Cytokine Overproduction and Immune System Dysregulation in alloHSCT and COVID-19 Patients

The COVID-19 pathomechanism depends on (i) the pathogenicity of the virus, (ii) ability of the immune system to respond to the cytopathic effect of the virus infection, (iii) co-morbidities. Inflammatory cytokine production constitutes a hallmark of COVID-19 that is facilitated by inability of adaptive immunity to control virus invasion. The effect of cytokine release syndrome is deleterious, but the severity of it depends on other confounding factors: age and comorbidities. In this study, we analyze the literature data on the post-transplant course of allogeneic hematopoietic stem cell transplanted (alloHSCT) patients, which is affected by generated inflammatory cytokines. The sequence of events boosting cytokine production was analyzed in relation to clinical and laboratory data highlighting the impact of cytokine generation on the post-transplant course. The collected data were compared to those from studies on COVID-19 patients. The similarities are: (i) the damage/pathogen-associated molecular pattern (DAMP/PAMP) stage is similar except for the initiation hit being sterile in alloHSCT (toxic damage of conditioning regimen) and viral in COVID-19; (ii) genetic host-derived factors play a role; (iii) adaptive immunity fails, DAMP signal(s) increases, over-production of cytokines occurs; (iv) monocytes lacking HLADR expression emerge, being suppressor cells hampering adaptive immunity; (v) immune system homeostasis is broken, the patient’s status deteriorates to bed dependency, leading to hypo-oxygenation and malnutrition, which in turn stimulates the intracellular alert pathways with vigorous transcription of cytokine genes. All starts with the interaction between DAMPs with appropriate receptors, which leads to the production of pro-inflammatory cytokines, the inflammatory process spreads, tissue is damaged, DAMPs are released and a vicious cycle occurs. Attempts to modify intracellular signaling pathways in patients with post-alloHSCT graft vs host disease have already been undertaken. The similarities documented in this study show that this approach may also be used in COVID-19 patients for tuning signal transduction processes to interrupt the cycle that powers the cytokine overproduction.

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Masp-2 Levels Following Allogeneic Hematopoietic Stem Cell Transplantation in Adults: Correlation with Development of a Thrombotic Microangiopathy and Implications for Therapy with Anti-Complement Agents

Blood ◽

10.1182/blood-2019-130919 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 3305-3305

Author(s):

Jeffrey Laurence ◽

Koen Van Besien ◽

Jasimuddin Ahamed ◽

Sonia Elhadad

Keyword(s):

