The role of skin tests with polyethylene glycol and polysorbate 80 in the vaccination campaign for COVID-19: results from an Italian multicenter survey.

Summary: Background. International guidelines suggested skin tests with Polyethylene-glycol (PEG) and polysorbate 80 (PS-80), to investigate a possible hypersensitivity to these excipients either to identify subjects at risk of developing allergic reactions to Covid-19 vaccines, or in patients with suspected IgE mediated hypersensitivity reactions (HR) to the Covid-19 vaccine. The main purpose of this study was to investigate the prevalence of PEG and PS sensitization in patients with a clinical history of HR to drugs containing PEG/PS and in patients with a suspected Covid-19 vaccine immediate HR. Methods. This was a multicenter retrospective study conducted by allergists belonging to 20 Italian medical centers. Skin testing was performed in 531 patients with either a clinical history of suspected hypersensitivity reaction (HR) to drugs containing PEG and/or PS-80 (group 1:362 patient) or a suspected HR to Covid-19 vaccines (group 2: 169 patient), as suggested by the AAIITO/SIAAIC guidelines for the "management of patients at risk of allergic reactions to Covid-19 vaccines" [1]. Results. 10/362 (0.02%) had positive skin test to one or both excipients in group 1, 12/169 (7.1%) in group 2 (p less than 0.01). In group 2 HRs to Covid-19 vaccines were immediate in 10/12 of cases and anaphylaxis occurred in 4/12 of patients. Conclusions. The positivity of skin test with PEG and or PS before vaccination is extremely rare and mostly replaceable by an accurate clinical history. Sensitization to PEG and PS has to be investigated in patients with a previous immediate HR to a Covid-19 vaccine, in particular in patients with anaphylaxis.

Effects of omalizumab treatment on serum cytokine concentrations of atopic patients with chronic spontaneous urticaria: a preliminary report.

SUMMARY: Omalizumab has recently obtained indication for chronic spontaneous urticaria both in the US and Europe. However, the mechanism of action of this drug has yet to be fully elucidated. Previous studies have shown elevations in cytokine serum levels in patients with chronic spontaneous urticaria, and it is not known whether omalizumab treatment may affect cytokine serum levels in this condition. Besides, a proportion of chronic spontaneous urticaria patients have concomitant atopy, which may be associated, at least in theory, with prevalence of serum Th2-type cytokines. In this study, serial serum samples from five patients (4 atopic and 1 nonatopic) with chronic spontaneous urticaria were assayed for cytokine concentrations by means of flow-cytometry-based multiplex bead assays, before and during omalizumab treatment. Omalizumab appeared to significantly affect the concentrations of multiple cytokines in a case of severe, long-lasting chronic spontaneous urticaria. Interestingly, IL-22 serum levels were found to progressively increase in three of five patients. Further studies are thus needed in larger patient populations, to conclusively establish whether the mechanism of action of omalizumab in chronic spontaneous urticaria also includes modulation of cytokine synthesis.

Molecular basis of inherited thrombocytopenias.

Inherited thrombocytopenias (IT) are a heterogeneous group of diseases caused by at least 20 different genes. At present, these genes account for approximately 50% of cases, suggesting that novel genes have yet to be identified for a comprehensive understanding of platelet biogenesis defects. This review provides an update of ITs focusing on the molecular basis and potential pathogenic mechanisms affecting megakaryopoiesis and platelet production.

R705H mutation of MYH9 is associated with MYH9-related disease and not only with non-syndromic deafness DFNA17.

MYH9-related disease (MYH9-RD) is a rare autosomal dominant disease caused by mutation of MYH9, the gene encoding for the heavy chain of non-muscle myosin IIA (NMMHC-IIA). MYH9-RD patients have macrothrombocytopenia and granulocyte inclusions (pathognomonic sign of the disease) containing wild-type and mutant NMMHC-IIA. During life they might develop sensorineural hearing loss, cataract, glomerulonephritis, and elevation of liver enzymes. One of the MYH9 mutations, p.R705H, was previously reported to be associated with DFNA17, an autosomal dominant non-syndromic sensorineural hearing loss without any other features associated. We identified the same mutation in two unrelated families, whose four affected individuals had not only hearing impairment but also thrombocytopenia, giant platelets, leukocyte inclusions, as well as mild to moderate elevation of some liver enzymes. Our data suggest that DFNA17 should not be a separate genetic entity but part of the wide phenotypic spectrum of MYH9-RD characterized by congenital hematological manifestations and variable penetrance and expressivity of the extra-hematological features.

