A woman heading to Cleveland Clinic to receive treatment for an autoimmune disease nearly died when she suffered an allergic reaction on an American Airlines flight — she was saved by a doctor from that hospital, who happened to be on board.

Ashley Spencer, 28, was flying in from Philadelphia on Sunday when she went into anaphylactic shock. Spencer told WEWS she was heading to Cleveland Clinic to enroll in a clinical trial for her eosinophilic granulomatosis with polyangiitis (EGPA), an autoimmune disease that causes a person's blood vessels to be inflamed.

"I stopped breathing," she recalled to WEWS. "I still had a pulse. That's when the stewardess said, 'Is there any medical professionals on the aircraft? It's an emergency.'"

Spencer said she has a severe peanut allergy and believed she was having an allergic reaction to a bag of chips she ate before the plane took off.

Dr. Erich Kiehl, who is an electrophysiology fellow at Cleveland Clinic, happened to be on the same flight as Spencer and stepped in to help her. Kiehl and another doctor from North Carolina injected Spencer with an EpiPen four times, the report stated.

The doctors monitored Spencer’s vitals as the plane made an emergency landing in Pittsburgh.

“When a person is going into anaphylactic shock it has to be taken seriously," Spencer said. "Having Dr. Kiehl on board was so important. He was monitoring the heart completely."

Spencer was taken to the hospital and recovered in the intensive care unit Saturday night.

She told WEWS she made it to her Cleveland Clinic appointment, where she hopes the treatment for EGPA will allow her to quit chemotherapy. She added that she plans to extend the trip by a day to give Kiehl a gift for saving her life.

"I am beyond thankful," Spencer said. "I could have died up there."