1163. HIV-1 NAAT Pitfalls in B-cell Lymphoblastic Leukemia Patients Following CAR-T Cell Therapy

Background CAR-T Cell Therapy is approved for the treatment of pediatric patients with relapsed/refractory B-ALL. Lentiviral vector technology, highly modified from HIV-1, is used to induce stable, long-term transgene expression by integration into the host genome. This integration may interfere with HIV-1 NAAT producing false-positive results. Methods A retrospective chart review of Pre-B ALL patients who underwent to CAR T cell therapy with KYMRIAH(tisagenlecleucel) at a single institution between January 2019 and May 2021 to assess for patients whose CAR-T infusion interfered with post-infusion HIV-1 testing. All patients had HIV NAAT pre and post CAR T-cell therapy (using platform, Roche COBAS AmpliPrep/Quantitative TaqMan HIV-1 T). Reactive HIV NAAT by Roche test were subsequently tested using different HIV-1 assay platforms to rule out or confirm HIV infection. Results We report three cases in which interpretation of HIV-1 NAAT testing was complicated by CAR T cell therapy. Case 1: 1-year-old male with refractory infantile leukemia was found to have a reactive HIV NAAT post CAR-T in routine infectious screening prior to SCT. Case 2: 3-year-old refractory ALL planned for SCT who had a reactive HIV NAAT 9 months post CART. Fourth-generation HIV-1 testing (targeting the p24 antigen and anti-HIV-1 antibodies) was negative pre and post CART. Viral loads were also undetectable indicating false-positive post-CAR-T HIV-1 NAT test results. Case 3: 21-year-old sexually active female with relapsed B cell ALL. Post CAR-T HIV NAAT was reactive, and a quantitative viral load was positive at 176 copies/mm3 one day prior to start of stem cell transplant conditioning regimen. Aptima HIV testing is typically used as confirmatory test for CAR-T associated false positive HIV NAT cases, but surprisingly, the Aptima test was also reactive. Additional testing with Abbott m2000 Realtime HIV-1 assay and 4th generation p24 antigen-based testing were both negative. Table 1 Summary of reported patients with false-positive HIV-1 NAAT test results following CAR T cell therapy and Table 2, HIV platforms used for screening and diagnosis with interpretations following CAR T cell therapy. Conclusion Clinicians need to be aware of potential false-positive HIV testing after CAR-T therapy. HIV testing platforms with targets not used in lentiviral vectors (4th generation test/P24, or Abbott test/integrase region) are highly recommended to avoid delays in subsequent therapy and unwanted stress for the patients, families, and clinicians Disclosures All Authors: No reported disclosures

A New Range of Chitosan Based Nano-antiviral Agents

ABSTRACT The current study involves the synthesis of fourteen analogs of oligochitosan and their screening for antiviral potential against human immunodeficiency virus (HIV), respiratory syncytial virus (RSV) and Coxsackie virus. The synthesized oligochitosan analogs were characterized by nuclear magnetic resonance (NMR) and FTIR techniques. HIV-1 p24 ELISA was performed using HIV-1 p24 antigen capture assay in order to estimate the viral infectivity loss. It was observed that sulfated oligochitosan was devoid of antiviral activity as compared to oligochitosan UN102 analog. The rest of UN102 analogs which include N-thiol (UN105), N-glutaryl (UN106), N-Azido (UN111) and N-phthaloyl (UN114) and N-citric analog (UN117) exhibited antiviral activity against HIV. The UN102 also decreased viral infection caused by RSV. In addition, UN102 was found to bind Coxsackie virus, which causes autoimmune myocarditis. The findings were of great interest to proceed for the development of novel antiviral agents.

Fourth-Generation ELISA Screening of Blood Donors: A Reliable Alternative to Nucleic Acid Testing

The gold standard for HIV screening of blood donors is individual nucleic acid amplification testing (NAT). However, individual NAT testing is cost-prohibitive, especially in a resource-limited setting. The fourth-generation ELISA that detects both p24 antigen and antibody to HIV-1 and 2 has been recommended as the minimum test for HIV to enhance blood transfusion safety and can be an alternative to NAT testing in resource-limited settings. The aim was to assess the performance of a fourth-generation ELISA in use at a regional blood transfusion service using nucleic acid amplification testing on units of screened blood negative to HIV. The study was a cross-sectional study conducted at the National Blood Transfusion Service center and the Plateau State Virology Research Centre, both in Jos, Nigeria. Between August and October 2016, one thousand and eighteen voluntary blood donors were recruited consecutively and had their samples tested using fourth-generation ELISA. One thousand p24 antigen-negative samples were pooled for NAT in an aliquot of 50 samples. All the pools of fifty samples of 1,000 HIV p24 antigen-antibody negative donor blood screened by the fourth-generation ELISA tested negative for HIV RNA on nucleic acid amplification. The yield of pooled NAT for HIV after a fourth-generation ELISA screening of blood donors was found to be zero in this study, thus establishing the fourth-generation ELISA's reliability. Therefore, we recommend adopting the fourth-generation ELISA test as a minimum requirement for blood donor screening.