Stem Cell ◽

Hematopoietic Stem Cell ◽

Complement Activation ◽

Thrombotic Microangiopathy ◽

Conditioning Regimen ◽

Clinical Manifestations ◽

Hematopoietic Stem ◽

Post Transplant ◽

Gvhd Prophylaxis ◽

The Impact

Introduction: 8500 adult allogeneic hematopoietic stem cell transplants (alloHSCT) are performed annually in the U.S. and 17,000 in Europe. HSCT-associated thrombotic microangiopathy (TMA), defined by thrombocytopenia, microangiopathic hemolytic anemia, and organ dysfunction in the absence of disseminated intravascular coagulation, complicates some 20% of these procedures. About half of post-alloHSCT TMAs may resolve when GvHD immunoprophylaxis is modified, but three year survival rates for those with severe HSCT-TMAs are a dismal 11%. Clinical manifestations are similar to other TMAs, but their pathophysiology may be distinct. Damage to vascular endothelium, independent of loss of ADAMTS13 activity, is thought to be critical. Fibrin-rich microthrombi, often accompanied by C4d and C5b-9 (membrane attack complex) deposition, occur in the microvasculature of multiple organs (Clin Adv Hematol Oncol 2014;12:565-573; Transplantation. 2013;96:217-223). This supports a role for complement activation in HSCT-TMA, but the importance of the various complement activation pathways is unclear. Recently, narsoplimab (OMS721), a monoclonal antibody inhibitor of MBL-associated serine protease-2 (MASP-2), a principal component of lectin-dependent complement activation, received Breakthrough Therapy Designation for HSCT-TMA, based on improved survival compared to historical controls in a phase 2 study. A phase 3 program is ongoing. Chemotherapy in association with autologous HSCT is linked to a marked increase in serum MASP-2 levels, persisting for about 4 weeks post-transplant (Front Immunol 2018;9:2153). However, TMAs are rare in autologous transplants, and circulating levels of MASP-2 following alloHSCT, and the impact of TMA development on those levels, are unknown. Methods: All individuals >18 years of age scheduled to undergo alloHSCT for hematologic malignancy at New York Presbyterian Hospital-Cornell were approached to participate in this study (NCT02604420). 100 of the first 101 subjects, age 58.3 +14 yrs, were enrolled and followed for >1.5 years post-transplant. This interval is consistent with the median time to HSCT-TMA diagnosis in adults of 90 days (range 32-733 days). Plasma was obtained at baseline (defined as between the time of consent and beginning of conditioning regimen), and at each regularly scheduled visit post-transplant-day 28 +5 days; day 100 +28 days; day 180 +28 days; and day 365 +28 days-as well as at the time of TMA diagnosis, based on the Consensus Criteria of Cho et al. (Transplantation 2010;90:918-926). A commercial ELISA (MyBioSource) was used to assess MASP-2 concentrations. Results: 20 subjects met study criteria for a HSCT-TMA diagnosis, occurring a median of 69 days (range 33-289) post-transplant. Three resolved following discontinuation of GvHD prophylaxis (mTOR or calcineurin inhibitor) and switch to mycophenolate and increased corticosteroid doses, and 7 had an intercurrent infection, 6 of whom expired with ongoing severe TMA despite a change in GvHD prophylaxis (Figure). TMAs persisted in the remaining 10 subjects. Median MASP-2 levels were significantly elevated in all subjects post-transplant, assessed at the time of TMA development or, in those not developing a TMA, at day 100 + 28 days post-transplant vs. controls (n=36, 86.2ng/ml (23.3-210.9): persistent TMA (n=9 (one plasma unavailable), 154ng/ml (range 82-209)); alloHSCT subjects who did not experience a TMA (n=40 evaluated to date, 113.5ng/ml (56-430.3)). (Figure). Lack of a significant rise in MASP-2 levels in patients with persistent TMAs vs. those who did not develop a TMA, combined with a significant decrease in variance of MASP-2 levels in the former group (p=0.005), may reflect consumption of product at sites of disease activity, i.e., the microvasculature. Conclusions: There is a significant increase in MASP-2 levels, with a wide variance, in post-alloHSCT patients evaluated at a time post-transplant typical of HSCT-TMA development. At time of development of a HSCT-TMA that persists despite withdrawal of GvHD prophylaxis, MASP-2 levels remain elevated over controls, but with a significantly lower variance vs. those not developing TMA. A study of additional samples, including longitudinal specimens, from this cohort is underway to determine if a change in MASP-2 levels correlates with HSCT-TMA development post-alloHSCT. Disclosures Van Besien: Miltenyi Biotec: Research Funding.

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Impact of Previous Invasive Fungal Infections on the Outcome of Patients Undergoing Allogeneic Hematopoietic Stem Cells

Blood ◽

10.1182/blood.v128.22.5748.5748 ◽

2016 ◽

Vol 128 (22) ◽

pp. 5748-5748

Author(s):

Gaetano Maffongelli ◽

Laura Cudillo ◽

Fabio Di Piazza ◽

...

Keyword(s):

