See also
IgG4-related ophthalmic disease
IgG4-related prostatitis
IgG4-related skin disease

References
External links

Overview of IgG4-related disease - UpToDates article on IgG4-related disease. DermNet NZ entry
The RAR receptor is dependent on retinoic acid for regulation of transcription.Eight other rare gene rearrangements have been described in APL fusing RARA to promyelocytic leukemia zinc finger (PLZF), nucleophosmin, nuclear matrix associated, signal transducer and activator of transcription 5b (STAT5B), protein kinase A regulatory subunit 1α (PRKAR1A), factor interacting with PAPOLA and CPSF1 (FIP1L1), BCL-6 corepressor or oligonucleotide/oligosaccharide-binding fold containing 2A (NABP1) genes. Some of these rearrangements are ATRA-sensitive or have unknown sensitivity to ATRA because they are so rare; STAT5B/RARA and PLZF/RARA are known to be resistant to ATRA.The fusion of PML and RARA results in expression of a hybrid protein with altered functions. This fusion protein binds with enhanced affinity to sites on the cells DNA, blocking transcription and differentiation of granulocytes. It does so by enhancing interaction of nuclear co-repressor (NCOR) molecule and histone deacetylase (HDAC). Although the chromosomal translocation involving RARA is believed to be the initiating event, additional mutations are required for the development of leukemia.RARA/PLZF gene fusion produces a subtype of APL that is unresponsive to tretinoin therapy and less responsive to standard anthracycline chemotherapy hence leading to poorer long-term outcomes in this subset of patients. Diagnosis
Acute promyelocytic leukemia can be distinguished from other types of AML based on microscopic examination of the blood film or a bone marrow aspirate or biopsy as well as finding the characteristic rearrangement. The presence of promyelocytes containing multiple Auer rods (termed faggot cells) on the peripheral blood smear is highly suggestive of acute promyelocytic leukemia.