Robert Royston Amos Coombs, immunologist: born London 9 January 1921; Stringer Fellow, King's College, Cambridge 1947-56; Fellow, Corpus Christi College, Cambridge 1962-2006; Reader in Immunology, Cambridge University 1963-66, Quick Professor in Immunology, 1966-88 (Emeritus); FRS 1965; married 1952 Anne Blomfield (one son, one daughter); died Cambridge 25 February 2006.
In 1945 Robin Coombs devised a test for detecting rhesus antibodies in pregnant women, and in the newborn babies of rhesus negative women. These babies used to die, and rhesus negative women often had a succession of pregnancies that ended in stillbirth or death in infancy. Coombs's test, which is now used throughout the world, enables recognition and treatment of the condition. Within a few years of the test's introduction, rhesus negative women could be assured that the outcome of their pregnancy was as good as that of rhesus positive women. The Coombs test is also routinely used to test blood for transfusion.
Coombs had previously devised a test for glanders, a serious disease of horses and donkeys, while a postgraduate student in the government veterinary research centre in Weybridge, and the work formed part of his PhD thesis. Shortly afterwards he went as a PhD student to Cambridge University's pathology department, where two senior colleagues, Robert Race and Arthur Mourant, were working on the recently discovered rhesus blood group system.
They faced the problem that rhesus antibodies are structurally incomplete and therefore do not make red blood cells clump together, as a complete antigen would. One day, while returning home from London on the train, Coombs realised that, although the red blood cells did not go into clumps, they would nevertheless become coated with immunoglobulin, which would remain on them when the incomplete antibodies were washed off them.
He realised that, if further antibodies were added, that recognised the globulins that were coating the red cells, these would then clump. They did, and the test proved spectacularly successful. Coombs and his two co-workers published their results in The Lancet in 1945, followed by a more detailed report in the British Journal of Experimental Pathology.
Coombs wrote, with his colleague Philip Gell, the definitive textbook, Clinical Aspects of Immunology (1963), which ran to five editions over 30 years. They devised a rational, science-based classification of hypersensitivity reactions (published in full in the third edition, 1975), which is named after them. This differentiated between the immediate allergic reactions that release histamine; antibody-dependent reactions, which are an immune response to another protein in the body; immune-complex reactions, which underpin rheumatoid arthritis and many other diseases; and cell-mediated (rather than antibody-mediated) reactions, which include early-onset diabetes and transplant rejection.
Robin Coombs was born in London and brought up in Cape Town. He trained as a vet at the Royal ("Dick") Veterinary College in Glasgow, qualifying in 1945. He spent a few months at the Weybridge laboratory, working on glanders, which was regarded as a potential biological warfare agent and kills horses and donkeys in the Third World, before going to Cambridge, where he spent the rest of his life, retiring as Emeritus Professor of Immunology.
He had a remarkable capacity to visualise how antibodies and antibodies react, and saw them in what can only be described as cartoon form. This enabled him to create numerous variants in the antiglobulin reaction, so that it could detect antigens as well antibodies. He developed methods of coating red cells with specific antibodies as a way of testing for viruses and other infectious agents - so providing a fast, cheap and sensitive way of testing for infections at the patient's bedside.
Coombs was a central figure in an international renaissance of immunology. It was poorly understood when he entered the field, and by the end of the last century was no longer a mystery. In the mid-1950s he and others set up the British Society of Immunology. He attracted the best PhD students and many of the world's leading immunologists trained under him, or under immunologists that he trained. His first PhD student, Anne Blomfeld, became his wife and collaborator.
Boffin-like, brilliant and benign, Coombs was elected a Fellow of the Royal Society in 1965 and received many honours and awards, including honorary fellowship of the Royal College of Physicians, a rare honour for a non-medical person. He published over 200 hundred scientific papers. With his wife and D.G. Ingram, he was the author of The Serology of Conglutination, and Its Relation to Disease (1961).
When Coombs retired, he developed his own theory of cot death, that it was caused by an acute allergic response to inhaling regurgitated cow's milk when infants are laid to sleep face down, which he published as Sudden Infant Death Syndrome: could a healthy infant succumb to inhalation-anaphylaxis during sleep leading to cot death? (with W.E. Parish and A.F. Walls, 2000). He tested his theory on guinea pigs, lightly anaesthetising them to simulate sleep.