Real-time investigation of an influenza A(H3N2) virus outbreak in a refugee community, November 2022.

OBJECTIVES: To report epidemiological and virological results of an outbreak investigation of influenza-like illness (ILI) among refugees in Northern Italy. STUDY DESIGN: Outbreak investigation of ILI cases observed among nearly 100 refugees in Northern Italy unvaccinated for influenza. METHODS: An epidemiological investigation matched with a differential diagnosis was carried out for each sample collected from ILI cases to identify 10 viral pathogens (SARS-CoV-2, influenza virus type A and B, respiratory syncytial virus, metapneumovirus, parainfluenza viruses, rhinovirus, enterovirus, parechovirus, and adenovirus) by using specific real-time PCR assays according to the Centers for Disease Control and Prevention (CDC) protocols. In cases where the influenza virus type was identified, complete hemagglutinin (HA) gene sequencing and the related phylogenetic analysis were conducted. RESULTS: The outbreak was caused by influenza A(H3N2): the attack rate was 83.3% in children aged 9-14 years, 84.6% in those aged 15-24 years, and 28.6% in adults ≥25 years. Phylogenetic analyses uncovered that A(H3N2) strains were closely related since they segregated in the same cluster, showing both a high mean nucleotide identity (100%), all belonging to the genetic sub-group 3C.2a1b.2a.2, as those mainly circulating into the general population in the same period. CONCLUSIONS: The fact that influenza outbreak strains as well as the community strains were genetically related to the seasonal vaccine strain suggests that if an influenza prevention by vaccination strategy had been implemented, a lower attack rate of A(H3N2) and ILI cases might have been achieved.

Patients' needs in proton therapy: A survey among ten European facilities.

Aims: The number of Proton Therapy (PT) facilities is still limited worldwide, and the access to treatment could be characterized by patients' logistic and economic challenges. Aim of the present survey is to assess the support provided to patients undergoing PT across Europe. Methods: Through a personnel contact, an online questionnaire (62 multiple-choice and open-ended questions) via Microsoft Forms was administered to 10 European PT centers. The questionnaire consisted of 62 questions divided into 6 sections: i) personal data; ii) general information on clinical activity; iii) fractionation, concurrent systemic treatments and technical aspects of PT facility; iv) indication to PT and reimbursement policies; v) economic and/ or logistic support to patients vi) participants agreement on statements related to the possible limitation of access to PT. A qualitative analysis was performed and reported. Results: From March to May 2022 all ten involved centers filled the survey. Nine centers treat from 100 to 500 patients per year. Paediatric patients accounted for 10-30%, 30-50% and 50-70% of the entire cohort for 7, 2 and 1 center, respectively. The most frequent tumours treated in adult population were brain tumours, sarcomas and head and neck carcinomas; in all centers, the mean duration of PT is longer than 3 weeks. In 80% of cases, the treatment reimbursement for PT is supplied by the respective country's Health National System (HNS). HNS also provides economic support to patients in 70% of centers, while logistic and meal support is provided in 20% and 40% of centers, respectively. PT facilities offer economic and/or logistic support in 90% of the cases. Logistic support for parents of pediatric patients is provided by HNS only in one-third of centers. Overall, 70% of respondents agree that geographic challenges could limit a patient's access to proton facilities and 60% believe that additional support should be given to patients referred for PT care. Conclusions: Relevant differences exist among European countries in supporting patients referred to PT in their logistic and economic challenges. Further efforts should be made by HNSs and PT facilities to reduce the risk of inequities in access to cancer care with protons.

Autologous adipose-derived stromal vascular fraction and platelet concentrates for the treatment of complex perianal fistulas.

BACKGROUND: Complex perianal fistulas are a major challenge for modern surgery since 10-35% of patients have functional problems after treatment. Sphincter-saving techniques have a wide range of efficacy (10-80%). We hypothesised that autologous adipose-derived stromal vascular fraction in combination with platelet rich plasma is a new therapeutic strategy with enhanced cure and function preservation rates. METHODS: Adult patients with complex cryptoglandular perianal fistulas were treated with injection of autologous adipose-derived stromal vascular fraction in combination with platelet rich plasma around and inside the fistulous tract between May 2018 and April 2019 at the General and Emergency Surgery Operative Unit of the University Hospital "P. Giaccone" of Palermo. Fistulas were confirmed by magnetic resonance imaging. Patients completed the Short Form-36 score on quality of life and the Wexner and Vaizey scores on faecal incontinence, and they were functionally studied using a three-dimensional anorectal manometry. The clinical and functional follow-up was performed at 1 year and 2 years after surgery. RESULTS: Nine patients (4 males, 5 females; median age 42 years [19-63 years]) with high trans-sphincteric or horseshoe fistulas were treated. The average number of previous surgeries per patient was 4.8. At 1 year follow-up, 77.7% of patients were cured, while at 2 years there was 1case of relapse. The variation in Short Form-36 score in cured patients was not significant (p = 0.0936). No statistically significant differences were found in continence scores. CONCLUSIONS: The proposed treatment is a treatment option that preserves sphincter integrity and function, potentially avoiding postoperative incontinence and the need of repeated treatments.

