The age again in the eye of the COVID-19 storm: evidence-based decision making

Background: One hundred fifty million contagions, more than 3 million deaths and little more than 1 year of COVID-19 have changed our lives and our health management systems forever. Ageing is known to be one of the significant determinants for COVID-19 severity. Two main reasons underlie this: immunosenescence and age correlation with main COVID-19 comorbidities such as hypertension or dyslipidaemia. This study has two aims. The first is to obtain cut-off points for laboratory parameters that can help us in clinical decision-making. The second one is to analyse the effect of pandemic lockdown on epidemiological, clinical, and laboratory parameters concerning the severity of the COVID-19. For these purposes, 257 of SARSCoV2 inpatients during pandemic confinement were included in this study. Moreover, 584 case records from a previously analysed series, were compared with the present study data. Results: Concerning the characteristics of lockdown series, mild cases accounted for 14.4, 54.1% were moderate and 31.5%, severe. There were 32.5% of home contagions, 26.3% community transmissions, 22.5% nursing home contagions, and 8.8% corresponding to frontline worker contagions regarding epidemiological features. Age > 60 and male sex are hereby confirmed as severity determinants. Equally, higher severity was significantly associated with higher IL6, CRP, ferritin, LDH, and leukocyte counts, and a lower percentage of lymphocyte, CD4 and CD8 count. Comparing this cohort with a previous 584-cases series, mild cases were less than those analysed in the first moment of the pandemic and dyslipidaemia became more frequent than before. IL-6, CRP and LDH values above 69 pg/mL, 97 mg/L and 328 U/L respectively, as well as a CD4 T-cell count below 535 cells/?L, were the best cut-offs predicting severity since these parameters offered reliable areas under the curve. Conclusion: Age and sex together with selected laboratory parameters on admission can help us predict COVID-19 severity and, therefore, make clinical and resource management decisions. Demographic features associated with lockdown might affect the homogeneity of the data and the robustness of the results

COVID-19 : Age, Interleukin-6, C-reactive protein, and lymphocytes as key clues from a multicentre retrospective study

Background: The SARS-CoV-2 infection has widely spread to become the greatest public health challenge to date, the COVID-19 pandemic. Different fatality rates among countries are probably due to non-standardized records being carried out by local health authorities. The Spanish case-fatality rate is 11.22%, far higher than those reported in Asia or by other European countries. A multicentre retrospective study of demographic, clinical, laboratory and immunological features of 584 Spanish COVID-19 hospitalized patients and their outcomes was performed. The use of renin-angiotensin system blockers was also analysed as a risk factor. Results: In this study, 27.4% of cases presented a mild course, 42.1% a moderate one and for 30.5% of cases, the course was severe. Ages ranged from 18 to 98 (average 63). Almost 60 % (59.8%) of patients were male. Interleukin 6 was higher as severity increased. On the other hand, CD8 lymphocyte count was significantly lower as severity grew and subpopulations CD4, CD8, CD19, and NK showed concordant lowering trends. Severity-related natural killer percent descents were evidenced just within aged cases. A significant severity-related decrease of CD4 lymphocytes was found in males. The use of angiotensin-converting enzyme inhibitors was associated with a better prognosis. The angiotensin II receptor blocker use was associated with a more severe course. Conclusions: Age and age-related comorbidities, such as dyslipidaemia, hypertension or diabetes, determined more frequent severe forms of the disease in this study than in previous literature cohorts. Our cases are older than those so far reported and the clinical course of the disease is found to be impaired by age. Immunosenescence might be therefore a suitable explanation for the hampering of immune system effectors. The adaptive immunity would become exhausted and a strong but ineffective and almost deleterious innate response would account for COVID-19 severity. Angiotensin-converting enzyme inhibitors used by hypertensive patients have a protective effect in regards to COVID-19 severity in our series. Conversely, patients on angiotensin II receptor blockers showed a severer disease

Papel de los linfocitos T foliculares en la fisiopatología de inmunodeficiencias primarias y enfermedades autoinmunitarias

