Preexisting autoantibodies as predictor of immune related adverse events (irAEs) for advanced solid tumors treated with immune checkpoint inhibitors (ICIs).

INTRODUCTION: Immune checkpoint inhibitors (ICIs) are now standard of care in many cancers. They can generate immune-related adverse events (irAEs), but no biomarkers are available to identify patients who are more likely to develop irAEs. We assess the association between pre-existing autoantibodies and occurrence of irAEs. PATIENTS AND METHODS: We prospectively collected data from consecutive patients receiving ICIs for advanced cancers, in a single center between May 2015 and July 2021. Autoantibodies testing was performed before ICIs initiation including AntiNeutrophil Cytoplasmic Antibodies, Antinuclear Antibodies, Rheumatoid Factor anti-Thyroid Peroxidase and anti-Thyroglobulin. We analyzed the associations of pre-existing autoantibodies with onset, severity, time to irAEs and with survival outcomes. RESULTS: Of the 221 patients included, most had renal cell carcinoma (n = 99; 45%) or lung carcinoma (n = 90; 41%). Grade ≥2 irAEs were more frequent among patients with pre-existing autoantibodies: 64 (50%) vs. 20 (22%) patients (Odds-Ratio= 3.5 [95% CI=1.8-6.8]; p < 0.001) in the positive vs negative group, respectively. irAEs occurred earlier in the positive group with a median time interval between ICI initiation and irAE of 13 weeks (IQR = 8.8-21.6) vs. 28.5 weeks (IQR=10.6-55.1) in the negative group (p = 0.01). Twelve patients (9.4%) experienced multiple (≥2) irAEs in the positive group vs. 2 (2%) in the negative group (OR = 4.5 [95% CI: 0.98-36], p = 0.04). After a median follow-up of 25 months, median PFS and OS were significantly longer among patients experiencing irAE (p = 0.00034 and p = 0.016, respectively). CONCLUSION: The presence of pre-existing autoantibodies is significantly associated with the occurrence of grade ≥2 irAEs, with earlier and multiple irAEs in patients treated with ICIs.

[Contribution of antiphosphatidylserine/prothrombin (anti-PS/PT) antibody detection in the diagnosis and management of antiphospholipid syndrome (APS)]. / Apport de la détection des anticorps antiphosphatidylsérine/prothrombine (aPS/PT) dans le diagnostic et la prise en charge du syndrome des antiphospholipides (SAPL).

Antiphospholipid syndrome (APS) is an autoimmune disease and one of the most common causes of acquired thrombophilia. It is characterised by the occurrence of thrombotic or obstetric events associated with the presence of persistent antiphospholipid antibodies. The diagnosis can be challenging, particularly because some biological tests can be disturbed by anticoagulant treatment or inflammation. In the recent years, new antiphospholipid antibodies, including anti-phosphatidylserine/prothrombin antibodies (anti-PS/PT), have emerged but their clinical significance and causality remain uncertain. Biologically, several studies have found a strong correlation between the presence of lupus anticoagulant (LA) and anti-PS/PT antibodies. Clinically, the presence of anti-PS/PT antibodies is associated with an increased risk of thrombosis and obstetric complications. There is also an association with thrombocytopenia, suggesting that the presence of anti-PS/PT antibodies may be associated with more severe clinical APS. Among seronegative APS patients, 6-17% of patients are positive for anti-PS/PT antibodies. This might influence the therapeutic management of patients. This article aims to provide an update on contribution of anti-PS/PT antibodies detection for the diagnosis and management of APS.

[Laboratory diagnosis of antiphospholipid syndrome: From criteria to practice]. / Diagnostic biologique du syndrome des antiphospholipides : des critères à la pratique.

The antiphospholipid syndrome is a bioclinical entity defined by thrombosis and/or obstetrical complications in the presence, at least 12 weeks apart, of antiphospholipid antibodies detected by coagulation test (lupus anticoagulant) or immunological assays (anticardiolipin, anti-ß2-glycoprotein I antibodies). Biological markers' improvement such as anti-phosphatidylserine/prothrombin and biological score should allow better patients' management and preventive therapeutic for thrombosis and obstetrical complications. This review describes different types of antibodies, link between biological profile and risk level of thrombosis events/obstetrical complications and gives practical advice to interpret biological results.

