OBJECTIVE: Leukocyte adhesion deficiency (LAD) represents a rare group of inherited inborn errors of immunity (IEI) characterized by bacterial infections, delayed umbilical stump separation, and autoimmunity. This single-center study aimed at describing the clinical, immunological, and molecular characterizations of 34 LAD-I Egyptian pediatric patients.
METHODS: Details of 34 patients\' personal medical history, clinical and laboratory findings were recorded; Genetic material from 28 patients was studied. Mutational analysis was done by Sanger sequencing.
RESULTS: Omphalitis, skin and soft tissue infections with poorly healing ulcers, delayed falling of the umbilical stump, and recurrent or un-resolving pneumonia were the most common presentations, followed by chronic otitis media, enteropathy, periodontitis; and recurrent oral thrush. Persistent leukocytosis and neutrophilia were reported in all patients, as well as CD18 and CD11b deficiency. CD18 expression was < 2% in around 90% of patients. Sixteen different pathological gene variants were detected in 28 patients who underwent ITGß2 gene sequencing, of those, ten were novel and six were previously reported. Three families received a prenatal diagnosis. Patients were on antimicrobials according to culture\'s results whenever available, and on prophylactic Trimethoprim-Sulfamethoxazole 5 mg/kg once daily, with regular clinical follow up. Hematopoietic stem cell transplantation (HSCT) was offered for 4 patients. However due to severity of the disease and delay in diagnosis, 58% of the patients passed away in the first 2 years of life.
CONCLUSIONS: This study highlights the importance of early diagnosis and distribution of ITGß2 gene mutation in Egyptian children. Further molecular studies, however, remain a challenging necessity for better disease characterization in the region.

UNASSIGNED: Leukocyte adhesion deficiency type 1 (LAD-1) is a congenital immunodeficiency leading to impaired trafficking of neutrophils to inflammation sites. Solitary or multiple pyoderma gangrenosum (PG)-like skin ulcers (PGLUs) have been reported previously in 13 children (aged 0.5-19 years) with LAD-1.
UNASSIGNED: Our aim was to report the case of a 10-year-old boy presenting with PGLUs as the first manifestation of LAD-1 treated with ustekinumab.
UNASSIGNED: We obtained in situ cytokine profiles.
UNASSIGNED: PGLUs were triggered by cutaneous ringworm infection (Trichophyton tonsurans). Skin biopsy samples showed increased intralesional expression of IL-17A, Il-23, and IL-1β as compared with their expression in healthy controls. After an unsuccessful attempt at treatment with oral methylprednisolone, ustekinumab induced regression of the ulcerations, associated with complete normalization of the cytokine profile.
UNASSIGNED: PGLUs, triggered by ringworm infection, can be a late harbinger of LAD-1. Ustekinumab is a safe and effective therapeutic option for patients with LAD-1 and PGLUs while bridging the time until stem cell transplantation.

Leukocyte adhesion deficiency-III (LAD-III) is a rare recessive autosomal disorder characterized by bleeding syndrome of Glanzmann-type and life-threatening infections. The main etiology of this condition is variations in the FERMT3 gene, which encodes kindlin-3, an integrin-binding protein. This protein is responsible for the activation of fibrinogen receptors and integrin-mediated hematopoietic cell adhesion. So far, only limited cases of LAD-III have been reported. This case report discusses a two-year-old male infant from the Asir region, Saudi Arabia, who was referred to the pediatric hematology service due to recurrent ecchymosis and epistaxis. He was born at full term with a history of transient tachypnea of the newborn and recurrent bronchiolitis. The patient exhibited normal platelet count and coagulation profiles alongside a familial history of bleeding disorders, including a cousin with a similar condition. The patient also presented with hypospadias and café-au-lait spots. Laboratory findings revealed anemia, microcytosis, and hypochromia indicative of iron deficiency anemia. Whole exome sequencing (WES) identified a homozygous variant of uncertain significance in the FERMT3 gene, associated with autosomal recessive LAD-III. The patient was subsequently referred to an immunology subspecialty for further investigation and bone marrow transplant preparation. This case underscores the importance of comprehensive clinical and genetic evaluations in pediatric patients with unexplained bleeding tendencies.

Leukocyte adhesion deficiency-III (LAD-III) is a rare genetic disease caused by defective integrin activation in hematopoietic cells due to mutations in the FERMT3 gene. The PTPRQ gene encodes the protein tyrosine phosphatase receptor Q and is essential for the normal maturation and function of hair bundle in the cochlea. Homozygous PTPRQ mutations impair the stereocilia in hair cells which lead to nonsyndromic sensorineural hearing loss (SNHL) with vestibular dysfunction. Here, we report two novel pathogenic homozygous mutations found in two genes, FERMT3 and PTPRQ , in a Brazilian patient with LAD-III and SNHL, which may develop our understanding of the phenotype-genotype correlation and prognosis of patients with these rare diseases.

Leukocyte adhesion deficiency (LAD), a disorder of neutrophil function, is characterized by a defect in leukocyte adhesion to the endothelium. Recurrent infections in the skin, soft tissue, gingiva, and lungs due to Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella sp. are common in these patients. Ecthyma gangrenosum (EG) is an ulcer of skin and subcutaneous tissue with a black eschar and surrounding erythematous halo secondary to a bacterial infection. Here, we report an unusual presentation of LAD type-1 with extensive EG of perineum secondary to Staphylococcus hominis bacteremia treated successfully with combination of granulocyte transfusion and diversion colostomy.