Characterization of pituitary cells targeted by antipituitary antibodies in patients with isolated autoimmune diseases without pituitary insufficiency may help to foresee the kind of future hypopituitarism.

PURPOSE: Detection of antipituitary antibodies (APA) at high levels and with a particular immunofluorescence pattern in patients with autoimmune polyendocrine syndromes may indicate a possible future autoimmune pituitary involvement. This longitudinal study was aimed at characterizing in patients with a single organ-specific autoimmune disease the pituitary cells targeted by APA at start, verifying whether this characterization allows to foresee the kind of possible subsequent hypopituitarism. METHODS: Thirty-six APA positive and 40 APA negative patients with isolated autoimmune diseases participated in the study. None of them had pituitary dysfunction at entry. Characterization by four-layer immunofluorescence of pituitary cells targeted by APA in APA positive patients at entry and study of pituitary function in all patients were performed every 6 months during a 5 year follow-up. RESULTS: Antipituitary antibodies immunostained selectively one type of pituitary-secreting cells in 21 patients (58.3 %, group 1), and several types of pituitary cells in the remaining 15 (41.7 %, group 2). All patients in group 1 showed subsequently a pituitary insufficiency, corresponding to the type of cells targeted by APA in 18 of them (85.7 %). Only 8 out of 15 patients in group 2 (53.3 %) showed a hypopituitarism, isolated in 7 and combined in the other one. None of APA negative patients showed hypopituitarism. CONCLUSIONS: The characterization of pituitary cells targeted by APA in patients with isolated autoimmune diseases, when the pituitary function is still normal, may help to foresee the kind of subsequent hypopituitarism, especially when APA immunostained selectively only one type of pituitary cells. A careful follow-up of pituitary function in these patients is advisable to allow an early diagnosis of hypopituitarism, even in subclinical phase and a consequent timely replacement therapy.

Localisation of the Fanconi anaemia complementation group A gene to chromosome 16q24.3.

Fanconi anaemia (FA) is an autosomal recessive disorder associated with diverse developmental abnormalities, bone-marrow failure and predisposition to cancer. FA cells show increased chromosome breakage and hypersensitivity to DNA cross-linking agents such as diepoxybutane and mitomycin C. Somatic-cell hybridisation analysis of FA cell lines has demonstrated the existence of at least five complementation groups (FA-A to FA-E), the most common of which is FA-A. This genetic heterogeneity has been a major obstacle to the positional cloning of FA genes by classical linkage analysis. The FAC gene was cloned by functional complementation, and localised to chromosome 9q22.3 (ref. 2), but this approach has thus far failed to yield the genes for the other complementation groups. We have established a panel of families classified as FA-A by complementation analysis, and used them to search for the FAA gene by linkage analysis. We excluded the previous assignment by linkage of an FA gene to chromosome 20q, and obtained conclusive evidence for linkage of FAA to microsatellite markers on chromosome 16q24.3. Strong evidence of allelic association with the disease was detected with the marker D16S303 in the Afrikaner population of South Africa, indicating the presence of a founder effect.

Spontaneous functional correction of homozygous fanconi anaemia alleles reveals novel mechanistic basis for reverse mosaicism.

Somatic mosaicism due to reversion of a pathogenic allele to wild type has been described in several autosomal recessive disorders. The best known mechanism involves intragenic mitotic recombination or gene conversion in compound heterozygous patients, whereby one allele serves to restore the wild-type sequence in the other. Here we document for the first time functional correction of a pathogenic microdeletion, microinsertion and missense mutation in homozygous Fanconi anaemia (FA) patients resulting from compensatory secondary sequence alterations in cis. The frameshift mutation 1615delG in FANCA was compensated by two additional single base-pair deletions (1637delA and 1641delT); another FANCA frameshift mutation, 3559insG, was compensated by 3580insCGCTG; and a missense mutation in FANCC(1749T-->G, Leu496Arg) was altered by 1748C-->T, creating a cysteine codon. Although in all three cases the predicted proteins were different from wild type, their cDNAs complemented the characteristic hypersensitivity of FA cells to crosslinking agents, thus establishing a functional correction to wild type.

