Absolute CD4 Research Articles

Plasma interleukin-7 correlation with human immunodeficiency virus RNA and CD4+ T cell counts, and interleukin-5 with circulating hepatitis B virus DNA may have implications in viral control

Chronic viral infections represent a leading cause of global morbidity and mortality. Chronic HBV, HCV, and HIV infections result in cytokine perturbations that may hold key implications in understanding the complex disease mechanisms driving virus persistence and/or resolution. Here, we determined the levels of various plasma cytokines using a commercial Bio-Plex Luminex cytokine array in chronic HBV (n = 30), HCV (n = 15), and HIV (n = 40) infections and correlated with corresponding plasma viral loads (PVLs) and liver parameters. We observed differential perturbations in cytokine profiles among the study groups. The cytokines levels positively correlated with PVL and liver transaminases. The monocyte-derived cytokines viz., MIP-1β, IL-8, and TNF-α, and Th2 cytokines like IL-4, IL-5, and IL-13 showed a better correlation with liver enzymes as compared to their corresponding PVLs. Our investigation also identified two cytokines viz., IL-5 and IL-7 that inversely correlated with HBV DNA and HIV PVLs, respectively. Regression analysis adjusted for age showed that every increase of IL-5 by one unit was associated with a reduction in HBV PVL by log10 0.4, whereas, every elevation by a unit of IL-7 was associated with decreased HIV PVL by log10 2.5. We also found that IL-7 levels correlated positively with absolute CD4+ T cell counts in HIV-infected patients. We concluded that plasma IL-5 and IL-7 may likely have a key role on viral control in HBV and HIV infections, respectively. A noteworthy increase in cytokines appears to bear protective and pathological significance, and indeed is reflective of the host's versatile immune armory against viral persistence.

A UNIQUE PRESENTATION OF GATA2 DEFICIENCY, EMBERGER SYNDROME

<h3>Introduction</h3> GATA2 deficiency is a genetic defect resulting in a group of disorders, including Emberger syndrome. It presents in childhood with lymphedema, sensorineural hearing loss, lymphocyte deficiency, pulmonary alveolar proteinosis, and one or more dysplasias, commonly myelodysplastic syndrome or acute myeloid leukemia. <h3>Case Description</h3> A 7-year-old female with left eye esotropia status post correction, presented with left leg swelling. Rheumatological workup and imaging studies were negative. CBC showed persistent anemia, leukopenia, and no monocytes. Immunological workup including TBNK, immunoglobulins, mitogen proliferation, DHR test, pneumococcal, diphtheria and tetanus IgG, TB Quant gold, CMV, EBV, and HSV were normal except inadequate Diphtheria and pneumococcal IgG, low absolute CD19 (19 K/CUMM), NK cells (4 K/CUMM) and a positive EBV IgG. Genetic testing identified autosomal dominant pathogenic c.1148dup in <i>GATA2</i> gene. CXR was negative for pulmonary alveolar proteinosis. Antivirals and azithromycin for prophylaxis were started. Bone marrow biopsy has been scheduled to evaluate for acute myeloid dysplasia. Bone marrow transplant is necessary for curative treatment. <h3>Discussion</h3> GATA2 deficiencies have variable presentations, but commonly present with opportunistic infections (CMV, EBV, HSV, VZV, mycobacteria), leukopenia, and myelodysplasias. Though our patient has no hearing loss or infections, she has lymphedema, anemia, and neutropenia consistent with Emberger syndrome. Despite monocyte/B/NK cell deficiencies, our patient did not fit the diagnosis of MonoMAC syndrome as there was no pulmonary alveolar proteinosis, infections, or leukemia/myelodysplasia.

S2177 Clostridium difficile-Like Diarrhea

Introduction: Clostridium difficile is an important cause of diarrhea in immunosuppressed patients, recent use of antibiotics and in patients presenting from nursing facility. We present a patient with HIV, recently treated with Augmentin and started on a new medication (Juluca) for HIV presenting with watery diarrhea and abdominal pain. Case Description/Methods: 62-year-old woman with HIV infection presented with abdominal pain and watery diarrhea for 2 days. She recently had ureteroscopy and was prescribed Augmentin which she completed about a week ago. She denied any GU complaints. She was started on Juluca (Dolutegravir/ Rilpivirine) for treatment of HIV one day before onset of symptoms. She had diffuse tenderness on abdominal exam and had leukocytosis (23.1k/mcl) with an absolute CD4 count of 568/mcl. On CT scan abdomen she had pancolitis with free fluid. She was found to have Clostridium antigen but without any toxin. On flexible sigmoidoscopy she had lesions shown in the Figure. Erythematous, edematous mucosa and inflamed plaques were seen on ulcerated mucosa with narrowing of sigmoid colon. No pseudomembranes or cytological atypia was seen on histopathology. Specimen culture did not show C. difficile. Discussion: There are multiple causes of inflammatory diarrhea in an immunocompromised host with HIV. Previous infection with C. difficile and recent use of antibiotics increase the risk of C. difficile diarrhea. As per the center of disease control, about a half a million people are infected with C. difficile annually and one in 6 patients will get recurrent infection in 2 to 8 weeks. Our patient presented with multiple risk factors including history of C. difficile, HIV and recent use of antibiotics. The images of sigmoidoscopy were suggestive of pseudomembranous colitis though the tissues without any pathological or microbiological evidence. It highlights the importance of considering other non infectious causes of inflammatory diarrhea like medications. Dolutegravir/ rilpivirine are new class of medications (Integrase inhibitors). In a study by Curtis et al less than 2% of cases had diarrhea but none were severe enough o warrant discontinuation of therapy. Our patient had severe symptoms and required discontinuation of Juluca with regression of his symptoms.Figure 1.: A and B- Images of recto-sigmoid showing pseudomembranes in an edematous, erythematous colon. C,D - Marked narrowing of the sigmoid colon.