Targeting renin-angiotensin system in malignant hypertension in atypical hemolytic uremic syndrome.

Hypertension is common in hemolytic uremic syndrome (HUS) and often difficult to control. Local renin-angiotensin activation is believed to be an important part of thrombotic microangiopathy, leading to a vicious cycle of progressive renal injury and intractable hypertension. This has been demonstrated in vitro via enhanced tissue factor expression on glomerular endothelial cells which is enhanced by angiotensin II. We report two pediatric cases of atypical HUS with severe refractory malignant hypertension, in which we targeted the renin-angiotensin system by using intravenous (IV) enalaprilat, oral aliskiren, and oral enalapril with quick and dramatic response of blood pressure. Both drugs, aliskiren and IV enalaprilat, were effective in controlling hypertension refractory to multiple antihypertensive medications. These appear to be promising alternatives in the treatment of severe atypical HUS-induced hypertension and hypertensive emergency.

Eculizumab for atypical hemolytic-uremic syndrome in India: First report from India and the challenges faced.

Much progress has been made in understanding the pathophysiology and treatment of atypical hemolytic uremic syndrome (aHUS). Plasma therapy is the mainstay of treatment for aHUS. The availability of the first effective anti-complement therapeutic agent, eculizumab, has dramatically changed the outlook of this disease. However, its use in clinical practice raises important questions, such as who should receive the drug, when to start such therapy, and is it safe to stop treatment once the disease is controlled. We describe here for the 1st time in India, use of eculizumab in a 12-year-old boy with aHUS. We also describe in this report challenges faced in procuring the drug, and an ideal, evidence-based method of treating aHUS in children.

Increased Performances of the Biological Diagnosis of the Antiphospholipid Syndrome by the Use of a Multiplex Assay.

Antiphospholipid syndrome (APS) is characterized by development of venous and/or arterial thrombosis and pregnancy morbidity. Biological criteria are the persistent presence of lupus anticoagulant (LA) and/or anti-cardiolipin (aCL) and/or anti-B2GP1 autoantibodies' positivity. The assays' performances are of crucial importance. We evaluated a multiplex assay allowing simultaneous detection of IgG anti-cardiolipin, anti-B2GP1, and anti-factor II. 300 samples were tested. Patients were categorized according to clinical scores of APS from 0 to 3 based on presence or not of arterial or venous thrombosis, fetal loss, and autoimmunity. We used a multiplex assay for APS for simultaneous detection of aCL, anti-B2GP1, and factor II and compared its performances to ELISA assays. Presence of LA was also assessed. We performed a correlation study of the tested assays and compared their clinical efficacy by ROC curve analysis. We obtained significantly higher performances with the multiplex assay than ELISA with higher area under the curve (AUC). The disease rate increased with the number of positive markers from 9% for 1 marker to 100% for 4 markers positive for patients with high risk scores. The multiplex APS assay exhibited higher performances particularly in case of primary APS and is useful for rapid diagnosis of APS.

[Atypical hemolytic-uremic syndrome related to abnormalities within the complement system]. / Syndrome hémolytique et urémique lié à des anomalies du complément.