[eng] Germinal center (GC) follicular helper T (Tfh) cells, expressing CD4 and CXCR5, are essential players in the regulation of B cell differentiation and maintenance of humoral immunity. Circulating (c)Tfh cells share phenotypic and functional properties with GC Tfh cells and distinct subpopulations (cTfh1, cTfh2, cTfh17 and cTfh17.1), with different functions and helper capabilities toward B cells, can be identified. Alterations in cTfh distribution and/or function have been described in infectious diseases, autoimmunity disorders and, more recently, several monogenic immunodeficiencies. The aim of the present study was to evaluate the role of cTfh cells in two different immunological disorders: common variable immunodeficiency disease (CVID), a primary immunodeficiency, and multiple sclerosis (MS), an autoimmune disease. B-cell differentiation into memory B cells or antibody-secreting cells is defective in CVID patients. Maturation and differentiation of B-cells are driven by Tfh-cells' help in GC through the IL-21/STAT3 signaling pathway or through T-independent extrafollicular pathways. For these reasons, we first investigated if alterations in the IL-21/STAT3 axis and/or cTfh cells frequency or distribution could be related to defects found in CVID B cells. In healthy controls, IL-21 induced higher STAT3 phosphorylation (pSTAT3) levels on naïve CD27− than memory CD27+ B-cells after B-cell receptor engagement (anti-IgM) or T-dependent (anti-CD40) activation. CD27− B-cells from CVID patients showed similar levels of pSTAT3 to those from healthy controls. However, CD27+ B-cells from CVID patients showed selective STAT3 hyper-phosphorylation after activation with anti-IgM or anti-CD40 alone and anti-IgM, anti-CD40 or CpG-ODN combined with IL21. cTfh cells frequency and distribution were also altered in CVID patients. CVID patients with lower percentage of switch memory B cells (smB- group) had increased percentages of cTfh cells exhibiting higher programmed death-1 (PD-1) expression and altered subpopulations distribution. In contrast to CVID patients with higher percentage of switch memory B cells (smB+ group) and controls, cTfh cells from smB- CVID patients showed lower percentage of cTfh17 subpopulation and higher percentages of cTfh1 and cTfh17.1, a population analogous to the recently described pathogenic CXCR3+CCR6+ Th17.1 cells. Moreover, follicular regulatory T (Tfr) cells were remarkably decreased only in smB- CVID patients. STAT3 hyper-phosphorylation during immune responses together with increased cTfh17.1 and cTfh1/cTfh17 ratio could influence B cell fate in smB- CVID patients, with a more compromised B cell compartment, and the decrease in Tfr cells may lead to an increased risk of autoimmune conditions in CVID patients. In the second part of the present study, we analysed cTfh subpopulations in relapsingremitting MS (RRMS) patients and evaluated the impact of dimethyl fumarate (DMF) treatment on the distribution of these subpopulations, relating them to B cells changes and humoral response. MS is considered a T cell-mediated autoimmune disease, although several evidences also demonstrate a B cell involvement in its etiology. DMF is a recently approved first-line treatment for RRMS patients and its mechanism of action is not completely understood. Untreated RRMS patients presented higher percentages of cTfh17.1 cells and lower percentages of cTfh2 cells consistent with a pro-inflammatory bias compared to healthy subjects. DMF treatment induced a progressive increase in cTfh2 cells, accompanied by a decrease in cTfh1 and also the pathogenic cTfh17.1 cells. A similar decrease of non-follicular Th1 and Th17.1 cells in addition to an increase in the anti-inflammatory Th2 subpopulation was also detected upon DMF treatment, accompanied by an increase in naïve B cells and a decrease in switch memory B cells and IgA, IgG2, and IgG3 serum levels. Interestingly, this effect was not observed in three patients in whom DMF had to be discontinued due to an absence of clinical response. Our results demonstrate a possible pathogenic cTfh proinflammatory profile in RRMS patients, defined by high cTfh17.1 and low cTfh2 subpopulations that is reverted by DMF treatment. Monitoring cTfh subsets during treatment may become a biological marker of DMF effectiveness.[spa] Los linfocitos T foliculares (Tfh) son una subpoblación de linfocitos T CD4+, localizada en los centros germinales (CG), caracterizada por la expresión del receptor CXCR5 y especializada en la diferenciación de los linfocitos B y en el mantenimiento de la inmunidad humoral. Los Tfh circulantes (c)Tfh comparten propiedades fenotípicas y funcionales con los Tfh. Encontramos distintas subpoblaciones de cTfh (cTfh1, cTfh2, cTfh17 y cTfh17.1) con diferentes funciones y capacidad de colaboración con el linfocito B. Alteraciones en el número, distribución y función de las subpoblaciones de cTfh han sido descritas en enfermedades infecciosas, trastornos autoinmunitarios y, más recientemente, en inmunodeficiencias primarias monogénicas. El objetivo del presente estudio fue evaluar el papel de los cTfh en dos trastornos inmunológicos: en una inmunodeficiencia