. The choice of medication depends on the site of infection, the fungal species involved, a...
Page AE, Johnson M, Parker JL, Jacob O, Swan M, Adam E.The use of dexamethasone to control equine asthma is a common and effective treatment. Although short-term systemic dexamethasone treatment has not been shown to induce systemic immunosuppression in the horse, the goal of this study was to determine whether inhaled ciclesonide, an FDA-approved drug for the treatment of equine asthma, exerts any systemic immunosuppressive effects when compared to dexamethasone-treated and untreated horses. Eighteen light, mixed breed horses, ranging in age from 3 to 8 years of age, were used for this study and randomly assigned to one of three treatment groups:...
Padjasek M, Qasem B, Cisło-Pakuluk A, Marycz K.Cyclosporine A (CsA) is a selective and reversible immunosuppressant agent that is widely used as a medication for a wide spectrum of diseases in humans such as graft versus host disease, non-infectious uveitis, rheumatoid arthritis, psoriasis, and atopic dermatitis. Furthermore, the CsA is used to treat keratoconjunctivitis sicca, chronic superficial keratitis, immune-mediated keratitis and equine recurrent uveitis in animals. The selective activity of Cyclosporine A (CsA) was demonstrated to be an immunomodulation characteristic of T-lymphocyte proliferation and inhibits cytokine gene expres...
Burroughs DL, Lorch G, Guo Y, Hill K, Schroeder EL, Cole LK, Phelps MA.Mycophenolate mofetil (MMF) is the prodrug of mycophenolic acid (MPA) which acts as an immunosuppressive agent. During the biotransformation of MMF to MPA, additional metabolites including MPA phenol glucuronide (MPAG), MPA acyl glucuronide (AcMPAG) and MPA phenol glucoside (MPG) are formed. Objective: To define the noncompartmental pharmacokinetic (PK) parameters of three single doses of intravenous (i.v.) MMF and its downstream metabolites in healthy horses. Methods: Six healthy Standardbred mares. Methods: Generic MMF (Par Pharmaceuticals; Chestnut Ridge, NY, USA) was reconstituted and admi...
Ehrmann C, Hartung S, Hirz M, Fey K.A 15-year-old Warmblood gelding was presented with multiple large, ulcerative, and crusty dermal lesions that had been existing for 4 years. Histopathology of a skin biopsy revealed cleft formation at the dermal-epidermal junction beneath the basal cells and above the basement membrane leading to the diagnosis of bullous pemphigoid. Immunosuppressive therapy with dexamethasone and azathioprine was initiated and after 14 weeks full remission of the ulcers was achieved. Scar tissue formation was evident in the areas of the formerly affected lesions. Following medication tapering over a perio...
Tham HL, Linder KE, Olivry T.Pemphigus is the term used to describe a group of rare mucocutaneous autoimmune bullous diseases characterized by flaccid blisters and erosions of the mucous membranes and/or skin. When the autoantibodies target desmosomes in the deep layers of the epidermis, deep pemphigus variants such as pemphigus vulgaris, pemphigus vegetans and paraneoplastic pemphigus develop. In this article, we will review the signalment, clinical signs, histopathology and treatment outcome of pemphigus vulgaris, pemphigus vegetans and paraneoplastic pemphigus in dogs, cats and horses; where pertinent, we compare the a...
Scheinberg P, Marte M, Nunez O, Young NS.Clones of glycosylphosphatidylinositol-anchor protein-deficient cells are characteristic in paroxysmal nocturnal hemoglobinuria and are present in about 40-50% of patients with severe aplastic anemia. Flow cytometry has allowed for sensitive and precise measurement of glycosylphosphatidylinositol-anchor protein-deficient red blood cells and neutrophils in severe aplastic anemia. Methods: We conducted a retrospective analysis of paroxysmal nocturnal hemoglobinuria clones measured by flow cytometry in 207 consecutive severe aplastic anemia patients who received immunosuppressive therapy with a h...