Expression cloning of a cDNA for the major Fanconi anaemia gene, FAA.

Fanconi anaemia (FA) is an autosomal recessive disorder characterized by a diversity of clinical symptoms including skeletal abnormalities, progressive bone marrow failure and a marked predisposition to cancer. FA cells exhibit chromosomal instability and hyper-responsiveness to the clastogenic and cytotoxic effects of bifunctional alkylating (cross-linking) agents, such as diepoxybutane (DEB) and mitomycin C (MMC). Five complementation groups (A-E) have been distinguished on the basis of somatic cell hybridization experiments, with group FA-A accounting for over 65% of the cases analysed. A cDNA for the group C gene (FAC) was reported and localized to chromosome 9q22.3 (ref.8). Genetic map positions were recently reported for two more FA genes, FAA (16q24.3) and FAD (3p22-26). Here we report the isolation of a cDNA representing the FAA gene, following an expression cloning method similar to the one used to clone the FAC gene. The 5.5-kb cDNA has an open reading frame of 4,368 nucleotides. In contrast to the 63-kD cytosolic protein encoded by the FAC gene, the predicted FAA protein (M(r) 162, 752) contains two overlapping bipartite nuclear localization signals and a partial leucine zipper consensus, which are suggestive of a nuclear localization.

Mutations in MYH9 result in the May-Hegglin anomaly, and Fechtner and Sebastian syndromes. The May-Heggllin/Fechtner Syndrome Consortium.

The autosomal dominant, giant-platelet disorders, May-Hegglin anomaly (MHA; MIM 155100), Fechtner syndrome (FTNS; MIM 153640) and Sebastian syndrome (SBS), share the triad of thrombocytopenia, large platelets and characteristic leukocyte inclusions ('Döhle-like' bodies). MHA and SBS can be differentiated by subtle ultrastructural leukocyte inclusion features, whereas FTNS is distinguished by the additional Alport-like clinical features of sensorineural deafness, cataracts and nephritis. The similarities between these platelet disorders and our recent refinement of the MHA (ref. 6) and FTNS (ref. 7) disease loci to an overlapping region of 480 kb on chromosome 22 suggested that all three disorders are allelic. Among the identified candidate genes is the gene encoding nonmuscle myosin heavy chain 9 (MYH9; refs 8-10), which is expressed in platelets and upregulated during granulocyte differentiation. We identified six MYH9 mutations (one nonsense and five missense) in seven unrelated probands from MHA, SBS and FTNS families. On the basis of molecular modelling, the two mutations affecting the myosin head were predicted to impose electrostatic and conformational changes, whereas the truncating mutation deleted the unique carboxy-terminal tailpiece. The remaining missense mutations, all affecting highly conserved coiled-coil domain positions, imparted destabilizing electrostatic and polar changes. Thus, our results suggest that mutations in MYH9 result in three megakaryocyte/platelet/leukocyte syndromes and are important in the pathogenesis of sensorineural deafness, cataracts and nephritis.

Effect of long-term cabergoline therapy on the immunological pattern and pituitary function of patients with idiopathic hyperprolactinaemia positive for antipituitary antibodies.