Oligo metastatic renal cell carcinoma: stereotactic body radiation therapy, if, when and how?

Background and purpose Renal cell carcinoma (RCC) has traditionally been considered radioresistant with a limited role for conventional fractionation as a local approach. Nevertheless, since the appearance of stereotactic body radiation therapy (SBRT), radiotherapy (RT) has been increasingly employed in the management of metastatic RCC (mRCC). The aim of this study was to evaluate the role of SBRT for synchronous and metachronous oligo metastatic RCC patients in terms of local control, delay of systemic treatment, overall survival and toxicity. Patients and methods A Monocentric single institution retrospective data collection was performed. Inclusion criteria were: (1) oligo-recurrent or oligo-progressive disease (less than 5 metastases) in mRCC patients after radical/partial nephrectomy or during systemic therapy, (2) metastasectomy or other metastasis-directed, rather than SBRT not feasible, (3) any contraindication to receive systemic therapy (such as comorbidities), (4) all the histologies were included, (5) available signed informed consent form for treatment. Tumor response and toxicity were evaluated using the response evaluation criteria in solid tumors and the Common Terminology Criteria for Adverse Events version 4.03, respectively. Progression-free survival in-field and out-field (in-field and out-field PFS) and overall survival (OS) were calculated via the Kaplan–Meier method. The drug treatment-free interval was calculated from the start of SBRT to the beginning of any systemic therapy. Results From 2010 to December 2018, 61 patients with extracranial and intracranial metastatic RCC underwent SBRT on 83 lesions. Intracranial and extracranial lesions were included. Forty-five (74%) patients were treated for a solitary metastatic lesion. Median RT dose was 25 Gy (range 10–52) in 5–10 fractions. With a median follow-up of 2.3 years (range 0–7.15), 1-year in-field PFS was 70%, 2-year in-field PFS was 55% (AU)

Oligo metastatic renal cell carcinoma: stereotactic body radiation therapy, if, when and how?

BACKGROUND AND PURPOSE: Renal cell carcinoma (RCC) has traditionally been considered radioresistant with a limited role for conventional fractionation as a local approach. Nevertheless, since the appearance of stereotactic body radiation therapy (SBRT), radiotherapy (RT) has been increasingly employed in the management of metastatic RCC (mRCC). The aim of this study was to evaluate the role of SBRT for synchronous and metachronous oligo metastatic RCC patients in terms of local control, delay of systemic treatment, overall survival and toxicity. PATIENTS AND METHODS: A Monocentric single institution retrospective data collection was performed. Inclusion criteria were: (1) oligo-recurrent or oligo-progressive disease (less than 5 metastases) in mRCC patients after radical/partial nephrectomy or during systemic therapy, (2) metastasectomy or other metastasis-directed, rather than SBRT not feasible, (3) any contraindication to receive systemic therapy (such as comorbidities), (4) all the histologies were included, (5) available signed informed consent form for treatment. Tumor response and toxicity were evaluated using the response evaluation criteria in solid tumors and the Common Terminology Criteria for Adverse Events version 4.03, respectively. Progression-free survival in-field and out-field (in-field and out-field PFS) and overall survival (OS) were calculated via the Kaplan-Meier method. The drug treatment-free interval was calculated from the start of SBRT to the beginning of any systemic therapy. RESULTS: From 2010 to December 2018, 61 patients with extracranial and intracranial metastatic RCC underwent SBRT on 83 lesions. Intracranial and extracranial lesions were included. Forty-five (74%) patients were treated for a solitary metastatic lesion. Median RT dose was 25 Gy (range 10-52) in 5-10 fractions. With a median follow-up of 2.3 years (range 0-7.15), 1-year in-field PFS was 70%, 2-year in-field PFS was 55%. One year out-field PFS was 39% and 1-year OS was 78%. Concomitant systemic therapy was employed for only 11 (18%) patients, for the others 50 (82%) the drug treatment-free rate was 70% and 50% at 1 and 2 years, respectively. No > G1 acute and late toxicities were reported. CONCLUSION: The pattern of failure was pre-dominantly out-of-field, even if the population was negatively selected and the used RT dose could be considered palliative. Therefore, SBRT appears to be a well-tolerated, feasible and safe approach in oligo metastatic RCC patients with an excellent in-field PFS. SBRT might play a role in the management of selected RCC patients allowing for a delay systemic therapy begin (one out of two patients were free from new systemic therapy at 2 years after SBRT). Further research on SBRT dose escalation is warranted.

