Pneumonitis in patients with thymoma and Good's syndrome.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. e20595-e20595
Author(s):  
Margaret Ottaviano ◽  
Pietro De Placido ◽  
Erica Pietroluongo ◽  
Marianna Tortora ◽  
Fernanda Picozzi ◽  
...  
Keyword(s):  
T Cells ◽  
Intensive Care ◽  
B Cells ◽  
Viral Infections ◽  
Disease Stage ◽  
Blood Levels ◽  
Histopathological Diagnosis ◽  
Good’S Syndrome ◽  
Rare Tumours ◽  
Life Threatening

e20595 Background: The association between thymoma (T) and immunological dysregulations is well acknowledged. Good’s syndrome (GS), which occurs in approximately 6% to 11% of T patients, is characterized by hypogammaglobulinemia, few or absent B-cells (CD19+), CD4 T cells lymphopenia, abnormal CD4/CD8 T ratio and impaired T cell mitogenic response. Patients with GS have increased susceptibility to bacterial, opportunistic and viral infections related to both humoral and cell-mediated immunodeficiency. The recent Sars-Cov-2 pandemic drew attention to the clinical condition of fatal viral pneumonitis and cytokines storm. Here we reported our monocentric experience of pneumonitis in patients with T and GS before the Sars-Cov-2 pandemic. Methods: We conducted a retrospective analysis of T patients with associated GS referred to the Rare Tumours Reference Center of University Federico II of Naples over a 10-year period (from 2009 to 2019). All the patients with radiological and/or clinical pneumonitis diagnosis were evaluated for this report. Immunological features, histopathological diagnosis and clinical outcome were registered. Results: A total of 41 patients with T and GS were identified, including 17 patients with local disease (stage I-II according to Masaoka-Koga) and 24 with advanced disease (stage III-IV). The majority (56.3%) had B2 T diagnosis. Radiological and/or clinical pneumonitis diagnosis was assessed in 23 cases (56%). Viral pneumonitis was detected in 8 patients: 3 patients with H1N1 infection, 3 patients with CMV infection, 2 patients with EBV infection. Bacterial pneumonitis was diagnosed in 9 patients (3 patients with K. pneumoniae, 4 patients with S. aureus, 2 patients with H. influenza). Opportunistic pneumonitis was found in 2 patients with Aspergillosis infection. In 2 cases no pathogenic agent was identified. The immunophenotyping, assessed in 4 patients with viral pneumonitis, displayed very low/undetectable levels of B cells, with median % value of CD3+T cells and NKT of respectively 9.8% and 0.4% of the total leukocytes. The median % of Treg was 4.7%. CD4+/CD8+ ratio was variable, ranging from 1,2 to 0,6. Interestingly the number of B cells was extremely low, independent of CD4+/CD8+ ratio. Blood levels of cytokines, chemokines and growth factors revealed elevated IL-4, Eotaxin, CCL2 / MCP-1 and CCL5 / RANTES ad strong reduction of IL-10. PDGF-BB levels were also elevated. 15 patients required admission to intensive care Six patients died for fatal pneumonitis. Conclusions: The management of T patients with GS is extremely challenging. Clear diagnostic algorithms do not yet exist and immune-profiling and quantitative immunoglobulins should be considered a part of diagnostic search in these patients. The coexistence of cancer, infections and immunosuppression may trigger life-threatening conditions, such as fatal pneumonitis, which often require intensive care and multidisciplinary approach.

The effect of alemtuzumab maintenance therapy on B and T lymphocytes in chronic lymphocytic leukemia

2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 7092-7092
Author(s):  
M. S. Kaufman ◽  
N. Driscoll ◽  
C. Johnson ◽  
A. Caramanica ◽  
D. Janson ◽  
...  
Keyword(s):  
T Cells ◽  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
T Lymphocytes ◽  
Maintenance Therapy ◽  
Cd4 T Cells ◽  
Opportunistic Infections ◽  
Lymphocytic Leukemia ◽  
Blood Levels ◽  
Time Point