OBJECTIVE: The occurrence of antipituitary antibodies (APA) in patients with idiopathic hyperprolactinaemia (IH) and the effects of dopamine agonists on these antibodies and long-term pituitary function outcome have been so far not evaluated. This longitudinal study was aimed at investigating, in patients with IH the occurrence of APA and the effect of cabergoline on the pituitary function and behaviour of APA. DESIGN: Sixty-six patients with IH were studied. APA (by indirect immunofluorescence) and pituitary function were investigated every year for 3 years. RESULTS: Seventeen patients resulted APA positive (Group 1) and 49 APA negative (Group 2). Eight patients of Group 1 (Group 1a) and 24 of Group 2 (Group 2a) were asymptomatic and then not treated; instead, nine patients in Group 1 (Group 1b) and 25 in Group 2 (Group 2b), showing symptoms of hyperprolactinaemia, were treated with cabergoline for 2 years. Among the untreated patients, during the follow-up, those with APA positive (Group 1a) showed an increase of APA titres and PRL levels with partial pituitary impairment in some of them; instead those with APA negative (Group 2a) persisted negative with normal pituitary function despite persistent hyperprolactinaemia. Among the treated patients, those with APA positive (Group 1b) showed normalization of PRL levels, APA disappearance and recovery of pituitary function (when initially impaired) during cabergoline treatment, persisting also at last observation (off-therapy). Instead all patients of Group 2b persisted with APA negative during the follow-up with normalization of PRL levels and stable normal pituitary function during cabergoline therapy but showing a further increase of PRL at the last observation. CONCLUSIONS: The presence of APA in some patients with IH suggests a possible occurrence of autoimmune hypophysitis at potential/subclinical stage; an early and prolonged cabergoline therapy could interrupt the progression to an overt clinical stage of the disease. However, the small amount of patients investigated suggests caution against generalization of our assumption and prompts to further controlled studies on a more numerous population to verify these conclusions.

A novel Leu153Ser mutation of the Fanconi anemia FANCD2 gene is associated with severe chemotherapy toxicity in a pediatric T-cell acute lymphoblastic leukemia.

Fanconi anemia (FA) is an autosomal recessive disease characterized by pancitopenia, congenital malformations, predisposition to cancers and chromosomal instability. We report the clinical and molecular features of a patient initially identified as a potential FA case only because of chemotherapy toxicity during the treatment of a T-lineage acute lymphoblastic leukemia (ALL). Cells from this patient showed a moderate chromosomal instability, increasing sensitivity to DNA crosslinking agents but normal response to ionizing radiation. The analysis of FA proteins demonstrated a marked reduction of FANCD2 (>95%), but normal levels of FANCA or FANCG. Interestingly, this defect was associated with a homozygous missense mutation of FANCD2, resulting in a novel amino-acid substitution (Leu153Ser) at residue Leu153, which is highly conserved through evolution. The FANCD2(L153S) protein, whose reduced expression was not due to impaired transcription, was detected also in its monoubiquitinated form in the nucleus, suggesting that the mutation does not affect post-translation modifications or subcellular localization but rather the stability of FANCD2. Therefore, the hypomorphic Leu153Ser mutation represents the first example of a FANCD2 defect that might promote clonal progression of tumors, such as T-ALL, and severe chemotherapy toxicity in patients without any clinical manifestations typical of FA.

Inherited thrombocytopenia caused by ANKRD26 mutations misdiagnosed and treated as myelodysplastic syndrome: report on two cases.

Essentials Thrombocytopenia 2 (THC2) is an inherited thrombocytopenia (IT) with dysmegakaryopoiesis. Physicians often do not suspect the genetic origin of thrombocytopenia in patients with THC2. We report two THC2 patients misdiagnosed with myelodysplasia and treated with chemotherapy. IT should be always considered in patients with isolated thrombocytopenia and dysmegakaryopoiesis. SUMMARY: Thrombocytopenia 2 (THC2) is an autosomal-dominant disorder caused by point substitutions in the 5'UTR of the ANKRD26 gene. Patients have congenital thrombocytopenia, normal platelet morphology and function, and dysmegakaryopoiesis. Thrombocytopenia is frequently discovered only in adulthood and physicians often do not suspect its genetic origin. We describe two unrelated patients referred to two different institutions for investigation of thrombocytopenia. Based on the finding of dysmegakaryopoiesis at bone marrow examination, patients were diagnosed with myelodysplastic syndrome (MDS) (refractory thrombocytopenia) and treated with several courses of 5-azacytidine. Subsequently, demonstration of thrombocytopenia in their relatives eventually led to molecular diagnosis of THC2 in both families. These cases highlight that patients with THC2 are at risk of being misdiagnosed with MDS and receiving undue myelosuppressive treatments. Because dysmegakaryopoiesis is a feature also of other forms of inherited thrombocytopenia, a genetic disorder must always be considered when a patient presents with isolated thrombocytopenia and dysmegakaryopoiesis.

