What are some effects of sleeping late at night for kidney transplants?

R u sleeping enough? If the total time sleeping is normal, then no effects are expected just from going to bed late. Sleep deprivation does increase the risk of infection. I would be most concerned about that since kidney transplants are already immunocompromised.
Sleep is important . Since we r creatures of habit to have a good sleep it is better to practice sleep hygene : going to bed at certain time and walking at certain time also .In addition u can discuss this with u physician.