7092 Background: We are conducting a pilot, exploratory study of the potential value of alemtuzumab(alem) in maintenance therapy of previously treated chronic lymphocytic leukemia (CLL) patients(pts) after they have achieved stable disease or partial remission with chemo or chemo-immunotherapy. We present the results of serially monitored CD19+ (B)lymphocytes and CD4+ (T) lymphocytes on eight evaluable patients. Methods: 30mg doses of alem were administered SC to all patients at the following schedule: wkly for 8 doses (8 wks), followed by q2 wks for 8 doses(16 wks), followed by q3 wks for 8 doses (24 wks). This schedule provides a total of 48 wks of maintenance treatment with alem. Patients received standard prophylaxis with sulfamethoxizole and acyclovir with regular CMV monitoring by quantitative PCR. Results: In the table we present data on the pattern of decrease in blood CD19+(B) cells and CD4+ (T) cells on eight evaluable pts at different time points after starting alem maintenance. Because flow cytometry was not done on all pts at each time point, the number of pts contributing to the calculation of mean counts at each given time point is variable. CD19+(B) cells were markedly reduced to 37% of baseline consistently, from 8 wks onward. CD4+(T) cells, on the other hand, were consistently higher than 50% of the baseline after 8 wks. No opportunistic infections were seen in any pt and treatment was well tolerated. Conclusion: These results from a single institution based pilot study demonstrate that alem used in maintenance schedule is effective in keeping the blood levels of CD19+(B) cells extremely low without concordant suppression of CD4+(T) lymphocytes. No significant financial relationships to disclose. [Table: see text]

Whole-Exome Sequencing Links CARD11 Inactivation with SCID

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 258-258
Author(s):  
Johann Greil ◽  
Tobias Rausch ◽  
Thomas Giese ◽  
Obul Reddy Bandapalli ◽  
Volker Daniel ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
T Lymphocytes ◽  
Exome Sequencing ◽  
B Lymphocytes ◽  
Whole Exome Sequencing ◽  
B Lymphocyte ◽  
Whole Exome ◽  
Life Threatening

Abstract Abstract 258 Primary immunodeficiencies represent model diseases for the mechanistic understanding of the human innate and the adaptive immune response and are per se clinically highly relevant, because in SCID patients infections by opportunistic pathogens are typically life-threatening early in life. We identified an infant of consanguineous parents suffering from a novel form of SCID, who presented with a life-threatening Pneumocystis jirovecii pneumonia. This entity was characterized by agammaglobulinemia and profoundly deficient T-cell function despite quantitatively normal T- and B-lymphocytes. Lymphocyte proliferation was strongly inhibited after stimulation of PBMCs with T-cell mitogens such as PHA, Con A, or anti-CD3 monoclonal antibody. The expression of several T-cell response associated cytokines upon stimulation with PMA/ionomycin was dramatically reduced in comparison to normal controls. By contrast, proliferation induced by the classical B-cell mitogen PWM was almost comparable to healthy controls. Immunophenotyping revealed a predominantly naïve phenotype (CD45RA+ CCR7+) in CD4+ and CD8+ T-lymphocytes, whereas central memory T-lymphocytes (CD45RA− CCR7+) were nearly absent. B-lymphocytes from peripheral blood were mainly naïve B-cells (CD27−) with a uniformly immature transitional B-lymphocyte phenotype (CD24++, CD38++). Patient B-lymphocytes retained the ability to proliferate and differentiate in response to BCR-independent stimuli, while their response to BCR activation was defective. Our findings thus revealed a combined defect of TCR-mediated T-lymphocyte functions and BCR-mediated B-lymphocyte functions but did not enable us to link the immunological phenotype with one of the known molecularly defined categories of SCID. Diagnostic whole-exome sequencing and systematic variant categorization revealed a single pathogenic homozygous nonsense mutation of the caspase recruitment domain 11 (CARD11) gene. CARD11 is a scaffold protein that is known to be required for the assembly and activation of the NF-kB complex. In reconstitution assays we demonstrated that the patient derived truncated CARD11 protein is defective in antigen receptor signaling and NF-kB activation. Several lines of evidence substantiate the involvement of the identified CARD11 mutation in the new form of SCID that we report here. First, PCR and Sanger re-sequencing validated the truncating CARD11 mutation to be homozygous in the patient and heterozygous in the parents, in agreement with the recessive transmission of the mutation through the healthy consanguineous parents. Second, CARD11 is a scaffold protein required for TCR- and BCR-induced NF-kB activation as well as lymphocyte activation and proliferation, which is specifically expressed in hematopoietic cells, consistent with a causative role of CARD11 mutations in the context of an immune disorder. Third, the GUK domain of CARD11, which is missing in the mutated form of CARD11 due to truncation, was previously reported to be necessary for NF-kB activation by PMA/ionomycin treatment, further supporting the presumed damaging nature of the homozygous CARD11 mutation observed in the female patient reported here. Finally, the immunological findings in this patient are compatible with the phenotype of a previously described Card11 −/− k.o. mouse, which shows a selective defect in NF-κB activation leading to diminished antigen receptor or PKC mediated proliferation and defective cytokine production in T-cells and B-cells. Thus, we have identified an inactivating CARD11 mutation linking defective NF-kB signaling with a novel cause of autosomal recessive SCID, which must be considered in the diagnostic assessment of patients with suspected SCID but with quantitatively normal T-cells. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Initiation of autoimmunity to the p53 tumor suppressor protein by complexes of p53 and SV40 large T antigen.

