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Barbara Glanemann, Associate Professor in Small Animal Medicine   

Most immune-mediated haemolytic anaemia (IMHA) treatments involve suppressing the immune system to stop the body from destroying its own red blood cells. Distressing side effects of the medications include increased thirst, appetite and urination, panting, muscle wastage, lethargy and behavioural changes.

There is consequently a major clinical need to understand how dogs can be treated effectively, while minimising the adverse effects experienced in treatment. At the RVC we are attempting to uncover new information on how IMHA develops in dogs and hoping to identify which treatment works best for individual dogs. This could have a major impact on the quality of life for dogs with this distressing disease.

We have been awarded a grant from the Morris Animal Foundation’s Donor Inspired Study programme to advance critical research into IMHA. The grant will support the exploration of mechanisms that cause the disease, using cutting-edge single cell RNA sequencing approaches, as well as evaluating different treatments ex vivo with the aim of understanding how individual dogs respond to different medications that are already available in veterinary practice.

This research is led by myself, in collaboration with RVC colleagues James Swann (Visiting Associate Professor), Balazs Szladovits (Associate Professor in Clinical Pathology) and Floryne Buishand (Lecturer in Soft Tissue Surgery).

Residual samples will be obtained from dogs presented and diagnosed with IMHA at the RVC and two collaborating referral centres – Davis Veterinary Specialists and Dick White Referrals. The findings will help improve understanding of which genes are turned on and off – therefore shedding light on what is going wrong with the patient’s immune system.

Comparing results to those from healthy dogs will help improve knowledge of how and why the immune system attacks red blood cells and may identify new therapeutic targets for drug development. As we will also investigate how those immune cells from dogs with IMHA respond to common medications, we can create prediction models, which would be available to vets to help decide which medication will be most effective for their individual patient.

Case study    

Milo, a three-year-old male entire cocker spaniel, presented to the Queen Mother Hospital for Animals with a 48hrs history of lethargy, anorexia and icterus. Being only mildly anaemic and thrombocytopenic with marked hyperbilirubinaemia on initial presentation to his primary care practice, he was referred for further management of a possible leptospirosis infection.

By the time of admission to the QMHA though, Milo had marked anaemia with typical hallmarks of immune-mediated haemolysis (e.g. positive Coombs test, spherocytosis, erythrophagocytosis on peripheral blood smear, hyperbilirubinaemia).

Further investigations were performed to rule out any potential underlying causes, and after initial transfusion of a matched red blood cell unit, Milo was subsequently started on immunosuppressive therapy, consisting of prednisolone and azathioprine. To minimise the risk of thromboembolic disease, clopidogrel therapy was also initiated.

Milo’s owner had kindly agreed for his residual blood samples to be used for research. From the residual EDTA blood sample at time of admission, we were able to isolate his peripheral blood mononuclear cells (PBMC) and expose those cells ex vivo to immunosuppressive drugs used commonly in veterinary medicine prior to evaluating their capacity to lyse red blood cells.

Furthermore, we will be able to perform single cell RNA sequencing of those PBMC to define the predominant T cell activation state. By comparing this to data from healthy control PBMC, we hope to understand how myeloid cells become hyperactivated to engage in phagocytosis of erythroid cells in patients with IMHA.

Following seven days of hospitalisation Milo’s PCV had stabilised and he was discharged for continued therapy at home. Immunosuppressive therapy will be tapered off gradually over the following weeks, while careful monitoring for any relapse and adverse treatment effects.