Cord blood in vitro expanded CD41 cells: identification of novel components of megakaryocytopoiesis.

BACKGROUND: Megakaryopoiesis represents a multi-step, often unclear, process leading to commitment, differentiation, and maturation of megakaryocytes (MKs) that release platelets. AIM: To identify the novel genes that might help to clarify the molecular mechanisms of megakaryocytopoiesis and be regarded as potential candidates of inherited platelet defects, global gene expression of hematopoietic lineages was carried out. METHODS: Human cord blood was used to purify CD34+ stem cells and in vitro expand CD41+ cells and burst-forming unit-erythroid (BFU-E). We investigated the expression profiles of these three hematopoietic lineages in the Affymetrix system and selected genes specifically expressed in MKs by comparing transcripts of the different lineages using the dchip and pam algorithms. RESULTS: A detailed characterization of MK population showed that 99% of cells expressed the CD41 antigen whereas 73% were recognizable as terminally differentiated fetal MKs. The profile of these cells was compared with that of CD34+ cells and BFU-E allowing us to select 70 transcripts (MK-core), which represent not only the genes with a well-known function in MKs, but also novel genes never detected or characterized in these cells. Moreover, the specific expression was confirmed at both RNA and protein levels, thus validating the 'MK-core' isolated by informatics tools. CONCLUSIONS: This is a global gene expression that for the first time depicts a well-characterized population of cord blood-derived fetal MKs. Novel genes have been detected, such as those encoding components of the extracellular matrix and basal membrane, which have been found in the cytoplasm of Mks, suggesting that new physiological aspects of MKs should be studied.

Molecular diagnosis of thrombocytopenia-absent radius syndrome using next-generation sequencing.

INTRODUCTION: Thrombocytopenia-absent radius (TAR) syndrome is a rare autosomal recessive disease. Patients are compound heterozygotes for a loss-of-function allele, which in most cases is a large genomic deletion on chromosome 1q21.1 containing the RBM8A gene, and a noncoding variant located in the 5'UTR (rs139428292) or intronic (rs201779890) regions of RBM8A. As the molecular genetic testing in TAR requires multiple techniques for detection of copy-number variations (CNV) and nucleotide substitutions, we tested whether a next-generation sequencing (NGS) approach could identify both alterations. METHODS: Two unrelated families were analyzed with Ion PGM sequencing using a target panel of genes responsible for different forms of inherited thrombocytopenia. A statistical quantitative evaluation of amplicon coverage was performed to detect CNV, in particular those on the RBM8A gene. RESULTS: All the probands were apparently homozygous for the rare allele inherited by the father at the rs139428292 locus, suggesting the presence of a deletion on the maternal chromosome. The statistical analysis confirmed the hemizygous condition of RBM8A. CONCLUSION: We concluded that NGS approaches could be used as a cost-effective method for molecular investigation of TAR as they could simultaneously detect CNV and point mutations.

Hereditary thrombocytopenia due to reduced platelet production--report on two families and mutational screening of the thrombopoietin receptor gene (c-mpl).

Hereditary thrombocytopenias represent heterogeneous clinical and genetic syndromes. They include a consistent group of families which are considered as a separate clinical entity, characterized by autosomal dominant transmission, incomplete penetrance in females, chronic thrombocytopenia with early age of onset and frequently increased platelet volume, without any other hematologic abnormality. The molecular defect in these families is still unknown. We describe 2 families in 3 generations (10 patients), and report the first study of the TPO/c-mpl system in autosomal dominant thrombocytopenia. We performed mutational screening of c-mpl coding, flanking introns and promoter regions in 2 probands from the two families by DNA sequencing. The results do not provide evidence of c-mpl sequence alterations in either of the 2 families investigated. Moreover, the normal TPO serum levels detected in 5 patients from each family leads us to exclude the possibility of a defect in TPO production in our families. Finally, the involvement of both c-mpl and TPO genes in the pathogenesis of thrombocytopenia in these two families was excluded by negative results of linkage analysis.