Patients with classic hydroa vacciniforme–like lymphoproliferative disorder (HVLPD) typically have high levels of Epstein-Barr virus (EBV) DNA in T cells and/or natural killer (NK) cells in blood and skin lesions induced by sun exposure that are infiltrated with EBV-infected lymphocytes. HVLPD is very rare in the United States and Europe but more common in Asia and South America. The disease can progress to a systemic form that may result in fatal lymphoma. We report our 11-year experience with 16 HVLPD patients from the United States and England and found that whites were less likely to develop systemic EBV disease (1/10) than nonwhites (5/6). All (10/10) of the white patients were generally in good health at last follow-up, while two-thirds (4/6) of the nonwhite patients required hematopoietic stem cell transplantation. Nonwhite patients had later age of onset of HVLPD than white patients (median age, 8 vs 5 years) and higher levels of EBV DNA (median, 1 515 000 vs 250 000 copies/ml) and more often had low numbers of NK cells (83% vs 50% of patients) and T-cell clones in the blood (83% vs 30% of patients). RNA-sequencing analysis of an HVLPD skin lesion in a white patient compared with his normal skin showed increased expression of interferon-γ and chemokines that attract T cells and NK cells. Thus, white patients with HVLPD were less likely to have systemic disease with EBV and had a much better prognosis than nonwhite patients. This trial was registered at www.clinicaltrials.gov as #NCT00369421 and #NCT00032513.

Objective Although it has been well established that fatigue is a common complaint among older adults with osteoarthritis (OA), relatively little is known about how fatigue in daily life affects physical activity. The purposes of this study were to examine the relationship between momentary fatigue and subsequent physical activity among people with OA who report clinically relevant levels of fatigue and to examine moderators of this relationship. Methods People with knee or hip OA and clinically relevant fatigue participated in physical performance assessments, completed questionnaires, and underwent a home monitoring period in which fatigue severity was measured 5 times per day over 5 days (N = 159). Physical activity was concurrently measured via a wrist-worn accelerometer. Multilevel modeling was used to examine the relationship of momentary fatigue and subsequent activity controlling for other factors (e.g., age, body mass index, pain, depression). Results Fatigue was the strongest predictor of reduced subsequent activity. Only functional mobility (TUG) moderated the relationship between fatigue and activity. The relationship between fatigue and activity was strongest for people with high functional mobility. Conclusions Momentary fatigue is a robust and important variable associated with decreased physical activity. Further, the moderating effect of functional mobility suggests this is a factor that should be considered when intervening on fatigue. While people with better functional mobility may benefit from an activity-based treatment approach (such as learning activity pacing techniques to reduce fatigue's impact on activity), those with worse functional mobility may benefit from treatment focusing on underlying impairments.

Our objective was to assess the quality of acne-related medical information present on TikTok, the world's fastest growing social media platform. We queried the TikTok mobile application for videos tagged with "#acne" on May 1, 2020, and assessed the top 100 videos meeting inclusion criteria for content quality using DISCERN, a validated and reliable instrument for evaluating consumer health information. The mean content quality rating of videos was 2.03 (SD 0.47) which, according to the DISCERN in-Dermatology