Point-of-care p24 antigen detection for early infant diagnosis of HIV infection: cross-sectional and longitudinal studies in Zambia

Background Early infant diagnosis of HIV infection is challenging in sub-Saharan Africa, particularly in rural areas, leading to delays in diagnosis and treatment. Use of a point-of-care test would overcome many challenges. This study evaluated the validity of a novel point-of-care p24 antigen detection test (LYNX) in rural and urban settings in southern Zambia. Methods Two studies were conducted: a cross-sectional study from 2014 to 2015 at Macha Hospital (LYNX Hospital study) and a longitudinal study from 2016 to 2018 at 12 health facilities in Southern Province, Zambia (NSEBA study). In both studies, children attending the facilities for early infant diagnosis were enrolled and a blood sample was collected for routine testing at the central lab and immediate on-site testing with the LYNX test. The performance of the LYNX test was measured in comparison to nucleic acid-based testing at the central lab. Results In the LYNX Hospital study, 210 tests were performed at a median age of 23.5 weeks (IQR: 8.9, 29.0). The sensitivity and specificity of the test were 70.0 and 100.0%, respectively. In the NSEBA study, 2608 tests were performed, including 1305 at birth and 1222 on children ≥4 weeks of age. For samples tested at birth, sensitivity was 13.6% (95% CI: 2.9, 34.9) and specificity was 99.6% (95% CI: 99.1, 99.9). While specificity was high for all ages, sensitivity increased with age and was higher for participants tested at ≥4 weeks of age (80.6%; 95% CI: 67.4, 93.7). Children with positive nucleic acid tests were more likely to be negative by the LYNX test if their mother received antiretroviral therapy during pregnancy (60.7% vs. 24.2%; p = 004). Conclusions Considering the high specificity and moderate sensitivity that increased with age, the LYNX test could be of value for early infant diagnosis for infants ≥4 weeks of age, particularly in rural areas where centralized testing leads to long delays. Point-of-care tests with moderate sensitivity and high specificity that are affordable, easy-to-use, and easily implemented and maintained should be developed to expand access to testing and deliver same-day results to infants in areas where it is not feasible to implement nucleic acid-based point-of-care assays.

The Relationship Between HIV Antibody Titer, HIV Viral Load, HIV p24 Antigen, and CD4 T-cell Count Among Iranian HIV-positive Patients

Objective: This study aimed to simultaneously measure and assess the correlation between the available HIV infection parameters including HIV antibody, p24 Antigen, CD4 cell count, and viral load at the different stages of HIV disease among HIV-positive individuals in Iran. Materials and methods: Fifty HIV-positive individuals were classified into three stages (1, 2, and 3) according to the HIV disease stages classification, available in Control of Disease and Prevention (CDC) guideline. 10 ml of the venous blood sample was collected to run the tests for HIV antibody and p24 Ag levels, CD4 cell counts, and viral load. Pearson’s correlation test was employed to calculate the coefficients for the in-between correlation of different HIV parameters in each stage. Results: Of 50 participants, 17 (34%), 25 (50%), and 8 (16%) patients belonged to stages 1, 2, and 3, respectively. Sexual relationship was the main route of HIV transmission among the patients (36%); however, injecting drug use (20%) was also reported frequently. There was no significant correlation between the parameters of HIV disease in different stages in the present study. Conclusion: The findings showed no correlation between HIV parameters in the present study. Considering the fact that the association of HIV antibodies with HIV disease progression in infected individuals is independent of HIV-1 RNA levels, combined measurement of HIV-1 RNA and CD4 cell counts should be routinely carried out in HIV infected patients follow up.

Contemporary diagnosis of HIV infection in pediatrician’s practice

The objective of the study: evaluation of the effectiveness of clinico-epidemiological and laboratory diagnostics of HIV infection in pediatric practice. Materials and methods. Under the supervision of pediatricians of the Department of motherhood and childhood of the St. Petersburg AIDS Center, there were 388 HIV-infected children aged from one month to 17 years inclusive. Due to the reasons of late detection and HIV dissidence of parents, 18 children (4%) died cumulatively among the children observed in St. Petersburg center for AIDS. The object of the immunohistochemical study was randomly selected HIV-infected children who applied to the center for prevention and control of AIDS for return visits. Material for testing for the presence of HIV-1 P24 antigen was taken from the back wall of the nasopharynx. Results. When analyzing the ways of HIV infection in children registered at the maternity and childhood Department of the Saint Petersburg AIDS Center, it turned out that 363 children were infected perinatally (93,6%), 23 (5,9%) sexually infected and 2 children through injecting drugs (0.5%). The proposed method of immunocytochemistry for the diagnosis of HIV infection in children can find its application, especially for primary diagnostics, which may simplify and reduce the cost of laboratory diagnostics.