primaria, la inmunodeficiencia variable común (IVC), y en una enfermedad autoinmunitaria, la esclerosis múltiple (EM). La diferenciación de los linfocitos B a células plasmáticas productoras de anticuerpos o a linfocitos B de memoria es defectuosa en los pacientes con IVC. La maduración y diferenciación de los linfocitos B puede producirse en el interior de los CG, mediante colaboración con los Tfh a través de la vía de señalización IL-21/STAT3, o en focos extrafoliculares, independientemente del CG. En el presente trabajo estudiamos en primer lugar si los defectos que presentan las células B de los pacientes con IVC pueden estar relacionados con alteraciones en la frecuencia y/o distribución de los cTfh o pueden ser debidos a problemas intrínsecos del propio linfocito B (alteraciones en la vía de señalización IL-21/STAT3). En controles sanos, la IL-21 indujo mayores niveles de fosforilación de STAT3 (pSTAT3) en las células B vírgenes (CD27-) que en las células B de memoria (CD27+) tras activación con estímulos T dependientes (anti-CD40) o a través del BCR (antiIgM). Los pacientes con IVC presentaron en las células B vírgenes (CD27-) unos niveles similares de pSTAT3 a los observados en controles sanos. Por el contrario, sus células B de memoria (CD27+) mostraron un aumento selectivo de pSTAT3 tras estimulación con anti-IgM o anti-CD40 y anti-IgM, anti-CD40 o CpG-ODN en combinación con IL-21. Además, en estos pacientes, describimos una alteración en la frecuencia y distribución de la subpoblación de cTfh. Concretamente los pacientes con menor porcentaje de células B de memoria que han experimentado el cambio de clase de inmunoglobulina (Ig) (grupo smB-) presentaron un incremento del porcentaje de los cTfh, con un aumento de los niveles de expresión de PD-1, y una alteración de la distribución de las subpoblaciones de cTfh. Los pacientes con IVC del grupo smB-, a diferencia de los controles sanos y de los pacientes con IVC con mayor porcentaje de células B de memoria (grupo smB+), presentan una disminución de la subpoblación de cTfh17 y un aumento de las subpoblaciones de cTfh1 y cTfh17.1, subpoblación análoga a la población patogénica Th17.1 descrita recientemente. También observamos una reducción, restringida de nuevo a los pacientes con IVC del grupo smB-, de los linfocitos T foliculares reguladores (Tfr). La hiperfosforilación de STAT3 durante las respuestas inmunitarias junto al aumento de la subpoblación cTfh17.1 y del ratio cTfh1/cTfh17 podría comprometer la función de las células B y la generación de una respuesta humoral eficiente en pacientes con IVC del grupo smB-. Asimismo, la disminución de la subpoblación de Tfr podría incrementar, en estos pacientes, el riesgo de padecer trastornos autoinmunitarios. En la segunda parte del estudio se analizaron las subpoblaciones de cTfh en pacientes con EM recurrente-remitente (EMRR). Además, se evaluó el impacto del tratamiento con dimetilfumarato (DMF) en la distribución de las cTfh y se relacionó con cambios en la población linfocitaria B y en la respuesta humoral. La EM se considera una enfermedad autoinmunitaria mediada por linfocitos T. Sin embargo, en los últimos años, diversos estudios sugieren la implicación de las células B en el curso de la enfermedad. El DMF es un fármaco de administración oral aprobado recientemente como tratamiento de primera línea para la EMRR y cuyo mecanismo de acción no se ha descrito completamente. Los pacientes con EMRR presentaron, previamente al tratamiento con DMF, un incremento de la subpoblación pro-inflamatoria cTfh17.1 junto con un descenso de la subpoblación cTfh2, que muestra un sesgo pro-inflamatorio comparado con los controles sanos. El tratamiento con DMF indujo un aumento progresivo de la subpoblación cTfh2, una disminución de las cTfh1 y de la subpoblación patogénica cTfh17.1. Una disminución similar de las subpoblaciones T efectoras no foliculares Th1 y Th17.1, y un aumento de la subpoblación anti-inflamatoria Th2 se observó también durante el tratamiento con DMF. Estos cambios se acompañaron de un aumento de las células B vírgenes, una disminución de las células B de memoria y la reducción de los niveles séricos de IgA, IgG2 e IgG3. Un hallazgo interesante, fue que en tres pacientes en los que hubo que interrumpir el tratamiento con DMF debido a la ausencia de respuesta clínica, el DMF no revirtió el perfil pro-inflamatorio de las subpoblaciones cTfh. Nuestros resultados demuestran un perfil pro-inflamatorio posiblemente patogénico de las células cTfh en pacientes con EMRR, definido por un incremento de las células cTfh17.1 y disminución de las cTfh2 que se revirtió con el DMF. La monitorización de las subpoblaciones de cTfh durante el tratamiento con DMF podría convertirse en un marcador biológico de eficacia terapéutica[cat] Els limfòcits T fol·liculars (Tfh) són una subpoblació de limfòcits T CD4+, localitzada als centres germinals (CG), caracteritzada per l’expressió del receptor CXCR5 i especialitzada en la regulació del procés de diferenciació de les cèl·lules B i en el manteniment de la immunitat humoral. Els limfòcits Tfh circulants (c)Tfh comparteixen propietats fenotípiques i funcionals