Application of guidelines for the management of nonalcoholic fatty liver disease in three prospective cohorts of HIV-monoinfected patients.

OBJECTIVES: Current guidelines recommend use of a diagnostic algorithm to assess disease severity in cases of suspected nonalcoholic fatty liver disease (NAFLD). We applied this algorithm to HIV-monoinfected patients. METHODS: We analysed three prospective screening programmes for NAFLD carried out in the following cohorts: the Liver Disease in HIV (LIVEHIV) cohort in Montreal, the Modena HIV Metabolic Clinic (MHMC) cohort and the Liver Pathologies in HIV in Palermo (LHivPa) cohort. In the LIVEHIV and LHivPa cohorts, NAFLD was diagnosed if the controlled attenuation parameter (CAP) was ≥ 248 dB/m; in the MHMC cohort, it was diagnosed if the liver/spleen Hounsfield unit (HU) ratio on abdominal computerized tomography scan was < 1.1. Medium/high-risk fibrosis category was defined as fibrosis-4 (FIB-4) ≥ 1.30. Patients requiring specialist referral to hepatology were defined as either having NAFLD and being in the medium/high-risk fibrosis category or having elevated alanine aminotransferase (ALT). RESULTS: A total of 1534 HIV-infected adults without significant alcohol intake or viral hepatitis coinfection were included in the study. Of these, 313 (20.4%) patients had the metabolic comorbidities (obesity and/or diabetes) required for entry in the diagnostic algorithm. Among these patients, 123 (39.3%) required specialist referral to hepatology, according to guidelines. A total of 1062 patients with extended metabolic comorbidities (any among obesity, diabetes, hypertension and dyslipidaemia) represented most of the cases of NAFLD (79%), elevated ALT (75.9%) and medium/high-risk fibrosis category (75.4%). When the algorithm was extended to these patients, it was found that 341 (32.1%) would require specialist referral to hepatology. CONCLUSIONS: According to current guidelines, one in five HIV-monoinfected patients should undergo detailed assessment for NAFLD and disease severity. Moreover, one in ten should be referred to hepatology. Expansion of the algorithm to patients with any metabolic comorbidities may be considered.

Is early recurrence of hepatocellular carcinoma in HCV cirrhotic patients affected by treatment with direct-acting antivirals? A prospective multicentre study.

BACKGROUND: Data on HCV-related hepatocellular carcinoma (HCC) early recurrence in patients whose HCC was previously cured, and subsequently treated by direct-acting antivirals (DAAs), are equivocal. AIM: To assess the risk of HCC early recurrence after DAAs exposure in a large prospective cohort of HCV-cirrhotic patients with previous successfully treated HCC, also looking for risk factors for cancer early recurrence. METHODS: We enrolled 143 consecutive patients with complete response after curative treatment of HCC, subsequently treated with DAAs and monitored by the web-based RESIST-HCV database. Clinical, biological, and virological data were collected. The primary endpoint was the probability of HCC early recurrence from DAA starting by Kaplan-Meier method. RESULTS: Eighty-six per cent of patients were in Child-Pugh class A and 76% of patients were BCLC A. Almost all patients (96%) achieved sustained virological response. Twenty-four HCC recurrences were observed, with nodular or infiltrative pattern in 83% and 17% of patients, respectively. The 6-, 12- and 18-month HCC recurrence rates were 12%, 26.6% and 29.1%, respectively. Main tumour size and history of prior HCC recurrence were independent risk factors for HCC recurrence by Cox multivariate model. CONCLUSIONS: Probability of HCC early recurrence in patients who had HCC previously cured remains high, despite HCV eradication by DAAs. Risk was comparable but not higher to that reported in literature in DAA-untreated patients. Previous HCC recurrence and tumour size can be used to stratify the risk of HCC early recurrence. Further studies are needed to assess impact of DAAs on late recurrence and mortality.

