Two Types of Immunological Poor Responders Showed Distinct Responses to Long-Term HAART

Abstract Objectives Most previous studies on immunological poor responders (IPRs) were performed on one cohort at one time-point following highly active antiretroviral therapy (HAART). We aimed to investigate whether IPRs have different subtypes and whether a certain population might achieve better immune reconstitution following longer HAART. Methods This study was designed as an ambispective cohort study, including a 4-5 year retrospective study, and a 2-year prospective follow-up investigation. We determined their thymic output, activated T-cell and Treg subset frequencies, the expression levels of IFN-stimulated genes, and their plasma concentration of neopterin at 4-5 years and 6-7 years following HAART initiation. Results We subdivided the IPRs into two populations after 4-5 years of HAART according to the kinetics of T cell recovery. The type II IPRs exhibited a significantly lower percentage of naive CD4+ T cells and CD31+ naive T cells compared with type I IPRs. After an additional 2-year HAART treatment, type I IPRs showed a better outcome than type II IPR. We further found that 2 years of additional HAART could persistently improve the thymic output. Conclusion The two IPR subgroups are different in terms of immune characteristics and response to prolonged HAART.