STAT3 and the Hyper-IgE syndrome: Clinical presentation, genetic origin, pathogenesis, novel findings and remaining uncertainties

Pathological and protective immunity to Pneumocystis infection

Pneumocystis jirovecii is a common opportunistic infection in the HIV-positive population and is re-emerging as a growing clinical concern in the HIV-negative immunosuppressed population. Newer targeted immunosuppressive therapies and the discovery of rare genetic mutations have furthered our understanding of the immunity required to clear Pneumocystis infection. The immune system can also mount a pathologic response against Pneumocystis following removal of immunosuppression and result in severe damage to the host lung. The current review will examine the most recent epidemiologic studies about the incidence of Pneumocystis in the HIV-positive and HIV-negative populations in the developing and developed world and will detail methods of diagnosis for Pneumocystis pneumonia. Finally, this review aims to summarize the known mediators of immunity to Pneumocystis and detail the pathologic immune response leading to Pneumocystis-related immune reconstitution inflammatory syndrome.

An overview of the effects of anti-IgE therapies

Omalizumab, a humanized mAb that binds to the CH3 domain near the binding site for the high-affinity type-I IgE Fc receptors of human IgE, can neutralize free IgE and inhibit the IgE allergic pathway without sensitizing mast cells and basophils. We found that omalizumab in patients with severe persistent asthma (SPA) was an effective therapy for asthma and the following co-morbid conditions: chronic urticaria (CU), bee venom allergy, latex allergy, atopic dermatitis, food allergy and Samter's syndrome. Information on the use of omalizumab in treatment of asthma and other allergic diseases has improved our understanding that treatment acts on many levels, including regulating levels of inflammatory proteins, including cytokines (copper-containing alpha- 2-glycoprotein, total antioxidant capacity, MDA, NO, H2O2, CXCL8, IL-10, TGF-β, GMCSF, IL-17, IL-1β), MPV, Hs-CRP, eosinophil cationic peptide, vitamin-D (25(OH)D), homocysteine (Hcy), OX-2, d- dimer, albumin, and sApo-2L. The decrease in Hcy concentrations and increase in 25(OH)D also support the existence of a vascular endothelial protection mechanism. Mediators and cells classically involved in pro-coagulant and anticoagulant pathways together play a role in SPA and CU pathophysiology and omalizumab effect. The mechanism of action of omalizumab in the treatment of asthma is believed to be multifactorial, and includes effects mediated through altered production of redox metabolites, extrinsic coagulation pathway, oxidative markers-related mi RNA, TRAIL-related mi RNA, and regulation of production of known inflammatory proteins.

Staphylococcus aureus - antimicrobial resistance and the immunocompromised child

Children with immunocompromising conditions represent a unique group for the acquisition of antimicrobial resistant infections due to their frequent encounters with the health care system, need for empiric antimicrobials, and immune dysfunction. These infections are further complicated in that there is a relative paucity of literature on the clinical features and management of Staphylococcus aureus infections in immunocompromised children. The available literature on the clinical features, antimicrobial susceptibility, and management of S. aureus infections in immunocompromised children is reviewed. S. aureus infections in children with human immunodeficiency virus (HIV) are associated with higher HIV viral loads and a greater degree of CD4 T-cell suppression. In addition, staphylococcal infections in children with HIV often exhibit a multidrug resistant phenotype. Children with cancer have a high rate of S. aureus bacteremia and associated complications. Increased tolerance to antiseptics among staphylococcal isolates from pediatric oncology patients is an emerging area of research. The incidence of S. aureus infections among pediatric solid organ transplant recipients varies considerably by the organ transplanted; in general however, staphylococci figure prominently among infections in the early posttransplant period. Staphylococcal infections are also prominent pathogens among children with a number of immunodeficiencies, notably chronic granulomatous disease. Significant gaps in knowledge exist regarding the epidemiology and management of S. aureus infection in these vulnerable children.