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Comorbidities are risk factors for development of severe coronavirus disease 2019 (COVID-19). However, the extent to which an underlying comorbidity influences the immune response to severe acute respiratory syndrome coronavirus 2 remains unknown.Our aim was to investigate the complex interrelations of comorbidities, the immune response, and patient outcome in COVID-19.We used high-throughput, high-dimensional, single-cell mapping of peripheral blood leukocytes and algorithm-guided analysis.We discovered characteristic immune signatures associated not only with severe COVID-19 but also with the underlying medical condition. Different factors of the metabolic syndrome (obesity, hypertension, and diabetes) affected distinct immune populations, thereby additively increasing the immunodysregulatory effect when present in a single patient. Patients with disorders affecting the lung or heart, together with factors of metabolic syndrome, were clustered together, whereas immune disorder and chronic kidney disease displayed a distinct immune profile in COVID-19. In particular, severe acute respiratory syndrome coronavirus 2-infected patients with preexisting chronic kidney disease were characterized by the highest number of altered immune signatures of both lymphoid and myeloid immune branches. This overall major immune dysregulation could be the underlying mechanism for the estimated odds ratio of 16.3 for development of severe COVID-19 in this burdened cohort.The combinatorial systematic analysis of the immune signatures, comorbidities, and outcomes of patients with COVID-19 has provided the mechanistic immunologic underpinnings of comorbidity-driven patient risk and uncovered comorbidity-driven immune signatures.

Background A subgroup of patients with common variable immunodeficiency (CVID) experience immune dysregulation manifesting as autoimmunity, lymphoproliferation, and organ inflammation and thereby increasing morbidity and mortality. Therefore treatment of these complications demands a deeper comprehension of their cause and pathophysiology. Objectives On the basis of the identification of an interferon signature in patients with CVID with secondary complications and a skewed follicular helper T-cell differentiation in defined monogenic immunodeficiencies, we sought to determine the profile of CD4 memory T cells in blood and secondary lymphatic tissues of these patients. Methods We quantified T H 1/T H 2/T H 17 CD4 memory T cells in blood and lymph nodes of patients with CVID using flow cytometry, analyzed their function, and correlated all findings to the burden of immune dysregulation. Results Patients with CVID with immune dysregulation had a skewed memory CD4 T-cell differentiation toward a CXCR3 + CCR6 − T H 1 phenotype both in blood and lymph nodes. Consistent with our phenotypic findings, we observed a higher IFN-γ production in peripheral CD4 memory T cells and lymph node–derived follicular helper T cells of patients with CVID compared with those of healthy control subjects. Increased IFN-γ production was accompanied by a poor germinal center output, an accumulation of T-box transcription factor (T-bet) + B cells in lymph nodes, and an accumulation of T-bet + CD21 low B cells in peripheral blood of affected patients. Conclusion Identification of excessive IFN-γ production by blood and lymph node–derived T cells of patients with CVID with immune dysregulation will offer new therapeutic avenues for this subgroup. CD21 low B cells might serve as a marker of this IFN-γ–associated dysregulation.

Background Most patients with MHC class I (MHC-I) deficiency carry genetic defects in transporter associated with antigen processing 1 (TAP1) or TAP2 . The clinical presentation can vary, and about half of the patients have severe skin disease. Previously, one report described β 2 -microglobulin (β 2 m) deficiency as another monogenetic cause of MHC-I deficiency, but no further immunologic evaluation was performed. Objective We sought to describe the molecular and immunologic features of β 2 m deficiency in 2 Turkish siblings with new diagnoses. Methods Based on clinical and serologic findings, the genetic defect was detected by means of candidate gene analysis. The immunologic characterization comprises flow cytometry, ELISA, functional assays, and immunohistochemistry. Results Here we provide the first extensive clinical and immunologic description of β 2 m deficiency in 2 siblings. The sister had recurrent respiratory tract infections and severe skin disease, whereas the brother was fairly asymptomatic but had bronchiectasis. Not only polymorphic MHC-I but also the related CD1a, CD1b, CD1c, and neonatal Fc receptor molecules were absent from the surfaces of β 2 m-deficient cells. Absent neonatal Fc receptor surface expression led to low serum IgG and albumin levels in both siblings, whereas the heterozygous parents had normal results for all tested parameters except β 2 m mRNA (B2M) expression. Similar to TAP deficiency in the absence of a regular CD8 T-cell compartment, CD8 + γδ T cells were strongly expanded. Natural killer cells were normal in number but not "licensed to kill." Conclusion The clinical presentation of patients with β 2 m deficiency resembles that of patients with other forms of MHC-I deficiency, but because of the missing stabilizing effect of β 2 m on other members of the MHC-I family, the immunologic defect is more extensive than in patients with TAP deficiency.