Humoral and cell-mediated immune responses to BNT162b2 vaccine against SARS-CoV-2 in people with cystic fibrosis.

People with cystic fibrosis (pwCF) were considered to be clinically vulnerable to COVID-19 and were therefore given priority in the vaccination campaign. Vaccines induced a humoral response in these patients that was comparable to the response observed among the general population. However, the role of the cell-mediated immune response in providing long-term protection against SARS-CoV-2 in pwCF has not yet been defined. In this study, humoral (antibody titre) and cell-mediated immune responses (interferon-γ release) to the BNT162b2 vaccine were measured at different time points, from around 6-8 months after the 2nd dose and up to 8 months after the 3rd dose, in 118 CF patients and 26 non-CF subjects. Subjects were sampled between November 2021 and September 2022 and followed-up for breakthrough infection through October 2022. pwCF mounted a cell-mediated response that was similar to that observed in non-CF subjects. Low antibody titres (<1st quartile) were associated with a higher risk of breakthrough infection (HR: 2.39, 95 % CI: 1.17-4.88), while there was no significant association with low INF-γ levels (<0.3 IU/mL) (HR: 1.38, 95 % CI: 0.64-2.99). Further studies are needed in subgroup of pwCF receiving immunosuppressive therapy, such as organ transplant recipients. This data is important for tailoring vaccination strategies for this clinically vulnerable population.

Secondary hemophagocytic lymphohystiocytosis in a Rubinstein Taybi syndrome patient.

Rubinstein-Taybi syndrome (RSTS) is an autosomal dominant disorder, caused by variants in CREBBP or EP300. Affected individuals present with distinctive craniofacial features, broad thumbs and/or halluces, intellectual disability and immunodeficiency. Here we report on one RSTS patient who experienced hemophagocytic lymphohystiocytosis (HLH) and disseminated herpes virus 1 ( HSV-1) disease. The clinical picture of RSTS is expanding to include autoinflammatory, autoimmune, and infectious complications. Prompt treatment of HLH and disseminated HSV-1 can lower the mortality rate of these life-threatening conditions.

Two siblings presenting with novel ADA2 variants, lymphoproliferation, persistence of large granular lymphocytes, and T-cell perturbations.

The presence of large granular lymphocytes has been reported in patients with ADA2 deficiency and T-LGL leukemia. Here we describe two siblings with novel ADA2 variants, expanding the mutational spectrum of ADA2 deficiency. We show that lymphoproliferation, persistence of large granular lymphocytes, T-cell perturbations, and activation of PI3K pathway, measured by means of phosphorylation levels of S6, are detectable in DADA2 patients without T-LGL leukemia.

Early diagnosis of PI3Kδ syndrome in a 2 years old girl with recurrent otitis and enlarged spleen.

Heterozygous gain of function mutations in the gene encoding p110δ subunit of PI3K have been recently associated with activated PI3K-δ syndrome (APDS), a novel combined immune deficiency characterized by recurrent sinopulmonary infections, lymphopenia, reduced class-switched memory B cells, lymphadenopathy, CMV and/or EBV viremia and EBV-related lymphoma. Here we report a dominant gain of function PIK3CD mutation (E1021K) in a patient presenting with recurrent otitis media, massive splenomegaly, and persistent EBV-viraemia. The immunological studies showed low IgA level, but normal IgM, IgG, and normal antibody response to diphtheria and tetanus toxoid vaccination. Analysis of B lymphocyte subsets revealed abnormal expansion of transitional B cells, and low percentage of switched CD27+IgD- and CD27+IgD+ memory B cells. Analysis of T cell compartment unveiled prevalence of terminally differentiated cells. This study suggests that PIK3CD gain of function mutations should be suspected despite incomplete phenotype in patients with early onset splenomegaly, persistent EBV viremia and abnormal B and T cell subsets despite normal IgG levels. Currently the optimal treatment is still debated, but prompt management can hopefully diminish incidence of severe long-lasting sequelae (i.e. bronchiectasis, ear and sinus damage).

A novel compound heterozygous TACI mutation in an autosomal recessive common variable immunodeficiency (CVID) family.

