PIK3CD and lymphoma: To date, 4 heterozygous GOF PIK3CD mutations (E1021K, N334K, E525K, and C416R) have been described, with E1021K the most common.1, 2, 6, 7, 8 Patients in both cohorts experienced recurrent respiratory tract infections, bronchiectasis, herpesvirus infections, nonneoplastic lymphoproliferation, and lymphoma.