Diffuse Alveolar Hemorrhage in Primary Versus Secondary Antiphospholipid Syndrome

MEK1/2- and ERK1/2-Mediated Lung Endothelial Injury and Altered Hemostasis Promote Diffuse Alveolar Hemorrhage in Murine Lupus

OBJECTIVE

About 3% of patients with lupus develop severe diffuse alveolar hemorrhage (DAH) with pulmonary vasculitis. C57BL/6 (B6) mice with pristane-induced lupus also develop DAH, but BALB/c mice are resistant. DAH is independent of Toll-like receptor signaling and other inflammatory pathways. This study examined the role of the MEK1/2 pathway (MEK1/2-ERK1/2, JNK, p38).

METHODS

B6 and BALB/c mice were treated with pristane with or without inhibitors of MEK1/2 (trametinib/GSK1120212 [GSK]), ERK1/2 (SCH772984 [SCH]), JNK, or p38. Effects on lung hemorrhage and hemostasis were determined.

RESULTS

GSK and SCH abolished DAH, whereas JNK and p38 inhibitors were ineffective. Apoptotic cells were present in lung samples from pristane-treated mice but not in mice receiving pristane and GSK, and endothelial dysfunction was normalized. Expression of the ERK1/2-regulated transcription factor early growth response 1 increased in pristane-treated B6, but not BALB/c, mice and was normalized by GSK. Pristane also increased expression of the anticoagulant genes Tfpi and Thbd in B6 mice. The ratio of Tfpi to tissue factor (F3) to Tfpi increased in B6 (but not BALB/c) mice and was normalized by GSK. Circulating thrombomodulin protein levels increased in B6 mice and returned to normal after GSK treatment. Consistent with augmented endothelial anticoagulant activity, pristane treatment increased tail bleeding in B6 mice.

CONCLUSION

Pristane treatment promotes lung endothelial injury and DAH in B6 mice by activating the MEK1/2-ERK1/2 pathway and impairing hemostasis. The hereditary factors determining susceptibility to lung injury and bleeding in pristane-induced lupus are relevant to the pathophysiology of life-threatening DAH in systemic lupus erythematosus and may help to optimize therapy.

Assessment of the 2023 ACR/EULAR antiphospholipid syndrome classification criteria in a Chinese cohort: Impact on clinical practice

OBJECTIVES

To evaluate the effectiveness of the 2023 ACR/EULAR criteria for antiphospholipid syndrome (APS) in a Chinese cohort, and compare them with the Sapporo and revised Sapporo criteria.

METHODS

A cohort comprising 436 patients diagnosed with APS and 514 control subjects was enrolled, including 83 with seronegative APS and 86 classified as antiphospholipid antibody (aPL) carriers. We assessed IgG and IgM anticardiolipin antibodies (aCL) and anti-β2-glycoprotein I (aβ2GPI) antibodies using ELISA, along with a systematic collection of lupus anticoagulant data. Subsequently, we compared the sensitivity and specificity across the three classification criteria.

RESULTS

The 2023 ACR/EULAR criteria exhibited improved specificity at 98 %, surpassing the revised Sapporo (90 %) and original Sapporo (91 %) criteria. However, this came with decreased sensitivity at 82 %, in contrast to higher sensitivities in the revised Sapporo (98 %) and Sapporo (91 %) criteria. Examining individual components sheds light on the scoring system's rationale within the new criteria. The inclusion of microvascular thrombosis, cardiac valve disease, and thrombocytopenia improved the identification of nine patients previously classified as "probable APS". Insufficient scoring in 78 previously diagnosed APS individuals was linked to traditional risk factor evaluations for thrombotic events, the emphasis on determining whether obstetric events are linked to severe preeclampsia (PEC) or placental insufficiency (PI), and the lower scores assigned to IgM aCL and/or aβ2GPI antibody. Seronegative APS remained a challenge, as non-criteria aPL and other methods were not included.

CONCLUSIONS

The new criteria presented notable advancements in specificity. This study provides detailed insights into the strengths and possible challenges of the 2023 ACR/EULAR criteria, enhancing our understanding of their impact on clinical practice.