Conflicts Of Interest ◽

Fungal Infections ◽

Conditioning Regimen ◽

P Value ◽

Period Range ◽

European Organization ◽

Hematopoietic Stem ◽

Allogeneic Hsct ◽

Post Transplant ◽

The Impact

Abstract Introduction: Outcome in allogeneic HSCT varies widely depending on disease type, stage, stem cell source, HLA-matched status and conditioning regimen. IFI is a possible complication of HSCT and a prior IFI increases the patient's risk for transplant related mortality due to the possibility of reactivation of the fungal infection. This study aimed to evaluate the impact of a previous IFI history on transplant outcome Methods: We retrospectively collected the clinical data of patients considered eligible for allogeneic HSCT during 2014 at the Rome Transplant Network (RTN), a JACIE accredited metropolitan transplant program established in Rome since 2006. The observation of patients was continued until 31 December 2015. The diagnosis of IFI were defined as possible, probable and proven as established by European Organization for Research and treatment of Cancer. Results: Twenty-one (37%) out of 57 eligible patients had an IFI episode before transplant: 6 of the episodes were proven, 4 probable and 11 possible. Overall, 10 (47%) pneumonia, 4 (19%) gastroenteritis, 3 sinusitis, 2 candida sepsis, 1 meningitis and 1 cutaneous abscess were registered. Five out of 21 patients (23%) died before HSCT versus 2 of 36 patients (5%) without previous documented IFI, [OR 5.31 95% CI 0.93- 30.40 , p value 0.06 Fisher Test], . A larger percentage of patients with past IFI waited HSCT over 6 months from the date of eligibility in comparison with those without previous IFI [43% vs 30% ; OR 1.87 95% CI 0.54-6.40 , p value 0.5 Yates test]; Sixteen (57%) out of 28 dead patients in the pre-transplant period have had a previous IFI episode vs 5(17%) out of patients alive [OR 6.4, 95% CI 1.89-21.68, p value: 0.004 Yates Test]. In the post-transplant period, only 6% of patients with a past IFI, experienced an engraftment in a time of < 15 days, vs 30% of patients without past IFI [OR 4.86 CI 95% 0,5-43,2, p value 0,2 Yates test]. In the post-transplant period, a IFI was diagnosed in 13 (26%) patients; ten (76%) out of 13 patients had a past IFI versus 9 (24%) of the patients without IFI.. [OR 7.87, CI 95% 1,8-34,2, p value 0,005 Yates test].Among the dead HSCT patients, those who had a previous IFI had a lower median survival [160 days (range 22- 480)] compared to patients without a previous IFI who died [196.5 days period (range 20-820)]. Conclusions: A previous IFI episode in the pre transplant period slow the accessibility to the transplant, adversely affects the engraftment, and is significantly associated with increased post-transplant mortality Disclosures No relevant conflicts of interest to declare.

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Post-transplant cyclophosphamide containing regimens after matched sibling, matched unrelated and haploidentical donor transplants in patients with acute lymphoblastic leukemia in first complete remission, a comparative study of the ALWP of the EBMT

Journal of Hematology & Oncology ◽

10.1186/s13045-021-01094-2 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Jaime Sanz ◽

Jacques-Emmanuel Galimard ◽

Myriam Labopin ◽

Boris Afanasyev ◽

Moiseev Ivan Sergeevich ◽

...

Keyword(s):

Acute Lymphoblastic Leukemia ◽

Cumulative Incidence ◽

Lymphoblastic Leukemia ◽

Hematopoietic Stem ◽

Free Survival ◽

Post Transplant ◽

Gvhd Prophylaxis ◽

Donor Type ◽

Matched Sibling ◽

The Impact

Abstract Background There is no information on the impact of donor type in allogeneic hematopoietic stem cell transplantation (HCT) using homogeneous graft-versus-host (GVHD) prophylaxis with post-transplant cyclophosphamide (PTCy) in acute lymphoblastic leukemia (ALL). Methods We retrospectively analyzed outcomes of adult patients with ALL in CR1 that had received HCT with PTCy as GVHD prophylaxis from HLA-matched sibling (MSD) (n = 78), matched unrelated (MUD) (n = 94) and haploidentical family (Haplo) (n = 297) donors registered in the EBMT database between 2010 and 2018. The median follow-up period of the entire cohort was 2.2 years. Results Median age of patients was 38 years (range 18–76). Compared to MSD and MUD, Haplo patients received peripheral blood less frequently. For Haplo, MUD, and MSD, the cumulative incidence of 100-day acute GVHD grade II–IV and III–IV, and 2-year chronic and extensive chronic GVHD were 32%, 41%, and 34% (p = 0.4); 13%, 15%, and 15% (p = 0.8); 35%, 50%, and 42% (p = 0.01); and 11%, 17%, and 21% (p = 0.2), respectively. At 2 years, the cumulative incidence of relapse and non-relapse mortality was 20%, 20%, and 28% (p = 0.8); and 21%, 18%, and 21% (p = 0.8) for Haplo, MUD, and MSD, respectively. The leukemia-free survival, overall survival and GVHD-free, relapse-free survival for Haplo, MUD, and MSD was 59%, 62%, and 51% (p = 0.8); 66%, 69%, and 62% (p = 0.8); and 46%, 44%, and 35% (p = 0.9), respectively. On multivariable analysis, transplant outcomes did not differ significantly between donor types. TBI-based conditioning was associated with better LFS. Conclusions Donor type did not significantly affect transplant outcome in patient with ALL receiving SCT with PTCy.