Geminal embedding scheme for optimal atomic basis set construction in correlated calculations.

We introduce an efficient method to construct optimal and system adaptive basis sets for use in electronic structure and quantum Monte Carlo calculations. The method is based on an embedding scheme in which a reference atom is singled out from its environment, while the entire system (atom and environment) is described by a Slater determinant or its antisymmetrized geminal power (AGP) extension. The embedding procedure described here allows for the systematic and consistent contraction of the primitive basis set into geminal embedded orbitals (GEOs), with a dramatic reduction of the number of variational parameters necessary to represent the many-body wave function, for a chosen target accuracy. Within the variational Monte Carlo method, the Slater or AGP part is determined by a variational minimization of the energy of the whole system in presence of a flexible and accurate Jastrow factor, representing most of the dynamical electronic correlation. The resulting GEO basis set opens the way for a fully controlled optimization of many-body wave functions in electronic structure calculation of bulk materials, namely, containing a large number of electrons and atoms. We present applications on the water molecule, the volume collapse transition in cerium, and the high-pressure liquid hydrogen.

Phase I and pharmacodynamic study of high-dose NGR-hTNF in patients with refractory solid tumours.

BACKGROUND: NGR-hTNF exploits the peptide asparagine-glycine-arginine (NGR) for selectively targeting tumour necrosis factor (TNF) to CD13-overexpressing tumour vessels. Maximum-tolerated dose (MTD) of NGR-hTNF was previously established at 45 µg m(-2) as 1-h infusion, with dose-limiting toxicity being grade 3 infusion-related reactions. We explored further dose escalation by slowing infusion rate (2-h) and using premedication (paracetamol). METHODS: Four patients entered each of 12 dose levels (n=48; 60-325 µg m(-2)). Pharmacokinetics, soluble TNF receptors (sTNF-R1/sTNF-R2), and volume transfer constant (K(trans)) by dynamic imaging (dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI)) were assessed pre- and post-treatment. RESULTS: Common related toxicity included grade 1/2 chills (58%). Maximum-tolerated dose was not reached. Both C(max) (P<0.0001) and area under the plasma concentration-time curve (P=0.0001) increased proportionally with dose. Post-treatment levels of sTNF-R2 peaked significantly higher than sTNF-R1 (P<0.0001). Changes in sTNF-Rs, however, did not differ across dose levels, suggesting a plateau effect in shedding kinetics. As best response, 12/41 evaluable patients (29%) had stable disease. By DCE-MRI, 28/37 assessed patients (76%) had reduced post-treatment K(trans) values (P<0.0001), which inversely correlated with NGR-hTNF C(max) (P=0.03) and baseline K(trans) values (P<0.0001). Lower sTNF-R2 levels and greater K(trans) decreases after first cycle were associated with improved survival. CONCLUSION: asparagine-glycine-arginine-hTNF can be safely escalated at doses higher than MTD and induces low receptors shedding and early antivascular effects.

Fluctuations in the ensemble of reaction pathways.

The dominant reaction pathway is a rigorous framework to microscopically compute the most probable trajectories, in nonequilibrium transitions. In the low-temperature regime, such dominant pathways encode the information about the reaction mechanism and can be used to estimate nonequilibrium averages of arbitrary observables. On the other hand, at sufficiently high temperatures, the stochastic fluctuations around the dominant paths become important and have to be taken into account. In this work, we develop a technique to systematically include the effects of such stochastic fluctuations, to order k(B)T. This method is used to compute the probability for a transition to take place through a specific reaction channel and to evaluate the reaction rate.

The conundrum of HLA-DRB1*14:01/*14:54 and HLA-DRB3*02:01/*02:02 mismatches in unrelated hematopoietic SCT.