1994 ◽  
Vol 179 (4) ◽  
pp. 1243-1252 ◽  
Author(s):  
X Dong ◽  
K J Hamilton ◽  
M Satoh ◽  
J Wang ◽  
W H Reeves
Keyword(s):  
Immune Response ◽  
T Cells ◽  
B Cells ◽  
Tumor Suppressor ◽  
Viral Infections ◽  
T Antigen ◽  
Tumor Suppressor Protein ◽  
Large T Antigen ◽  
P53 Tumor Suppressor Protein ◽  
Self Antigen

Antinuclear antibodies (ANAs) reactive with a limited spectrum of nuclear antigens are characteristic of systemic lupus erythematosus (SLE) and other collagen vascular diseases, and are also associated with certain viral infections. The factors that initiate ANA production and determine ANA specificity are not well understood. In this study, high titer ANAs specific for the p53 tumor suppressor protein were induced in mice immunized with purified complexes of murine p53 and the Simian virus 40 large T antigen (SVT), but not in mice immunized with either protein separately. The autoantibodies to p53 in these mice were primarily of the IgG1 isotype, were not cross-reactive with SVT, and were produced at titers up to 1:25,000, without the appearance of other autoantibodies. The high levels of autoantibodies to p53 in mice immunized with p53/SVT complexes were transient, but low levels of the autoantibodies persisted. The latter may have been maintained by self antigen, since the anti-p53, but not the SVT, response in these mice could be boosted by immunizing with murine p53. Thus, once autoimmunity to p53 was established by immunizing with p53/SVT complexes, it could be maintained without a requirement for SVT. These data may be explained in at least two ways. First, altered antigen processing resulting from the formation of p53/SVT complexes might activate autoreactive T helper cells specific for cryptic epitopes of murine p53, driving anti-p53 autoantibody production. Alternatively, SVT-responsive T cells may provide intermolecular-intrastructural help to B cells specific for murine p53. In a second stage, these activated B cells might themselves process self p53, generating p53-responsive autoreactive T cells. The induction of autoantibodies during the course of an immune response directed against this naturally occurring complex of self and nonself antigens may be relevant to the generation of specific autoantibodies in viral infections, and may also have implications for understanding the pathogenesis of ANAs in SLE. In particular, our results imply that autoimmunity can be initiated by a "hit and run" mechanism in which the binding of a viral antigen to a self protein triggers an immune response that subsequently can be perpetuated by self antigen.