Hemolytic uremic syndrome (HUS) is a thrombotic microangiopathy (TMA) disorder characterised by the association of haemolytic anaemia, thrombocytopenia and acute renal failure. Atypical forms (non-shigatoxin related forms) may be familial or sporadic, frequently with relapses and most of them lead to end stage renal failure. During the last years, different groups have demonstrated genetic predisposition to atypical HUS (aHUS) involving five genes encoding for complement components which play a role in the activation or control of the alternative pathway: encoding factor H (CFH), accounting for 30% of aHUS; CD46 (encoding membrane cofactor protein [MCP]) accounting for approximately 10% of aHUS; CFI (encoding factor I) accounting for an estimated 5-15% of patients; C3 (encoding C3) accounting for approximately 10% of aHUS; and rarely CFB (encoding factor B). Predisposition to aHUS is inherited with incomplete penetrance. It is admitted that mutations confer a predisposition to develop aHUS rather than directly causing the disease and that a second event (genetic or environmental) is required for disease manifestation. HUS onset follows a triggering event in most cases (frequently banal seasonal infection and pregnancy). Uncontrolled C3 convertase leads to increased deposition of C3b on vascular endothelium and participates to the prothrombotic state. The phenotype of aHUS is variable ranging from mild forms, with complete recovery of renal function to severe forms with end stage renal disease within the first year after the onset. Overall, the outcome is severe with a mortality rate of 10% and with more than 60% of patients on dialysis. The most severe prognosis was in the CFH mutation group. There is a high risk of recurrence of the disease after renal transplantation in patients with mutations in CFH, CFI, CFB and C3. Plasma therapy may allow complete haematological remission but frequently with persistent renal damage. Some patients are plasma resistant and some are plasma dependent. The recent progress in the determination of the susceptibility factors for aHUS, have allowed to propose new diagnostic tests including a molecular genetic testing and may permit to consider some new specific treatments in this disease (human plasma-derived CFH or complement inhibitors).

Clinical significance of anti-Ro52 (TRIM21) antibodies non-associated with anti-SSA 60kDa antibodies: results of a multicentric study.

Ro52 antigen has recently been identified as TRIM21 protein, but the clinical significance of anti-Ro52/TRIM21 antibodies remains controversial. The aim of this multicentric study was to investigate the significance of anti-Ro52 antibodies without anti-SSA/Ro60 antibodies in various connective diseases. Sera were selected by each laboratory using its own method (ELISA, immunodot or Luminex technology), and then performed with ANA Screen BioPlex™ reagent (BIO-RAD). Among the 247 screened sera, 155/247 (63%) were confirmed as anti-Ro52 positive and anti-SSA/Ro60 negative. These sera were analyzed for the detection of other antibodies in relation with clinical settings. Isolated anti-Ro52 antibodies were detected in 89/155 (57%) sera. For the remaining sera (66/155), the main antibodies associations were Sm/SmRNP or Chromatin (n=38; 57%), Jo1 (n=17; 26%) and CenpB (n=9; 14%). Clinical data from the 155 patients showed high prevalence in autoimmune diseases (73%) including myositis or dermatomyositis (n=30), lupus (n=23); Sjögren and/or sicca syndrome (n=27); CREST or Systemic sclerosis (n=11) and autoimmune hepatitis (n=11). We found that pulmonary manifestations were often associated with the presence of anti-Ro52 antibodies (n=34, 22%), in addition with anti-tRNA synthetases, anti-SRP or anti-Ku antibodies (18/34) or isolated in half of cases (16/34). Separate detection of anti-Ro52 antibodies might be useful in related antisynthetase syndrome diagnosis. The presence of anti-Ro52 antibodies should probably precede development of autoimmune disease and must induce sequential follow-up of positive patients, particularly in interstitial lung disease progression.

Anti-Factor H autoantibodies in a fifth renal transplant recipient with atypical hemolytic and uremic syndrome.

Hemolytic uremic syndrome (HUS) associated with anti-Factor H (anti-FH) autoantibodies is a recently described pathophysiological entity. Monitoring of anti-FH IgG titer may be a sensitive marker of disease activity and guide treatment to eliminate circulating anti-FH antibodies. We report here a case of atypical HUS (aHUS) in which anti-FH autoantibodies were detected during the course of a fifth kidney transplant, 30 years after the first flare of aHUS. This exceptional case suggests that early, specific management based on immunosuppressive therapy and plasma exchanges monitored by anti-FH IgG titer may result in long-term graft survival.

The high frequency of complement factor H related CFHR1 gene deletion is restricted to specific subgroups of patients with atypical haemolytic uraemic syndrome.

