April 10 (Reuters) - U.S. stock index futures gained slightly on Friday after March inflation data calmed some concerns over the inflationary fallout of the Middle East conflict on the U.S. economy.

A Labor Department report showed the Consumer Price Index rose 3.3% on an annual basis, in line with an estimated 3.3% rise according to economists polled by Reuters. On a monthly basis, it rose 0.9% versus an expected rise of 0.9%.

The core figure, which excludes volatile food and energy components, rose 2.6% annually, below an expected 2.7% rise. On a monthly basis, it rose 0.2% compared with an estimated 0.3% rise.

At 08:31 a.m. ET, Dow E-minis YMcv1 were up 33 points, or 0.07%, S&P 500 E-minis EScv1 were up 11.5 points, or 0.17%, and Nasdaq 100 E-minis NQcv1 were up 62 points, or 0.25%.