Hemophagocytic lymphohistiocytosis (HLH) and related disorders

Hematology ◽  
2009 ◽  
Vol 2009 (1) ◽  
pp. 127-131 ◽  
Author(s):  
Alexandra H. Filipovich
Keyword(s):  
T Cells ◽  
Hemophagocytic Lymphohistiocytosis ◽  
Hematopoietic Cell Transplantation ◽  
Viral Infections ◽  
Clinical Findings ◽  
Antiinflammatory Therapy ◽  
Genetic Causes ◽  
Life Threatening ◽  
Genetically Determined ◽  
Antigen Presenting

Abstract Hemophagocytic lymphohistiocytosis (HLH), which has many genetic causes, is characterized by multi-system inflammation. HLH is a reactive process resulting from prolonged and excessive activation of antigen presenting cells (macrophages, histiocytes) and CD8+ T cells. Hemophagocytosis, which is mediated through the CD163 heme-scavenging receptor, is a hallmark of activated macrophages/histiocytes and is the characteristic finding for which the disorder was named. The majority of genetic causes identified to date affect the cytotoxic function of NK and T cells, crippling immunologic mechanisms that mediate natural immune contraction. The predominant clinical findings of HLH are fevers (often hectic and persistent), cytopenias, hepatitis and splenomegaly. Due to the life-threatening implications of the diagnosis of genetically determined HLH, antiinflammatory therapy, often consisting of steroids, etoposide or antithymocyte globulin (ATG), should be instituted promptly, followed by curative hematopoietic cell transplantation. Secondary HLH, associated with autoimmune disorders or viral infections in teens and adults, also carries a significant mortality rate and should be managed in consultation with specialists familiar with the diagnosis and treatment of such disorders.

scholarly journals Differential alterations in peripheral lymphocyte subsets in COVID-19 patients: upregulation of double-positive and double-negative T cells

2021 ◽  
Vol 16 ◽  
Author(s):  
Asmaa M. Zahran ◽  
Zeinab Albadry M. Zahran ◽  
Yasmeen H. Mady ◽  
Essam Eldeen M.O. Mahran ◽  
Alaa Rashad ◽  
...  
Keyword(s):  
T Cells ◽  
B Cells ◽  
Natural Killer ◽  
Lymphocyte Subsets ◽  
Viral Infections ◽  
Complete Blood Count ◽  
Laboratory Data ◽  
Double Negative ◽  
Double Positive ◽  
Neutrophil Lymphocyte Ratio

Background: Viral infections cause alteration in the total number of lymphocytes and their subset distribution. We aimed to study peripheral blood lymphocyte subsets in COVID-19 patients and to correlate these subsets with clinical and laboratory data, which may help in clarifying the pathogenesis to develop novel diagnostic and prognostic biomarkers for COVID-19.Methods: Twenty-six reverse-transcription polymerase chain reaction (RT-PCR) confirmed COVID-19 patients were subjected to medical history-taking and a thorough clinical examination. Laboratory tests included complete blood count, D dimer, ferritin, and C-reactive protein (CRP). Chest CT was used to diagnose COVID-19 pneumonia. Lymphocyte subsets were compared with those in 20 healthy controls using flow cytometry.Results: Leucopenia, relative neutrophilia, lymphopenia, eosinopenia together with marked elevation in neutrophil/lymphocyte ratio were observed in our COVID-19 patients. A marked reduction was observed in T cells, including both CD4 and CD8 cells, natural killer (NK), and natural killer T cells (NKT). Double-positive T (DPT) cells, double-negative T (DNT) cells, and B cells were elevated in the patients relative to the other lymphocyte subsets.Conclusion: Immune-inflammatory parameters are of utmost importance in understanding the pathogenesis and in the provisional diagnosis of COVID-19. Yet, due care must be taken during their interpretation because of the vast discrepancies observed between studies even in the same locality. Further studies are needed to clarify the role of B cells, DPT, and DNT cells in the pathogenesis and control of COVID-19.

scholarly journals Syngeneic monoclonal antiidiotype can induce cellular immunity to reovirus.