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Conditioning with Fludarabine-Busulfan versus Busulfan-Cyclophosphamide Is Associated with Lower aGVHD and Higher Survival but More Extensive and Long Standing Bone Marrow Damage

BioMed Research International ◽

10.1155/2016/3071214 ◽

2016 ◽

Vol 2016 ◽

pp. 1-10 ◽

Cited By ~ 2

Author(s):

Xin He ◽

YongBin Ye ◽

XiaoJun Xu ◽

Jing Wang ◽

YuXian Huang ◽

...

Keyword(s):

Bone Marrow ◽

Bone Marrow Cells ◽

Conditioning Regimen ◽

Clinical Manifestations ◽

Major Complication ◽

Clinical Situation ◽

Hematopoietic Stem ◽

T Cell Infiltration ◽

Bone Marrow Damage ◽

The Impact

Acute graft-versus-host disease (aGVHD) is a major complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT) and a major cause of nonrelapse mortality after allo-HSCT. A conditioning regimen plays a pivotal role in the development of aGVHD. To provide a platform for studying aGVHD and evaluating the impact of different conditioning regimens, we established a murine aGVHD model that simulates the clinical situation and can be conditioned with Busulfan-Cyclophosphamide (Bu-Cy) and Fludarabine-Busulfan (Flu-Bu). In our study, BALB/c mice were conditioned with Bu-Cy or Flu-Bu and transplanted with 2×107 bone marrow cells and 2×107 splenocytes from either allogeneic (C57BL/6) or syngeneic (BALB/c) donors. The allogeneic recipients conditioned with Bu-Cy had shorter survivals (P<0.05), more severe clinical manifestations, and higher hepatic and intestinal pathology scores, associated with increased INF-γ expression and diminished IL-4 expression in serum, compared to allogeneic recipients conditioned with Flu-Bu. Moreover, higher donor-derived T-cell infiltration and severely impaired B-cell development were seen in the bone marrow of mice, exhibiting aGVHD and conditioned with Flu-Bu. Our study showed that the conditioning regimen with Bu-Cy resulted in more severe aGVHD while the Flu-Bu regimen was associated with more extensive and long standing bone marrow damage.

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Absolute Lymphocyte Count (ALC) Less Than 100 Predicts Adverse Transplant Outcomes with Rabbit Thymoglobulin in Patients Undergoing Matched Unrelated Allogeneic Hematopoietic Stem Cell Transplantation

Blood ◽

10.1182/blood-2019-125437 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 4527-4527

Author(s):

Dipenkumar Modi ◽

Malini Surapaneni ◽

Seongho Kim ◽

Lois Ayash ◽

Asif Alavi ◽

...

Keyword(s):