S2799 Disseminated Cryptococcosis Masquerading as Large Abdominal Mass Concerning for Pancreatic Malignancy in HIV-Positive Patient

Introduction: Gastrointestinal cryptococcus is a rare occurrence in HIV-positive patients. Symptoms may be nonspecific thus the differential for abdominal masses must remain broad. We report a patient with HIV who presented with abdominal pain and watery diarrhea, found to have a large abdominal mass on computed tomography initially thought to be lymphoma or a primary pancreatic tumor. He underwent endoscopic ultrasound-guided (EUS) biopsy of the mass which was consistent with a cryptococcoma. Case Description/Methods: A 55-year-old male presented with severe, diffuse abdominal pain for one week duration associated with profuse watery, non-bloody diarrhea and intermittent chills. Medical history included HIV for 30 years with poor compliance with antiretroviral regimen, recent pneumocystis pneumonia and previous cryptococcal meningitis. Physical exam revealed an ill appearing, cachectic male with abdominal tenderness. Labs revealed a white blood cell count of 18.5 K/uL (ref: 4.0-10.8 K/uL) with 84% neutrophils (ref: 40-75%), sodium of 132 mmol/L (ref: 135-146 mmol/L) and potassium 2.7 mmol/L (ref: 3.5-5.1 mmol/L). His viral load was 109,385 copies/mL (ref: neg copies/mL) and absolute CD4 count was 56 lymphocytes/uL (ref: 330-1520 lymphocytes/uL). Liver chemistries were unremarkable. Stool studies for regional pathogens, ova and parasites, and clostridium difficile were negative. A CT scan of the abdomen and pelvis revealed ill-defined cystic/necrotic upper abdominal lymphadenopathy with mass effect and possible invasion of the adjacent liver (Figure 1A). The pancreas and caudate lobe of the liver were inseparable from the mass which raised concern for primary pancreatic tumor or lymphoma. He underwent EUS-guided biopsy of the peripancreatic mass (Figure 1B) with pathology consistent with a cryptococcoma (Figure 1C, 1D). He was started on amphotericin B and transitioned to high dose fluconazole due to adverse effects. Repeat imaging revealed significant reduction of the mesenteric lymphadenopathy (Figure 1E). He was discharged in stable condition and remained on fluconazole indefinitely. Discussion: Cryptococcal infection remains the second most common cause of acquired immunodeficiency syndrome related mortality after tuberculosis. The most common sites of cryptococcal infection are the lungs, brain, eyes, or central nervous system; abdominal dissemination is rare. Biopsy via EUS can be useful in diagnosis of cryptococcoma. Early identification and treatment of cryptococcal infections can increase survival rates.Figure 1.: A) CT image showing ill-defined cystic/necrotic upper abdominal lymphadenopathy with mass effect and possible invasion of the adjacent liver B) Endoscopic ultrasound imaging showing peripancreatic mass C) Hematoxylin and Eosin cellblock at 40X magnification showing abundant neutrophils and necrotic debris D) Grocott’s Methenamine Silver stain showing fungal yeast with narrow base budding E) Significant reduction of the mesenteric lymphadenopathy after antifungal therapy initiation.

Low absolute CD4+ T cell counts in peripheral blood: an independent predictor of inferior survival in natural killer/T-cell lymphoma-a retrospective cohort study.

Lymphopenia at diagnosis is considered a negative prognostic factor for patients with extra-nodal natural killer (NK)/T-cell lymphoma (ENKTL), especially that of the absolute cluster of differentiation 4+ T cell count (ACD4C), which has previously been identified as an independent prognostic factor in other hematologic malignancies. However, there is limited data available regarding the prognostic value of peripheral blood T lymphocyte subsets in ENKTL patients. The purpose of this study was to investigate the prognostic value of lymphocyte subsets, especially the ACD4C in ENKTL as a clinical biomarker. We analyzed the clinical data of 176 patients who met the inclusion criteria in Cancer Center of Integrated Hospital of Traditional Chinese Medicine, Southern Medical University from 2000 to 2018, including baseline clinical factors and ACD4C detected by flow cytometry, and examined the correlation between the results and clinical parameters and long-term outcomes. The complete response rate of the high ACD4C group was 57.6%, which was significantly higher than that of the low ACD4C group (15.1%, P<0.001). The univariate analysis results showed that at a median follow-up time of 58.2 months, patients with a high ACD4C had significantly superior progression-free survival (PFS) and overall survival (OS) (P=0.034 and P=0.001, respectively). The multivariate analysis results revealed that Eastern Cooperative Oncology Group performance status (ECOG PS) and the ACD4C were independent prognostic factors for OS [RR (95% CI): 2.288 (1.209-4.328), P=0.011 and RR (95% CI): 2.058 (1.070-3.968), P=0.031, respectively]. ECOG PS was also an independent prognostic factor for PFS [RR (95% CI): 1.858 (1.064-3.244), P=0.029], while ACD4C tended to be independently correlated with PFS (P=0.085). In this large cohort study, we found that the ACD4C was associated with survival outcomes in ENKTL patients. It is a potential biomarker, which may potentially be applied to clinical.