Chang MH, Kim KH, Kim HS, Jun HJ, Kim DH, Jang JH, Kim K, Jung CW.Immunosuppressive therapy (IST) with antithymocyte globulin (ATG) plus cyclosporine (CSA) is standard therapy in patients with severe aplastic anemia (SAA) who do not have an available HLA-matched sibling donor. Methods: The current study aimed to determine the predictive factors for response to IST in patients with SAA and to identify prognostic factors following IST. A total of 62 patients diagnosed with SAA who received IST with either rabbit ATG (n = 33) or horse ATG (n = 29) plus CSA between October 1994 and December 2007 were included. Results: With a median follow-up duration of 60.5 mo...
White SD, Maxwell LK, Szabo NJ, Hawkins JL, Kollias-Baker C.To determine pharmacokinetics of azathioprine (AZA) and clinical, hematologic, and serologic effects of i.v. and oral administration of AZA in horses. Methods: 6 horses. Methods: In study phase 1, a single dose of AZA was administered i.v. (1.5 mg/kg) or orally (3.0 mg/kg) to 6 horses, with at least 1 week between treatments. Blood samples were collected for AZA and 6-mercaptopurine (6-MP) analysis 1 hour before and at predetermined time points up to 4 hours after AZA administration. In study phase 2, AZA was administered orally (3 mg/kg) every 24 hours for 30 days and then every 48 hours for ...
Gallen F, Kernaonet E, Foulet A, Goldstein A, Lebon P, Babinet F.Rhodococcus Equi, a strictly aerobic Gram positive coco-bacillus, is a pathogen for horses and foals. It may induce opportunistic infections and is described in AIDS infected patients. We report the case of a 47-year old man, breeder of horses, with kidney transplant who has presented, 8 years after his graft, an impairment of health, a fever and evidence of pulmonary disease. The pulmonary biopsy under scanner guidance and microbiology study, has displayed the diagnosis of Rhodococcus equi infection. The evolution has been favorable with double antibiotherapy (follow-up 27 months). Ten compar...
Tumas DB, Hines MT, Perryman LE, Davis WC, McGuire TC.The immune control of chronic equine infectious anaemia (EIA) lentiviral infection was investigated by specifically depleting CD5+ T lymphocytes in vivo with monoclonal antibody (MAb) or by immunosuppression with corticosteroids. MAb was given at 25 to 50 mg/day intravenously for 11 days. Murine IgG1 anti-equine CD2 MAb (n = 2 horses) or IgG1 (n = 2) and IgG2a control MAb (n = 2 normal; 2 EIA-infected) did not deplete CD2+ T lymphocytes in horses. Horses given murine IgG2a anti-CD5 MAb HB19A (n = 4 normal; 5 EIA-infected) had depletion of peripheral blood CD5+ T lymphocytes during treatment. T...
Oladosu LA, Olufemi BE.An investigation was carried out to study the haematology of steroid immunosuppressed horses experimentally infected with Babesia equi and Ehrlichia equi, separately or simultaneously. Horses infected with both pathogens showed less marked changes in their haematology than those inoculated with either pathogen separately. This appeared to result from early elimination of the more pathogenic Babesia as Ehrlichia spread through the granulocytes. The apparent suppression of Babesia by Ehrlichia is of field clinical importance and merits further investigation for its apparent useful potentials in ...
Prescott JF.Recent isolations of Rhodococcus equi from cavitatory pulmonary disease in patients with AIDS have aroused interest among medical microbiologists in this unusual organism. Earlier isolations from humans had also been in immunosuppressed patients following hemolymphatic tumors or renal transplantation. This organism has been recognized for many years as a cause of a serious pyogranulomatous pneumonia of young foals and is occasionally isolated from granulomatous lesions in several other species, in some cases following immunosuppression. The last decade has seen many advances in understanding o...
The Journal of urologyDecember 1, 1986
Volume 136, Issue 6 1314-1315 doi: 10.1016/s0022-5347(17)45327-4
Wheeler JS, Culkin DJ, O'Connell J, Winters G.The immunocompromised patient after organ transplantation is susceptible to unusual and life-threatening infections. We report a case of epididymitis that evolved into testicular nocardiosis after cardiac transplantation. An awareness of the potential for these infections and early diagnosis may prevent extensive morbidity in the post-transplantation patient.