T Cell ◽

Relapse Rate ◽

Peripheral Blood ◽

Conditioning Regimen ◽

Advisory Board ◽

Hematopoietic Stem ◽

Post Transplant ◽

Transplant Outcomes ◽

Gvhd Prophylaxis

Introduction: Rabbit thymoglobulin, an in-vivo T-cell depleting agent, is widely used as a part of GVHD prophylaxis regimen. Current dosing of thymoglobulin is often weight based and does not consider patient related factors. This results in highly variable exposure of thymoglobulin. Although higher doses (>7mg/kg) of thymoglobulin have shown to reduce the risk of GVHD, it is associated with increased rate of opportunistic infections and disease recurrence. Conversely, lower dose (2.5mg/kg) of thymoglobulin is associated with increased risk of GVHD. Thus, optimum dosing of thymoglobulin remains undefined. We hypothesized that recipient peripheral blood ALC on the first day of thymoglobulin infusion would interact with the dose of thymoglobulin administered and predict post-transplant outcomes. We plan to identify association of thymoglobulin dose with the ALC on the first day of thymoglobulin. Methods: We retrospectively evaluated clinical outcomes of adult patients (pts) who underwent matched unrelated donor AHSCT and received tacrolimus, mycophenolate (cellcept) and thymoglobulin as GVHD prophylaxis. Thymoglobulin was given at a total dose of 4.5mg/kg in divided fashion (0.5mg/kg on day -3, 1.5mg/kg on day -2 and 2.5mg/kg on day -1). The objectives were to determine rate of GVHD, overall survival (OS), relapse-free survival (RFS), relapse rate and non-relapse mortality (NRM) following AHSCT using Cox proportional hazard regression and competing risk models. Results: Between January 2005 and December 2017, 217 pts underwent AHSCT. The most common indications for AHSCT were AML (n=95, 44%), MDS (n=57, 26%), non-Hodgkin's lymphoma (n=23, 11%), and ALL (n=22, 10%). Median age of pts was 60 years (range, 18-79). All pts received peripheral blood stem cells. Ninety-eight pts (45%) received full intensity conditioning regimen and 119 pts (55%) received reduced intensity regimen. The median ALC on the first day of thymoglobulin administration was 200 K/cubic millimeter. The 6-month cumulative incidence rate (CIR) of grade III-IV acute GVHD was 14.8% and the 2-year CIR of chronic extensive GVHD was 35.4%. With a median follow up of 3.82 years for surviving patients, the 2-year RFS, OS, relapse and NRM were 50%, 57.1, 20.1%, and 30.2%, respectively. CMV and EBV reactivation rates were 37% and 11%, respectively. Four pts developed CMV disease. By our lowest ALC cutoff of 100 K/cubic millimeter, pts were divided into two groups (ALC ≤ 100 vs. ALC > 100). Multivariable analysis revealed that ALC > 100 was associated with significantly superior OS (HR 0.51, 95% CI 0.33-0.79, p=0.002), RFS (HR 0.49, 95% CI 0.33-0.74, p=0.001) and lower NRM (SHR 0.57, 95% CI 0.34-0.97, p=0.038) and marginally lower relapse rate (SHR 0.57, 95% CI 0.31-1.05, p=0.070). In addition, higher infused total nucleated cells was associated with higher NRM (SHR 1.70, 95% CI 1.02-2.83, p=0.041). No impact of disease risk index, KPS, conditioning regimen, infused CD34 cells on NRM, relapse, RFS or OS was observed. Conclusion: Our study indicates that ALC ≤ 100 is associated with adverse post-transplant outcomes when thymoglobulin dose of 4.5mg/kg is used for in-vivo T cell depletion. This finding may indicate that in pts with lower ALC, thymoglobulin dose may need to be adjusted to optimize its efficacy and avoid toxicities. In the future prospective studies, which evaluate dose reduction of thymoglobulin in pts with low ALC need to be planned to confirm these results. Disclosures Deol: Agios: Other: Advisory board; Novartis: Other: Advisory board; Kite: Other: Advisory board.

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Impact of Different T Cell Depletion Protocols on Immune Reconstitution Following Allogeneic Hematopoietic Stem Cell Transplantation

Blood ◽

10.1182/blood-2020-139208 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 43-44

Author(s):

Amandine Pradier ◽

Adrien Petitpas ◽

Anne-Claire Mamez ◽

Federica Giannotti ◽

Sarah Morin ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Immune Reconstitution ◽