Uncertainty still exists on the role of polymorphisms outside the HLA-DRB1 binding site or inside the HLA-DRB3 binding groove in unrelated hematopoietic SCT (HSCT). The ideal model to solve the conundrum consists of the transplants mismatched for HLA-DRB1*14:01/*14:54 and/or for HLA-DRB3*02:01/*02:02. A task force was set up in Italy to recruit transplanted pairs defined as HLA-DRB1*14:01 before 2006, the year crucial for the proper definition of the HLA-DRB1*14:54 allele in molecular biology. Out of 2723 unrelated pairs, 189 transplanted in Italy from 1995 to 2006 were HLA-DRB1*14:01 positive; 103/189 pairs with good historical DNA were retyped for HLA-DRB1*14 and HLA-DRB3 at-high resolution level; 31/103 pairs had HLA-DRB1*14 and/or HLA-DRB3 mismatched; 99/103, having complete clinical data, underwent statistical analysis for OS, TRM, disease-free survival and acute and chronic GvHD. No significant involvement of HLA-DRB1*14:01/*14:54 or HLA-DRB3*02:01/*02:02 mismatches was found, either alone or combined. Our findings suggest that disparities at exon 3 of the HLA-DRB1 gene seem unlikely to influence the outcome after HSCT. The same may be envisaged for HLA-DRB3(*)02:01 and (*)02:02 alleles which, although differing in the Ag binding site, seem unable to modulate an appreciable immune response in an HSCT setting.

Two doses of NGR-hTNF in combination with capecitabine plus oxaliplatin in colorectal cancer patients failing standard therapies.

BACKGROUND: asparagine-glycine-arginine-human tumour necrosis factor (NGR-hTNF), an agent selectively damaging the tumour vasculature, showed a biphasic dose-response curve in preclinical models. Previous phase I trials of NGR-hTNF indicated 0.8 and 45 µg/m(2) as optimal biological and maximum-tolerated dose, respectively. PATIENTS AND METHODS: Two sequential cohorts of 12 colorectal cancer (CRC) patients who had failed standard therapies received NGR-hTNF 0.8 or 45 µg/m(2) in combination with capecitabine-oxaliplatin (XELOX). RESULTS: Median number of prior treatment lines was 3 in the low-dose and 2 in the high-dose cohort. Overall, 21 patients had been pretreated with oxaliplatin-based regimens. No grade 3-4 NGR-hTNF-related toxicities were observed. Grade 1-2 chills were reported in 43% and 40% of cycles in the low-dose and high-dose cohorts, respectively. In the low-dose cohort, one patient achieved a partial response and five had stable disease for a median of 4.6 months. In the high-dose cohort, six patients had stable disease for a median of 3.6 months. Three-month progression-free survival (PFS) rates were 50% and 33% in the low-dose and high-dose cohort, respectively. Three patients in low-dose cohort experienced PFS longer than PFS on last prior therapy. CONCLUSIONS: Both NGR-hTNF doses were safely combined with XELOX in pretreated CRC patients. Hint of activity was apparent only with low-dose NGR-hTNF.

[Atheroembolic renal disease]. / La malattia renale ateroembolica.

Atheroembolic renal disease can be defined as renal failure due to occlusion of the renal arterioles by cholesterol crystal emboli usually dislodged from ulcerated atherosclerotic plaques of the aorta. Atheroembolic renal disease is part of multisystem disease, since the embolization usually involves other organ systems such as the gastrointestinal system, central nervous system, and lower extremities. The kidney is frequently involved because of the proximity of the renal arteries to the abdominal aorta, where erosion of atheromatous plaques is most likely to occur. Embolization may occur spontaneously or after angiographic procedures, vascular surgery, and anticoagulation. In the last decade, atheroembolic renal disease has become a recognizable cause of renal disease. An ante-mortem diagnosis of the disease is possible in a significant proportion of cases as long as the level of diagnostic suspicion is high. The disease can severely affect kidney and patient survival. Although no specific treatment has been proven efficacious, use of statins may be justifiable and such therapy would be a reasonable choice for future treatment trials.

[Choosing the right treatment approach in focal and segmental glomerular sclerosis with chronic renal failure]. / Il trattamento della glomerulosclerosi focale e segmentaria con insufficienza renale cronica: quale approccio?

Focal and segmental glomerular sclerosis (FSGS) is a heterogeneous disease from a clinical, etiological and clinical point of view. FSGS may be idiopathic, usually associated with nephrotic syndrome, which requires an ''etiological'' treatment approach. In addition, hereditary and secondary forms of FSGS have been described. The response to therapy, including steroids, cytotoxic drugs and calcineurin inhibitors, is considered the best clinical indicator of outcome. Many uncertainties exist regarding the best therapeutic approach to FSGS in patients presenting with chronic renal failure. In this setting, before planning any treatment, the physician should always assess the presence of superimposed functional renal insufficiency and evaluate the severity of the renal impairment, the histological picture, previous immunosuppressive treatments, and the individual patient's risk for side effects. Keeping in mind these considerations and in the absence of appropriate studies, we can formulate the following suggestions: 1. there is no absolute contraindication to the use of full-dose prednisone as initial therapy, although the likelihood of a good response is low; 2. the use of cytotoxic drugs is not recommended unless the patient presents with a steroid-responsive form of the disease; 3. in patients with a glomerular filtration rate of less than 40 mL/min, the use of calcineurin inhibitors should be avoided.

