Prolonged decrease of CD4+ T lymphocytes in HIV-1-infected patients after radiotherapy for a solid tumor.

Background: In HIV-negative patients, radiotherapy (RT) decreases CD4 T-cell counts. We studied the effects of RT in HIV-1 positive patients.

Methods: HIV-1 positive patients with a subsequent diagnosis of a solid tumor were selected from the Dutch national observational HIV cohort, Aids Therapy Evaluation in the Netherlands (ATHENA). The patients were grouped according to whether they had received RT or not. Primary endpoint of the study was the time from baseline to reaching CD4 cell counts higher than those at baseline. Kaplan-Meier estimates of the percentage of patients reaching the endpoint were calculated.

Results: Ninety patients were included of whom 36 received RT and 54 did not. Median duration of RT was 46 [interquartile range (IQR) 30-63] days. Median first CD4 cell count after stopping RT was 150 (IQR 30-270) × 10/L lower compared with baseline. In 13 of the 36 patients receiving RT, CD4 cell counts recovered to baseline, after a median of 469 (IQR 345-595) days. In 35 of the 54 patients without RT, the CD4 cell count recovered to baseline or higher, after a median of 112 (IQR 42-182) days. After 3 years, in 39% of patients who had RT compared with 71% of patients without RT, CD4 cell counts recovered to baseline or higher (P < 0.0001). In a Cox regression adjusted for potential confounders, RT was associated with a longer (hazard ratio 0.29; 95% confidence interval 0.13 to 0.63) and combination antiretroviral therapy use with a shorter time to return to baseline [hazard ratio 2.46 (95% confidence interval 1.11 to 5.48)].

Conclusions: RT resulted in a significant and prolonged decrease in CD4 cell counts.