Is there a role for Pneumocystis jiroveci pneumonia prophylaxis in giant cell arteritis or polymyalgia rheumatica?

BACKGROUND: Pneumocystis jiroveci pneumonia (PJP) is an opportunistic fungal infection that affects immunocompromised patients. The objective of this study was to describe the incidence of PJP among patients with giant cell arteritis (GCA) or polymyalgia rheumatica (PMR). METHODS: A retrospective cohort study of incident cases of GCA and PMR was conducted using claims data from the TriNetX database to describe the incidence of PJP during the first 6 months of therapy. Additionally, a systematic review was performed to identify other publications describing PJP among patients with GCA or PMR. RESULTS: During 547 patient-years of follow-up time, no cases of PJP were identified among 1,168 cases of GCA (incident rate 0 per 1,000 person-years); during 7,446 patient-years of follow up time, one case of PJP was identified out of 15,575 cases of PMR (incident rate 0.07 cases per 1,000 patient-years). This patient was alive at last follow up. Our systematic review identified 1 case-control study, 4 cohort studies, and 18 case series / case reports of PJP among patients with GCA or PMR. The incident rate of PJP was reported from one additional study for GCA and was estimated at 0.08 cases per 1,000 person years; no additional cohort studies were identified for patients with PMR. Over the entirety of the published literature, the total number of cases identified among case series and case reports was 33, from which 4 total deaths were identified. CONCLUSIONS: Patients with newly diagnosed GCA or PMR rarely develop PJP. Existing data does not support routine prescribing of PJP prophylaxis for either group of patients.

Comparative Efficacy Randomized Controlled Trials in Rheumatology Guidelines.

BACKGROUND: Comparative efficacy randomized controlled trials (RCTs) compare two active interventions in a head-to-head design. They are useful for informing clinical practice guidelines, but the degree to which such trials inform clinical practice guidelines in rheumatology is unknown. METHODS: The American College of Rheumatology (ACR) and European Alliance of Associations for Rheumatology (EULAR) websites were searched from January 1, 2017, to June 12, 2021, for clinical practice guidelines. RCTs referenced by each guideline were identified, and information regarding design and outcomes were extracted. Clinical practice recommendations from each guideline were also analyzed. RESULTS: Fifteen ACR- and nine EULAR-endorsed guidelines were included, which cited 609 RCTs and provided 481 recommendations. Referenced RCTs enrolled an average of 418 patients (SD 985), most commonly evaluated biologic/targeted synthetic disease-modifying antirheumatic drugs (70.1%), and infrequently used a head-to-head design (28%). A minority of recommendations received a high level of evidence (LOE) by the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) methodology (2.9%) or an "A" grade by the Oxford Centre for Evidence based Medicine Standards (OCEBM) methodology (28.9%). LOE was higher for recommendations informed by RCTs (P < 0.001) or head-to-head RCTs (P = 0.008). Many recommendations received a strong recommendation despite low (8 [2.6%]) or very low (25 [8.3%]) LOE. CONCLUSION: Less than one in six rheumatology guideline recommendations are informed by head-to-head RCTs. Recommendations that were informed by head-to-head RCTs were more likely to have a high LOE by both GRADE and OCEBM. Efforts to introduce more comparative efficacy RCTs should be undertaken.

Exosome-educated macrophages and exosomes differentially improve ligament healing.

Recently, our group used exosomes from mesenchymal stromal/stem cells (MSCs) to simulate an M2 macrophage phenotype, that is, exosome-educated macrophages (EEMs). These EEMs, when delivered in vivo, accelerated healing in a mouse Achilles tendon injury model. For the current study, we first tested the ability of EEMs to reproduce the beneficial healing effects in a different rodent model, that is, a rat medial collateral ligament (MCL) injury model. We hypothesized that treatment with EEMs would reduce inflammation and accelerate ligament healing, similar to our previous tendon results. Second, because of the translational advantages of a cell-free therapy, exosomes alone were also examined to promote MCL healing. We hypothesized that MSC-derived exosomes could also alter ligament healing to reduce scar formation. Similar to our previous Achilles tendon results, EEMs improved mechanical properties in the healing ligament and reduced inflammation, as indicated via a decreased endogenous M1/M2 macrophage ratio. We also showed that exosomes improved ligament remodeling as indicated by changes in collagen production and organization, and reduced scar formation but without improved mechanical behavior in healing tissue. Overall, our findings suggest EEMs and MSC-derived exosomes improve healing but via different mechanisms. EEMs and exosomes each have attractive characteristics as therapeutics. EEMs as a cell therapy are terminally differentiated and will not proliferate or differentiate. Alternatively, exosome therapy can be used as a cell free, shelf-stable therapeutic to deliver biologically active components. Results herein further support using EEMs and/or exosomes to improve ligament healing by modulating inflammation and promoting more advantageous tissue remodeling.

Oxidative stress in songbirds exposed to dietary methylmercury.

Long-term, sublethal methylmercury exposure can cause reproductive depression, immune suppression, endocrine disruption and other problems in birds. We used two biomarkers to detect oxidative stress in livers of zebra finches (Taeniopygia guttata) developmentally exposed to sublethal levels of dietary methylmercury (0.0, 0.3, 0.6, 1.2, or 2.4 µg/g wet weight in diet). Our findings indicate that young adult finches exposed to environmentally relevant concentrations of mercury in ovo and through their diets, exhibited oxidative stress in their livers. We measured the ratio of the antioxidant glutathione in its reduced form (GSH) versus its oxidized form (GSSG) and the activity of the superoxide dismutase (SOD) enzyme suite. Blood total mercury served as a proxy for liver mercury concentration, and was on average 8.4 times the dietary dose (e.g., birds consuming 0.6 µg/g had blood mercury levels of ~5 µg/g on a wet weight basis). Consistent with what is known from large, aquatic bird species, there was a significant, negative relationship between GSH/GSSG ratios and tissue mercury concentrations, which is indicative of oxidative stress. This relationship was driven by a significant increase in the oxidized glutathione in the livers of birds with higher blood mercury levels. SOD activity was also found to have a significant, negative relationship with blood mercury.