Secondary hemophagocytic lymphohistiocytosis, HScore and COVID-19

COVID-19 in patients with anemia and haematological malignancies: risk factors, clinical guidelines, and emerging therapeutic approaches

Extensive research in countries with high sociodemographic indices (SDIs) to date has shown that coronavirus disease 2019 (COVID-19) may be directly associated with more severe outcomes among patients living with haematological disorders and malignancies (HDMs). Because individuals with moderate to severe immunodeficiency are likely to undergo persistent infections, shed virus particles for prolonged periods, and lack an inflammatory or abortive phase, this represents an overall risk of morbidity and mortality from COVID-19. In cases suffering from HDMs, further investigation is needed to achieve a better understanding of triviruses and a group of related variants in patients with anemia and HDMs, as well as their treatment through vaccines, drugs, and other methods. Against this background, the present study aimed to delineate the relationship between HDMs and the novel COVID-19, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Besides, effective treatment options for HDM cases were further explored to address this epidemic and its variants. Therefore, learning about how COVID-19 manifests in these patients, along with exploiting the most appropriate treatments, may lead to the development of treatment and care strategies by clinicians and researchers to help patients recover faster. Video Abstract.

Common bone marrow signature in COVID-19-associated multisystem inflammatory syndrome in children: A first-wave small case series experience

The hyper-inflammatory response, also known as multisystem inflammatory syndrome in children (MIS-C), represents a major concern in children with SARS-CoV-2 infection. We report bone marrow features of three patients with MIS-C who were diagnosed during the first wave of the SARS-CoV-2 pandemic. A bone marrow evaluation was performed at onset of the inflammatory condition in order to exclude secondary hemophagocytic lymphohistiocytosis (sHLH). The bone marrows of the patients presented common features: the erythroid and megakaryocytic lineages were prominently affected and hemophagocytosis was moderately increased, differently than observed in sHLH. Megakaryocytopoiesis was increased, representing a peculiar feature of MIS-C differing from sHLH. SARS-CoV-2 RT-PCR and viral panel were studied in bone marrow aspiration samples. MIS-C is a rare complication of SARS-CoV-2 infections in children. An immuno-dysregulation considering both innate and adaptive immunity together with vascular inflammation and endothelial dysfunction play a major role. Our observations, although limited due to the small sample size, suggest that there are unique features in the bone marrow of patients with MIS-C that are likely secondary to immuno-dysregulation, and there are notable differences in bone marrow features compared to those reported in sHLH.

COVID-19 and the differences in physiological background between children and adults and their clinical consequences

The SARS-CoV-2 pandemic has indeed been one of the most significant problems facing the world in the last decade. It has affected (directly or indirectly) the entire population and all age groups. Children have accounted for 1.7 % to 2 % of the diagnosed cases of COVID-19. COVID-19 in children is usually associated with a mild course of the disease and a better survival rate than in adults. In this review, we investigate the different mechanisms which underlie this observation. Generally, we can say that the innate immune response of children is strong because they have a trained immunity, allowing the early control of infection at the site of entry. Suppressed adaptive immunity and a dysfunctional innate immune response is seen in adult patients with severe infections but not in children. This may relate to immunosenescence in the elderly. Another proposed factor is the different receptors for SARS-CoV-2 and their differences in expression between these age groups. In infants and toddlers, effective immune response to viral particles can be modulated by the pre-existing non-specific effect of live attenuated vaccines on innate immunity and vitamin D prophylaxis. However, all the proposed mechanisms require verification in larger cohorts of patients. Our knowledge about SARS-CoV-2 is still developing.

Association of HScore Parameters with Severe COVID-19: A Systematic Review and Meta-Analysis

BACKGROUND

Several reports have associated the severe Coronavirus disease-2019 (sCOVID-19) with secondary-hemophagocytic lymphohistiocytosis (sHLH) and proposed utilizing the hemophagocytic syndrome diagnostic score (HScore) for sCOVID-19 patients. We conducted a systematic review and meta-analysis to find the possible association of HScore parameters with severity in COVID-19 patients.

METHODS

A systematic search was performed in Medline via PubMed, EMBASE, and Cochrane databases using all HScore and COVID-19 keywords. The studies were all from 2020, and the study language was limited to English. The records were screened based on inclusion/exclusion criteria. Random/fixed-effect models were employed for meta-analysis, based on the I2 index of parameters. The pooled mean differences were estimated for continuous parameters. The pooled odds-ratio was estimated for fever. The level of significance was set at 0.05.

RESULTS

Eighteen studies (comprising 2459 patients) out of 26151 screened studies were included in this meta-analysis. The results showed that the level of leukocyte, neutrophil, aspartate transaminase (AST), ferritin, and fibrinogen were significantly higher in sCOVID-19 patients than in non-severe ones. Significant lower levels of lymphocyte, platelet, and hemoglobin were also found in sCOVID-19 patients than non-severe patients. Fever was nearly associated with two times increased odds of sCOVID-19 (P=0.051).

CONCLUSION

Lymphopenia, thrombocytopenia, hypohemoglobinemia, hyperferritinemia, high levels of AST, and fever are common features of both sCOVID-19 and HLH. However, the leukocytosis, neutrophilia, and hyperfibrinogenemia found in sCOVID-19 are in contrast with HScore. Conclusively, HScore parameters could be risk factors for sCOVID-19. However, some parameters' roles are contradictory, suggesting the need for further investigation and a new way of HScore interpretation in sCOVID-19 patients.A preprint of this study was published at https://www.researchsquare.com/article/rs-54490/v2.

