Denis Mitchison, groundbreaking tuberculosis researcher – obituary

Denis Mitchison
Mitchison in the lab Credit:  frank baron

Denis "Denny" Mitchison, who has died aged 98, was part of the research team which developed a treatment regime for tuberculosis and proved its effectiveness through clinical trials in London; he later helped to design a ground-breaking care programme in India.

In 1946 Mitchison was a pathologist at Brompton Hospital in London, where a small subcommittee was trying to determine the usefulness of the antibiotic streptomycin. The drug had been developed during the Second World War, and while it was initially effective against TB, antibiotic resistance was on the rise.

Treatment also had serious side-effects for many patients. To counteract some of these problems, Mitchison and his colleagues looked at various synthetic compounds. They found that patients who received streptomycin in combination with an anti-TB drug called para-aminosalicylic acid fared a lot better than those on streptomycin alone.

The establishment of the NHS in 1948 gave Mitchison and his colleagues access to vast troves of patient data, allowing them to compare records and design clinical trials that could put their findings on a firm scientific footing. However, there were several difficulties to overcome before a form of mass treatment for TB could be considered.

Streptomycin was expensive, and the drug regime had to be adhered to for more than a year. This was a long time for anyone to spend in hospital, and in poorly resourced, TB-ridden countries such as India it was simply not feasible.

In 1956 Mitchison was appointed director of the Medical Research Council Unit for Research on Drug Sensitivity in Tuberculosis at the Royal Postgraduate Medical School in Hammersmith. Here he worked closely with Wallace Fox on designing a programme that could be rolled out across India.

The first trial, based in Madras (now Chennai), kept some patients in sanatoria while allowing others to be treated at home. The results showed that home care was just as effective as being held in a sanatorium for months on end. The World Health Organisation then began work on a new plan to get treatment out to those who needed it.

Denis Anthony Mitchison was born on September 6 1919 into a family of scientific and scholarly distinction. His maternal grandfather, John Scott Haldane, had conducted intrepid experiments on himself as part of his study of the mechanics of breathing, while his mother’s brother was the geneticist and biochemist JBS Haldane. Denis’s father, GR “Dick” Mitchison, was a barrister who would serve as Labour MP for Kettering from 1945-64, and his mother was the novelist Naomi Mitchison.

After Abbotsholme School in Staffordshire, Denis studied Natural Sciences at Trinity College, Cambridge. Initially he did badly in exams but after developing a belated enthusiasm for learning he went on to win a senior scholarship and embarked on clinical training as a doctor. After completing postgraduate studies in pathology he got a job at Brompton Hospital.

At that time the mortality rate for those who contracted tuberculosis was around 50 per cent. Laboratories had no safety precautions, and Mitchison suffered what he described as “a small attack” of TB himself. He had mixed feelings over the introduction of more stringent rules, however, observing that it would have been “quite impossible” to do the work that had led to those earliest breakthroughs in a more risk-averse climate.

Mitchison was the author of some 250 scientific papers and the recipient of numerous awards, including the British Thoracic Society Medal and the Stop TB Partnership Kochon Prize.

Despite being officially retired in 1985, he continued to conduct research, moving to St George’s, University of London, in the 1990s. There, as an emeritus professor, he began work at eight every morning – though he allowed himself to take Mondays off after he reached the age of 90. “You never run out of questions to put,” he observed.

He married, first, in 1940, Ruth Sylvia Gill, who died in 1992. They had four children, of whom two survive, Clare and Terence. In 1993 he married, secondly, Honora Carlin, who died in 2012.

Denis Mitchison, born September 6 1919, died July 2 2018

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