Laboratory diagnosis of HIV: a contemporary overview in the Australian context

Challenges in HIV Diagnosis Algorithm: Experience of the Confirmation Laboratory

This study aimed to evaluate the effectiveness of the algorithm used in HIV diagnosis and to propose an effective new algorithm for rapid diagnosis. In accordance with CDC algorithm, our laboratory uses Architect HIVAg/Ab for screening and Geenius HIV1/2 and Artus HIVirus-1 QS-RGQ for confirmation. The Geenius test was used as a reflex and the HIV-1-RNA required clinician order. The HIVAg/Ab test was performed in 82,882 sera and found to be reactive in 262 (0.3%). HIV-antibody confirmatory testing was performed on 79% of samples with a reactive screening test, and the presence of HIV-1 antibodies was confirmed in 51% (105/206). Half of the samples with positive-screening but negative-antibody confirmatory results were tested for HIV1-RNA, and viremia was detected in 5, confirming acute HIV1 infection. HIV1-RNA was not ordered for 49 samples with positive-screening and negative antibody-confirmation tests, and 16 of these were considered false-reactive by the clinician. The Geenius assay result was indeterminate in 1.45% (3/206) of the samples. In the algorithm, the number of Geenius tests would have been reduced by 25% if HIV-1-RNA had been applied as a reflex test to HIV-Ag/Ab positive samples and Geenius testing had been performed on RNA negative samples. A retrospective analysis showed that the HIV diagnostic algorithm was not fully implemented. An important factor was that clinicians did not order HIV-1-RNA-PCR from ELISA reactive and Geenius test negative patients. Requesting HIV-1 RNA PCR as a reflex test is thought to prevent patient losses and shorten the turnaround time of the HIV diagnosis.

Should men who have ever had sex with men be allowed to donate blood in Brazil?

Many countries have modified their policies on banning or deferring blood donation by men who have sex with men (MSM) in light of ethical concerns and new evidence about transfusion risks. In Brazil, MSM were not eligible to donate blood unless they had been celibate for the previous 12 months. However, in May 2020, the Brazilian Federal Supreme Court overturned this restriction. Many authors have attempted to stress possible risks of transfusion-transmitted infection under various scenarios of changes in bans or restrictions on donations by MSM using mathematical models, but we consider that it is a difficult task due to the wide variety of sexual behaviors, attitudes, and practices. Among these factors, we highlight sex under the influence of illicit drugs, and the fact that people with an undetectable human immunodeficiency virus viral load have the potential to transmit should their blood be transfused. Despite these possible risks, we believe that some MSM can donate blood regardless of the time elapsed since their last sexual contact, especially because blood donations by MSM were occurring even when there were time-based deferral rules. Blood banks should always seek to use screening algorithms to identify high-risk sexual behaviors using gender-neutral criteria, and education about transfusion risks should be offered to healthcare workers and MSM.

Seronegative HIV-1 infection in a Japanese man presenting with Pneumocystis pneumonia: Analysis of long-term antibody response and literature review

Seronegative human immunodeficiency virus (HIV) infection, where an HIV-specific antibody response is lacking even in chronic or late-stage HIV infections, is extremely rare. Here, we report the case of a 50-year-old Japanese man presenting with Pneumocystis pneumonia who did not produce antibodies against HIV-1 until the initiation of antiretroviral therapy (ART). Fourth-generation antigen-antibody testing temporarily reverted from weakly positive to negative soon after initiating ART, likely due to a reduction in viral load (assessed by p24 antigen levels). His HIV-1 antibody titers remained low or indeterminate even after four years of ART. A literature review suggested that the absence of HIV-1-specific antibody production may be associated with unimpeded HIV replication and rapid CD4+ T cell decline. Seronegative HIV infection can lead to deferred diagnosis and treatment, thereby increasing the risk of transmitting the virus to others or developing opportunistic illnesses. It is important to combine multiple tests for diagnosis, depending on the medical condition. Further studies are required to investigate the host factors involved in the production of HIV-1-specific antibodies.

Breakthrough Acute HIV Infections among Pre-Exposure Prophylaxis Users with High Adherence: A Narrative Review

Pre-exposure prophylaxis (PrEP) is a pivotal intervention among HIV prevention strategies. We aimed to narratively revise the topic of HIV acute infection in the setting of PrEP exposure with a focus on diagnostic options, clinical features, and future PrEP perspectives, with a particular focus on users with high adherence to PrEP. We searched the main databases (PubMed, Embase, and Scopus) with the keywords "PrEP" or "Pre-Exposure Prophylaxis" and "HIV" or "PLWH" and "breakthrough" or "acute infection" or "primary infection". We included all randomized clinical trials and non-experimental studies (both case reports and observational studies) ever published. In the present narrative review, we revise the diagnostic challenges related to HIV diagnosis in the setting of PrEP and the clinical characteristics and symptoms of breakthrough infections. We discuss the management of acute HIV infection during PrEP and the new challenges that arise from the use of long-acting drugs for PrEP. Our review underlines that although extremely rare, HIV seroconversions are still possible during PrEP, even in a context of high adherence. Efforts to promptly identify these events must be included in the PrEP follow-up in order to minimize the chance of overlooked HIV breakthrough infections and thus exposure to suboptimal concentrations of antiretrovirals.