Lonely Little Boy

My son told my dh that he doesn't have any friends in his class. He says no one talks to him or plays with him. He says he's very lonely on the playground. Sometimes a couple boys will let him play but he mostly swings by himself. He doesn't talk to anyone at lunch. OMG - That is the sadest thing I've ever heard. I took out his class photo to make sure none of these kids were his friends. He told us about who plays with who and who talks to who. He's in none of those groups. That makes me so freakin sad. Any suggestions??????????