ABCL-385 CD4 Counts and Viral Loads for Screening of HIV-Associated Lymphoma

Lymphoma is a leading cause of death in HIV patients, with up to 400-fold increased incidence compared to HIV-negative individuals. There tends to be a downtrend in CD4 lymphocyte counts noted at the diagnosis of lymphoma in HIV patients, despite virologic control. Some reports have described a preceding downtrend of CD4 counts almost a year prior to lymphoma diagnosis. The pathophysiology of this CD4 decline remains largely unknown, and the implications of this finding on prognosis, infection risk, or response to therapy are unclear. To date, there are no significant interventions suggested in response to this finding. Further characterization of this decline may provide clinical utility for identifying high-risk patients and intervening earlier, both by way of treatment and prophylaxis. We performed a retrospective chart review of patients with HIV-associated lymphoma treated at the UTMB oncology clinic between 2020 to 2021. We identified 3 patients with HIV-associated lymphoma, all notably with diffuse large B-cell lymphoma (DLBCL). We analyzed their CD4 counts and HIV viral loads from the time of diagnosis to 1 year after treatment completion, their rates of infectious complications, and lymphoma treatment outcomes. Hematology and Oncology Clinic Results: All patients had CD4 counts <100 with undetectable HIV on quantitative PCR at lymphoma diagnosis. All received chemo-immunotherapy, predominantly the R-EPOCH regimen, and standard infection prophylaxis according to guidelines. Two patients presented with a significant rise in absolute CD4 levels throughout the treatment course, whereas 1 had minimally rising levels initially that then declined. All patients achieved complete responses to systemic therapy with no infectious complications and no significant relapses. There is a lack of clear explanation for CD4 lymphopenia decline prior to and at the time of HIV-associated lymphoma diagnosis, despite optimal HIV control. Lymphocyte recruitment to lymphomagenesis sites may contribute to the low CD4 count in peripheral blood, which may explain their preceding decline. Screening such patients for lymphoma diagnosis might help with early-stage diagnosis and prognosis improvement. Large-scale studies are needed to better evaluate the implications of our findings and make potential changes to the management algorithm of HIV-associated lymphoma.

Rare Case of Persistently Depressed T Lymphocyte Subsets After SARS-CoV-2 Infection

BACKGROUND On rare occasions, viral infections are known to also depress immune cell lines, further worsening clinical outcomes. We describe a patient who presented 3 weeks after recovery from mild COVID-19 disease with clinical features of an atypical pneumonia and was found to have a low CD4+ T-cell count. CASE REPORT An 82-year-old man with a past medical history of coronary artery disease, rheumatoid arthritis, gout, hypertension, and atrial fibrillation presented with a 1-week history of progressively worsening shortness of breath and cough. He was noted to have recovered from mild SARS-CoV-2 infection 3 weeks prior to his current presentation and had been at his baseline level of health following infection. A T cell subset panel was obtained, which revealed an absolute CD3 count of 92 (reference range 840-3060), absolute CD4 count of 52 (reference range 500-1400), absolute CD8 count of 37 (reference range 180-1170), and a normal CD4: CD8 ratio. He was subsequently started on atovaquone for pneumocystis jiroveci pneumonia prophylaxis. CONCLUSIONS This case highlights the need for a high index of suspicion for lymphocyte depletion in older patients with multiple comorbidities who present during or after SARS-CoV-2 infection with atypical symptoms that are suggestive of immunosuppression. In such instances, there should be a low threshold to start prophylactic therapy for possible opportunistic infections.

Differential distribution and prognostic value of CD4+ T cell subsets before and after radioactive iodine therapy in differentiated thyroid cancer with varied curative outcomes.