BACKGROUND: Deletion of the complement factor H related 1 (CFHR1) gene is a consequence of non-allelic homologous recombination and has been reported to be more frequent in atypical haemolytic uraemic syndrome (aHUS) patients than in the normal population. Therefore, it is considered a susceptibility factor for the disease. aHUS is associated with hereditary or acquired abnormalities that lead to uncontrolled alternative pathway complement activation. We tested the CFHR1 deletion for association with aHUS in a population of French aHUS cases and controls. Furthermore, we examined the effect of the deletion in the context of known aHUS risk factors. METHODS AND RESULTS: 177 aHUS patients and 70 healthy donors were studied. The number of CFHR1 alleles was quantified by multiplex ligation dependant probe amplification (MLPA). The frequency of the deleted allele was significantly higher in aHUS patients than in controls (22.7% vs 8.2%, p<0.001). The highest frequency was in the subgroup of patients exhibiting anti-factor H (FH) autoantibodies (92.9%, p<0.0001 vs controls) and in the group of patients exhibiting a factor I (CFI) gene mutation (31.8%, p<0.001 vs controls). The CFHR1 deletion was not significantly more frequent in the cohort of aHUS patients when patients with anti-FH IgG or CFI mutation were excluded. CONCLUSIONS: The high frequency of CFHR1 deletion in aHUS patients is restricted to the subgroups of patients presenting with anti-FH autoantibodies or, to a lesser degree, CFI mutation. These results suggest that the CFHR1 deletion plays a secondary role in susceptibility to aHUS.

The development of atypical haemolytic-uraemic syndrome is influenced by susceptibility factors in factor H and membrane cofactor protein: evidence from two independent cohorts.

BACKGROUND: In both familial and sporadic atypical haemolytic-uraemic syndrome (aHUS), mutations have been reported in regulators of the alternative complement pathway including factor H (CFH), membrane cofactor protein (MCP), and the serine protease factor I (IF). A characteristic feature of both MCP and CFH associated HUS is reduced penetrance and variable inheritance; one possible explanation for this is that functional changes in complement proteins act as modifiers. OBJECTIVE: To examine single nucleotide polymorphisms in both CFH and MCP genes in two large cohorts of HUS patients (Newcastle and Paris). RESULTS: In both cohorts there was an association with HUS for both CFH and MCP alleles. CFH and MCP haplotypes were also significantly different in HUS patients compared with controls. CONCLUSIONS: This study suggests that there are naturally occurring susceptibility factors in CFH and MCP for the development of atypical HUS.

Restricted genetic defects underlie human complement C6 deficiency.

Complement C6 homozygous deficiency (C6D) has been rarely observed in Caucasians but was reported at higher prevalence among African-Americans. We report on the molecular basis of C6D in seven unrelated black individuals of North or Central Africa descent who live in France. These patients have presented Neisseria meningitidis infection (four cases), focal and segmental glomerulosclerosis with hyalinosis (one case), systemic lupus erythematosus (one case) or Still's disease (one case). All patients exhibited undetectable antigenic C6 by using a sensitive ELISA assay. An additional four cases of complete C6 deficiency with no associated disease have been characterized after family studies. Exons 6, 7 and 12 have been described recently as the location of molecular defects on the C6 gene in randomly chosen black Americans. Genomic DNA from the seven patients were subjected to direct polymerase chain reaction amplification of these three exons. Nucleotide sequencing analysis of the amplified DNA fragments revealed a homozygous single-base deletion (1936delG) in exon 12 in three cases and four compound heterozygous deletions for a single base in exon 7 (1195delC) or in exon 6 (878delA) associated with the same deletion in exon 12 (1936delG). Our observations further establish the restricted pattern of genetic defects associated with homozygous C6 complement deficiency in individuals of African descent.

Molecular basis of a selective C1s deficiency associated with early onset multiple autoimmune diseases.

