Model-based analysis of CD4+ lymphocyte dynamics in HIV infected individuals

The previously suggested mathematical model of CD4+ lymphocyte depletion in HIV-infected individuals is analyzed and further developed. The model assumes that CD4+ lymphocyte depletion is caused by HIV products. Fairly good simulation of CD4+ lymphocyte dynamics is obtained, when limitation of HIV growth by specific cytotoxic T cells is included in the model. As it is probable that the substantial decrease of CD4+ lymphocytes, this type of influx control mechanism is also included in the model. It is shown that the simulated CD4+ lymphocyte dynamics agree with the observed data, analogously as in the earlier considered case of the constant influx. Moreover, the depleting effect of HIV products on mature and/or immature CD4+ lymphocytes is analyzed by the model. Also, another modification of the model assuming that CD4+ lymphocyte depletion is due to their destruction by cytotoxic T cells specific for HIV antigens, gives simulation results comparable to those obtained by the original version of the model, where the mechanism of the depletion is not specified.