Sex Differences in Clinical Presentation and Outcomes among Patients with Complement-Gene-Variant-Mediated Thrombotic Microangiopathy

Thrombotic Microangiopathy After Hematopoietic Stem Cell and Solid Organ Transplantation: A Review for Intensive Care Physicians

Intensive care physicians may assume the primary care of patients with transplant-associated thrombotic microangiopathy (TA-TMA), an uncommon but potentially critical complication of hematopoietic stem cell transplants (HSCTs) and solid organ transplants. TA-TMA can have a dramatic presentation with multiple organ dysfunction syndrome (MODS) associated with high morbidity and mortality. The typical presenting clinical features are hemolytic anemia, thrombocytopenia, refractory hypertension, proteinuria and worsening renal failure. Intestinal involvement, with abdominal pain, nausea and vomiting, gastrointestinal bleeding, and ascites are also common. Cardiopulmonary involvement may develop from various causes including pulmonary arteriolar hypertension, pleural and pericardial effusions, and diffuse alveolar hemorrhage. Due to other often concurrent complications after HSCT, early diagnosis and effective management of TA-TMA may be challenging. Close collaboration between ICU and transplant physicians, along with other relevant specialists, is needed to best manage these patients. There are currently no approved therapies for the treatment of TA-TMA. Plasma exchange and rituximab are not recommended unless circulating factor H (CFH) antibodies or thrombotic thrombocytopenic purpura (TTP; ADAMTS activity < 10%) are diagnosed or highly suspected. The role of the complement pathway activation in the pathophysiology of TA-TMA has led to the successful use of targeted complement inhibitors, such as eculizumab. However, the relatively larger studies using eculizumab have been mostly conducted in the pediatric population with limited data on the adult population. This review is focused on the role of intensive care physicians to emphasize the clinical approach to patients with suspected TA-TMA and to discuss diagnosis and treatment strategies.

Pregnancy in Complement-Mediated Thrombotic Microangiopathy: Maternal and Neonatal Outcomes

Rationale & Objective

Pregnancy, delivery, and neonatal outcomes in women with complement-mediated thrombotic microangiopathy (cTMA) have not been well described. A better understanding of these outcomes is necessary to provide women with competent pregnancy counseling.

Study Design

Cohort study.

Setting and Participants

Women with a history of cTMA and pregnancies enrolled into the Vienna thrombotic microangiopathy cohort.

Exposure

New onset or relapses of cTMA.

Outcomes

Pregnancy, delivery, and neonatal outcomes of pregnancies in women (a) before cTMA manifestation, (b) complicated by pregnancy-associated cTMA (P-cTMA), and (c) after first manifestation of cTMA or P-cTMA.

Analytical Approach

Mixed models were used to adjust the comparison of pregnancy, delivery, and neonatal outcomes between conditions (before, with, and after cTMA) for repeated pregnancies using the mother's ID as random factor. In addition, the fixed factors, mother's age and neonate's sex, were used for adjustment. For (sex-adjusted and age-adjusted) centile outcomes, only the mother's age was used. Adjusted odds ratios were derived from a generalized linear mixed model with live birth as the outcome. Least squares means and pairwise differences between them were derived from the linear mixed models for the remaining outcomes.

Results

28 women reported 74 pregnancies. Despite higher rates of fetal loss before the diagnosis of P-cTMA and preterm births with P-cTMA, most of the women were able to conceive successfully. Neonatal development in all 3 conditions of pregnancies was excellent. Pregnancy and neonatal outcomes were better in women with a pregnancy after the diagnosis of cTMA.

Limitations

Although our data set comprises a considerable number of 74 pregnancies, the effective sample size is lower because only 28 mothers with multiple pregnancies were observed. The statistical power for detecting clinically relevant effects was probably low. A recall bias for miscarriages cannot be ruled out.

Conclusions

Prepregnancy counseling of women with a history of cTMA can be supportive of their desire to become pregnant.

Clinical Characteristics of Posner-Schlossman Syndrome Patients in China

Background

To explore the clinical characteristics of Posner-Schlossman syndrome (PSS) patients in China, especially the risk factors associated with the dynamic changes of corneal endothelial cell (CEC) density and retinal nerve fiber layer (RNFL) thickness during the course of the disease.

Methods

In this retrospective cohort study, patients consequently suffering from PSS were recruited. Patients data including gender, age of onset, frequency of attack, and disease duration. We performed detailed ophthalmology examinations including intraocular pressure (IOP), best-corrected visual acuity (BCVA), slit-lamp examination, optical coherence tomography (OCT), assessing RNFL thickness, and determined CEC density in the outpatient department. The unaffected eyes served as control.

