Graft-versus-host disease in two immunocompetent dogs

Area of Science:

• Veterinary Medicine
• Immunology
• Oncology

Background:

• Graft-versus-host disease (GVHD) is a serious complication following allogeneic stem cell transplantation.
• BCG (Bacillus Calmette-Guérin) is an immunotherapy agent used in cancer treatment.
• The role of BCG immunization in GVHD induction in immunocompetent hosts is not well understood.

Purpose of the Study:

• To investigate the potential of BCG-immunized lymphocytes to induce GVHD in dogs.
• To characterize the clinical and pathological manifestations of GVHD in this context.

Main Methods:

• Two dogs received lymphocytes from BCG-immunized donors.
• Clinical signs, pathological findings, and cytogenetic analysis were used to assess GVHD.
• Lymphocyte transformation assays with phytohemagglutinin (PHA) were performed to evaluate immunocompetence.

Main Results:

• Both dogs developed GVHD, characterized by bone marrow depression, enteritis, cholangiohepatitis, thymic atrophy, pancreatitis, lymphadenopathy, and weight loss.
• Donor cell repopulation was confirmed by cytogenetics in one dog.
• Both dogs exhibited immunocompetence based on PHA response.

Conclusions:

• BCG immunization may enhance the ability of lymphocytes to induce GVHD, even in immunocompetent recipients without immunosuppression.
• This finding suggests a potential mechanism for BCG-mediated graft-versus-leukemia effects.
• Further research is warranted to elucidate the immunomodulatory effects of BCG in transplantation.