Differentiated thyroid cancer is the most frequently diagnosed endocrine tumor. While differentiated thyroid cancers often respond to initial treatment, little is known about the differences in circulating immune cells amongst patients who respond differently. A prospective study of 39 patients with differentiated thyroid cancer was conducted. Serum thyroglobulin levels and thyroid and immunological functions were tested before and after radioactive iodine treatment (RAIT). Efficacy assessments were performed 6 to 12 months after radioactive iodine treatment. Most patients showed an excellent response to radioactive iodine treatment. Before radioactive iodine treatment, the excellent response group had considerably fewer circulating CD4+ T cell subsets than the non-excellent response group. Both the excellent response and non-excellent response groups had considerably lower circulating CD4+ T lymphocyte subsets 30 days after radioactive iodine treatment, but those of the excellent response group were still lower than those of the non-excellent response group. All circulating CD4+ T cell subsets in the excellent response group rose by varying degrees by the 90th day, but only Treg cell amounts increased in the non-excellent response group. Interestingly, in the non-excellent response group, we noticed a steady drop in Th1 cells. However, the bulk of circulating CD4+ T cell subsets between the two groups did not differ appreciably by the 90th day. Finally, we discovered that CD4+ T cell subsets had strong predictive potential, and we thus developed high-predictive-performance models that deliver more dependable prognostic information. In conclusion, in individuals with differentiated thyroid cancer, there is great variation in circulating immune cells, resulting in distinct treatment outcomes. Low absolute CD4+ T cell counts is linked to improved clinical outcomes as well as stronger adaptive and resilience capacities.

Cryptococcal Antigen Screening and Missed Opportunities for Earlier Diagnosis Among People With HIV and Poor Virologic Control in the Bronx, NY.

Background:There is no established cryptococcal antigen (CrAg) screening guideline for people with HIV who are antiretroviral therapy experienced but have poor virologic control. We assessed factors associated with CrAg screening and describe missed opportunities for earlier testing.Setting:Ambulatory clinics affiliated with Montefiore Medical Center, Bronx, NY.Methods:This was a retrospective chart review of CrAg screening among asymptomatic people with HIV with absolute CD4 counts200 cells/mm3 and HIV viral loads (VLs) > 200 copies/mL receiving HIV care from 2015 to 2020. We used Cox proportional hazards regression to identify predictors of screening, including longitudinal CD4 count and HIV VL as time-varying covariables. Among cases of diagnosed cryptococcosis, we assessed for opportunities for earlier diagnosis.Results:Screening CrAg was performed in 2.9% of 2201 individuals meeting the inclusion criteria. Compared with those not screened, those who were screened had a shorter duration of HIV infection (0.09 vs. 5.1 years; P = 0.001) and lower absolute CD4 counts (12 vs. 24 cells/mm3; P < 0.0001). In a multivariable model stratified by median HIV duration, CD4 < 100 [hazard ratio (HR), 7.07; 95% confidence interval (CI): 2.43 to 20.6], VL > 10,000 (HR, 15.0; 95% CI: 4.16 to 54.0), and a shorter duration of HIV infection (HR, 0.60; 95% CI: 0.42 to 0.86) were associated with screening for those with HIV < 5 years. Among those diagnosed with cryptococcosis (n = 14), 6 individuals had an ambulatory visit in the preceding 6 months but did not undergo screening.Conclusion:CrAg screening was infrequently performed in this at-risk population. Those with a longer duration of HIV infection were less likely to undergo CrAg screening, highlighting potential missed opportunities for earlier diagnosis.

Flow-Cytometry Intracellular Detection and Quantification of HIV1 p24 Antigen and Immunocheckpoint Molecules in T Cells among HIV/AIDS Patients.

IntroductionHIV p24 antigen-positive T cells measured by flow cytometry (FCM) correlate directly with HIV viral load, inversely with CD4+ T cells, and decrease with antiretroviral therapy (ART). However, the sensitivity of FCM assays depends on the protocol of intracellular staining. Therefore, this study aimed to evaluate the diagnostic performance of our FCM protocol for detection of HIV p24-positive T cells and measure the level of immunocheckpoint molecules (PD1 and TIM3) in T cells.MethodsThe study was conducted at the University of Leipzig hospital between January 2020 and November 2020. Viremic and ART-suppressed HIV-positive patients and negative controls were included in this study. HIV1 p24 KC57-, p24 28B7-, PD1-, and TIM3-positive CD4 and CD3 T cells were analyzed from whole blood using a BD FACS Canto II flow cytometer equipped with FACSDiva software. HIV1 p24 antigen FCM results were compared with HIV1 RNA viral load results measured by Alinity M assays on the fully automated random-access platform. We analyzed the data using SPSS 20.ResultsThe absolute CD4+ and CD4+:CD8+ T-cells ratio showed a significant inverse correlation with HIV1 viral load. Moreover, the absolute CD4+ T-cells count showed a significant inverse correlation with p24 KC57-positive CD4 T cells. The percentage of p24 KC57, p24 28B7, and double-positive CD4 T cells showed significant correlation with HIV1 viral load. PD1 expressing CD4 T cells were higher in ART-viremic cases than controls, while TIM3-expressing CD4 T cells were lower in ART-viremic cases than controls. Sensitivity, specificity, PPV, and NPV of p24 KC57-positive CD4 T cells were 64%, 82%, 78%, and 69%, respectively, for the diagnosis of HIV infection and 55%, 73%, 40%, and 83%, respectively, for treatment monitoring.ConclusionOur protocol showed moderate performance for the diagnosis of HIV infection and treatment monitoring. Therefore, the p24 KC57 but not the p24 28B7 clone could be considered as a simple alternative method for rapid diagnosis of HIV infections and treatment monitoring, particularly in low- and middle-income countries.