Results

We recruited 121 patients (eyes, n = 125), including 69 (57.0%) males and 52 (43.0%) females with Posner-Schlossman syndrome. The age of first-onset was 33.81 ± 13.63 years old. The majority of these patients were aged 20-50 years (80.2%). The peak IOP was 47.67 ± 13.31 mmHg in the affected eyes. The frequency of PSS attack was 2.7 ± 3.7 times per year. The disease duration was 9.5 ± 10.4 years. Among all patients, there were 27 (22.31%) patients with a history of digestive disorders, 25 (20.66%) patients with a history of allergies, and 24 (19.83%) patients with a history of infectious disease. In the affected eyes, CEC density (2532.94 ± 490.83/mm² vs. 2777.13 ± 356.87/mm², p < 0.001), the RNFL thickness of four quadrants (superior 105.46 ± 29.86 μm vs. 121.33 ± 17.30 μm, p < 0.001; temporal 74.58 ± 22.21 μm vs. 81.94 ± 18.20 μm, p = 0.009; inferior 110.50 ± 33.42 μm vs. 128.29 ± 14.39 μm, p < 0.001; nasal 54.85 ± 14.48 μm vs. 63.49 ± 15.40 μm, p < 0.001) and central papillary (87.11 ± 21.18 μm vs. 99.18 ± 7.97 μm, p < 0.001) were significantly reduced compared to the fellow eyes. The disease duration and recurrent frequency were significantly associated with CEC density (p < 0.001 and p = 0.029) and the disease duration was significantly associated with RNFL thickness (p = 0.002).

Conclusions

In this study, CEC loss and RNFL thinning were present in the affected eyes. Our results indicated that disease duration and recurrent frequency played an important role in the progression of PSS.

Eculizumab use in a tertiary care nephrology center: data from the Vienna TMA cohort

Background

Practice patterns of eculizumab use are not well described. We examined indications for, and outcomes of, eculizumab therapy in a tertiary care nephrology center.

Methods

We used the “Vienna TMA cohort” and the hospital pharmacy database at the Medical University of Vienna to identify patients that received eculizumab treatment between 2012 and 2019. We describe clinical characteristics, details of eculizumab use, and outcomes of patients with complement gene-variant mediated TMA (cTMA), secondary TMA (sTMA) and C3 glomerulopathy (C3G).

Results

As of December 2019, 23 patients received complement blockade at the Division of Nephrology and Dialysis: 15 patients were diagnosed with cTMA, 6 patients with sTMA and 2 patients with C3G. Causes of sTMA were bone marrow transplantation (n = 2), malignant hypertension, malignant tumor, systemic lupus erythematosus, antiphospholipid syndrome and lung transplantation (each n = 1). Across all indications, patients had a median age of 31 and were predominantly female (78%) and the median duration of treatment was 227 days. Hematological recovery was seen in most patients, while renal response was best in patients with cTMA. Adverse events were recorded in 26%.

Conclusions

In summary, eculizumab is the treatment of choice for cTMA patients that do not respond to plasma therapy. In patients with sTMA and C3G, the response rates to therapy are much lower and therefore, the decision to start therapy needs to be considered carefully.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s40620-021-00981-8.

CFH I62V as a Putative Genetic Marker for Posner-Schlossman Syndrome

Objective: Posner-Schlossman syndrome (PSS), also known as glaucomatocyclitic crisis, is an ocular condition characterized by recurrent attacks of anterior uveitis and raised intraocular pressure. Previous studies by our team and others have identified the genetic association of complement pathway genes with uveitis and glaucoma. This study aimed to investigate the complement genes in PSS patients with the view of elucidating the genetic background of the disease.

Methods: A total of 331 subjects (56 PSS patients and 275 controls) were recruited for this study. We selected 27 variants in six complement pathway genes (SERPING1, C2, CFB, CFH, C3, and C5) and detected them using TaqMan single nucleotide polymorphism (SNP) Genotyping Assays. Univariate SNP association analysis, haplotype-based association analysis, gene-gene interaction analysis among complement genes, and genotype-phenotype correlation analysis were performed.

Results: Among the 27 variants of six complement pathway genes, the functional variant I62V (rs800292) at the CFH gene was found to be significantly associated with PSS; there was a significant increase in the frequency of A allele and AA homozygosity in PSS patients than in controls (P = 1.79 × 10⁻⁴; odds ratio (OR) 2.18, 95% CI: 1.44–3.29; P = 4.65 × 10⁻⁴; OR 3.66, 95% CI: 1.70–7.85, respectively). The additive effect of CFH-rs800292 and SERPING1-rs3824988 was identified with an OR of 12.50 (95% CI: 2.16–72.28). Genotype-phenotype analysis indicated that the rs800292 AA genotype was associated with a higher intraocular pressure and higher frequency of recurrence. Unlike a high proportion of human leukocyte antigen (HLA)-B27 positivity in anterior uveitis, only 3 in 56 (5.36%) PSS patients were HLA-B27 positive. In addition, one haplotype block (GC) in the SERPING1 gene showed a nominal association with PSS with an increased risk of 2.04 (P = 0.01; 95% CI: 1.18–3.53), but the P-value could not withstand the Bonferroni correction (P_corr > 0.05).

Conclusion: This study revealed a genetic association of a CFH variant with PSS as well as its clinical parameters, implying that the alternative complement pathway might play an important role in the pathogenesis of PSS. Further studies to enrich the understanding of the genetic background of PSS and the role of the complement system in ocular inflammation are warranted.