Immunosuppression in acute myeloid leukemia (AML) is an important mechanism of tumor escape. CD200, as an immunosuppressive molecule, is overexpressed in some hematological malignancies and it has also been shown to be an independent prognostic factor in AML. In the current study, simultaneous CD200 expression and Foxp3(+) regulatory T cell levels were investigated in Iranian patients with AML by flow cytometry. We also assessed the effect of CD200-CD200R blockade on Th1 and T-reg cytokine production and T cell proliferation in autologous AML- and monocyte-DC mixed lymphocyte reactions (MLRs). ELISA assay was performed to detect IL-2, IL-12, IFN-γ, IL-10, and TGF-β production in MLR supernatants. Expression of Foxp3, IL-10, and TGF-β mRNAs in MLRs were detected by real-time PCR. Our results demonstrated significant overexpression of CD200 (P = 0.001) in association with higher frequencies of Foxp3(+) T cells in AML patients (r = 0.8, P < 0.001). Blocking of CD200-CD200R interaction demonstrated a significant decrease in TGF-β and IL-10 expression in AML-DC MLRs and a significant increase in IL-12 and IFN-γ expression in monocyte-DC MLRs. Elevated T cell levels with lower Foxp3 intensity was also shown in CD200-CD200R-blocked MLRs. Expression of IL-10 mRNA declined significantly only in AML-DC MLRs where CD200-CD200R interaction was blocked and the same result was observed for TGF-β and Foxp3 mRNA in both AML- and monocyte-DC MLRs. These data present a significant role for CD200 in suppressing anti-tumor immune response through stimulation of regulatory mechanisms in AML patients and suggest that CD200 may have a prognostic value in this malignancy and its blockade may be used as a target for AML immunotherapy.

T-cell receptor excision circles (TRECs) and κ-deleting recombination excision circles (KRECs) are recently used for detection of T or B cell lymphopenia in neonates based on region-specific cutoff levels. Here, we report cutoffs for TREC and KREC copies useful for newborn screening and/or diagnosis of primary immunodeficiency diseases (PID) in Iran. DNA was extracted from a single 3.2 mm punch of dried blood spots collected from 2160 anonymized newborns referred to two major referral health centers between 2014 and 2016. For refinement of the cutoffs, 51 patients with a definite diagnosis of severe combined immunodeficiency, X-linked agammaglobulinaemia and combined immunodeficiency, including ataxia telangiectasia, human phosphoglucomutase 3 and Janus kinase-3 deficiency, as well as 47 healthy controls were included. Samples from patients with an X-linked hyper-IgM-syndrome, Wiskott-Aldrich syndrome and DNA ligase 4 deficiency were considered as disease controls. Triplex-quantitative real-time PCR was used. Cutoffs were calculated as TRECs < 11 and KRECs < 6 copies with an ACTB > 700 copies with sensitivity of 100% for TREC and 97% for KREC. Among thirty anonymized newborn samples (1.5%) with abnormal results for TREC and/or KREC, only twenty one available cases were retested and shown to be in the normal range except for three samples (0.15%). All of the patients with a definitive diagnosis were correctly identified based on our established TREC/KREC copy numbers. Determining cutoffs for TREC/KREC is essential for correctly identifying children with PID in newborn screening. Early diagnosis of PID patients enables appropriate measures and therapies like stem cell transplantation. This article is protected by copyright. All rights reserved.

Research involving human participants. Informed consent for participation in this study was obtained in accordance with local regulations, with approval from the IRB.Informed consent. Written informed consent was obtained from the guardians of the patient.

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Human cells homozygous for rare loss-of-expression (LOE) TYK2 alleles have impaired, but not abolished, cellular responses to IFN-α/β (underlying viral diseases in the patients) and to IL-12 and IL-23 (underlying mycobacterial diseases). Cells homozygous for the common P1104A TYK2 allele have selectively impaired responses to IL-23 (underlying isolated mycobacterial disease). We report three new forms of TYK2 deficiency in six patients from five families homozygous for rare TYK2 alleles (R864C, G996R, G634E, or G1010D) or compound heterozygous for P1104A and a rare allele (A928V). All these missense alleles encode detectable proteins. The R864C and G1010D alleles are hypomorphic and loss-of-function (LOF), respectively, across signaling pathways. By contrast, hypomorphic G996R, G634E, and A928V mutations selectively impair responses to IL-23, like P1104A. Impairment of the IL-23–dependent induction of IFN-γ is the only mechanism of mycobacterial disease common to patients with complete TYK2 deficiency with or without TYK2 expression, partial TYK2 deficiency across signaling pathways, or rare or common partial TYK2 deficiency specific for IL-23 signaling.

Dendritic cells (DCs) are recognized as key regulators of the immune system. Active DC immunization protocols are quickly obtaining interest as an alternative therapeutic approach in acute myeloid leukemia patients. Despite apparent progress in DC-based immunotherapy, some discrepancies were reported in generating potent DCs and their source. In addition to monocytes, DCs can be differentiated from leukemic blasts of acute myeloid leukemia (AML) patients (AML-DC) possessing the ability of stimulating anti-leukemic immune response. In this study, we differentiated peripheral blood blasts of 16 out of 20 AML patients in vitro in the presence of GM-CSF and IL-4 into immature AML-DC. Then, DCs matured using different combinations of Toll-like receptor (TLR) ligands to obtain functional DCs as demonstrated by cell morphology, immunophenotype, and functional activity. Autologous cytotoxic T cell induction of matured DCs was evaluated in four patients and compared with immature counterparts. Our results showed that although the TLR3 agonist (Poly I:C) has a synergistic effect on the TLR4 agonist (lipopolysaccharide, LPS), the addition of the TLR7/8 agonist (R848) is necessary to reinforce the effect of LPS or LPS + POLY(I:C) to produce efficient DCs with the higher level of IL-12 (30 to 90 times). Such DCs activate allogeneic T cells and effectively prime autologous cytotoxic T cells in vitro. In contrast, FSL-1 as a TLR2/6 agonist has a negative effect on LPS + Poly(I:C) and LPS + R848 to produce IL-12. Thus, DCs prepared using a maturation mixture including a TLR7/8 agonist may be used as a potential tool for DC-based immunotherapy purposes in leukemic patients.

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Assessment of the number of T-cell receptor excision circles (TREC) and kappa-deleting recombination excision circles (KREC) copies has been recently described as biomarkers of newly formed T and B cells respectively. In this study, we aimed to explore the effects of demographic variables including age, gender, weight, height and ethnicity on these two episomal DNA molecules. Second, for the first time in our country, we determined the reference values of TREC and KREC copy numbers in different age groups of Iranian healthy individuals as a threshold for identifying T cell and B cell lymphopenia.  The TREC and KREC copy numbers were evaluated in 251 dried blood spot (DBS) samples from healthy volunteers (age range: 0-60 years). Six primary immunodeficiency (PID) patients were included as disease controls. TREC and KREC copies were markedly reduced with increasing age. Although the levels of TREC and KREC were higher in females than males, this difference did not reach statistical significance. These findings suggest that demographic variables including age should be considered for interpretation results of the TREC/KREC assay.