1984 ◽  
Vol 160 (4) ◽  
pp. 1195-1205 ◽  
Author(s):  
A H Sharpe ◽  
G N Gaulton ◽  
K K McDade ◽  
B N Fields ◽  
M I Greene
Keyword(s):  
T Cells ◽  
B Cells ◽  
Cellular Immunity ◽  
Viral Infections ◽  
Cellular Responses ◽  
Antiidiotypic Antibody ◽  
Viral Hemagglutinin ◽  
Variant Virus ◽  
Protein Molecules ◽  
Antiidiotypic Antibodies

A syngeneic monoclonal antiidiotypic antibody was generated in BALB/c mice after repeated immunization with a BALB/c monoclonal anti-reovirus hemagglutinin (HA) antibody. The resultant syngeneic monoclonal antiidiotypic antibody, in the absence of adjuvant, was found to be capable of priming both BALB/c (H-2d, Igh-1a) and C3H/Hej (H-2k, Igh-1j) mice for Lyt-1+- and Lyt-2+-dependent responses against the mammalian reovirus. By the use of intertypic reassortants and variant virus analysis, the specificity of the response was finely mapped to the neutralization domain of the viral hemagglutinin (HA). Using purified monoclonal antiidiotype, we were able to compare the potency of antiidiotype to virus in terms of induction of immunity. 8 X 10(8) protein molecules were able to prime for cellular responses to reovirus. These studies indicate that in the reovirus system, T cells and B cells share idiotypic configurations, and that antiidiotypic antibodies of the type described herein may be useful in the development of vaccines against certain viral infections.

scholarly journals Generation of glucocorticoid resistant SARS-CoV-2 T-cells for adoptive cell therapy

2020 ◽  
Author(s):  
Rafet Basar ◽  
Nadima Uprety ◽  
Emily Ensley ◽  
May Daher ◽  
Kimberly Klein ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Therapy ◽  
Peripheral Blood ◽  
Gene Editing ◽  
Viral Infections ◽  
Receptor Gene ◽  
Adoptive Cell Therapy ◽  
Culture Conditions ◽  
Glucocorticoid Receptor Gene ◽  
Life Threatening

SUMMARYAdoptive cell therapy with viral-specific T cells has been successfully used to treat life-threatening viral infections, supporting the application of this approach against COVID-19. We expanded SARS-CoV-2 T-cells from the peripheral blood of COVID-19-recovered donors and non-exposed controls using different culture conditions. We observed that the choice of cytokines modulates the expansion, phenotype and hierarchy of antigenic recognition by SARS-CoV-2 T-cells. Culture with IL-2/4/7 but not other cytokine-driven conditions resulted in >1000 fold expansion in SARS-CoV-2 T-cells with a retained phenotype, function and hierarchy of antigenic recognition when compared to baseline (pre-expansion) samples. Expanded CTLs were directed against structural SARS-CoV-2 proteins, including the receptor-binding domain of Spike. SARS-CoV-2 T-cells could not be efficiently expanded from the peripheral blood of non-exposed controls. Since corticosteroids are used for the management of severe COVID-19, we developed an efficient strategy to inactivate the glucocorticoid receptor gene (NR3C1) in SARS-CoV-2 CTLs using CRISPR-Cas9 gene editing.

scholarly journals Disease stage-specific pathogenicity of CD138 (syndecan 1)-expressing T cells in systemic lupus erythematosus

2020 ◽  
Author(s):  
Lunhua Liu ◽  
Kazuyo Takeda ◽  
Mustafa Akkoyunlu
Keyword(s):  
T Cells ◽  
B Cells ◽  
Lupus Erythematosus ◽  
Cell Formation ◽  
Receptor Expression ◽  
Disease Stage ◽  
Established Disease ◽  
Autoreactive Antibody ◽  
Central Memory Phenotype

