The transplant of organs is one of the greatest therapeutic achievements of the twentieth century. In organ transplantation, the adaptive immunity is considered the main response exerted to the transplanted tissue, since the principal target of the immune response is the MHC (major histocompatibility complex) molecules expressed on the surface of donor cells. However, we should not forget that the innate and adaptive immunities are closely interrelated and should be viewed as complementary and cooperating. When a human transplant is performed, HLA (human leukocyte antigens) molecules from a donor are recognized by the recipient's immune system triggering an alloimmune response Matching of donor and recipient for MHC antigens has been shown to have a significant positive effect on graft acceptance. This paper will present MHC, the innate and adaptive immunities, and clinical HLA testing.

Objective: We aimed to describe the persistence of symptoms in coronavirus disease 2019 (COVID-19) and quality of life (QoL) among patients 90 days after their discharge from the hospital for infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and to determine differences in QoL domains concerning the absence or presence of persistent symptoms. Methods: To measure QoL, we used a validated Spanish version of the 36-item Short Form Health Survey (SF-36). Results: We included 141 patients. Ninety days after discharge, COVID-19 symptoms persisted in 107 patients (75.9%), with fatigue (55.3%) and joint pain (46.8%) being the most frequent. According to the SF-36, the role-physical score was the dimension with the lowest values (median score, 25; interquartile range, 0–75). Patients with joint pain, fatigue, and dyspnea had lower scores than patients without those symptoms, with 10 of the 13 evaluated SF-36 scales showing lower levels. Conclusion: Ninety days after hospital discharge from COVID-19 reference centers, most patients had persistent symptoms and had lower SF-36 scores than patients without symptoms. It is important to follow-up patients discharged from the hospital after SARS-CoV-2 infection, ideally through a post-COVID-19 health care clinic and rehabilitation program, to improve QoL in these patients.

Background and Objectives: Patients infected with SARS-CoV-2 can have persistent symptoms after acute illness, which affects their quality of life (QoL). Research and data about this topic in Latin American ambulatory patients are scarce. Materials and Methods: We conducted an observational, prospective, transversal, and analytical study. To measure QoL, we used a validated Spanish version of the MOS/RAND 36-Item Short Form Health Survey (SF-36). Results: We included 206 outpatients in the study. A total of 73.3% patients had persistence of one or more symptoms. The most frequent persistent symptoms were fatigue (36.9%), anxiety (26.2%), and headache (24.8%). No statistically significant difference in the SF-36 QoL scores and the frequency of persistent COVID-19 symptoms was found when comparing the ≤5 and >5 months groups, except for myalgia, which was less frequently observed in the >5 months group after COVID-19 (26.2% vs. 14.1%, p < 0.038). Female gender was associated with an increased risk of persistence of symptoms (OR = 2.95, 95% CI 1.56–5.57). Having comorbidities/sequelae attributed to COVID-19 and persistence of COVID-19 symptoms were associated risk factors for poor physical component summary (PCS); on the other hand, female gender, anxiety, and depression were associated with poor mental component summary (MCS). Conclusion: Most outpatients had persistent COVID-19 symptoms after infection. Persistence of symptoms was associated with poor MCS and PCS. It is important to follow-up not only patients discharged from the hospital after SARS-CoV-2 infection, but also those under ambulatory management to provide them with rehabilitation and psychological therapy to improve their QoL.

Background and Objectives: An association between high red blood cell distribution width (RDW) and mortality has been found in several diseases, including infection and sepsis. Some studies have aimed at determining the association of elevated RDW with adverse prognosis in COVID-19, but its usefulness has not been well established. The objective of this study was to determine the accuracy of the RDW, measured at hospital admission and discharge, for predicting death in patients with COVID-19. Materials andMethods: An observational, retrospective, longitudinal, and analytical study was conducted in two different COVID-19 reference centers in the state of Guanajuato, Mexico. A total of 323 patients hospitalized by COVID-19 were included. Results: We found higher RDW levels at the time of hospital admission in the non-survivors group compared to levels in survivors (median = 13.6 vs. 13.0, p < 0.001). Final RDW levels were even higher in the deceased group when compared with those of survivors (median = 14.6 [IQR, 12.67–15.6] vs. 12.9 [IQR, 12.2–13.5], p < 0.001). For patients who died, an RDW > 14.5% was more common at the time of death than for patients who survived at the time of discharge (81 vs. 13 patients, p < 0.001; RR = 2.3, 95% CI 1.89–2.81). Conclusions: The RDW is an accessible and economical parameter that, together with other characteristics of the presentation and evolution of patients with COVID-19, can be helpful in determining the prognosis. An RDW that increases during hospitalization could be a more important mortality predictor than the RDW at hospital admission.