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True long-term nonprogressors (LTNPs)/elite controllers (ECs) maintain durable control over HIV replication without antiretroviral therapy. Herein we describe 4 unique persons who were distinct from conventional LTNPs/ECs in that they had extraordinarily low HIV burdens and comparatively weak immune responses. As a group, typical LTNPs/ECs have unequivocally reactive HIV-1 Western blots, viral loads below the lower threshold of clinical assays, low levels of persistent viral reservoirs, an over-representation of protective HLA alleles, and robust HIV-specific CD8(+) T-cell responses. The 4 unique cases were distinguished from typical LTNPs/ECs based on weakly reactive Western blots, undetectable plasma viremia by a single copy assay, extremely low to undetectable HIV DNA levels, and difficult to isolate replication-competent virus. All 4 had at least one protective HLA allele and CD8(+) T-cell responses that were disproportionately high for the low antigen levels but comparatively lower than those of typical LTNPs/ECs. These unique persons exhibit extraordinary suppression over HIV replication, therefore, higher-level control than has been demonstrated in previous studies of LTNPs/ECs. Additional insight into the full spectrum of immune-mediated suppression over HIV replication may enhance our understanding of the associated mechanisms, which should inform the design of efficacious HIV vaccines and immunotherapies.

Since the introduction of highly active antiretroviral therapies (ART), the prognosis for HIV-1 patients has improved immensely. However, approximately 25% of patients can experience a variety of inflammatory symptoms that are collectively known as immune reconstitution inflammatory syndrome (IRIS). Studying the etiology and immunopathology of IRIS has been hampered by the fact that the symptoms and associated opportunistic infections are highly varied. We hypothesized that there is a common mechanism underlying IRIS pathogenesis and investigated a patient group with IRIS related to different pathogens. Functional and phenotypic characterization of PBMC samples was performed by polychromatic flow cytometry after in vitro stimulation with relevant antigenic preparations. In most patients, IRIS events were characterized by the robust increase of preexisting polyfunctional, highly differentiated effector CD4(+) T-cell responses that specifically targeted the antigens of the underlying co-infection. T-cell responses to HIV-1 or other underlying infections were not affected and did not differ between IRIS and non-IRIS patients. These data suggest that patients with IRIS do not have a generalized T-cell dysfunction; instead, IRIS represents a dysregulated CD4(+) T-cell response against residual opportunistic infection antigen. These studies were registered at www.clinical-trials.gov as NCT00557570 and NCT00286767.

Immune reconstitution inflammatory syndrome (IRIS) is a considerable problem in the treatment of HIV-infected patients. To identify immunologic correlates of IRIS, we characterized T-cell phenotypic markers and serum cytokine levels in HIV patients with a range of different AIDS-defining illnesses, before and at regular time points after initiation of antiretroviral therapy. Patients developing IRIS episodes displayed higher frequencies of effector memory, PD-1(+), HLA-DR(+), and Ki67(+) CD4(+) T cells than patients without IRIS. Moreover, PD-1(+) CD4(+) T cells in IRIS patients expressed increased levels of LAG-3, CTLA-4, and ICOS and had a Th1/Th17 skewed cytokine profile upon polyclonal stimulation. Elevated PD-1 and Ki67 expression was also seen in regulatory T cells of IRIS patients. Furthermore, IRIS patients displayed higher serum interferon-γ, compared with non-IRIS patients, near the time of their IRIS events and higher serum interleukin-7 levels, suggesting that the T-cell populations are also exposed to augmented homeostatic signals. In conclusion, our findings indicate that IRIS appears to be a predominantly CD4-mediated phenomenon with reconstituting effector and regulatory T cells showing evidence of increased activation from antigenic exposure. These studies are registered online at http://clinicaltrials.gov as NCT00557570 and NCT00286767.