ABSTRACTObjectiveTo identify and characterize CD138 (syndecan 1)-expressing T cells in SLE-prone mice.MethodsWe characterized CD138-expressing T cells in MRL/Lpr mice by flow cytometry assay and by gene analysis. Functional properties of TCRβ+CD138+ cells were assessed either by activating through TCR or by co-incubating with purified B cells in the presence of auto-antigens. Purified TCRβ+CD138+ cells were adoptively transferred into MRL/Lpr mice and lupus disease was assessed by measuring serum auto-antibodies, proteinuria and by histopathological evaluation of kidney.ResultsWe found that the frequency of TCRβ+CD138+ cells was significantly higher in MRL/Lpr mice than in wild-type MRL mice (p < 0.01), and the increase in their numbers correlated with disease severity. Majority of the TCRβ+CD138+ cells were CD4 and CD8 double-negative and 20% were CD4. Compared to TCRβ+CD138− cells, TCRβ+CD138+ cells exhibited central memory phenotype with reduced ability to proliferate, and produce the cytokines IFNγ and IL-17. When co-cultured with B cells, the ability of TCRβ+CD138+ cells to promote plasma cell formation and autoreactive antibody production was dependent on the presence of auto-antigens and CD4 co-receptor expression. Surprisingly, adoptively transferred TCRβ+CD138+ cells slowed down the disease progression in young MRL/Lpr mice but had the opposite effect when DNA was co-administered or when TCRβ+CD138+ cells were transferred into older MRL/Lpr mice with established disease.ConclusionHere, we provided evidence for the pathogenic role of CD138-expressing T cells when auto-antigens are exposed to immune system. Thus, monitoring the changes in TCRβ+CD138+ cell-frequency may serve as a tool to assess SLE severity. Moreover, CD138-expressing T cells may be targeted to alleviate lupus progression.

Costimulation Through GITR Increases Follicular Helper T Cell Formation and Leads To Control Of A Chronic Viral Infection

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3496-3496
Author(s):  
Fernanda M Pascutti ◽  
Tomasz Poplonski ◽  
René A.W. Van Lier ◽  
Claudia Brandao ◽  
Martijn A. Nolte
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Cd4 T Cells ◽  
Viral Infections ◽  
Conflicts Of Interest ◽  
Cell Formation ◽  
Absolute Number ◽  
Costimulatory Receptor ◽  
Follicular Helper

Abstract The glucocorticoid-induced TNF receptor family-related protein (GITR) is an important costimulatory receptor on T cells. We have previously shown that enhanced costimulation through GITR increases the formation of both effector and regulatory CD4+ T cells. Here we explored whether it could also affect humoral immunity and T cell help to B cells. Although development of mature B cells was not affected in GITRL transgenic (tg) mice, we found that the number of follicular helper T cells (CXCR5+ PD1+ CD4+ T cells, Tfh) was significantly increased, including the absolute number of Tfh-B cell conjugates, as revealed by ImageStream analysis. Tfh from GITRL tg mice had normal expression levels of ICOS, SLAM and CD44 and slightly lower levels of CD62L and CCR7 compared to wild-type (WT) littermates. Interestingly, Tfh from GITRL tg mice produced more IFN-g and IL-10, which was accompanied by a biased antibody repertoire (decreased IgG3 and increased IgA, IgG2a and IgG2b). Since Tfh have been implicated in the late control of viral replication, we infected WT and GITRL tg mice with LCMV Clone 13. Surprisingly, at day 30 after infection, we could not detect viral genome in spleen and liver from GITRL tg mice, while WT mice were still infected. Also, PD-1 expression was strongly decreased on virus-specific CD8+ T cells, which correlated with faster viral clearance. All in all, these results indicate that GITR-mediated costimulation enhances the control of chronic viral infections, by boosting and modulating Tfh cell responses. Disclosures: No relevant conflicts of interest to declare.

