Attempted reconstitution of a foal with primary severe combined immunodeficiency.

This research article delves into an unsuccessful attempt to treat a foal with primary severe combined immunodeficiency (SCID) by using two bone marrow transfusions from a sibling donor, prophylactic antibiotic therapy, plasma from a hyperimmunised sibling, and methotrexate therapy. Despite the treatments, the foal passed away due to, what was most likely, an electrolyte imbalance.

Overview

• This study focuses on an intervention attempted on a foal diagnosed with primary severe combined immunodeficiency (SCID) within its first two weeks of life. The foal was cared for in a semi-isolated environment, alongside its mother.

Treatment Details

• To manage the foal’s condition, it was put on continuous prophylactic antibiotic therapy and received plasma from a sibling that was hyperimmunised with an equine adenovirus vaccine. It also received intensive general nursing care.
• For the purpose of bone marrow transplantation, a full sibling female was selected as a donor based on red blood cell cross-matching and mixed lymphocyte reactions.
• The foal was administered cyclophosphamide prior to two bone marrow transfusions which happened at 35 and 73 days of age.
• The study also notes that to avoid graft versus host disease (an issue where the donor cells attack the recipient’s body), the foal was maintained on methotrexate therapy.

Outcome of the Treatment

• Despite the attempted intervention, the foal didn’t show signs of reconstitution, nor were signs of graft versus host disease observed.
• The foal suddenly died four days after the second bone marrow transfusion when it was 77 days old.
• Posthumously, the animal was found to be largely free of any serious infectious disease, which was viewed as a positive outcome of the treatments.
• The necropsy report of the foal showed bilateral nephrosis (a kidney disorder), degeneration, and fibrosis of the myocardium (heart muscle). The cause of death is believed to have been an electrolyte imbalance, primarily a lack of potassium or hypokalaemia, which might have affected the horse’s heart.
• The study suggests that the renal toxicity caused by the cytotoxic drugs, especially cyclophosphamide, may have contributed to the electrolyte imbalance.