Harkiss GD.An isotype-specific microELISA is presented for the measurement of antibodies to equine antithymocyte globulin in human heart transplant recipients. The assay conditions were optimized and evaluated in serial samples from 40 patients receiving a cardiac allograft. The results demonstrate that despite steroid immunosuppression and T cell cytopenia the majority of patients receiving antithymocyte globulin develop significant antibody responses, with some producing very high titres. IgM and IgG isotypes tended to predominate, with peak antibody responses occurring during the second and third week...
Kono Y, Hirasawa K, Fukunaga Y, Taniguchi T.Horses which had passed a few months to a few years asymptomatically after the last recurrence of equine infectious anemia (EIA) showed a typical febrile response after treatment with the immunosuppressive agent, dexamethasone (DM) or cyclophosphamide (CY). In horses showing a febrile response, EIA virus which had not been neutralized by neutralizing antibody previously produced was propagated. In DM-treated horses it disappeared from the blood soon after pyretolysis and antibody against the virus was produced promptly. In contrast, detectable viremia persisted in CY-treated horses for 10 to 8...
Diethelm AG, Aldrete JS, Shaw JF, Cobbs CG, Hartley MW, Sterling WA, Morgan JM.Equine antithymocyte globulin combined with azathioprine and prednisone as immunosuppressive therapy in 50 transplant recipients prolonged allograft survival and seemed to modify the severity of rejection episodes. Although nine patients died from a variety of causes, only three kidneys were lost to rejection, one of which was hyperacute. There were no serious untoward hematologic or systemic effects caused by the ATG, and all patients completed the course of therapy. Infection, a serious and frequent complication of transplant patients, was encountered no more often than in other transplant s...
Prescott JF.Recent isolations of Rhodococcus equi from cavitatory pulmonary disease in patients with AIDS have aroused interest among medical microbiologists in this unusual organism. Earlier isolations from humans had also been in immunosuppressed patients following hemolymphatic tumors or renal transplantation. This organism has been recognized for many years as a cause of a serious pyogranulomatous pneumonia of young foals and is occasionally isolated from granulomatous lesions in several other species, in some cases following immunosuppression. The last decade has seen many advances in understanding o...
Kono Y, Hirasawa K, Fukunaga Y, Taniguchi T.Horses which had passed a few months to a few years asymptomatically after the last recurrence of equine infectious anemia (EIA) showed a typical febrile response after treatment with the immunosuppressive agent, dexamethasone (DM) or cyclophosphamide (CY). In horses showing a febrile response, EIA virus which had not been neutralized by neutralizing antibody previously produced was propagated. In DM-treated horses it disappeared from the blood soon after pyretolysis and antibody against the virus was produced promptly. In contrast, detectable viremia persisted in CY-treated horses for 10 to 8...
Scheinberg P, Marte M, Nunez O, Young NS.Clones of glycosylphosphatidylinositol-anchor protein-deficient cells are characteristic in paroxysmal nocturnal hemoglobinuria and are present in about 40-50% of patients with severe aplastic anemia. Flow cytometry has allowed for sensitive and precise measurement of glycosylphosphatidylinositol-anchor protein-deficient red blood cells and neutrophils in severe aplastic anemia. Methods: We conducted a retrospective analysis of paroxysmal nocturnal hemoglobinuria clones measured by flow cytometry in 207 consecutive severe aplastic anemia patients who received immunosuppressive therapy with a h...
Chang MH, Kim KH, Kim HS, Jun HJ, Kim DH, Jang JH, Kim K, Jung CW.Immunosuppressive therapy (IST) with antithymocyte globulin (ATG) plus cyclosporine (CSA) is standard therapy in patients with severe aplastic anemia (SAA) who do not have an available HLA-matched sibling donor. Methods: The current study aimed to determine the predictive factors for response to IST in patients with SAA and to identify prognostic factors following IST. A total of 62 patients diagnosed with SAA who received IST with either rabbit ATG (n = 33) or horse ATG (n = 29) plus CSA between October 1994 and December 2007 were included. Results: With a median follow-up duration of 60.5 mo...