BPX-501 Cells (donor T cells transduced with iC9 suicide gene) Are Able to Clear Life-Threatening Viral Infections in Children with Primary Immune Deficiencies Given Alpha/Beta T-Cell Depleted HLA-Haploidentical Hematopoietic Stem Cell Transplantation (haplo-HSCT)

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 4299-4299
Author(s):  
Barbarella Lucarelli ◽  
Pietro Merli ◽  
Alice Bertaina ◽  
Matilde Sinibaldi ◽  
Stefania Gaspari ◽  
...  
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Viral Infections ◽  
Immune Deficiencies ◽  
Life Threatening ◽  
Transplantation Patient ◽  
Cmv Dnaemia ◽  
Over Time

Abstract Background: T-cell depleted haplo-HSCT is an established treatment for children with primary immune deficiencies (PID). However, children given this type of allograft are exposed to the risk of fatal events due to viral infections because of the prolonged impairment of adaptive immunity. We recently developed a novel method of selective T-cell depletion based on physical elimination of α/β T cells (ClinicalTrial.gov identifier: NCT01810120), which was shown to be safe and more effective than transplantation of positively-selected CD34+ cells for preventing life-threatening infections. However, we recorded some severe and even fatal viral infections, which prompted us to explore innovative approaches to accelerate the recovery of adaptive immunity. For this purpose, we designed an ongoing phase I/II trial aimed at testing the safety and the efficacy of post-transplant infusion of BPX-501 cells in children with malignant or non-malignant disorders (ClinicalTrials.gov identifier: NCT02065869). We report 3 cases of children with either severe combined immune deficiency (SCID) or Wiskott-Aldrich syndrome (WAS), who were enrolled in the dose escalation phase of the study and who cleared cytomegalovirus (CMV) or Adenovirus (AdV) infections likely due to the contribution of the BPX-501 cells. Patients and methods: Patient #1, affected by SCID, was transplanted from the HLA-haploidentical father. Before transplantation she had CMV-DNAemia which was treated with ganciclovir until donor stem cell infusion. She was given 2.5 x 105/kg BPX-501 cells on day 17 after transplantation. Patient #2, also affected by SCID, was transplanted from the HLA-haploidentical mother. Before transplantation she had AdV-DNAemia and high load of the virus in stools. She was given 5 x 105/kg BPX-501 cells on day 15 after transplantation. Patient #3 was affected by WAS and referred to the transplant unit; in the months preceding haplo-HSCT the child had developed CMV retinitis and hepatitis with high levels of CMV-DNAemia. This patient was transplanted from the father and received 1 x 106/kg BPX-501 cells on day 15 after haplo-HSCT. Basic phenotype of circulating lymphocytes was assessed by flow cytometry on fresh heparinized peripheral blood samples at 10, 20, 30, 60, 90, 120 and 150 days post haplo-HSCT, respectively. Since BPX-501 cells are CD3+/CD19+, it was easy to track the presence of these genetically modified cells. CMV specific reconstitution was also monitored through the INF gamma ELISPOT assay. In particular, peripheral blood mononuclear cells were stimulated for 16hrs in the presence of peptide libraries derived from pp65, IE1 and IE2 CMV-specific antigens. Results: The increase in the number of both CD3+ T lymphocytes and BPX-501 cells over time after transplantation together with the modifications of DNAemia of both CMV and AdV in the 3 patients are reported in Panel A, B and C, respectively, of Figure 1. In all of these patients, the pre-existing viral infection was progressively cleared once the BPX-501 cells were infused. These cells expanded in vivo and are still persisting, contributing to the recovery of adoptive immunity. The median time to reach an absolute number of α/β CD3+ cells greater than 0.5x109/L was 90, 90 and 30 days, respectively. None of these patients experienced either acute or chronic Graft-versus-Host Disease (GvHD) and no organ inflammatory-related toxicity was recorded. All children are alive and disease free, without infections, at day +200, +180 and +160, respectively. The 2 patients with CMV infection showed a specific response for at least one CMV-derived antigen; indeed, one patient showed a prevalence in pp65 response, whereas in the second one, we observed a specific anti-CMV response against all three tested antigens (Figure 1 - Panel D). Conclusions: Infusion of BPX-501 cells is able to accelerate the recovery of adaptive T-cell immunity in children with PID given haplo-HSCT after depletion of α/β T cells, thus rendering the procedure safer even in children with active infections at time of transplantation. These cells, once infused, expand in vivo and persist over time, contributing to the clearance of viral infections, without inducing GvHD. Figure 1. Figure 1. Disclosures Moseley: Bellicum Pharmaceuticals: Employment, Equity Ownership.

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