COVID-19 disease induced alteration of oxidative stress and clinical laboratory parameters in moderate and severe patients.

The aim of our study was to present the clinical alterations of CRP, LDH, neutrophil to lymphocyte ratio, platelets to lymphocyte ratio, D-dimer, blood gas analyses, vitamin D, VEGF, IL-6, IFN-γ, CD4+, CD8+) and their correlation with oxidative stress index (OSI) in hospitalized COVID-19 patients. Oxidative stress index and clinical parameters were determined at admission and/or 7 days after hospitalization in 50 patients divided in moderate and severe group. In the moderate group of patients, a good correlation (R2 = 0.7400, p<0.05) was found between OSI and PLR, D-dimers and LDH at admission and after 7 days. The OSI correlated well with vitamin D, INF-γ, IL-6, CD4+, CD8+ and the absolute CD8 cell number on admission (R2=0.7635, p<0.05). Vitamin D deficiency (15.37 ng/mL ± 2.81) was observed at admission in the severe group, accompanied by increased levels of IL-6 (295.3 pg/mL ± 40.06), INF-γ (1.603 pg/mL ± 0.134), VEGF (546.8 pg/mL ± 124.2) compared to non-infected individuals. All patients had low partial pressure of oxygen, although it did not show statistically significant difference between the two groups. All investigated parameters were altered in both groups of patients and a good correlation between them was demonstrated.

Unsuppressed HIV infection impairs T cell responses to SARS-CoV-2 infection and abrogates T cell cross-recognition.

In some instances, unsuppressed HIV has been associated with severe COVID-19 disease, but the mechanisms underpinning this susceptibility are still unclear. Here, we assessed the impact of HIV infection on the quality and epitope specificity of SARS-CoV-2 T cell responses in the first wave and second wave of the COVID-19 epidemic in South Africa. Flow cytometry was used to measure T cell responses following peripheral blood mononuclear cell stimulation with SARS-CoV-2 peptide pools. Culture expansion was used to determine T cell immunodominance hierarchies and to assess potential SARS-CoV-2 escape from T cell recognition. HIV-seronegative individuals had significantly greater CD4+ T cell responses against the Spike protein compared to the viremic people living with HIV (PLWH). Absolute CD4 count correlated positively with SARS-CoV-2-specific CD4+ and CD8+ T cell responses (CD4 r=0.5, p=0.03; CD8 r=0.5, p=0.001), whereas T cell activation was negatively correlated with CD4+ T cell responses (CD4 r=-0.7, p=0.04). There was diminished T cell cross-recognition between the two waves, which was more pronounced in individuals with unsuppressed HIV infection. Importantly, we identify four mutations in the Beta variant that resulted in abrogation of T cell recognition. Taken together, we show that unsuppressed HIV infection markedly impairs T cell responses to SARS-Cov-2 infection and diminishes T cell cross-recognition. These findings may partly explain the increased susceptibility of PLWH to severe COVID-19 and also highlights their vulnerability to emerging SARS-CoV-2 variants of concern.

Prevalence of Cryptococcus gattii in Ugandan HIV-infected patients presenting with cryptococcal meningitis.

IntroductionCryptococcal meningitis (CM) is a life threatening disease and leading cause of opportunistic fungal-related mortality in HIV/AIDS. Most CM infections are caused by C. neoformans species complexes but the prevalence of Cryptococcus gattii species complexes in Uganda is unknown however, it is known in a few other parts of Africa. We estimated the prevalence of C. gattii in patients living with HIV and a diagnosis of cryptococcal meningitis in Uganda.MethodsCryptococcus isolates (n = 200) obtained from cerebrospinal fluid of patients with CM recruited at the Infectious Diseases Institute, Kampala, Uganda, were tested by phenotypic methods. The Cryptococcus isolates were sub-cultured on Sabouraud Dextrose Agar plates for 48 hours. The yeast colonies were examined by India ink stain, urea hydrolysis, and C. gattii was identified by blue pigmentation on CGB agar. The results were analyzed for frequency of C. gattii. Patient demographic characteristics were collected from the case record forms.ResultsFrom the 200 patients’ case record forms, 87 (43.5%) were female and 113 (56.5%) were male. The median age was 35 (19–64) years. Most patients, 93% (187/200) were from Central Uganda in the districts of Kampala and Wakiso. 97.51% (157/161) of the patients had absolute CD4 lymphocyte counts of less than 200 cells per cubic millimeter; 1.86% (3/161) 200–350 cells per cubic millimeter and 0.62% (1/161) above 500 cells per cubic millimeter. 45.4% (74/163) were not yet on HAART and 54.6% (89/163) were on HAART. 66.7% (58/87) had poor adherence to HAART treatment and 33.3% (29/87) had reported good adherence to HAART treatment. A total of 200 clinical isolates of Cryptococcus isolates were tested. No (0% (0/200) C. gattii was identified among the Cryptococcus isolates.ConclusionIn this study among patients living with HIV and a diagnosis of cryptococcal meningitis in Uganda, we found no C. gattii infections.