We have investigated the molecular basis of selective and complete C1s deficiency in 2-year-old girl with complex autoimmune diseases including lupus-like syndrome, Hashimoto's thyroiditis, and autoimmune hepatitis. This patient's complement profile was characterized by the absence of CH50 activity, C1 functional activity <10%, and undetectable levels of C1s Ag associated with normal levels of C1r and C1q Ags. Exon-specific amplification of genomic DNA by PCR followed by direct sequence analysis revealed a homozygous nonsense mutation in the C1s gene exon XII at codon 534, caused by a nucleotide substitution from C (CGA for arginine) to T (TGA for stop codon). Both parents were heterozygous for this mutation. We used the new restriction site for endonuclease Fok-1 created by the mutation to detect this mutation in the genomic DNA of seven healthy family members. Four additional heterozygotes for the mutation were identified in two generations. Our data characterize for the first time the genetic defect of a selective and complete C1s deficiency in a Caucasian patient.

Lack of evidence of a specific role for C4A gene deficiency in determining disease susceptibility among C4-deficient patients with systemic lupus erythematosus (SLE).

The aim of the present study was to investigate the prevalence of C4 and C2 deficiencies and to characterize genomic alterations in C4 genes in a large cohort of 125 unselected patients with SLE. We determined the protein concentration and functional activity of C2 and C4, as well as the C4 phenotype. C4 genotyping included Taq 1 restricted fragment lengh polymorphism (RFLP) analysis and polymerase chain reaction using sequence-specific primers (SSP-PCR). Type I C2 deficiency was diagnosed by PCR. Overall, 79.2% of the patients exhibited abnormalities of the C4 genes including deletion, non-expression, gene conversion and duplication. Among C4-deficient patients (n = 66, 52.8% prevalence), 41.0% of the patients exhibited a C4A deficiency and 59.0% a C4B deficiency. Half of the C4 deficiencies were due to a gene deletion. There was a strong association between C4A and C4B gene deletion and the presence of the DRB1*03 allele. Among the silent C4A genes, only two cases were related to a 2-bp insertion in exon 29 of the C4A gene. A gene conversion was demonstrated in eight patients (6.4%). One patient had a homozygous C4A deficiency. Three (2.4%) patients presented with a heterozygous type I C2 deficiency and none with homozygous deficiency. Our results argue against a specific role for C4A gene deficiency in determining disease susceptibility among patients with SLE that are C4-deficient.

Expression of low-affinity Fc gamma receptor by a human metastatic melanoma line.

The class IIa of low-affinity receptors for the Fc region of IgG, Fc gamma RIIa, are expressed on immune cells. The cross-linking of Fc gamma RIIa by complexed IgG triggers activation of protein tyrosine kinase and internalization of immune complexes. In this report, we demonstrate the expression of Fc gamma RIIa by a human melanoma cell line (VIO) derived from a metastasis of a patient with regressive melanoma. The analysis of Fc gamma RIIa functions was performed in VIO cells and Fc gamma RlIa- or Fc gamma RIlb-transfected human melanoma cells (A375). The Fc gamma RIIa cross-linking induced protein tyrosine phosphorylation, including Fc gamma RIIa phosphorylation, and led to its internalization in a clathrin-independent way in human melanoma cells. Moreover, we showed that a part of internalized Fc gamma RIIa migrates in late endosomes, lysosomes and class II-containing compartments. These results suggest that melanoma cells can express functional Fc gamma RII, which might play a role in tumor-host relationships.

Non-Hodgkin's lymphomas and myeloid disorders: deletions associated with t(2;5) and t(3;5) detected by FISH.

The nucleophosmin (NPM) gene is involved in two recurrent translocations in hematological malignancies: t(2;5) (p23;q35) in anaplastic large cell lymphoma (ALCL) and t(3;5)(q25.1;q34-35) in myelodysplasia and acute non-lymphocytic leukemia (ANLL). Using eight YACs encompassing the 5q34-q35 region, we could easily detect these two translocations. In both types of translocation, probable unexpected deletions were also discovered downstream of the breakpoint at 5q35.