Background: Laboratory abnormalities associated with disease severity and mortality in patients with coronavirus disease 2019 (COVID-19) have been reported in many observational studies. However, there are significant heterogeneities in patient characteristics and research methodologies in these studies. Objectives: We aimed to provide an updated synthesis of the association between laboratory abnormalities and COVID-19 prognosis. Methods: We conducted an electronic search of PubMed, Scopus, Ovid, Willey, Web of Science, and the China National Knowledge Infrastructure (CNKI) for studies reporting hematological, coagulation, inflammatory, and immunological results during hospital admission of COVID-19 patients with different severities and outcomes. Results: A total of 64 studies were included in the current meta-analysis, with 8 hematological, 3 coagulation, 5 inflammatory, and 23 immunological variables reported. Of them, white blood cell (WBC) and neutrophil counts, D-dimer level, procalcitonin (PCT), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), ferretin, serum amyloid A (SAA), interleukins (ILs)–2R, IL-6, and IL-10 were significantly increased in severely ill patients and non-survivors. Meanwhile, non-severely ill patients and survivors presented significantly higher counts of eosinophils, lymphocytes, and CD4+ and CD8+ T cells. Conclusions: The current meta-analysis provides a comprehensive and updated synthesis of the association between admission laboratory abnormalities with severity and mortality of COVID-19. Our results highlight that increases in the levels of PCT, ESR, CRP, ferretin, SAA, IL-2R, IL-6, and IL-10 were associated with disease deterioration, whereas elevated eosinophils, lymphocytes, and T-cell subsets might serve as indicators of favorable outcomes.

Background: The modulations of subcutaneous allergen immunotherapy (SCIT) on lymphocyte subsets and cytokine productions are not fully clarified. Objective: We investigated the changes of T-lymphocyte subsets and serum Dermatophagoides pteronyssinus specific immunoglobulin G4 (Der-p-sIgG4), and cytokine productions in allergic asthmatics during Der-p SCIT. Methods: This study involved 20 allergic asthmatics receiving 156-week Der-p SCIT, 20 patients without SCIT (non-SCIT). Symptom and medication scores (SMS), serum Der-p-sIgG4 levels, CD4+CD25+Foxp3+ T regulatory (Treg), CD4+IL-4-IFN-γ+ T-helper (Th) 1, CD4+IL-4+IFN-γ- Th2 lymphocyte percentage in peripheral blood mononuclear cells (PBMCs) with/without Der-p extract stimulation at weeks 0, 4, 12, 16, 52, 104, and 156 were measured. Serum from SCIT and non-SCIT patients were incubated with Der-p allergen and Der-p sensitized PBMCs. Levels of interleukin (IL) -4, IL-5, IL-10, IL-13, IL-17, interferon (IFN) -γ, tumor necrosis factor (TNF) -α and transfer growth factor (TGF) -β1 in supernatant were detected. Results: SCIT patients had significantly lower SMS after week 52. Der-p-sIgG4 levels in SCIT patients significantly increased at week 16 compared to non-SCIT subjects. CD4+IL-4+IFN-γ- Th2 percentage in SCIT patients showed a significant decrease from week 104 to 156 comparing to week 0, while no change was observed in CD4+CD25+Foxp3+ Treg and CD4+IL-4-IFN-γ+ Th1 percentage. IL-5, IL-13, IL-4, IL-17, and TNF-α levels in supernatant of Der-p-sensitized PBMCs, cultured with serum of SCIT patients after 16 weeks decreased significantly compared with non-SCIT patients, and showed significant reverse associations with Der-p-sIgG4 levels. Conclusion: SCIT down-regulated Th2 cytokine productions associated reversely with Dep-p-sIgG4 levels in Der-p allergic asthma patients.