Extending gains for the sixth session in a row, the BSE benchmark Sensex rose by nearly 86 points in early trade today on buying by funds and retailers.The 30-share barometer, which has gained over 541 points in the past five sessions, rose by another 85.76 points, or 0.48 per cent, to 17,938.71.All the sectoral indices, led by metals and realty, were trading with gains of up to 0.76 per cent.The wide-based National Stock Exchange index Nifty regained 5,400 points level by rising 21.65 points, or 0.40 per cent, to 5,411.65.In Asian region, Hong Kong's Hang Seng index rose by 1.13 per cent and Japan's Nikkei was up by 1.46 per cent in early trade. The US Dow Jones Industrial Average ended 0.52 per centhigher in yesterday's trade.