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In hosts with damaged or impaired immune systems such as those undergoing hematopoietic cell transplant (HCT) or intensive chemotherapy, breakthrough fungal infections can be fatal. Risk factors for breakthrough infections include severe neutropenia, use of corticosteroids, extended use of broad-spectrum antibiotics, and intensive care unit admission. An individual's cumulative state of immunosuppression directly contributes to the likelihood of experiencing increased infection risk. Incidence of invasive fungal infection (IFI) after HCT may be up to 5-8%. Early intervention may improve IFI outcomes, although many infections are resistant to standard therapies (voriconazole, caspofungin, micafungin, amphotericin B, posaconazole or itraconazole, as single agents or in combination). We review herein several contributing factors that may contribute to the net state of immunosuppression in recipients of HCT. We also review a new approach for IFI utilizing adjunctive therapy with sargramostim, a yeast-derived recombinant human granulocyte-macrophage colony-stimulating factor (rhu GM-CSF)., (Copyright © 2021. Published by Elsevier Inc.)

Granulocyte-macrophage-colony stimulating factor (GM-CSF), can direct the activation, proliferation and differentiation of myeloid-derived cells. It is also responsible for maturation and function of professional antigen presenting cells thereby impacting adaptive immune responses, while assisting to maintain epithelial barrier function. GM-CSF in combination with other endogenous cytokines and secondary stimuli, such as tumor necrosis factor can modulate pro-inflammatory monocyte priming via chromatin remodeling and enhanced transcriptional responses, a concept termed "trained immunity". An increase in the incidence of opportunistic fungal infections was recently reported in patients with hematological cancers receiving treatment with the BTK inhibitor, Ibrutinib. Tec Kinase BTK is known to influence the expression of GM-CSFRα and regulates downstream signaling pathways, suggesting a role for GM-CSF in maintenance of defense against fungal infections in immune competent hosts. Further examination of the potential mechanism(s) of action for naturally occurring GM-CSF and recombinant human GM-CSF (rhu-GM-CSF) expressed in yeast (sargramostim) are reviewed., Competing Interests: Declaration of competing interest In compliance with the ICMJE uniform disclosure form, all authors declare the following: Financial relationships: Luis O. Leal declares employment from Partner Therapeutics who manufactures and commercializes sargramostim. Other relationships: All other authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2019 Elsevier Inc. All rights reserved.)

CCR5 expression on CD4(+)CD25(high)Foxp3(+) regulatory T cells (Tregs) has been reported to be crucial for limiting Th1 inflammation associated with autoimmunity and bacterial infections. We inquired whether abnormalities in chemokine receptors expressed on Tregs might be involved in the psoriatic pathogenesis. Indeed, the proportion of CCR5(+) Treg was 58.8% in healthy individuals (n=9), whereas only half as many CCR5(+) Treg cells were found in psoriatic individuals (29.1%, n=8, p<0.01). The flow-enriched control CCR5(+) Tregs consistently exceeded the suppressive capacity of unsorted Tregs in autologous MLR assays (n=5, p<0.05) showing that CCR5(+) Treg subset is a high potency regulatory T cell population. Interestingly, psoriatic CCR5(+) Treg cells exhibited significantly less migratory capacity toward CCR5 ligands MIP-1β and RANTES in vitro compared to CCR5(+) Treg controls (n=3, p<0.05). Our data demonstrate that psoriatic CCR5(+) Tregs cells are numerically-, functionally- and chemotactically-deficient compared to controls and may pose a triple impairment on the ability of psoriatic Tregs to restrain inflammation., (© 2013. Published by Elsevier Inc. All rights reserved.)

Immunocellular migrations out of and into the skin and modulations of functional cell surface molecules on antigen-presenting cells (APCs), as well as their immunoregulatory cytokine production, are important factors involved in the mechanism of UV-induced immunosuppression and tolerance. Of particular interest here are the effects of low-dose UVB exposures that can suppress the ability of a contact sensitizer to induce contact hypersensitivity (CHS) through the site (local immunosuppression) without inducing suppression of CHS induced through skin distant to the UV exposure. Such UV-irradiated skin has many changes with respect to composition of immunocompetent cells and cytokine production. After UV exposure, Langerhans cells/dendritic cells migrate from the skin to draining lymph nodes (DLNs) as they do from contact sensitizer-applied normal skin. On the other hand, UV causes monocytic/macrophagic cells to infiltrate into the dermis and then into the epidermis; these can also be shown to be induced by contact sesitizers to migrate to DLNs. Alterations in cell surface and immunoregulatory cytokine phenotypes of the cutaneous APCs in both the skin and DLNs are critical for CHS suppression and tolerance induction. Here we describe the phenotypic changes of immunocompetent cells in UV-irradiated skin in regard to CHS suppression and tolerance and methodologies to approach this area.

The production of autoimmune antibodies during infection with the hemoflagellate parasite Trypanosoma cruzi has been previously reported by this and other laboratories. The present investigation indicates a potential target in normal heart tissue that may be the binding site for the autoimmune antibodies. Using Western blot analysis, sera obtained from chronically infected C57 B1/6 mice was examined for its ability to recognize normal tissue antigens from uninfected syngeneic animals. Antibodies from chronic sera recognized an antigen in normal mouse heart and skeletal muscle tissue at a molecular weight between 43 and 45 kilodaltons (kDa). This proposed target antigen was found in cytoplasmic extracts from normal heart antigen preparations. The autoantibody recognition of the normal tissue in Western blots was inhibited by periodate oxidation of the antigen sample. This suggests that the binding of the autoantibodies may be dependent upon a glycosylation present on the antigen targets. Isotype analysis indicated that the autoreactive antibodies are of the IgM and IgG2b isotypes. These results suggest that a target for autoantibodies in Chagas' disease may be a 43- to 45-kDa glycoprotein found in normal heart and skeletal muscle tissue. Exposure of the immune system to this antigen may follow the damaging effects of the parasite itself, or of the immune response toward the parasite. In either scenario the identification of a target in the ongoing autoimmunity may help to define the autoimmune process in American Trypanosomiasis.

Preimmunization with attenuated Corpus Christi stain Trypanosoma cruzi provides survival to C3H mice and enhances resistance of C57 mice to Brazil strain infection. C3H(He) and C57 B1/6 mice surviving acute infection of T. cruzi are shown to have heart specific autoantibodies through acute and chronic infection. ELISA assays were performed using nondenatured extract of hearts from normal syngeneic mice as target antigen reacted with sera from immunized and/or infected mice. Surviving C3H mice developed a specific anti-heart response as early as Day 21 of infection and this response continued at a high level to Day 300. The response in C57 mice, both immunized-infected and infected only, increased to Day 100 followed by a decline in intensity. The heart specificity of the response in mice was suggested by negligible reaction of sera with smooth muscle preparations and a reduced autoreactivity with skeletal muscle. Laminin, a suggested target of autoimmunity in Chagas' disease, was shown not to be the target of the responses in these mice. Immunoaffinity-purified heart specific antibodies show strong cross-reactivity with parasite antigen and like purified parasite specific antibodies, reacted with heart antigen.