Abstract 4151: Effect of camidanlumab tesirine (Cami) as monotherapy and in combination with pembrolizumab (PEM) on the immune cell profile in patients with selected advanced solid tumors

Abstract Background: Cami, an investigational anti-CD25, pyrrolobenzodiazepine-based antibody drug conjugate, imparts cytotoxicity on CD25+ regulatory T cells (Tregs), leading to immunomodulatory effects (eg, modifying effector T cell [Teff]:Treg intratumoral balance). Objective: Describe the pharmacokinetics (PK) and circulating immune cell profile of Cami monotherapy and in combination with PEM in patients with advanced solid tumors. Methods: In the dose-escalation phase 1b trial of Cami (NCT03621982) in patients with advanced solid tumors after failure of recommended therapies, we investigated Cami monotherapy (n=44; doses: 20, 30, 45, 60, 80, 100, 125, and 150 µg/kg every 3 weeks [Q3W]) and Cami combination therapy (n=12; doses: 30, 45, and 60 µg/kg with PEM 200 mg Q3W). Serum conjugated antibody (cAb) and total antibody (tAb) were quantified by a validated chemoimmunoluminescence assay. Soluble CD25 was quantified by a qualified enzyme-linked immunoassay. Circulating immune cell absolute counts were assessed by flow cytometry for Tregs (FoxP3+CD25+CD127low) as a fraction of absolute CD4+ cells, Teff (CD8+), and Teff:Treg. Statistical analyses were performed using a linear mixed-effects model (maximum likelihood) for the biomarker effects model with cAb area under the curve (AUC) during cycle 1, therapy (monotherapy vs combination), and treatment cycle as fixed effects and log AUC slope with intercept by subject or visit day as random effects. Results: PK analysis found Cmax and AUC of cAb and tAb increased during cycles 1 and 2 with Cami monotherapy and combination therapy across the range of doses. Variability of AUCinf for cAb in cycle 1 appeared modest to marked across discrete dose groups (CV=14.7-98.1%). The clearance of cAb ranged from 1.34 to 3.52 L/day in cycle 1 with no apparent differences between monotherapy and combination therapy. Biomarker modeling demonstrated that cAb AUC and cycle were associated with a significant Tregs depletion and a significant positive effect on Teff:Treg ratio but with no relevant effect on Teff. Within cycle, treatment-related modulation of Teff and Tregs was observed for all doses and conditions. Soluble CD25 appears to be significantly positively affected by cycle 2 treatment. Conclusions: PK exposure of Cami was dose-related with varying degrees of interpatient variability. Circulating Tregs were significantly decreased and Teff:Treg was significantly increased by Cami exposure, demonstrating the intended immunomodulatory effect of Cami in circulation and suggesting that a combination approach with Cami could address an immune-resistance mechanism. Future analyses will consider discrete PEM effect, correlates to tumor biopsy expression and response, and combined Cami+PEM effect in tumor biopsies. Funding: ADC Therapeutics; medical writing: CiTRUS Health Group. Citation Format: Igor Puzanov, Christopher T. Chen, Patricia LoRusso, Kyriakos P. Papadopoulos, Shivaani Kummar, Erika Hamilton, Yvan LeBruchec, Karin Havenith, Serafino Pantano, Marie Toukam, Jens Wuerthner, Joseph Boni. Effect of camidanlumab tesirine (Cami) as monotherapy and in combination with pembrolizumab (PEM) on the immune cell profile in patients with selected advanced solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 4151.

Reference Intervals for Absolute and Percentage CD4+ T Lymphocytes among an Apparently Healthy Population in Addis Ababa, Ethiopia

BackgroundReference intervals for clinical laboratory parameters differ based on several factors, including age, sex, genetic variation, and geographic location. This variation influences clinical decisions and treatment monitoring. Currently, Ethiopia has used adopted reference intervals from manufacturer values derived from non-Africans. Therefore, the aim this study was to determine reference intervals for absolute and percentage CD4+ T cells for an apparently healthy population in Addis Ababa, Ethiopia.MethodsA community-based cross-sectional study was conducted on 361 apparently healthy people in four subcities in Addis Ababa from January to June 2019. Sociodemographic and clinical data were collected using a structured questionnaire after informed consent had been obtained. Blood samples were collected and CD4+ T-lymphocyte enumeration performed using a BD FACSPresto near-patient CD4 counter. Data were entered and analyzed using SPSS 20. Reference intervals were determined by a nonparametric test estimating percentiles 2.5 (lower limit) and 97.5 (upper limit) with 95% CIs. P<0.05 was considered statistically significant.ResultsA total of 337 (183 female and 154 male) healthy participants of median age 28 (IQR 17–35) years were included in the final analysis. Medians of absolute and percentage CD4+ T-cell counts (932.0 and 42.9, respectively) of female participants were significantly higher than male participants (802.5 and 38.7, respectively; P<0.05). Reference intervals for absolute CD4+ T-cell count and percentages in males were 483.8–1,310 cells/µL and 18.1–57.3 and in females 447.8–1,479.8 cells/µL and 25.6–58.9, respectively.ConclusionThe CD4+ T-count reference intervals established in this study showed some inconsistency from the manufacturer’s provided values and other studies and also revealed sex differences, necessitating sex-specific locally established reference intervals.

