You can read an item from a transient data queue only once, because whenever you read from a transient data queue, CICS deletes the entry (by performing a "destructive read"). Therefore, if you specify security with SEC=YES as a system initialization parameter, CICS requires a minimum authorization level of UPDATE for all TD commands (DELETEQ, WRITEQ, and READQ).
For information about the access authorization levels for system programming commands which apply to transient data queues, see Resource and command check cross reference.