Acquired B lymphocyte deficiency and chronic enterocolitis in a 3-year-old quarter horse.

The study investigates a recorded case of a 3-year-old American Quarter Horse suffering from a rare deficiency in B lymphocytes, one of the main types of white blood cells. The study further elaborates on the symptoms, diagnosis and postmortem findings of the examined subject.

Description of the Immune Deficiency

• This research demonstrates a case of acquired immunodeficiency in a 3-year-old American Quarter Horse.
• The horse showed major symptoms including chronic diarrhea induced by Salmonella typhimurium and bacterial pneumonia.
• In order to categorize the immunodeficiency, several experiments were conducted that include in vivo phytohemagglutinin (PHA) intradermal testing. This method aimed to test the skin’s responsivity to antigens and, therefore, validate immune system deficiency.
• In vitro lymphocyte proliferation in response to concanavalin A was also investigated to assess the degree to which immune cells were capable of responding to this stimulant.

Diagnostic Procedures and Findings

• Immunofluorescence flow cytometry data on blood lymphocytes was used to count and sort various types of immune cells present in the blood sample, this was key to diagnosing the type of deficiency.
• Serum protein electrophoresis and immunoglobulin (Ig) quantification were performed to study the protein profile in the blood sample and measure the concentration of antibodies respectively in the horse’s serum.
• The tests indicated that the horse had a deficiency in B lymphocytes, a type of white blood cell responsible for producing antibodies. This resulted in deficiencies in serum IgG, IgA and IgM, which are types of antibodies crucial for the immune response.
• There was also a reported decrease in T cell function, another very important immune cell, thus further aggravating the animal’s immune system response.

Postmortem Examination and Conclusions

• An autopsy on the horse did not reveal any evidence of lymphosarcoma, a cancer of the lymphatic system.
• This particular case introduces a previously undocumented variant of young adult-onset B cell deficiency.

The study underlines the significance of understanding different manifestations of immune system deficiencies in animals. Further research will contribute to improving diagnostic and treatment methods for similar cases in the veterinary field.