A phase 1b/2a study of safety and efficacy of NT-I7 in combination with anti-PD-L1 (atezolizumab) in patients with anti-PD-1/PD-L1 naïve or relapsed/refractory (R/R) high-risk skin cancers: The phase 1b report.

9561 Background: Novel immunotherapy approaches have changed the treatment landscape of patients (pts) with high-risk cancers like melanoma, Merkel cell carcinoma (MCC) and cutaneous squamous cell carcinoma (cSCC). However, despite the widespread use of checkpoint inhibitors (CPI) in these indications, most pts either fail to respond or eventually have progressed. NT-I7 (efineptakin alfa) is a long-acting human IL-7 that can increase the number and functionality of T-cells in peripheral blood and within the tumors. NT-I7 in combination with atezolizumab (atezo), may augment the efficacy in high-risk skin cancers. Methods: This is a phase 1b/2a study to evaluate the safety and efficacy of NT-I7 in combination with atezo in pts with CPI- naïve or relapsed/refractory (R/R) high-risk skin cancers. Phase 1b dose escalation followed a 3+3 design, in which pts who received NT-I7 IM every 3 weeks (Q3W) at 3 dose levels (DL1-3): 120, 360, and 840 µg/kg or Q6W at DL4 1200 µg/kg, and atezo IV 1200 mg Q3W. The objectives of the phase 1b were to evaluate dose-limiting toxicity (DLT), determine the MTD and the recommended phase 2 dose (RP2D), pharmacokinetics (PK), pharmacodynamics and preliminary antitumor activity. Results: As of January 14, 2022, 16 pts were enrolled in phase 1b: DL1 (n = 3), DL2 (n = 3), DL3 (n = 7), and DL4 (n = 3). The median age was 66 years [46-86], with ECOG PS 0 in 6 (37%), 1 in 7 (44%) and 2 in 3 (19%), and median number of prior therapies 1 [1-2]. One pt had a DLT at DL3 [Grade (G)3 confusion and G3 increased AST] but no DLTs were reported at DL4 and MTD was not reached. The RP2D was 1200 µg/kg Q6W of NT-I7 plus atezo 1200 mg Q3W. All pts had drug related AEs. Most AEs were G 1- 2 in 11(69%) pts; 5 (31%) in G3. There were no related G4/G5 AEs. Eleven pts had stable disease and the disease control rate was 69% (11/16). Preliminary PK analysis of DL1- 3 showed dose dependent Cmax, with Tmax at ̃24hr and T½ ranging ̃75hr to 125hr. NT-I7 dose-dependent expansion of the absolute lymphocyte count, CD3+, CD4+ and CD8+ T-cells peaked after one dose and the increase was maintained by repeat dosing until the end of treatment. Immunophenotyping of memory T-cell subsets showed a 5-fold expansion in most T-cell subsets and a 30-fold expansion of the stem cell memory CD8+ T-cell subset (Tscm) at DL4. Conclusions: This trial is the first time an IL-7 cytokine-based therapy and CPI has been assessed in UV induced high-risk skin cancers including in IO refractory pts. The combination of NT-I7 and atezo showed favorable safety and anticancer activity. NT-I7 significantly increased total lymphocyte and the T-cell compartment, with a greatest expansion of the CD8+ Tscm, a vital population for eliciting antitumor activity. Additional safety and efficacy updates will be provided by the ongoing phase 2a trial in CPI-naïve cSCC and MCC and CPI R/R MCC, cSCC and melanoma. Clinical trial information: NCT03901573.

Prospective two center study of CD38 bright CD8+ effector memory T-cells as a predictor of acute GVHD

IntroductionWe conducted a prospective validation study at Cincinnati Children's Hospital Medical Center and Ohio State University Medical Center to test if absolute CD38 bright CD8+TEM cells > 30/µL would predict acute GVHD, similar to our pilot data. MethodsBlood was collected twice weekly following HSCT. If CD38 bright CD8+ TEM ≥ 30 cells/µL, Epstein-Barr virus and cytomegalovirus specificity was determined by tetramer staining, granzyme B content was assessed, Ki-67 staining performed to assess T-cell proliferation. Cells were incubated with alemtuzumab, daratumumab and cyclophosphamide in vitro to determine susceptibility to depletion. ResultsOf the 182 enrolled patients, 83 (45.6%) developed acute GVHD by day+100 but 171 patients were evaluable (acute GVHD n = 77 and no GVHD n = 94). There was no difference in the maximum absolute CD38 bright CD8+TEM cells prior to clinical symptoms and also after CMV and EBV tetramer positive patients were excluded from both cohorts. Ki-67 or Granzyme B expression in patients were comparable between patients with and without acute GVHD. Lastly CD38 bright CD8+ T-cells were effectively depleted with alemtuzumab and cyclophosphamide in vitro. ConclusionAbsolute peripheral blood CD38 bright CD8+TEM cells ≥30 do not predict acute GVHD in a large validation cohort of adult and pediatric HSCT recipients.

