Clinical indications and biological mechanisms of splenic irradiation in autoimmune diseases.
BACKGROUND
Splenic irradiation (SI) is a fairly unknown treatment modality in autoimmune disorders like autoimmune thrombocytopenia (AIT) or autoimmune hemolytic anemia (AIHA), which may provide an effective, low toxic and cost-effective treatment for selected patients.


METHODS
This article reviews the limited experiences on splenic irradiation in autoimmune thrombocytopenia by analyzing the current studies including 71 patients and some preliminary reports on splenic irradiation in autoimmune hemolytic anemia.


RESULTS
In autoimmune thrombocytopenia between 40 and 90% of all patients responded, but most of them relapsed within 4 to 6 months after splenic irradiation. Between 10 and 20% of all patients had a sustained response. The efficacy of splenic irradiation in HIV-associated cases of thrombocytopenia is probably lower than in other forms of autoimmune thrombocytopenia, but especially in this group immunosuppressive drug treatment of autoimmune thrombocytopenia exposes some problems. In autoimmune hemolytic anemia there are some case reports about efficacy of splenic irradiation. Toxicity of splenic irradiation in both diseases was very moderate.


CONCLUSIONS
For HIV patients, for elderly patients or patients at high risk for complications following splenectomy splenic irradiation might be a treatment option. Splenic irradiation as preoperative treatment in patients not responding to or not suitable for immunosuppressive drugs prior to splenectomy may be a promising new application of splenic irradiation to reduce adverse effects of splenectomy in thrombocytopenic patients. A further analysis of the biological mechanisms underlying splenic irradiation may help to improve patient selection, to optimize dose concepts and treatment schedules and will improve understanding of radiotherapy as an immunomodulatory treatment modality.
Department of Radiation Oncology, University of Tübingen, Germany. martin.weinmann@med.uni-tuebingen.de
M
M
Weinmann
G
G
Becker
H
H
Einsele
M
M
Bamberg
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000744:Anemia, Hemolytic, Autoimmune / Q000188:drug therapy / Q000532:radiotherapy* / Q000601:surgery; D019380:Anti-HIV Agents / Q000627:therapeutic use; D003037:Cobalt Radioisotopes / Q000627:therapeutic use; D015658:HIV Infections / Q000150:complications / Q000188:drug therapy; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D010315:Particle Accelerators; D018579:Patient Selection; D010976:Platelet Count; D011446:Prospective Studies; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000188:drug therapy / Q000532:radiotherapy* / Q000601:surgery; D011867:Radioisotope Teletherapy; D011879:Radiotherapy Dosage; D012008:Recurrence; D012307:Risk Factors; D013154:Spleen / Q000528:radiation effects*; D013156:Splenectomy; D013921:Thrombocytopenia / Q000150:complications / Q000532:radiotherapy; D013997:Time Factors
D019380:Anti-HIV Agents; D003037:Cobalt Radioisotopes; D007166:Immunosuppressive Agents