amb els Tfh. Trobem distintes subpoblacions de cTfh (cTfh1, cTfh2, cTfh17, cTfh17.1) amb diferents funcions i capacitats de col·laboració amb el limfòcit B. S’han descrit alteracions en el nombre, distribució i funció de les subpoblaciones de cTfh a malalties infeccioses, trastorns autoimmunitaris i, més recentment, en immunodeficiències primàries monogèniques. L’objectiu d’aquest estudi fou avaluar el paper de les cèl·lules cTfh en dos trastorns immunològics: en una immunodeficiència primària, la immunodeficiència variable comú (IVC), i en una malaltia autoimmunitària, l’esclerosi múltiple (EM). La diferenciació dels limfòcits B a cèl·lules plasmàtiques productores d’anticossos o limfòcits B de memòria és defectuosa als pacients amb IVC. La maduració i diferenciació dels limfòcits B pot produir-se a l’interior dels CG mitjançant la col·laboració dels Tfh per la via de senyalització IL-21/STAT3 o als focus extrafol·liculars, independents del GC. En aquest estudi s’avaluà en primer lloc si els defectes que caracteritzen les cèl·lules B en pacients amb IVC poden estar relacionats amb alteracions en la freqüència i/o distribució de les cTfh, o amb problemes intrínsecs dels propis limfòcits B (alteracions a la via de senyalització IL-21/STAT3). En controls sans, la IL-21 va induir majors nivells de fosforilació de STAT3 (pSTAT3) a les cèl·lules B verges (CD27-) que a les cèl·lules B de memòria (CD27+) després d’una activació amb estímuls T-depenents (anti-CD40) o mitjançant BCR (anti-IgM). Els pacients amb IVC van presentar a cèl·lules B verges (CD27-) nivells de pSTAT3 semblants als controls sans. Per altra banda, les cèl·lules B de memòria (CD27+) mostraren un augment selectiu de pSTAT3 posterior a l’estimulació amb anti-IgM o anti-CD40, i anti-IgM, anti-CD40 o CpG-ODN en combinació amb IL-21. A més, descrivim una alteració en la freqüència i distribució de la población de cTfh en pacients amb IVC. Concretament, els pacients amb menor percentatge de cèl·lules B de memòria que han realitzat el canvi de classe d´immunoglobulina (Ig) (grup smB-) mostraren un augment de cèl·lules cTfh, amb major nivells en l’expressió de PD-1, i una alteració en la distribució de les subpoblacions de cTfh. Els pacients amb IVC del grup smB-, a diferència dels controls sans i dels pacients amb IVC amb un percentatge major de cèl·lules B de memòria (grup smB+) van presentar una disminució de la subpoblació de limfòcits cTfh17 i augment dels cTfh1 i cTfh17.1, subpoblació anàloga a la Th17.1 descrita recentment. A banda d’això, també s’observà una reducció restringida de nou, als pacients amb IVC del subgrup smB- dels limfòcits T fol·liculars reguladors (Tfr). La hiperfosforilació de STAT3 durant les respostes immunitàries juntament amb l'augment de la subpoblació cel·lular cTfh17.1 i de la ràtio cTfh1/cTfh17 podria comprometre la funció de les cèl·lules B i induir una resposta humoral eficient en els pacients amb IVC del grup smB-. A més, la disminució de les cèl·lules Tfr podrien incrementar el risc dels pacients amb IVC a patir trastorns autoimmunitaris. En la segona part de l’estudi, s’analitzaren les subpoblacions de limfòcits cTfh en pacients amb EM recurrent-remitent (EMRR) i, a més, es va avaluar l'impacte del tractament amb dimetilfumarat (DMF) en la distribució d'aquestes subpoblacions (cTfh) i es va relacionar amb canvis en la població limfocitària B i la resposta humoral. L´EM és considerada una malaltia autoimmunitària mediada per limfòcits T, no obstant això, en els últims anys diverses investigacions suggereixen la implicació de les cèl·lules B en el desenvolupament de la malaltia. El DMF és un fàrmac d´aministració oral aprovat com a tractament de primera línia per el tractament de pacients amb EMRR; el seu mecanisme d’acció no s’ha descrit completament. Els pacients amb EMRR, previ tractament amb DMF, van presentar un increment de la subpoblació pro-inflamatòria cTfh17.1 juntament amb una disminució de la subpoblació cTfh2, donant lloc a un biaix pro-inflamatori comparat amb els controls sans. El tractament amb DMF va induir un augment progressiu de la subpoblació cTfh2, i al mateix temps una disminució de les subpoblacions cTfh1 i cTfh17.1. Una disminució semblant de les subpoblacions Th no fol·liculars Th1 i Th17.1, conjuntament amb l’augment de la subpoblació anti-inflamatoria Th2, s’observà durant el tractament amb DMF. Aquests canvis es van produir alhora d’un augment en les cèl·lules B verges, disminució en les cèl·lules B de memòria i una reducció dels nivells sèrics d´IgA, IgG2 i IgG3. Una de les troballes importants, fou que aquest efecte no es va observar en tres pacients en els que es va interrompre el tractament amb DMF per l'absència de resposta clínica. En aquests pacients el DMF no va revertir el perfil proinflamatori de les subpoblacions cTfh. Els nostres resultats demostren un perfil proinflamatori de les cTfh possiblement patogènic en pacients amb EMRR, definit per un increment de les cèl·lules cTfh17.1 i disminució de cTfh2 que és revertit pel tractament amb DMF. La monitorització dels subconjunts de cTfh durant el tractament pot esdevenir un marcador biològic de l'eficàcia terapèutica del DMF

