Disrupted sleep London - Arabstoday A disturbed sleeping pattern can lead to illness, scientists say. Researchers have found that the circadian clock – the genetic mechanism which regulates our sleep – controls the level of a gene vital to our immune system. Scientists from Yale University linked the gene TLR-9 to the cycle in mice. When the gene was at its most active, it was able to respond best to bacteria and viruses and the mice responded better to infection and vaccinations. In theory, the principles should also apply for the same gene in humans. Disruptions to the cycle can make us more susceptible to illness, reports journal Immunity. This suggests that jet lag may contribute directly to illness and that there may be ideal times of the day to receive vaccinations. Professor Erol Fikrig said: ‘People intuitively know that when their sleep patterns are disturbed, they are more likely to get sick.’ He also suggested further study was needed into how noise and artificial light in intensive care units could be affecting patients. He said: ‘Sleep patterns of patients in intensive care are often disrupted because of the noise and prolonged exposure to artificial light. ‘It will be important to investigate how these factors influence immune system response.’