Antiphospholipid antibody-related hepatic vasculitis in a juvenile after non-severe COVID-19: a case report and literature review

Antiphospholipid antibodies (aPL) are both laboratory evidence and causative factors for a broad spectrum of clinical manifestations of antiphospholipid syndrome (APS), with thrombotic and obstetric events being the most prevalent. Despite the aPL-triggered vasculopathy nature of APS, vasculitic-like manifestations rarely exist in APS and mainly appear associated with other concurrent connective tissue diseases like systemic lupus erythematous. Several studies have characterized pulmonary capillaritis related to pathogenic aPL, suggesting vasculitis as a potential associated non-thrombotic manifestation. Here, we describe a 15-year-old girl who develops hepatic infarction in the presence of highly positive aPL, temporally related to prior non-severe COVID-19 infection. aPL-related hepatic vasculitis, which has not been reported before, contributes to liver ischemic necrosis. Immunosuppression therapy brings about favorable outcomes. Our case together with retrieved literature provides supportive evidence for aPL-related vasculitis, extending the spectrum of vascular changes raised by pathogenic aPL. Differentiation between thrombotic and vasculitic forms of vascular lesions is essential for appropriate therapeutic decision to include additional immunosuppression therapy. We also perform a systematic review to characterize the prevalence and clinical features of new-onset APS and APS relapses after COVID-19 for the first time, indicating the pathogenicity of aPL in a subset of COVID-19 patients.

Clinical features, risk factors, and outcomes of diffuse alveolar hemorrhage in antiphospholipid syndrome: A mixed-method approach combining a multicenter cohort with a systematic literature review

BACKGROUND

Antiphospholipid syndrome (APS) is a systemic autoimmune disease clinically associated with thrombotic and obstetric events. Additional manifestations have been associated with APS, like diffuse alveolar hemorrhage (DAH). We aimed to summarize all the evidence available to describe the presenting clinical features, their prognostic factors, and short- and long-term outcomes.

METHODS

We performed a mixed-method approach combining a multicenter cohort with a systematic literature review (SLR) of patients with incident APS-associated DAH. We described their clinical features, treatments, prognostic factors, and outcomes (relapse, mortality, and requirement of mechanical ventilation [MV]). Kaplan-Meier methods were used to estimate relapse and mortality rates, and Cox and logistic regression models were used to assess the factors associated as appropriate.

RESULTS

We included 219 patients with incident APS-associated DAH (61 from Mayo Clinic and 158 from SLR). The median age was 39.5 years, 51% were female, 29% had systemic lupus erythematosus, and 34% presented with catastrophic APS (CAPS). 74% of patients had a history of thrombotic events, and 26% of women had a history of pregnancy morbidity; half of the patients had a history of thrombocytopenia, and a third had valvulopathy. Before DAH, 55% of the patients were anticoagulated. At DAH onset, 65% of patients presented hemoptysis. The relapse rate was 47% at six months and 52% at one year. Triple positivity (HR 4.22, 95% CI 1.14-15.59) was associated with relapse at six months. The estimated mortality at one and five years was 30.3% and 45.8%. Factors associated with mortality were severe thrombocytopenia (< 50 K/μL) (HR 3.10, 95% CI 1.39-6.92), valve vegetations (HR 3.22, 95% CI 1.14-9.07), CAPS (HR 3.80, 95% CI 1.84-7.87), and requirement of MV (HR 2.22, 95% CI 1.03-4.80). Forty-two percent of patients required MV on the incident DAH episode. Patients presenting with severe thrombocytopenia (OR 6.42, 95% CI 1.77-23.30) or CAPS (OR 4.30, 95% CI 1.65-11.16) were more likely to require MV.

CONCLUSION

APS-associated DAH is associated with high morbidity and mortality, particularly when presenting with triple positivity, thrombocytopenia, valvular involvement, and CAPS.

