With one drug in a moderate dose, or high dose short-term, you are safe

With two drugs in low–moderate dose you are safe. With one of two in high dose there is risk of over-immunosuppression

With three drugs there is always risk of over-immunosuppression irrespective of dose

Usually a certain degree of immunosuppression can be obtained with different combinations of drugs

Conventional drugs (steroids, antimetabolites and calcineurin inhibitors) have short-term effect (days to weeks)

Biological drugs (polyclonal and monoclonal antibodies) have long-term effects (months to years)