Tacrolimus therapy in primary Sjögren's syndrome with refractory immune thrombocytopenia: a retrospective study.

To evaluate the efficacy and safety of tacrolimus (TAC) for the treatment of primary Sjögren's syndrome (pSS) with refractory immune thrombocytopenia (RITP). Twenty-three pSS patients with RITP treated with TAC from June 2018 to June 2021 at the First Affiliated Hospital of Soochow University were enrolled in this retrospective cohort study. Platelet response, clinical and immunological parameters, toxicity and safety were compared and analysed at baseline and different points after TAC treatment. At 4 weeks after treatment, 2 patients (8.7%) attained a complete response (CR, platelet count ≥100×109/L and no bleeding), 15 patients (65.2%) achieved a partial response (PR, platelet count ≥ 30×109/L but <100×109/L and no bleeding or a platelet count at least twice that before treatment), and the other 6 patients (26.1%) did not respond to TAC treatment. At 8 weeks after treatment, a CR was seen in 4 patients (17.4%), and the percentage of patients with a PR increased to 78.3% (18 patients). The percentage of patients with a CR increased to 47.8% (11 patients), and 9 patients (39.1%) achieved a PR without relapse at 12 weeks after treatment. At 24 weeks after treatment, 14 patients (60.9%) achieved a CR, and 8 patients (34.8%) achieved a PR. Compared to before treatment, the level of IgG was decreased significantly at 24 weeks after treatment, whereas there was no significant difference in the levels of IgM or IgA between baseline and 24 weeks after treatment. Additionally, the absolute CD3+ T cell count, European SS Disease Activity Index (ESSDAI) score, and levels of IL-2 and INF-γ were significantly decreased at 24 weeks after treatment. TAC is effective and well tolerated by pSS patients with RITP, and the mechanism underlying the effect of TAC in these patients may be related to reduced Th1 cytokine expression.

HIV-1 subtype C Tat exon-1 amino acid residue 24K is a signature for neurocognitive impairment.

Variation and differential selection pressures on Tat genes have been shown to alter the biological function of the protein, resulting in pathological consequences in a number of organs including the brain. We evaluated the impact of genetic variation and selection pressure on 147 HIV-1 subtype C Tat exon 1 sequences from monocyte-depleted peripheral lymphocytes on clinical diagnosis of neurocognitive impairment. Genetic analyses identified two signature amino acid residues, lysine at codon 24 (24K) with a frequency of 43.4% and arginine at codon 29 (29R) with a frequency of 34.0% in individuals with HIV-associated neurocognitive impairment. The analyses also revealed two signature residues, asparagine, 24N (31.9%), and histidine, 29H (21.3%), in individuals without neurocognitive impairment. Both codons, 24 and 29, were associated with high entropy but only codon 29 was under positive selection. The presence of signature K24 increased by 2.08 times the risk of neurocognitive impairment, 3.15 times higher proviral load, and 69% lower absolute CD4 T-cell count compared to those without the signature. The results support a linkage between HIV-1 C Tat N24K polymorphism, proviral load, immunosuppression, and neurocognitive impairment. The signature may induce more neurotoxic effects, which contributes to establishment and severity of HIV-associated neurocognitive impairment.

Effects of Sodium Chlorophyllin Copper on APO-1 Expression in Bone Marrow Mesenchymal Stem Cells of Rats with Aplastic Anaemia.

Background Aplastic anaemia (AA) is a highly prevalent blood disorder in the East and Southeast Asian countries, and a proportion of the patients is poorly treated with immunosuppressive agents. This study is aimed at exploring the effects of sodium copper chlorophyllin (SCC) on rats with AA and at providing the theoretical basis for the treatment of AA using traditional Chinese medicine. Methods A rat model of AA was induced by combining 5-fluorouracil with busulfan, and different groups were treated with 25 mg/kg cyclosporin A (CsA) and low-, medium-, and high-dose SCC (25-, 50-, and 100-mg/kg; L-, M-, and H-SCC, respectively). A comparative analysis of peripheral blood counts, T-cell subsets, cytokine levels, bone marrow pathology, and APO-1 expression in mesenchymal stem cells in each group was conducted. Results SCC can increase the platelet count and haemoglobin concentration in the peripheral blood of AA rats, whereas bone marrow biopsies revealed that the number of nucleated cells and megakaryocytes of SCC-treated rats increased compared with the model group. This was particularly evident in the H-SCC group. As regards the correction of immune function, unlike CsA, which reduced the absolute CD8+ T-cell count, SCC corrected the imbalanced CD4/CD8 ratio by increasing the absolute CD4+ T-cell count, whereas SCC increased the number of regulatory T-cells and reduced the level of interferon-γ in AA rats. When comparing the expression of APO-1 in the MSCs, results of the reverse-transcriptase polymerase chain reaction and Western blot analysis showed that SCC can increase the expression of APO-1 both at the mRNA and protein levels. Conclusion We found that SCC can improve haematopoietic function and regress immune disorders in AA rats, which enhanced the expression of APO-1 in bone marrow MSCs. This may be one of the mechanisms of SCC in treating AA.