Molecular aspects of a novel HLA-A*02 allele (A*0297): the first HLA class I allele mutated at codon 232.

We describe a new HLA-A*02 allele, identified in a cord blood unit and in her mother. Nucleotide sequence analysis showed the presence of a new HLA-A*02 allele identical to HLA-A*02010101 except for a non-synonymous nucleotide exchange in exon 4 modifying codon 232 from GAG (Glu) to GAC (Asp). No other human leucocyte antigen class I allele sequenced so far shows this triplet at codon 232. The amino acid exchange affects a position that is part of the membrane proximal domain of class I major histocompatibility complex (MHC), designated alpha 3, and involved in the interaction with CD8 molecule. Using molecular modelling approach, the interactions between different subunits of the native and mutated forms of MHC-I resulted in relevant changes.

Role of non-HLA genetic polymorphisms in graft-versus-host disease after haematopoietic stem cell transplantation.

Graft-versus-host disease (GvHD) is the main complication after haematopoietic stem cells transplantation (HSCT) and acute forms (aGvHD) occur in 20-40% of cases even after donor (D) and recipient (R) HLA matching, apparently because of D/R minor histocompatibility antigen (mHA) mismatches and cytokine polymorphisms. The genotype of cytokines and mHA of 77 haematological R following HSCT from HLA identical siblings were determined to detect genetic polymorphisms correlated with GvHD. We analysed TNFA (-863 C/A, -857 C/T and G/A at positions -574, -376, -308, -244, -238), IL-10 (-1082 G/A, -819 C/A, -592 C/T), IL-1B (T/C +3953), IL-1RA (VNTR), HA-1 (H/R allele) and CD-31 (C/G at codon 125, A/G at codon 563). Allele frequencies were in Hardy-Weinberg equilibrium and similar to those of 77 healthy controls. We observed positive correlations between a lower risk of clinically significant aGvHD and both the presence of -1082G -819C -592C IL-10 haplotype when both R and D are considered together and the absence of R IL-1RA allele 2. Furthermore, we observed an association between the absence of TNF-A -238 A allele and the risk of extensive chronic GvHD. mHA and cytokines genotyping would thus seem a valid source of information for the prior identification of recipients with a higher risk of aGvHD.

Identification of a new allele, HLA-DRB5*0113, through three different molecular biology techniques.

A new HLA-DRB5 allele, HLA-DRB5*0113, has been identified in an Italian patient during routine HLA typing in order to activate a bone marrow donor search. HLA typing was performed by different molecular biology techniques, and the results showed that the HLA-DRB5*0113 allele differs from HLA-DRB5*010101 allele for three nucleotide substitutions at codons 57 (GAC-->GAT; Asp) and 58 (GCT-->GAG; Ala-->Glu) of exon 2.

Molecular bases of type II protein S deficiency: the I203-D204 deletion in the EGF4 domain alters GLA domain function.

OBJECTIVE: To characterize the first type II protein S (PS) deficiency affecting the epidermal growth factor (EGF)4 domain, a calcium-binding module with a poorly defined functional role. PATIENTS: The proband suffered from recurrent deep vein thrombosis and showed reduced PS anticoagulant activity (31%), and total, free PS antigen and C4bBP levels in the normal range. RESULTS: Reverse transcription-polymerase chain reaction analysis showed the presence of the IVSg-2A/T splicing mutation that, by activating a cryptic splice site, causes the deletion of codons Ile203 and Asp204. Free PS, immunopurified from proband's plasma, showed an altered electrophoretic pattern in native condition or in the presence of Ca2+. The recombinant PS (rPS) mutant showed reduced anticoagulant (<10%) and activated protein C-independent activities (24-38%) when compared with wild-type rPS (rPSwt). Binding of the rPS variant to phospholipid vesicles (Kd 235.7 +/- 30.8 nM, rPSwt; Kd 15.2 +/- 0.9 nM) as well as to Ca2+-dependent conformation-specific monoclonal antibodies for GLA domain was significantly reduced. CONCLUSIONS: These data aid in the characterization of the functional role of the EGF4 domain in the anticoagulant activities of PS and in defining the thrombophilic nature of type II PS deficiency.