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The X-ray luminosities $L_X$ of early-type galaxies are known to be strongly correlated with their optical (blue) luminosities $L_B$, but with a large scatter in $L_X$ for a given $L_B$. Using the most recent X-ray samples of early-type galaxies, we find that the residuals of $L_X$ from the mean $L_X-L_B$ relation are correlated with environment: relatively X-ray-underluminous galaxies have more bright neighbors. This suggests that ram-pressure stripping may modulate the X-ray properties of early-type galaxies.