Effect of splenectomy on slowing human immunodeficiency virus disease progression.

Background: Lymphoreticular tissue is the most important site for human immunodeficiency virus (HIV) replication in HIV-infected individuals.

Objective: To compare the long-term effect of splenectomy on survival and time to development of acquired immunodeficiency syndrome in subjects who had undergone splenectomy with subjects who had not undergone splenectomy.

Design: A cohort study with a follow-up of up to 13.4 years.

Setting: Subjects were recruited from a hospital outpatient clinic population and a multicenter study of patients with hemophilia.

Participants: Forty-five HIV-infected individuals were observed prospectively for up to 13.4 years (17 had undergone splenectomy and 28 had not undergone splenectomy). Five subjects underwent splenectomy before acquiring HIV infection and 12 underwent splenectomy during the asymptomatic phase of HIV infection. The group who did not undergo splenectomy consisted of HIV-infected individuals who were asymptomatic at study enrollment.

Main Outcome Measures: A Cox proportional hazards model was used to test the effects of splenectomy on survival and time to development of acquired immunodeficiency syndrome when adjusting for potential confounders (age, initial CD4+ cell count, and treatment with antiretroviral drugs). Splenectomy was treated as a time-dependent covariate to account for the variation in its timing.

Results: During the average follow-up of 8.6 years, 9 (53%) of the 17 subjects who underwent splenectomy and 23 (82%) of the 28 subjects who did not undergo splenectomy died; acquired immunodeficiency syndrome developed in 6 (35%) of the subjects who underwent splenectomy and 23 (82%) of the subjects who did not undergo splenectomy. Splenectomy was associated with a significant reduction of risk of developing acquired immunodeficiency syndrome (adjusted relative risk [RR] <0.4, P<.05), whereas the effect on risk of mortality approached, although it did not reach, significance (adjusted RR approximately 0.5, P approximately .10).

Conclusion: The absence of a spleen during the asymptomatic phase of HIV infection seems to have a beneficial effect on HIV disease progression.