Tumas DB, Hines MT, Perryman LE, Davis WC, McGuire TC.The immune control of chronic equine infectious anaemia (EIA) lentiviral infection was investigated by specifically depleting CD5+ T lymphocytes in vivo with monoclonal antibody (MAb) or by immunosuppression with corticosteroids. MAb was given at 25 to 50 mg/day intravenously for 11 days. Murine IgG1 anti-equine CD2 MAb (n = 2 horses) or IgG1 (n = 2) and IgG2a control MAb (n = 2 normal; 2 EIA-infected) did not deplete CD2+ T lymphocytes in horses. Horses given murine IgG2a anti-CD5 MAb HB19A (n = 4 normal; 5 EIA-infected) had depletion of peripheral blood CD5+ T lymphocytes during treatment. T...
The Journal of urologyDecember 1, 1986
Volume 136, Issue 6 1314-1315 doi: 10.1016/s0022-5347(17)45327-4
Wheeler JS, Culkin DJ, O'Connell J, Winters G.The immunocompromised patient after organ transplantation is susceptible to unusual and life-threatening infections. We report a case of epididymitis that evolved into testicular nocardiosis after cardiac transplantation. An awareness of the potential for these infections and early diagnosis may prevent extensive morbidity in the post-transplantation patient.
Tham HL, Linder KE, Olivry T.Pemphigus is the term used to describe a group of rare mucocutaneous autoimmune bullous diseases characterized by flaccid blisters and erosions of the mucous membranes and/or skin. When the autoantibodies target desmosomes in the deep layers of the epidermis, deep pemphigus variants such as pemphigus vulgaris, pemphigus vegetans and paraneoplastic pemphigus develop. In this article, we will review the signalment, clinical signs, histopathology and treatment outcome of pemphigus vulgaris, pemphigus vegetans and paraneoplastic pemphigus in dogs, cats and horses; where pertinent, we compare the a...
Diethelm AG, Aldrete JS, Shaw JF, Cobbs CG, Hartley MW, Sterling WA, Morgan JM.Equine antithymocyte globulin combined with azathioprine and prednisone as immunosuppressive therapy in 50 transplant recipients prolonged allograft survival and seemed to modify the severity of rejection episodes. Although nine patients died from a variety of causes, only three kidneys were lost to rejection, one of which was hyperacute. There were no serious untoward hematologic or systemic effects caused by the ATG, and all patients completed the course of therapy. Infection, a serious and frequent complication of transplant patients, was encountered no more often than in other transplant s...
Padjasek M, Qasem B, Cisło-Pakuluk A, Marycz K.Cyclosporine A (CsA) is a selective and reversible immunosuppressant agent that is widely used as a medication for a wide spectrum of diseases in humans such as graft versus host disease, non-infectious uveitis, rheumatoid arthritis, psoriasis, and atopic dermatitis. Furthermore, the CsA is used to treat keratoconjunctivitis sicca, chronic superficial keratitis, immune-mediated keratitis and equine recurrent uveitis in animals. The selective activity of Cyclosporine A (CsA) was demonstrated to be an immunomodulation characteristic of T-lymphocyte proliferation and inhibits cytokine gene expres...
Oladosu LA, Olufemi BE.An investigation was carried out to study the haematology of steroid immunosuppressed horses experimentally infected with Babesia equi and Ehrlichia equi, separately or simultaneously. Horses infected with both pathogens showed less marked changes in their haematology than those inoculated with either pathogen separately. This appeared to result from early elimination of the more pathogenic Babesia as Ehrlichia spread through the granulocytes. The apparent suppression of Babesia by Ehrlichia is of field clinical importance and merits further investigation for its apparent useful potentials in ...