Cell Depletion ◽

Unrelated Donor ◽

T Cell Depletion ◽

Hematopoietic Stem ◽

Post Transplant ◽

The Impact

Introduction Allogeneic hematopoietic stem cell transplantation (HSCT) is a well-established therapeutic modality for a variety of hematological malignancies and congenital disorders. One of the major complications of the procedure is graft-versus-host-disease (GVHD) initiated by T cells co-administered with the graft. Removal of donor T cells from the graft is a widely employed and effective strategy to prevent GVHD, although its impact on post-transplant immune reconstitution might significantly affect anti-tumor and anti-infectious responses. Several approaches of T cell depletion (TCD) exist, including in vivo depletion using anti-thymocyte globulin (ATG) and/or post-transplant cyclophosphamide (PTCy) as well as in vitro manipulation of the graft. In this work, we analyzed the impact of different T cell depletion strategies on immune reconstitution after allogeneic HSCT. Methods We retrospectively analysed data from 168 patients transplanted between 2015 and 2019 at Geneva University Hospitals. In our center, several methods for TCD are being used, alone or in combination: 1) In vivo T cell depletion using ATG (ATG-Thymoglobulin 7.5 mg/kg or ATG-Fresenius 25 mg/kg); 2) in vitro partial T cell depletion (pTCD) of the graft obtained through in vitro incubation with alemtuzumab (Campath [Genzyme Corporation, Cambridge, MA]), washed before infusion and administered at day 0, followed on day +1 by an add-back of unmanipulated grafts containing about 100 × 106/kg donor T cells. The procedure is followed by donor lymphocyte infusions at incremental doses starting with 1 × 106 CD3/kg at 3 months to all patients who had received pTCD grafts with RIC in the absence of GVHD; 3) post-transplant cyclophosphamide (PTCy; 50 mg/kg) on days 3 and 4 post-HSCT. Absolute counts of CD3, CD4, CD8, CD19 and NK cells measured by flow cytometry during the first year after allogeneic HSCT were analyzed. Measures obtained from patients with mixed donor chimerism or after therapeutic DLI were excluded from the analysis. Cell numbers during time were compared using mixed-effects linear models depending on the TCD. Multivariable analysis was performed taking into account the impact of clinical factors differing between patients groups (patient's age, donor type and conditioning). Results ATG was administered to 77 (46%) patients, 15 (9%) patients received a pTCD graft and 26 (15%) patients received a combination of both ATG and pTCD graft. 24 (14%) patients were treated with PTCy and 26 (15%) patients received a T replete graft. 60% of patients had a reduced intensity conditioning (RIC). 48 (29%) patients received grafts from a sibling identical donor, 94 (56%) from a matched unrelated donor, 13 (8%) from mismatched unrelated donor and 13 (8%) received haploidentical grafts. TCD protocols had no significant impact on CD3 or CD8 T cell reconstitution during the first year post-HSCT (Figure 1). Conversely, CD4 T cells recovery was affected by the ATG/pTCD combination (coefficient ± SE: -67±28, p=0.019) when compared to the T cell replete group (Figure 1). Analysis of data censored for acute or chronic GVHD requiring treatment or relapse revealed a delay of CD4 T cell reconstitution in the ATG and/or pTCD treated groups on (ATG:-79±27, p=0.004; pTCD:-100±43, p=0.022; ATG/pTCD:-110±33, p<0.001). Interestingly, pTCD alone or in combination with ATG resulted in a better reconstitution of NK cells compared to T replete group (pTCD: 152±45, p<0.001; ATG/pTCD: 94±36, p=0.009; Figure 1). A similar effect of pTCD was also observed for B cells (pTCD: 170±48, p<.001; ATG/pTCD: 127±38, p<.001). The effect of pTCD on NK was confirmed when data were censored for GVHD and relapse (pTCD: 132±60, p=0.028; ATG/pTCD: 106±47, p=0.023) while only ATG/pTCD retained a significant impact on B cells (102±49, p=0.037). The use of PTCy did not affect T, NK or B cell reconstitution when compared to the T cell replete group. Conclusion Our results indicate that all TCD protocols with the only exception of PTCy are associated with a delayed recovery of CD4 T cells whereas pTCD of the graft, alone or in combination with ATG, significantly improves NK and B cell reconstitution. Figure 1 Disclosures No relevant conflicts of interest to declare.

