IntroductionSurvivors of COVID-19 frequently endure chronic disabilities. We hypothesize that diaphragm function has a long recovery time after COVID-19 hospitalization, and may play a role in post-COVID syndrome. The aim of this study was to assess diaphragm function during COVID-19 hospitalization and during recovery.MethodsWe conducted a prospective single-center cohort study in 49 patients enrolled, of which 28 completed one-year follow-up. Participants were evaluated for diaphragm function. Diaphragm function was assessed using ultrasound measuring of diaphragm thickening fraction (TF) within 24 h after admission, after 7 days of admission or at discharge, whichever came first, and three and twelve months after hospital admission.ResultsEstimated mean TF increased from 0.56 (95% CI 0.46–0.66) on admission to 0.78 (95% CI 0.65–0.89) at discharge or seven days after admission, to 1.05 (95% CI 0.83–1.26) three months after admission to 1.54 (95% CI 1.31–1.76) twelve months after admission. The improvements from admission to discharge, 3 months and 12 months were all significant (linear mixed modeling; p=0.020, p<0.001, and p<0.001, respectively) and the improvement from discharge to three months follow-up was borderline significant (p<0.1).ConclusionDiaphragm function was impaired during hospitalization for COVID-19. During recovery in hospital and up to one-year follow-up, diaphragm TF improved, suggesting a long recovery time of the diaphragm. Diaphragm ultrasound may be a valuable modality in the screening and follow-up of (post-)COVID-19 patients for diaphragm dysfunction.

The value of thymus and activation related chemokine immunohistochemistry in classic Hodgkin lymphoma diagnostics Aims: Classic Hodgkin lymphoma (cHL) should be distinguished from its wide variety of histological mimics, including reactive conditions and mature B and T cell neoplasms. Thymus and activation-related chemokine (TARC) is produced in extremely high quantities by the Hodgkin/Reed-Sternberg (HRS) tumour cells and is largely responsible for the attraction of CD4 + T cells into the cHL tumour micro-environment. In the current study we evaluated the diagnostic potential of TARC immunohistochemistry in daily practice in a tertiary referral centre in the Netherlands. Methods and results: A total of 383 cases, approximately half of which were cHL mimics, were prospectively evaluated in the period from June 2014 to November 2020. In 190 cHL cases, 92% were TARCpositive and the majority of cases showed strong and highly specific staining in all HRS cells (77%). In most cases, TARC could discriminate between nodular lymphocyte-predominant and lymphocyte-rich Hodgkin lymphoma. HRS-like cells in mature lymphoid neoplasms were rarely positive (6.4%) and there was no TARC staining at all in 64 reactive lymphadenopathies. Conclusions: TARC immunohistochemistry has great value in differentiating between cHL and its mimics, including nodular lymphocyte-predominant Hodgkin lymphoma, reactive lymphadenopathies and mature lymphoid neoplasms with HRS-like cells.

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