Longitudinal monitoring of laboratory markers characterizes hospitalized and ambulatory COVID-19 patients

Early detection of severe forms of COVID-19 is absolutely essential for timely triage of patients. We longitudinally followed-up two well-characterized patient groups, hospitalized moderate to severe (n = 26), and ambulatory mild COVID-19 patients (n = 16) at home quarantine. Human D-dimer, C-reactive protein (CRP), ferritin, cardiac troponin I, interleukin-6 (IL-6) levels were measured on day 1, day 7, day 14 and day 28. All hospitalized patients were SARS-CoV-2 positive on admission, while all ambulatory patients were SARS-CoV-2 positive at recruitment. Hospitalized patients had higher D-dimer, CRP and ferritin, cardiac troponin I and IL-6 levels than ambulatory patients (p < 0.001, p < 0.001, p = 0.016, p = 0.035, p = 0.002 respectively). Hospitalized patients experienced significant decreases in CRP, ferritin and IL-6 levels from admission to recovery (p < 0.001, p = 0.025, and p = 0.001 respectively). Cardiac troponin I levels were high during the acute phase in both hospitalized and ambulatory patients, indicating a potential myocardial injury. In summary, D-dimer, CRP, ferritin, cardiac troponin I, IL-6 are predictive laboratory markers and can largely determine the clinical course of COVID-19, in particular the prognosis of critically ill COVID-19 patients.

Systemic and organ-specific immune-related manifestations of COVID-19

Immune-related manifestations are increasingly recognized conditions in patients with COVID-19, with around 3,000 cases reported worldwide comprising more than 70 different systemic and organ-specific disorders. Although the inflammation caused by SARS-CoV-2 infection is predominantly centred on the respiratory system, some patients can develop an abnormal inflammatory reaction involving extrapulmonary tissues. The signs and symptoms associated with this excessive immune response are very diverse and can resemble some autoimmune or inflammatory diseases, with the clinical phenotype that is seemingly influenced by epidemiological factors such as age, sex or ethnicity. The severity of the manifestations is also very varied, ranging from benign and self-limiting features to life-threatening systemic syndromes. Little is known about the pathogenesis of these manifestations, and some tend to emerge within the first 2 weeks of SARS-CoV-2 infection, whereas others tend to appear in a late post-infectious stage or even in asymptomatic patients. As the body of evidence comprises predominantly case series and uncontrolled studies, diagnostic and therapeutic decision-making is unsurprisingly often based on the scarcely reported experience and expert opinion. Additional studies are required to learn about the mechanisms involved in the development of these manifestations and apply that knowledge to achieve early diagnosis and the most suitable therapy.

Haemophagocytic syndrome and COVID-19

Primary and secondary haemophagocytic lymphohistiocytosis (HLH) are hyperferritinaemic hyperinflammatory syndromes with a common terminal pathway triggered by different etiopathogenetic factors. HLH is characterised by a decreased capacity of interferon gamma production with an activated NK phenotype profile similar to other hyperinflammatory syndromes. Viruses are closely linked to the development of HLH as infectious triggers, and the break of tolerance to self-antigens is considered a critical mechanism involved in the development of immune-mediated conditions triggered by viral infections. Emerging studies in patients with COVID-19 are suggesting a key role of monocytes/macrophages in the pathogenesis of this viral infection, and there is a significant overlap between several features reported in severe COVID-19 and the features included in the HLH-2004 diagnostic criteria. Therefore, SARS-Cov-2, as other respiratory viruses, may also be considered a potential etiological trigger of HLH. The frequency of HLH in adult patients with severe COVID-19 is lower than 5%, although this figure could be underestimated considering that most reported cases lacked information about some specific criteria (mainly the histopathological criteria and the measurement of NK cell function and sCD25 levels). Because HLH is a multi-organ syndrome, the diagnostic approach in a patient with severe COVID-19 in whom HLH is suspected must be carried out in a syndromic and holistic way, and not in the light of isolated clinical or laboratory features. In COVID-19 patients presenting with persistent high fever, progressive pancytopenia, and hepatosplenic involvement, together with the characteristic triad of laboratory abnormalities (hyperferritinaemia, hypertriglyceridaemia, and hypofibrinogenaemia), the suspicion of HLH is high, and the diagnostic workup must be completed with specific immunological and histopathological studies.

COVID-19-associated coagulopathy and disseminated intravascular coagulation

The pathology of coronavirus disease 2019 (COVID-19) is exacerbated by the progression of thrombosis, and disseminated intravascular coagulation (DIC), and cytokine storms. The most frequently reported coagulation/fibrinolytic abnormality in COVID-19 is the increase in d-dimer, and its relationship with prognosis has been discussed. However, limits exist to the utility of evaluation by d-dimer alone. In addition, since the coagulation/fibrinolytic condition sometimes fluctuates within a short period of time, regular examinations in recognition of the significance of the examination are desirable. The pathophysiology of disseminated intravascular coagulation (DIC) associated with COVID-19 is very different from that of septic DIC, and both thrombotic and hemorrhagic pathologies should be noted. COVID-19 thrombosis includes macro- and microthrombosis, with diagnosis of the latter depending on markers of coagulation and fibrinolysis. Treatment of COVID-19 is classified into antiviral treatment, cytokine storm treatment, and thrombosis treatment. Rather than providing uniform treatment, the treatment method most suitable for the severity and stage should be selected. Combination therapy with heparin and nafamostat is expected to develop in the future. Fibrinolytic therapy and adsorption therapy require further study