Relapsing–Remitting Multiple Sclerosis Is Characterized by a T Follicular Cell Pro-Inflammatory Shift, Reverted by Dimethyl Fumarate Treatment

Multiple sclerosis (MS) is considered a T cell-mediated autoimmune disease, although several evidences also demonstrate a B cell involvement in its etiology. Follicular T helper (Tfh) cells, a CXCR5-expressing CD4+ T cell subpopulation, are essential in the regulation of B cell differentiation and maintenance of humoral immunity. Alterations in circulating (c)Tfh distribution and/or function have been associated with autoimmune diseases including MS. Dimethyl fumarate (DMF) is a recently approved first-line treatment for relapsing–remitting MS (RRMS) patients whose mechanism of action is not completely understood. The aim of our study was to compare cTfh subpopulations between RRMS patients and healthy subjects and evaluate the impact of DMF treatment on these subpopulations, relating them to changes in B cells and humoral response. We analyzed, by flow cytometry, the distribution of cTfh1 (CXCR3+CCR6−), cTfh2 (CXCR3−CCR6−), cTfh17 (CXCR3−CCR6+), and the recently described cTfh17.1 (CXCR3+CCR6+) subpopulations of CD4+ Tfh (CD45RA−CXCR5+) cells in a cohort of 29 untreated RRMS compared to healthy subjects. CD4+ non-follicular T helper (Th) cells (CD45RA−CXCR5−) were also studied. We also evaluated the effect of DMF treatment on these subpopulations after 6 and 12 months treatment. Untreated RRMS patients presented higher percentages of cTfh17.1 cells and lower percentages of cTfh2 cells consistent with a pro-inflammatory bias compared to healthy subjects. DMF treatment induced a progressive increase in cTfh2 cells, accompanied by a decrease in cTfh1 and the pathogenic cTfh17.1 cells. A similar decrease of non-follicular Th1 and Th17.1 cells in addition to an increase in the anti-inflammatory Th2 subpopulation were also detected upon DMF treatment, accompanied by an increase in naïve B cells and a decrease in switched memory B cells and serum levels of IgA, IgG2, and IgG3. Interestingly, this effect was not observed in three patients in whom DMF had to be discontinued due to an absence of clinical response. Our results demonstrate a possibly pathogenic cTfh pro-inflammatory profile in RRMS patients, defined by high cTfh17.1 and low cTfh2 subpopulations that is reverted by DMF treatment. Monitoring cTfh subsets during treatment may become a biological marker of DMF effectiveness

