BACKGROUND. Fatal cases of COVID-19 are increasing globally. We retrospectively investigated the potential of immunologic parameters as early predictors of COVID-19. METHODS. A total of 1018 patients with confirmed COVID-19 were enrolled in our 2-center retrospective study. Clinical feature, laboratory test, immunological test, radiological findings, and outcomes data were collected. Univariate and multivariable logistic regression analyses were performed to evaluate factors associated with in-hospital mortality. Receiver operator characteristic (ROC) curves and survival curves were plotted to evaluate their clinical utility. RESULTS. The counts of all T lymphocyte subsets were markedly lower in nonsurvivors than in survivors, especially CD8 + T cells. Among all tested cytokines, IL-6 was elevated most significantly, with an upward trend of more than 10-fold. Using multivariate logistic regression analysis, IL-6 levels of more than 20 pg/mL and CD8 + T cell counts of less than 165 cells/μL were found to be associated with in-hospital mortality after adjusting for confounding factors. Groups with IL-6 levels of more than 20 pg/mL and CD8 + T cell counts of less than 165 cells/μL had a higher percentage of older and male patients as well as a higher proportion of patients with comorbidities, ventilation, intensive care unit admission, shock, and death. Furthermore, the receiver operating curve of the model combining IL-6 (>20 pg/mL) and CD8 + T cell counts (<165 cells/μL) displayed a more favorable discrimination than that of the CURB-65 score. The Hosmer-Lemeshow test showed a good fit of the model, with no statistical significance. CONCLUSION. IL-6 (>20 pg/mL) and CD8 + T cell counts (<165 cells/μL) are 2 reliable prognostic indicators that accurately stratify patients into risk categories and predict COVID-19 mortality.

The results of this study suggest that increased levels of IL-8 in the keratinocytes of psoriatic plaques play a contributing role in the migration of mast cells to lesion sites.

The results of our study suggest that SP- and CGRP-containing neuropeptide nerve fibers are more dense in the psoriatic epidermis. Both SP and CGRP are chemotactic to neutrophils and mitogenic to keratinocytes and endothelial cells. In addition, SP activates T lymphocytes and induces adhesion molecules on the endothelial cells. Our observations suggest that neuropeptides may play a significant role in the inflammatory and proliferative process of psoriasis.

The results of this study confirm that fractalkine is upregulated at sites of inflammation. Thus, it is likely that this molecule plays a key part in cell trafficking. An increased expression of fractalkine at the dermal papillae provides a plausible explanation for the migration and accumulation of T cells at these sites in psoriasis. Earlier studies have reported an increased number of dermal dendrocytes in psoriatic tissue; however, the functional role of these cells in the pathogenesis of psoriasis is largely unknown. Expression of fractalkine on the surface of dermal dendrocytes suggests an active role for these cells in localization and activation of lesional T cells.

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