Common variable immunodeficiency (CVID) is a primary immune disorder characterized by low immunoglobulin serum levels and increased susceptibility to infections. Underlying genetic causes are only known in less than 15% of patients and encompass mutations in the genes encoding for ICOS, TACI, BAFF-R, CD19, CD20, CD81 and MSH5. TACI is the most frequently mutated gene among CVID patients. We report on two pediatric Italian male siblings with hypogammaglobulinemia and recurrent respiratory and gastrointestinal infections in association with a novel compound heterozygous TACI mutation. Both patients carry the I87N/C104R mutation that has not been reported yet. This results in aberrant TACI expression and abrogates APRIL binding on EBV B cells. This study identifies a novel combined mutation in TNFRSF13B increasing the spectrum of TACI mutations associated with CVID.

Clinical and genetic features of Warts, Hypogammaglobulinemia, Infections and Myelokathexis (WHIM) syndrome.

WHIM syndrome is a dominantly inherited primary immunodeficiency disorder representing the first identified example of human disease caused by mutations in the gene encoding for the chemokine receptor CXCR4. Pathogenesis is mediated by CXCR4 hyperfunction, leading to increased responsiveness to its unique ligand CXCL12 (also known as SDF-1). The altered CXCR4/CXCL12 interaction likely impairs cellular homeostasis and trafficking, resulting in immunological dysfunctions. The acronym WHIM resumes the main features of the syndrome: Warts, Hypogammaglobulinemia, Infections and Myelokathexis, which is abnormal retention of mature neutrophils in the bone marrow. WHIM patients suffer from recurrent bacterial infections since childhood and manifest a specific susceptibility to HPV infections. Hematological findings include neutropenia, lymphopenia and hypogammaglobulinemia. Because of the rarity of the disease and the heterogeneity in clinical presentation, diagnosis is often delayed. In the majority of patients, the phenotype is incomplete at the onset and WHIM syndrome is not suspected. Early identification may improve clinical and therapeutic management. Symptomatic treatments include G-CSF, substitutive immunoglobulins and antibiotic prophylaxis. A new therapeutic strategy might include the potent inhibitor of CXCR4 function plerixafor (Mozobil), as an agent specifically targeting the molecular defect in order to attenuate the phenotypic manifestations of the syndrome.

PTX3 genetic variations affect the risk of Pseudomonas aeruginosa airway colonization in cystic fibrosis patients.

Cystic fibrosis (CF) is a common life-threatening autosomal recessive disorder in the Caucasian population, and the gene responsible is the CF transmembrane conductance regulator (CFTR). Patients with CF have repeated bacterial infection of the airways caused by Pseudomonas aeruginosa (PA), which is one of the predominant pathogen, and endobronchial chronic infection represents a major cause of morbidity and mortality. Pentraxin 3 (PTX3) is a gene that encodes the antimicrobial protein, PTX3, which is believed to have an important role in innate immunity of lung. To address the role of PTX3 in the risk of PA lung colonization, we investigated five single nucleotide polymorphisms of PTX3 gene in 172 Caucasian CF patients who were homozygous for the F508del mutation. We observed that PTX3 haplotype frequencies were significantly different between patients with PA colonization, as compared with noncolonized patients. Moreover, a protective effect was found in association with a specific haplotype (odds ratio 0.524). Our data suggest that variations within PTX3 affect lung colonization of Pseudomonas in patients with CF.

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy syndrome: time to review diagnostic criteria?

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is an autosomal-recessive syndrome defined by two of the following conditions: chronic mucocutaneous candidiasis, hypoparathyroidism, or Addison's disease. Other autoimmune conditions may be associated, such as hypothyroidism, hypogonadism, insulin-dependent diabetes mellitus, chronic active hepatitis, pernicious anemia, vitiligo, alopecia, biliary cirrhosis, and ectodermal dysplasia. APECED is caused by mutations in the autoimmune regulator gene, mapping to 21q22.3. We report on three patients whose clinical and molecular features challenge the currently used diagnostic criteria for APECED. AR presented at 15 yr of age with a history of recurrent infections and mucocutaneous candidiasis. He is now 21 yr old, and no other signs or symptoms of APECED have appeared to date. DR presented at 7 yr of age with hypocalcemia and a prolonged Q-T interval on the electrocardiogram. He also had minor facial dysmorphisms and mild mental retardation. Serum calcium levels were low, PTH levels were undetectable, and hypoparathyroidism was therefore diagnosed. All other biochemical, immunological, and endocrinological tests were normal. DR is now 8 yr old with no other signs or symptoms of APECED. ST presented at 14 yr of age for alopecia aerata and pitted nail dystrophy and goiter. Thyroid function was normal in the presence of thyroid-specific antibodies. No other signs or symptoms of APECED have appeared to date. Genetic analysis revealed a typical mutation (R257X) on a single allele in both AP and DR; in ST, heterozygosity for a novel mutation (V484M) involving one of the zinc fingers of the plant homeodomain of the protein was found. The finding of a typical APECED mutation in two patients presenting with one isolated major clinical APECED feature and of a novel mutation in a patient presenting with atypical features of APECED onset suggests that the time might have come for updating the diagnostic criteria of this syndrome.

