Low-dose splenic irradiation in the treatment of immune thrombocytopenia in HIV-infected patients

Detrimental effects of high-dose dexamethasone in severe, refractory, HIV-related thrombocytopenia

OBJECTIVE

To report a case of HIV-related thrombocytopenia in which high-dose dexamethasone was ineffective and immunologically detrimental.

CASE SUMMARY

A 39-year-old white man with persistent, severe, HIV-1-related thrombocytopenia was admitted for epistaxis, bleeding gums, petechiae, and bruising. Previous unsuccessful attempts to reverse the thrombocytopenia included zidovudine, prednisone, vincristine, interferon alfa, and intravenous immune globulins. Based on previous anecdotal reports of the effectiveness of high-dose dexamethasone in refractory, HIV-related thrombocytopenia, we instituted treatment with intravenous dexamethasone 40 mg/d for four sequential days every 28 days. After three cycles of therapy, the platelet count remained < 15 x 10(9)/L; however, the CD4+ lymphocyte count decreased progressively from 1447 x 10(6)/L at baseline to 560 x 10(6)/L three months after the third cycle. Due to persistent, severe thrombocytopenia and bleeding, the patient underwent splenectomy, resulting in normalization of the platelet count.

DISCUSSION

High-dose dexamethasone has been proposed as treatment for patients with immune thrombocytopenia as an alternative to chronic oral corticosteroids and claimed to be associated with better effectiveness and fewer adverse effects. The results of this treatment in our patient show that this regimen may not only be ineffective, but may also be immunologically detrimental in HIV-infected patients. Although the deterioration of the immunologic status of our patient cannot be fully attributed to high-dose dexamethasone based on the Naranjo scale, the previous long-lasting stability of CD4+ cells and the temporal relationship of a decrease in the CD4+ cell count coinciding with administration of high-dose dexamethasone suggest a causative role of the treatment.

CONCLUSIONS

A possible cause-effect relationship between the treatment and the decrease in the CD4+ cell count suggests that the use of high-dose dexamethasone may not be justified in patients with severe, HIV-related thrombocytopenia.

The role of splenic irradiation in treating HIV-associated immune thrombocytopenia

PURPOSE

To evaluate our experience in treating patients with HIV-associated thrombocytopenia using splenic irradiation.

METHODS AND MATERIALS

From 1993 to 1998, 10 patients with HIV-related immune thrombocytopenia (ITP) were treated in our department with low-dose splenic irradiation. All patients had either failed more conventional treatment modalities or possessed some contraindication to them.

RESULTS

Nine of 10 patients had at least a small, transient rise in their platelet counts, but only two received a substantial therapeutic benefit. Of these two, one died shortly after completing his course of radiation therapy while the other maintained near normal platelet counts up to approximately 3(1/2) years following treatment. There were no treatment-related morbidities and one patient was treated twice.

CONCLUSION

While most patients with HIV-associated ITP may initially respond favorably to splenic irradiation with small rises in platelet count, few responses are likely to be sustained or provide clinically significant outcomes. Our results support those previously reported by others treating this same condition. What remains to be investigated is whether there are any prognostic indicators to help identify those patients most likely to respond to this treatment, thus enabling us to reserve splenic irradiation for those who might derive a substantial benefit from it.