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Introduction to Clinical Immunology: Overview of the Immune Response, Autoimmune Conditions, and Immunosuppressive Therapeutics for Rheumatic Diseases

10.2310/im.1328 ◽

2016 ◽

Author(s):

Steven K. Lundy ◽

Alison Gizinski ◽

David A. Fox

Keyword(s):

Immune Response ◽

Immune System ◽

T Cell ◽

Immune Responses ◽

Autoimmune Diseases ◽

Adaptive Immunity ◽

Cell Populations ◽

Hematopoietic Stem ◽

Innate And Adaptive Immunity ◽

Adaptive Immune

The immune system is a complex network of cells and mediators that must balance the task of protecting the host from invasive threats. From a clinical perspective, many diseases and conditions have an obvious link to improper functioning of the immune system, and insufficient immune responses can lead to uncontrolled acute and chronic infections. The immune system may also be important in tumor surveillance and control, cardiovascular disease, health complications related to obesity, neuromuscular diseases, depression, and dementia. Thus, a working knowledge of the role of immunity in disease processes is becoming increasingly important in almost all aspects of clinical practice. This review provides an overview of the immune response and discusses immune cell populations and major branches of immunity, compartmentalization and specialized immune niches, antigen recognition in innate and adaptive immunity, immune tolerance toward self antigens, inflammation and innate immune responses, adaptive immune responses and helper T (Th) cell subsets, components of the immune response that are important targets of treatment in autoimmune diseases, mechanisms of action of biologics used to treat autoimmune diseases and their approved uses, and mechanisms of other drugs commonly used in the treatment of autoimmune diseases. Figures show the development of erythrocytes, platelets, lymphocytes, and other immune system cells originating from hematopoietic stem cells that first reside in the fetal liver and later migrate to the bone marrow, antigen–major histocompatibility complex recognition by T cell receptor control of T cell survival and activation, and Th cells as central determinants of the adaptive immune response toward different stimuli. Tables list cell populations involved in innate and adaptive immunity, pattern recognition receptors with known ligands, autoantibody-mediated human diseases: examples of pathogenic mechanisms, selected Food and Drug Administration–approved autoimmune disease indications for biologics, and mechanism of action of biologics used to treat autoimmune diseases. This review contains 3 highly rendered figures, 5 tables, and 64 references.

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A Preliminary Investigation towards the Risk Stratification of Allogeneic Stem Cell Recipients with Respect to the Potential for Development of GVHD via Their Pre-Transplant Plasma Lipid and Metabolic Signature

Cancers ◽

10.3390/cancers11081051 ◽

2019 ◽

Vol 11 (8) ◽

pp. 1051 ◽

Cited By ~ 3

Author(s):

Daniel Contaifer ◽

Catherine H. Roberts ◽

Naren Gajenthra Kumar ◽

Ramesh Natarajan ◽

Bernard J. Fisher ◽

...

Keyword(s):

Mass Spectrometry ◽

Stem Cell ◽

Risk Stratification ◽

Metabolic Profile ◽

Unrelated Donor ◽

Hematopoietic Stem ◽

Post Transplant ◽

Metabolic Signature ◽

Chromatography Mass Spectrometry ◽

The Impact

The clinical outcome of allogeneic hematopoietic stem cell transplantation (SCT) may be influenced by the metabolic status of the recipient following conditioning, which in turn may enable risk stratification with respect to the development of transplant-associated complications such as graft vs. host disease (GVHD). To better understand the impact of the metabolic profile of transplant recipients on post-transplant alloreactivity, we investigated the metabolic signature of 14 patients undergoing myeloablative conditioning followed by either human leukocyte antigen (HLA)-matched related or unrelated donor SCT, or autologous SCT. Blood samples were taken following conditioning and prior to transplant on day 0 and the plasma was comprehensively characterized with respect to its lipidome and metabolome via liquid chromatography/mass spectrometry (LCMS) and gas chromatography/mass spectrometry (GCMS). A pro-inflammatory metabolic profile was observed in patients who eventually developed GVHD. Five potential pre-transplant biomarkers, 2-aminobutyric acid, 1-monopalmitin, diacylglycerols (DG 38:5, DG 38:6), and fatty acid FA 20:1 demonstrated high sensitivity and specificity towards predicting post-transplant GVHD. The resulting predictive model demonstrated an estimated predictive accuracy of risk stratification of 100%, with area under the curve of the ROC of 0.995. The likelihood ratio of 1-monopalmitin (infinity), DG 38:5 (6.0), and DG 38:6 (6.0) also demonstrated that a patient with a positive test result for these biomarkers following conditioning and prior to transplant will be at risk of developing GVHD. Collectively, the data suggest the possibility that pre-transplant metabolic signature may be used for risk stratification of SCT recipients with respect to development of alloreactivity.

