Analysis of the adult thymus in reconstitution of T lymphocytes in HIV-1 infection

A key question in understanding the status of the immune system in HIV-I in fection is whether the adult thymus contributes to reconstitution of periph eral T lymphocytes. We analyzed the thymus in adult patients who died of HI V-1 infection. In addition, we studied the clinical course of HIV-1 infecti on in three patients thymectomized for myasthenia gravis and determined the effect of antiretroviral therapy on CD4(+) T cells. We found that five of seven patients had thymus tissue at autopsy and that all thymuses identifie d had inflammatory infiltrates surrounding lymphodepleted thymic epithelium . Two of seven patients also had areas of thymopoiesis; one of these patien ts had peripheral blood CD4(+) T-cell levels of <50/mm(3) for 51 months pri or to death. Of three thymectomized patients, one rapidly progressed to AID S, one progressed to AIDS over seven years (normal progressor), whereas the third remains asymptomatic at least seven years after seroconversion. Both latter patients had rises in peripheral blood CD4(+) T cells after antiret roviral therapy Most patients who died of complications of HIV-1 infection did not have functional thymus tissue, and when present, thymopoiesis did n ot prevent prolonged lymphopenia. Thymectomy before HIV-1 infection did not preclude either peripheral CD4(+) T-cell rises or clinical responses after antiretroviral therapy.