High-throughput sequencing technology facilitates the discovery of novel biomarkers for antiphospholipid syndrome

Antiphospholipid syndrome (APS) is characterized by arterial and venous thrombosis and/or morbid pregnancy, accompanied by persistent antiphospholipid antibody (aPL) positivity. However, due to the complex pathogenesis of APS and the large individual differences in the expression of aPL profiles of patients, the problem of APS diagnosis, prognosis judgment, and risk assessment may not be solved only from the antibody level. It is necessary to use new technologies and multiple dimensions to explore novel APS biomarkers. The application of next-generation sequencing (NGS) technology in diseases with a high incidence of somatic mutations, such as genetic diseases and tumors, has been very mature. Thus, we try to know the research and application progress of APS by NGS technology from genome, transcriptome, epigenome and other aspects. This review will describe the related research of NGS technology in APS and provide more reference for the deep understanding of APS-related screening markers and disease pathogenesis.

Diffuse alveolar hemorrhage secondary to sarcoidosis

Diffuse alveolar hemorrhage (DAH) is a pulmonary condition that can be caused by autoimmune disorders such as lupus, small vessel vasculitis, and antiphospholipid syndrome. Sarcoidosis as a cause of DAH has been reported; however, the literature remains limited. We performed a chart review for patients with a diagnosis of both sarcoidosis and DAH. Seven patients met inclusion criteria. Mean (range) patient age was 54 years (39-72), and 3 patients had a history of tobacco use. Diagnosis of DAH and sarcoidosis were concurrent for 3 patients. Corticosteroids were used for treatment of DAH in all patients; 2 (including 1 with refractory DAH) were successfully treated with rituximab. We believe sarcoidosis-associated DAH is more common than previously reported. It is essential to consider sarcoidosis in the differential diagnosis of immune-mediated DAH. Key Points • Sarcoidosis can cause diffuse alveolar hemorrhage (DAH); more extensive studies are needed to estimate this condition's prevalence. • BMI of 25 or higher appears to be a risk factor for the development of sarcoidosis-associated DAH.

Preliminary Study on the Imbalance Between Th17 and Regulatory T Cells in Antiphospholipid Syndrome

Objective

Patients with antiphospholipid syndrome (APS) have immune cell abnormalities that remain poorly understood. This study compared primary APS (PAPS) and secondary APS (SAPS) patients with healthy controls with respect to peripheral blood lymphocytes, CD4+T cell subsets, and cytokine levels. The correlation between antiphospholipid antibody titres and T helper 17 (Th17) and T regulatory (Treg) cell subsets was also analyzed, together with the correlations between cytokine profiles and the clinical characteristics of APS patients.

Methods

The retrospective study population consisted of 67 APS patients (12 with PAPS, 55 with SAPS) and 40 healthy controls. Absolute numbers of peripheral blood lymphocyte subsets and CD4+ T cell subsets were detected by flow cytometry, and serum cytokine levels by flow cytometry bead array.

Results

Patients with SAPS had lower absolute values of T, B and CD4+T cells than the healthy control group, while only natural killer (NK) cell levels were decreased in patients with PAPS. Absolute numbers of T, B, NK, and CD4+T cells were significantly higher in the PAPS than SAPS group. The trends in CD4+T cell subsets were the same in PAPS and SAPS patients as in healthy controls, with increased Th1, decreased Th2, and decreased Treg levels, and thus an increased Th17/Treg ratio. Th2, Th17, and Treg cell counts were higher in the PAPS than SAPS group. Cytokine analysis showed that only IL-10 levels differed between the two APS groups. However, the levels of all of the studied cytokines were higher in APS patients than healthy controls, and correlated with the clinical characteristics of the patients. In the PAPS group, the titres of two autoantibodies correlated positively with the Th17/Treg ratio and negatively with the levels of D-dimer and Treg subsets.

Conclusions

Our study clearly showed that APS patients have immune disturbances, the most prominent of which is an increase in the Th17/Treg ratio, due to a decrease in the number of Treg cells. These abnormalities may be involved in the occurrence and progression of APS. An additional finding was a higher level of peripheral blood lymphocytes in PAPS than SAPS patients, which may be related to the immunosuppressive treatment of SAPS patients.