The prognostic impact of monocyte fluorescence, immunosuppressive monocytes and peripheral blood immune cell numbers in HIV-associated Diffuse Large B-cell Lymphoma

Abstract

Introduction Diffuse large B-cell lymphoma (DLBCL) is a high grade non-Hodgkin lymphoma which is common among immunodeficient people. Derangements of peripheral blood immune cells have been described to have a prognostic impact in DLBCL in high income countries, including a monocytosis, the ratios of lymphocytes to both monocytes (L:M) and neutrophils (N:L), as well as the numbers of regulatory T-cells (Tregs) and immunosuppressive monocytes (HLA-DRlow monos). To date, the impact of these variables has not been assessed in the setting of HIV-associated DLBCL (HIV-DLBCL), which is among the most common malignancies seen in people living with HIV. In this study, we assessed these factors in a cohort of South African patients with DLBCL and a high HIV-seropositivity-rate. In addition, we evaluated the prognostic value of monocyte activation (as reflected by monocyte fluorescence (MO-Y) on a Sysmex haematology analyser). This parameter has to date not been assessed in the setting of DLBCL. Methods A full blood count and differential count as well as flow cytometry for HLA-DRlow monocyte and Treg enumeration were performed in patients with incident DLBCL referred to the Chris Hani Baragwanath Academic Hospital in Johannesburg, South Africa between November 2019 and May 2022. Additional clinical and laboratory data were recorded from the patient charts and laboratory information system. Results Seventy-six patients were included, of whom 81.3% were people living with HIV with a median CD4 count of 148 cells/ul. Most patients had advanced stage disease (74.8%) and were predominantly treated with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP)-based chemotherapy (without Rituximab). At a median follow-up period of 19 months, the median survival time was 3.5 months, with a 12-month survival rate of 27.0%. All of the immune-cell-related variables (with the exception of the CD4 count) were similar between the people living with HIV and the HIV-negative individuals. In contrast to previous studies, a high monocyte count, the L:M and increased numbers of HLA-DRlow monocytes were not significantly associated with survival in HIV-DLBCL, while a neutrophilia (>8 x 109/L), the N:L (>6:1), high numbers of Tregs (≥5.17% of CD4s) and lymphopenia (<1.3 x 109/L) were. In addition, increased monocyte fluorescence (MO-Y >115.5) was associated with superior outcomes, which we speculate to reflect a more robust antitumour immune response among individuals with high levels of monocyte activation. On Cox Proportional hazard analysis, immune-cell factors independently associated with survival included a CD4 count <150 cells/ul and a neutrophilia. Conclusion The monocyte count, L:M and the number of HLA-DRlow monos are not strong prognostic indicators in HIV-DLBCL, while a low CD4 count and neutrophilia are. Elevation of the MO-Y shows some promise as a potential biomarker of antitumour immunity; further study in this regard would be of interest.

Derangements of immunological proteins in HIV-associated diffuse large B-cell lymphoma: the frequency and prognostic impact

“…As we have reported previously ( Vaughan et al., 2022 ; Vaughan et al., 2023 ), survival rates in this cohort were poor as compared to those reported in high income countries (5 year survival rates over 60%) ( Sehn and Salles, 2021 ), as well as in two regional studies, one performed in Malawi among 86 adult patients with a HIV-seropositivity rate of 59% (2 year survival rate of 38%) ( Painschab et al., 2019 ), and the other in a South African study among 36 patients with HIV-DLBCL (2 year overall survival ~40%) ( de Witt et al., 2013 ). This was at least partially attributable to a very high early death rate (~30%), with over half of the patients who demised early doing so before they could be given chemotherapy.…”

“…This hypothesis is supported by the significant relationship seen between TGFβ levels and peripheral blood numbers of Helios and CD39-expressing Tregs (markers of more potent immunosuppressive Treg potential), as well as the marginally significant correlation between TGFβ and Kynurenine levels (a metabolite which is cytotoxic to T-cells, and has an immune tolerising effect) ( Suchard et al., 2020 ). Notably, TGFβ levels also showed a significant correlation with the neutrophil count, which may account for the poorer survival we showed previously in this cohort among patients with a neutrophilia ( Vaughan et al., 2023 ). Interestingly, TGFβ resistance has been shown to be linked to epigenetic silencing of the expression of the TGFβ receptor, which can be partially reversed with demethylating agent therapy (thus resensitising tumour cells to the pro-apoptotic effect of TGFβ) ( Chen et al., 2007 ).…”

“…Seventy-six adult patients with newly diagnosed DLBCL at Chris Hani Baragwanath Academic Hospital (CHBAH) in Johannesburg were enrolled between November 2019 and May 2022 as reported previously ( Vaughan et al., 2023 ). Where possible, IL-6, IL-10, TGFβ, SFLC and KTR levels were measured on a peripheral blood sample prior to the commencement of chemotherapy.…”

“…ferritin and CRP were measured using a Cobas 8000 e602 module and a Cobas 8000 c702/c502 module, respectively (Roche Products, Basel, Switzerland). Treg numbers and expression of CD39 and Helios were measured in a subset of patients using a DuraClone IM Treg antibody panel (Beckman Coulter Inc, Brea, USA) (as described previously) ( Vaughan et al., 2023 ). Additional relevant information was retrieved from the laboratory information system (TrakCare, InterSystems, Cambridge, Massachusetts, United States) and the patient hospital records.…”

“…We have previously shown differential effects of immune-cell abnormalities in a South African cohort of patients with DLBCL and a high HIV-prevalence as compared to that reported in immunocompetent patients. For instance, while high numbers of Tregs, lymphopenia, low CD4 counts and neutrophilia were associated with inferior outcomes, high monocyte counts were not ( Vaughan et al., 2023 ). In this follow-up study on the same cohort, we aimed to assess the levels and prognostic relevance of immunological proteins previously shown to have a prognostic impact in DLBCL among dominantly immunocompetent patients.…”