John Louis Ryan, PhD, MD 

John Louis Ryan of Philadelphia PA and Guilford CT, passed away peacefully at home August 31, 2026, surrounded by family, at the age of 83. He was the devoted husband of Karen McDonnell and loving father of Brent D. (Lorena Bello), Elizabeth H., Philip G. (Jill), Diana H. (Luis Soto), Julia H. (Rahul Jaswa) and John P “Jack”. Proud grandfather to Ryan Wozniak, Wiley Ryan, Silas Ryan, Isla Soto. Cherished brother of Philip William “Bill” (Jill) and uncle to seven beloved nieces and nephews. He was preceded in death by his dear brother Gerald P. (survived by his wife Janet).John touched many hearts and accomplished much in his 83 well-lived years. He was born on April 6, 1943, in Bristol, CT where he quickly proved to be an unusually bright child. He spoke in crisp, full sentences well before age two, skipped a grade in entering primary school, and preferred to read World Book encyclopedias over children’s books.A graduate of Thomaston High School, John attended Yale University BS’64 where he received a PhD in Biophysics in 1969. He was always an adventurer, spending college summers in Utah and Arizona prospecting for mineral deposits with a Yale geology professor, leading to a deep love of the Southwest region and the people he met there. He concluded his education as a member of the inaugural class at the University of California, San Diego Medical School, graduating with honors without ever having bought a textbook.John’s career spanned five decades across academia, research, and the pharmaceutical industry. As a post-doc, he broke ground in researching endotoxins at the NIH, leading to a publication in Nature in 1977. He then joined the faculty at Yale University where he led a laboratory at the West Haven VA Hospital conducting cutting-edge research on bacterial endotoxins, sepsis, and immunology. In addition to his lab work, he was a dedicated attending physician in medicine and infectious diseases at Yale and the VA Hospital where he was beloved by his colleagues for his quick wit, tireless good humor, and extraordinary diagnostic capabilities. John loved being a professor and delighted in sparking in his students the same intellectual curiosity that animated his own life.After more than a decade in academia, John transitioned to the pharmaceutical industry, joining Merck Research Laboratories in Philadelphia where he and his team were instrumental in the development of the first chicken pox vaccine. He later joined Genetics Institute in Cambridge, Massachusetts where he played a leading role developing treatments for hemophilia and cancer. He went on to hold leadership positions at Wyeth, mentoring many in advancing their careers. He was particularly proud of those who followed his advice to use company educational benefits and obtain PhDs (often remarking it was his proudest degree). After Wyeth, John turned his attention to helping smaller biotech companies develop mature clinical programs, including Aveo and Cerulean. He finally retired in 2022, after serving as Chief Medical Officer of Kadmon in New York City for more than 10 years, taking the Company through an IPO and successful product approvals.John was a devoted father, brother, and husband who remained close to his Connecticut roots his entire life. He and his brothers were avid sports fans, attending nearly every Super Bowl from Super Bowl X to Super Bowl LIV, and countless Yale football, Celtics, Bruins, and Red Sox games.He loved being a father and was deeply proud of the diverse lives of his six children. He eagerly invited family and friends to join him on his wide ranging travels to homelands of Ireland and Italy, to Oktoberfest in Germany, to more than a dozen New Orleans Jazz Fests, and to follow a curiosity such as experiencing white truffle season in the Piemonte countryside or traveling to St. Petersburg by train “leaving Finland station.” When at home, he delighted his family by waking them with coffee delivered bedside, stacks of chocolate chip pancakes and crispy bacon, and took great pride in preparing his family’s legendary homemade lasagna. He loved cultivating a tan on the deck of his Ocean City NJ home, and hosting family dinners at the Ocean City Yacht Club. He was a collector of Native American pottery and American coins, proudly showing off the pennies he began collecting in the early 1950s. An avid reader and a lifelong lover of learning, he possessed a remarkable breadth of knowledge and an insatiable intellectual curiosity.Throughout his adult life in coastal Connecticut, Lexington, MA, and Philadelphia, John remained deeply connected to the family, friends, and colleagues who enriched each chapter of his life. He will be deeply missed by all who knew and loved him.Family and Friends are invited to calling hours on Friday, September 4 from 5 – 7 pm at the Guilford Funeral Home, 115 Church St, Guilford. Mass of Christian Burial will be celebrated on Saturday, September 5 at 10 am. in St. George Church, 33 Whitfield St, Guilford. 

A second Mass of Christian Burial will be celebrated on Friday September 11, 2026 10:00 am at Our Mother of Consolation Church, 9 E Chestnut Hill Ave. Philadelphia, PA where the family will receive guests from 9:00 am until 9:45.  Interment in Holy Sepulchre Cemeter.