Plasma from patients undergoing allogeneic hematopoietic stem cell transplantation promotes NETOSIS in vitro and correlates with inflammatory parameters and clinical severity

IntroductionNETosis, the mechanism by which neutrophils release extracellular traps (NETs), is closely related to inflammation. During the allogeneic hematopoietic stem cell transplantation (allo-HSCT), different stimuli can induce NETs formation. Inflammation and endothelial injury have been associated with acute graft-versus-host disease (aGVHD) and complications after allo-HSCT. We focus on the study of NETosis and its relation with cytokines, hematological and biochemical parameters and clinical outcomes before, during and after allo-HSCT.MethodsWe evaluate the capacity of plasma samples from allo-HSCT patients to induce NETosis, in a cell culture model. Plasma samples from patients undergoing allo-HSCT had a stronger higher NETs induction capacity (NETsIC) than plasma from healthy donors throughout the transplantation process. An optimal cut-off value by ROC analysis was established to discriminate between patients whose plasma triggered NETosis (NETs+IC group) and those who did not (NETs-IC group).ResultsPrior to conditioning treatment, the capacity of plasma samples to trigger NETosis was significantly correlated with the Endothelial Activation and Stress Index (EASIX) score. At day 5 after transplant, patients with a positive NETsIC had higher interleukin (IL)-6 and C-reactive protein (CRP) levels and also a higher Modified EASIX score (M-EASIX) than patients with a negative NETsIC. EASIX and M-EASIX scores seek to determine inflammation and endothelium damage, therefore it could indicate a heightened immune response and inflammation in the group of patients with a positive NETsIC. Cytokine levels, specifically IL-8 and IL-6, significantly increased after allo-HSCT with peak levels reached on day 10 after graft infusion. Only, IL-10 and IL-6 levels were significantly higher in patients with a positive NETsIC. In our small cohort, higher IL-6 and IL-8 levels were related to early severe complications (before day 15 after transplant).DiscussionAlthough early complications were not related to NETosis by itself, NETosis could predict overall non-specific but clinically significant complications during the full patient admission. In summary, NETosis can be directly induced by plasma from allo-HSCT patients and NETsIC was associated with clinical indicators of disease severity, cytokines levels and inflammatory markers