Burroughs DL, Lorch G, Guo Y, Hill K, Schroeder EL, Cole LK, Phelps MA.Mycophenolate mofetil (MMF) is the prodrug of mycophenolic acid (MPA) which acts as an immunosuppressive agent. During the biotransformation of MMF to MPA, additional metabolites including MPA phenol glucuronide (MPAG), MPA acyl glucuronide (AcMPAG) and MPA phenol glucoside (MPG) are formed. Objective: To define the noncompartmental pharmacokinetic (PK) parameters of three single doses of intravenous (i.v.) MMF and its downstream metabolites in healthy horses. Methods: Six healthy Standardbred mares. Methods: Generic MMF (Par Pharmaceuticals; Chestnut Ridge, NY, USA) was reconstituted and admi...
Ehrmann C, Hartung S, Hirz M, Fey K.A 15-year-old Warmblood gelding was presented with multiple large, ulcerative, and crusty dermal lesions that had been existing for 4 years. Histopathology of a skin biopsy revealed cleft formation at the dermal-epidermal junction beneath the basal cells and above the basement membrane leading to the diagnosis of bullous pemphigoid. Immunosuppressive therapy with dexamethasone and azathioprine was initiated and after 14 weeks full remission of the ulcers was achieved. Scar tissue formation was evident in the areas of the formerly affected lesions. Following medication tapering over a perio...
Harkiss GD.An isotype-specific microELISA is presented for the measurement of antibodies to equine antithymocyte globulin in human heart transplant recipients. The assay conditions were optimized and evaluated in serial samples from 40 patients receiving a cardiac allograft. The results demonstrate that despite steroid immunosuppression and T cell cytopenia the majority of patients receiving antithymocyte globulin develop significant antibody responses, with some producing very high titres. IgM and IgG isotypes tended to predominate, with peak antibody responses occurring during the second and third week...
Gallen F, Kernaonet E, Foulet A, Goldstein A, Lebon P, Babinet F.Rhodococcus Equi, a strictly aerobic Gram positive coco-bacillus, is a pathogen for horses and foals. It may induce opportunistic infections and is described in AIDS infected patients. We report the case of a 47-year old man, breeder of horses, with kidney transplant who has presented, 8 years after his graft, an impairment of health, a fever and evidence of pulmonary disease. The pulmonary biopsy under scanner guidance and microbiology study, has displayed the diagnosis of Rhodococcus equi infection. The evolution has been favorable with double antibiotherapy (follow-up 27 months). Ten compar...
White SD, Maxwell LK, Szabo NJ, Hawkins JL, Kollias-Baker C.To determine pharmacokinetics of azathioprine (AZA) and clinical, hematologic, and serologic effects of i.v. and oral administration of AZA in horses. Methods: 6 horses. Methods: In study phase 1, a single dose of AZA was administered i.v. (1.5 mg/kg) or orally (3.0 mg/kg) to 6 horses, with at least 1 week between treatments. Blood samples were collected for AZA and 6-mercaptopurine (6-MP) analysis 1 hour before and at predetermined time points up to 4 hours after AZA administration. In study phase 2, AZA was administered orally (3 mg/kg) every 24 hours for 30 days and then every 48 hours for ...
Page AE, Johnson M, Parker JL, Jacob O, Swan M, Adam E.The use of dexamethasone to control equine asthma is a common and effective treatment. Although short-term systemic dexamethasone treatment has not been shown to induce systemic immunosuppression in the horse, the goal of this study was to determine whether inhaled ciclesonide, an FDA-approved drug for the treatment of equine asthma, exerts any systemic immunosuppressive effects when compared to dexamethasone-treated and untreated horses. Eighteen light, mixed breed horses, ranging in age from 3 to 8 years of age, were used for this study and randomly assigned to one of three treatment groups:...
Melo UP, Ferreira C, Barreto SWM.Respiratory diseases considerably affect equine athletes, being the second most common cause of poor performance. Among these diseases, fungal pneumonia in horses, caused specifically by Aspergillus spp., is relatively rare but potentially fatal. Fungal pneumonia typically affects horses exposed to fungal elements due to environmental factors, immunosuppression, or previous debilitating illnesses. Treatment is complex, with minimal success due to late diagnosis and serious concomitant underlying diseases. The choice of medication depends on the site of infection, the fungal species involved, a...