X-chromosome inactivation analysis in a female carrier of FOXP3 mutation.

Immune dysregulation, polyendocrinopathy and enteropathy with X-linked inheritance (IPEX) is a serious disease arising from mutations in FOXP3. This gene codifies for a transcription factor whose dysfunction results in hyperactivation of T cells. It is not clear, however, why an intermediate phenotype is not seen in heterozygous females, who are completely healthy. In order to address this question, we investigated X-chromosome inactivation in peripheral blood lymphocytes from a heterozygous female with a child affected by IPEX. No preferential inactivation was shown in freshly sorted CD4+, CD8+, CD19+ cells or in IL-2 cultured CD4 and CD8 T cells, indicating that peripheral blood lymphocytes in these women are randomly selected. Moreover, only one single FOXP3 transcript was expressed by CD4 T cell clones analysed by RT-PCR, confirming that this gene is subject to X- inactivation. We hypothesize that hyper-activation of T cell in carriers of FOXP3 mutations is regulated by the presence of normal regulatory T cells.

Mutations of CD40 gene cause an autosomal recessive form of immunodeficiency with hyper IgM.

CD40 is a member of the tumor necrosis factor receptor superfamily, expressed on a wide range of cell types including B cells, macrophages, and dendritic cells. CD40 is the receptor for CD40 ligand (CD40L), a molecule predominantly expressed by activated CD4(+) T cells. CD40/CD40L interaction induces the formation of memory B lymphocytes and promotes Ig isotype switching, as demonstrated in mice knocked-out for either CD40L or CD40 gene, and in patients with X-linked hyper IgM syndrome, a disease caused by CD40L/TNFSF5 gene mutations. In the present study, we have identified three patients with an autosomal recessive form of hyper IgM who fail to express CD40 on the cell surface. Sequence analysis of CD40 genomic DNA showed that one patient carried a homozygous silent mutation at the fifth base pair position of exon 5, involving an exonic splicing enhancer and leading to exon skipping and premature termination; the other two patients showed a homozygous point mutation in exon 3, resulting in a cysteine to arginine substitution. These findings show that mutations of the CD40 gene cause an autosomal recessive form of hyper IgM, which is immunologically and clinically undistinguishable from the X-linked form.

Interaction of Bartonella henselae with the murine macrophage cell line J774: infection and proinflammatory response.

Bartonella henselae is the causative agent of cat scratch disease (CSD), a self-limiting condition characterized by a subacute regional lymphadenopathy that may develop into disseminated bartonellosis in immunocompromised subjects. Mice experimentally infected with B. henselae display typical liver and spleen granulomas rich in T cells and macrophages. So far there are no data on the interaction between bartonellae and macrophages. In order to clarify this topic, we investigated the interaction of B. henselae with J774, a mouse macrophage cell line. Analysis of bacterial uptake by functional assays and transmission electron microscopy indicates that bartonellae can enter and survive inside J774. Entry occurred within 30 min postinfection and reached a plateau at 160 min. Infection of J774 was followed by a dose-dependent release of the proinflammatory cytokines tumor necrosis factor alpha, interleukin 1beta (IL-1beta), and IL-6. Bartonellae persisted intracellularly without loss of viability for at least 8 h, and their number slightly decreased 24 h postinfection. Gamma interferon (IFN-gamma) treatment of J774 significantly decreased the number of recoverable bacteria at 8 and 24 h. This enhancement of macrophage bactericidal activity was associated with nitric oxide (NO) release and was prevented by the addition of the competitive inhibitor of NO synthesis N(G)-monomethyl L-arginine. These findings suggest that IFN-gamma-mediated activation of macrophages may be important for the clearing of B. henselae infection and that anti-B. henselae microbicidal activity of IFN-gamma-activated macrophages is mediated to a large extent by NO production.

CD38 expression and functional activities are up-regulated by IFN-gamma on human monocytes and monocytic cell lines.