Hyperinflammatory Immune Response in COVID-19: Host Genetic Factors in Pyrin Inflammasome and Immunity to Virus in a Spanish Population from Majorca Island

The hyperinflammatory response caused by SARS-CoV-2 infection contributes to its severity, and many critically ill patients show features of cytokine storm (CS) syndrome. We investigated, by next-generation sequencing, 24 causative genes of primary immunodeficiencies whose defect predisposes to CS. We studied two cohorts with extreme phenotypes of SARS-CoV-2 infection: critical/severe hyperinflammatory patients (H-P) and asymptomatic patients (AM-risk-P) with a high risk (older age) to severe COVID-19. To explore inborn errors of the immunity, we investigated the presence of pathogenic or rare variants, and to identify COVID-19 severity-associated markers, we compared the allele frequencies of common genetic polymorphisms between our two cohorts. We found: 1 H-P carries the likely pathogenic variant c.887-2 A>C in the IRF7 gene and 5 H-P carries variants in the MEFV gene, whose role in the pathogenicity of the familial Mediterranean fever (FMF) disease is controversial. The common polymorphism analysis showed three potential risk biomarkers for developing the hyperinflammatory response: the homozygous haplotype rs1231123A/A-rs1231122A/A in MEFV gene, the IFNAR2 p.Phe8Ser variant, and the CARMIL2 p.Val181Met variant. The combined analysis showed an increased risk of developing severe COVID-19 in patients that had at least one of our genetic risk markers (odds ratio (OR) = 6.2 (95% CI) (2.430–16.20))

Relapsing-Remitting Multiple Sclerosis is characterized by a T follicular pro-inflammatory shift, reverted by Dimethyl Fumarate treatment

[eng] Multiple sclerosis (MS) is considered a T cell-mediated autoimmune disease, although several evidences also demonstrate a B cell involvement in its etiology. Follicular T helper (Tfh) cells, a CXCR5-expressing CD4+ T cell subpopulation, are essential in the regulation of B cell differentiation and maintenance of humoral immunity. Alterations in circulating (c)Tfh distribution and/or function have been associated with autoimmune diseases including MS. Dimethyl fumarate (DMF) is a recently approved first-line treatment for relapsing-remitting MS (RRMS) patients whose mechanism of action is not completely understood. The aim of our study was to compare cTfh subpopulations between RRMS patients and healthy subjects and evaluate the impact of DMF treatment on these subpopulations, relating them to changes in B cells and humoral response. We analyzed, by flow cytometry, the distribution of cTfh1 (CXCR3+CCR6−), cTfh2 (CXCR3−CCR6−), cTfh17 (CXCR3−CCR6+), and the recently described cTfh17.1(CXCR3+CCR6+) subpopulations of CD4+ Tfh (CD45RA−CXCR5+) cells in a cohort of 29 untreated RRMS compared to healthy subjects. CD4+ non-follicular T helper (Th) cells (CD45RA−CXCR5−) were also studied. We also evaluated the effect of DMF treatment on these subpopulations after 6 and 12 months treatment. Untreated RRMS patients presented higher percentages of cTfh17.1 cells and lower percentages of cTfh2 cells consistent with a pro-inflammatory bias compared to healthy subjects. DMF treatment induced a progressive increase in cTfh2 cells, accompanied by a decrease in cTfh1 and the pathogenic cTfh17.1 cells. A similar decrease of non-follicular Th1 and Th17.1 cells in addition to an increase in the anti-inflammatory Th2 subpopulation were also detected upon DMF treatment, accompanied by an increase in naïve B cells and a decrease in switched memory B cells and serum levels of IgA, IgG2, and IgG3. Interestingly, this effect was not observed in three patients in whom DMF had to be discontinued due to an absence of clinical response. Our results demonstrate a possibly pathogenic cTfh pro-inflammatory profile in RRMS patients, defined by high cTfh17.1 and low cTfh2 subpopulations that is reverted by DMF treatment. Monitoring cTfh subsets during treatment may become a biological marker of DMF effectiveness