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TLR2 and Dectin-1 Signaling in Mouse Hematopoietic Stem and Progenitor Cells Impacts the Ability of the Antigen Presenting Cells They Produce to Activate CD4 T Cells

Cells ◽

10.3390/cells9051317 ◽

2020 ◽

Vol 9 (5) ◽

pp. 1317 ◽

Cited By ~ 1

Author(s):

Alba Martínez ◽

Cristina Bono ◽

Daniel Gozalbo ◽

Helen S. Goodridge ◽

M. Luisa Gil ◽

...

Keyword(s):

Bone Marrow ◽

Progenitor Cells ◽

Proinflammatory Cytokine ◽

Cytokine Production ◽

Antigen Presenting Cells ◽

Proinflammatory Cytokine Production ◽

Hematopoietic Stem ◽

Stem And Progenitor Cells ◽

Antigen Presenting ◽

The Impact

Microbial recognition by pattern recognition receptors (PRRs) expressed on hematopoietic stem and progenitor cells (HSPCs) not only activates myelopoiesis but also programs the function of the monocytes and macrophages they produce. For instance, changes in HSPC programming modify the ability of macrophages derived from them to produce inflammatory cytokines. While HSPCs exposed to a TLR2 agonist give rise to tolerized macrophages (lower proinflammatory cytokine production), HSPCs treated with Dectin-1 ligands produce trained macrophages (higher proinflammatory cytokine production). However, nothing is known about the impact of HSPC exposure to microbes on the function of antigen presenting cells (APCs). In this study we evaluated whether treatment of murine bone marrow HSPCs with a TLR2 or Dectin-1 ligand impacts the antigen presenting capacity of APCs derived from them in vitro. Following activation with microbial ligands or Candida albicans yeasts, APCs derived from TLR2/Dectin-1-programed HSPCs exhibit altered expression of MHCII (signal 1), co-stimulatory molecules (CD40, CD80 and CD86; signal 2) and cytokines (TNF-α, IL-6, IL-12 p40 and IL-2; signal 3). Moreover, APCs derived from TLR2/Dectin-1-programed HSPCs prime enhanced Th1 and Th17 responses, which are important for antifungal defense, in CD4 T cell cocultures. Overall, these results demonstrate for the first time that microbial detection by bone marrow HSPCs can modulate the adaptive immune response by inducing the production of APCs with an altered phenotype.

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Critical windows in development of the rodent immune system

Human & Experimental Toxicology ◽

10.1191/0960327102ht287oa ◽

2002 ◽

Vol 21 (9-10) ◽

pp. 493-498 ◽

Cited By ~ 85

Author(s):

K S Landreth

Keyword(s):

Stem Cells ◽

Immune System ◽

Chemical Exposure ◽

Anatomical Location ◽

Hematopoietic Stem ◽

Windows Of Vulnerability ◽

The Impact ◽

Timing Of Exposure ◽

Developmental Immunotoxicity ◽

Developmental Windows

The immune system of rodents, like that in humans, develops from a population of pluripotential hematopoietic stem cells (HSC) that are generated early in gestation from uncommitted mesenchymal stem cells in the intra-embryonic splanchnoplure surrounding the heart. This early population of HSC gives rise to all circulating blood cell lineages, including cells of the innate and acquired immune system. To access the impact of chemical exposure on the developing immune system and establish developmental windows of potential vulnerability to these exposures, it is essential to first consider the anatomical development of hematopoietic and lymphopoietic tissues and the sequence of appearance of cells that give rise to the immune system. This is particularly true in embryonic development because, after they initially appear in intra-embryonic mesenchyme early in gestation, HSC migrate through an orderly series of tissues before establishing residence in the bone marrow and thymus. The effect of exposure to chemical insults in utero, then, may differ depending on the specific timing of exposure and anatomical location of hematopoiesis. Mechanisms and consequences of developmental immunotoxicity in experimental animals will need to be considered in that context. This review presents an overview of developmental hematopoiesis and a working hypothesis of critical developmental windows of vulnerability of this developmental system to toxic insult by chemical exposure.

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