Human CD38, a surface molecule expressed by immature and activated T and B lymphocytes, has been characterized as a molecule transducing activation and proliferation signals, and intervening in adhesion to endothelium via its ligand CD31. CD38 is also a complex ectoenzyme featuring ADP-ribosyl cyclase/cyclic ADP-ribose hydrolase activities, leading to the synthesis and degradation of cADPR, a Ca+-mobilizing agent. We investigated the effects of monocyte-activating stimuli (IFN-gamma, IL-2, LPS, TNF-alpha, and GM-CSF) on the expression and function of CD38, starting from the observation that human monocytes and the derived lines U937, THP-1, and Mono-Mac-6 bear the molecule on their surface. Our results indicate that IFN-gamma is a strong up-modulator of CD38, and IL-2 increases its expression only modestly. LPS, TNF-alpha, and GM-CSF had no detectable effects. Treatment with IFN-gamma produced a dose- and time-dependent up-regulation of CD38 in monocytes and monocytic lines, which was paralleled by increased ADP-ribosyl cyclase/cyclic ADP-ribose hydrolase activities. Furthermore, CD38 ligation by specific MoAb reduced the IFN-gamma-dependent enhancement of monocyte-dynamic adhesion to endothelial monolayers. These findings identify IFN-gamma as a modulator of monocytic CD38 expression and indicate that CD38 plays a specific role in the activation and adhesion processes performed by monocytes.

Prenatal molecular diagnosis of Wiskott-Aldrich syndrome by direct mutation analysis.

We have performed prenatal diagnosis for Wiskott Aldrich syndrome (WAS) in two unrelated families by direct gene analysis. Using a combined non-radioactive analysis of single-strand conformational polymorphism (SSCP) and heteroduplex formation (HD), followed by automated sequencing, we studied DNA from chorionic villus sampling (CVS), allowing the diagnosis of one affected and one healthy male at the 12th week of gestation.

Expression of inducible nitric oxide synthase in human granulomas and histiocytic reactions.

Inducible nitric oxide synthase (iNOS) is required in immune response against infections and is involved in granuloma formation in animals; in murine macrophages, iNOS is induced by lipopolysaccharide and interferon-gamma. In contrast, the role of iNOS in human immune response against infections is still questioned, and its expression in granulomas is poorly investigated. Using Western blotting and immunohistochemistry, we investigated iNOS expression in human lymph nodes with nonspecific reactions and in tissues containing granulomas caused by mycobacteria, Toxoplasma, Cryptococcus neoformans, Leishmania, Bartonella, noninfectious granulomas (sarcoidosis, foreign body), and other hystiocitic reactions (Kikuchi's disease, Omenn syndrome). iNOS was undetectable in nonspecific reactive lymphadenitis, foreign-body granulomas, and Omenn syndrome, whereas it was strongly expressed in infectious granulomas, sarcoidosis, and Kikuchi's diseases. Immunohistochemistry demonstrated that iNOS was selectively expressed by the epithelioid and multinucleated giant cells within the granulomas. Use of an anti-nitrotyrosine antibody, recognizing nitrosilated amino acid residues derived from nitric oxide production, revealed a consistent positivity within the cells expressing iNOS, thus suggesting that iNOS is functionally active. Detection of cytokines by reverse transcriptase-polymerase chain reaction demonstrated that tissues that were positive for iNOS, also expressed the Thl-type cytokine interferon-gamma mRNA, but not the Th2-type cytokine interleukin-4. Taken together, these results indicate that iNOS is involved in different human immune reactions characterized by histiocytic/granulomatous inflammation and associated with Th1-type cytokine secretion.

Molecular and biochemical characterization of JAK3 deficiency in a patient with severe combined immunodeficiency over 20 years after bone marrow transplantation: implications for treatment.

Severe combined immunodeficiency (SCID) comprises a heterogenous group of disorders that are fatal unless treated by bone marrow transplantation (BMT). The most common form of SCID (T-B+ SCID) is due to mutations of either the common gamma chain (gammac) or of gammac-coupled JAK3 kinase. We report an unusual JAK3 defect in a female who was successfully treated > 20 years ago with a BMT using her HLA-identical father as the donor. Persistence of genetically and biochemically defective autologous B cells, associated with reconstitution of cellular and humoral immunity, suggests that integrity of the gammac-JAK3 signalling pathway is not strictly required for immunoglobulin production.