Six patients with human immunodeficiency virus (HIV)-associated non-Hodgkin lymphoma receiving chemotherapy (CT) with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) plus granulocyte colony-stimulating factor were sequentially monitored to study the effects of these treatments on their immunologic status (CD4 and CD8 cell counts) and on HIV plasma viremia. We show that mean CD4 cell counts declined significantly after the third cycle of CT (187 +/- 117/microliters before CT versus 92.4 +/- 60/microliters; p = 0.04) and remained significantly reduced 4 months after completion of CT. Modifications of CD8 cell counts were not statistically significant. The effects of CT on plasma viremia, as measured by a competitive polymerase chain reaction technique, were delayed until the fourth cycle, when an increase of viral load ranging from 0.6 to 2 logs (p = 0.027) was observed. After this point, viremia returned to baseline levels, with the exception of two patients who later developed opportunistic infections and one who underwent disease progression. These results suggest that, contrary to CD4 cell counts, plasma viremia could be a faithful surrogate marker for monitoring of HIV disease progression in patients undergoing CT.