Decreased levels of Th17 cells are associated with invasion fungal infections after allogeneic hematopoietic stem cell transplantation

Pharmacological MEK inhibition promotes polyclonal T-cell reconstitution and suppresses xenogeneic GVHD

Rapid immune reconstitution without developing graft-versus-host disease (GVHD) is required for the success of allogeneic hematopoietic stem cell transplantation. Here, we analyzed the effects of pharmacological MEK inhibition on human polyclonal T-cell reconstitution in a humanized mouse GVHD model utilizing deep sequencing-based T-cell receptor (TCR) repertoire analysis. GVHD mice exhibited a skewed TCR repertoire with a common clone within target organs. The MEK inhibitor trametinib ameliorated GVHD and enabled engraftment of diverse T-cell clones. Furthermore, trametinib also ameliorated GVHD sparing diverse T cell repertoire, even when it was given from day 15 through 28. Although tacrolimus also reduced development of GVHD, it disturbed diverse T cell reconstitution and resulted in skewed TCR repertoire. Thus, trametinib not only suppresses GVHD-inducing T cells but also promotes human T cell reconstitution in vivo, providing a novel rationale for translational studies targeting human GVHD.

Effect of Candida albicans bronchial colonization on hospital-acquired bacterial pneumonia in patients with systemic lupus erythematosus

Background

To investigate the effect of Candida albicans airway colonization on hospital-acquired bacterial pneumonia (HABP) in patients with systemic lupus erythematosus (SLE).

Methods

SLE patients with HAP were enrolled in this retrospective cohort study from January 2015 to December 2018. According to the culture results of respiratory tract secretions and antifungal treatment, patients were divided into non-C. albicans colonization group (NCG), C. albicans colonization with antifungal treatment group (CTG) and C. albicans colonization without antifungal treatment group (CNTG). Twenty-eight days of all-cause mortality after the onset of HABP of each group was assessed, total duration of antibiotic treatment, changes of inflammatory cytokines and markers of immune status were documented.

Results

A total of 269 SLE patients with HABP were finally included in the study. Among them, 69.1% (186/269) were found C. albicans airway colonization, and 36.1% (97/269) received antifungal treatment. No difference of 28 days of all-cause mortality after HABP onset was found among the three groups (10.8% vs. 13.4% vs. 15.7%, P>0.05). Duration of antibiotic treatment of HABP due to Acinetobacter baumannii was shorter in CTG (11.21±2.45 days) than that in CNTG (12.89±3.87 days) as well as HABP due to Pseudomonas aeruginosa (10.57±2.66 vs. 12.56±3.04 days) (P<0.05, respectively). Antifungal treatment could decrease the level of interleukin-1β, interleukin-6, tumor necrosis factor-α and interferon-γ in CTG than in CNTG (P<0.05, respectively). In addition, it could regulate immune function by decrease the concentration of interleukin-17 and elevate the counts of CD4+Th lymphocyte as well (P<0.05, respectively).

Conclusions

C. albicans airway colonization was not associated with HABP mortality in SLE patients. Antifungal therapy in these patients might shorten the duration of antibiotics in treating HABP due to A. baumannii and P. aeruginosa.