UNASSIGNED: Partial leukocyte adhesion deficiency type 1 (LAD-1) deficiency is extremely rare condition with milder infectious manifestation and immune system imbalance leads to increased risks of autoinflammatory complications, such as pyoderma gangrenosum, that can be triggered by trauma or pregnancy. In patients with spice-site ITGB2 variants, partial expression can occur due to different β2 integrin isophorms expression.
UNASSIGNED: LAD-1, OMIM ID #116920 is a rare, autosomal recessive disorder that results from mutations in the ITGB2 gene that encodes the CD18 β2 integrin subunit. According to the CD18 expression, LAD-1 is categorized as severe (<2%), moderate (2%-30%), or mild (>30%). Here, we describe a 22-year-old female, who presented with inflammatory skin disease and oral cavity, as well as respiratory tract infections during the first year of life. LAD-1 was diagnosed at the age of 2 years by low expression of CD18 (1%). Whole-exome sequencing identified homozygous c. 59-10C>A variant in the ITGB2 gene. Despite severe phenotype, the patient survived to adulthood without hematopoietic stem cell transplantation and became pregnant at the age of 20 years, with pregnancy complicated by a pyoderma gangrenosum-like lesion. During her life, CD18 expression increased from 1% to 9%; at 22 years of age, 5% of neutrophils and 9% of lymphocytes were CD18+. All CD18+-lymphocytes were predominantly memory/effector cytotoxic T cells. However, revertant mosaicism was not being established suggesting that CD18 expression variability may be mediated by other mechanisms such as different β2 integrin isophorms expression.

In 15 Turkish LAD-1 patients and controls, we assessed the impact of pathogenic ITGB2 mutations on Th17/Treg differentiation and functions, and innate lymphoid cell (ILC) subsets. The percentage of peripheral blood Treg cells, in vitro-generated induced Tregs differentiated from naive CD4+ T cells were decreased despite the elevated absolute counts of CD4+ cells in LAD-1 patients. Serum IL-23 levels were elevated in LAD-1 patients. Post-curdlan stimulation, LAD-1 patient-derived PBMCs produced more IL-17A. Additionally, the percentages of CD18-deficient Th17 cells expanded from total or naïve CD4+ T cells were higher. The blood ILC3 subset was significantly elevated in LAD-1. Finally, LAD-1 PBMCs showed defects in trans-well migration and proliferation and were more resistant to apoptosis. Defects in de novo generation of Tregs from CD18-deficient naïve T cells and elevated Th17s, and ILC3s in LAD-1 patients\' peripheral blood suggest a type 3-skewed immunity and may contribute to LAD-1-associated autoimmune symptoms.

Pyoderma gangrenosum is a rare neutrophilic dermatosis characterized by painful skin ulcers with necrotic, undermined margins. In severe cases, particularly in pediatric patients, work-up for an associated autoimmune, inflammatory, malignant, or genetic disorder should be considered based on the clinical presentation. We report a unique case of pediatric pyoderma gangrenosum with a leukemoid reaction, secondary to an autosomal recessive leukocyte adhesion deficiency type 1.

Leukocyte adhesion deficiency-III (LAD-III) is an extremely rare autosomal recessive syndrome caused by mutations in FERMT3, the gene encoding kindlin-3. The genetic alterations in this gene lead to abnormal expression or activity of kindlin-3 in leukocytes and platelets. Kindlin-3 acts as an important regulator of integrin activation. LAD-III has features of the bleeding syndrome of Glanzmann and also of leukocyte adhesion deficiency. In this study, we report on two families, one of Turkish and one of Syrian origin, with clinical features of LAD-III, loss of kindlin-3 protein expression, and a functional leukocyte defect. A novel, homozygous deletion in FERMT3 (c.921delC, p.Ser307Argfs*21) was found in the Turkish patient. The parents were carriers of the mutation, consistent with an autosomal recessive inheritance. A common c.1525C > T (p.Arg509*) mutation was found in the Syrian patient. In conclusion, beside the variant c.1525C > T in the FERMT3 gene, which was previously found in more than 15 patients in Anatolia, our study is the first to identify the novel homozygous variant c.921delC in the FERMT3 gene.

Leukocyte adhesion deficiency type I (LAD-I) is a rare autosomal recessive inborn error of immunity (IEI) caused by the defects in CD18, encoded by the ITGB2 gene. LAD-I is characterized by defective leukocyte adhesion to the vascular endothelium and impaired migration of leukocytes. Allogeneic hematopoietic cell transplant (HCT) is the only curative treatment for LAD-I. In an absence of ideal donor for HCT, human leukocyte antigen (HLA)-haploidentical HCT is performed. Posttransplant cyclophosphamide (PT-CY) is a relatively new graft-versus-host disease (GVHD) prophylactic measure and has been increasingly used in HLA-haploidentical HCT for malignant and nonmalignant diseases. However, experience in using PT-CY for rare IEIs, such as LAD-I, is very limited. We report a case of LAD-I successfully treated with HLA-haploidentical HCT with PT-CY. Complete chimerism was achieved, and the patient was cured. Her transplant course was complicated by mild GVHD, cytomegalovirus reactivation and veno-occlusive disease/sinusoidal obstruction syndrome, which were successfully treated. HLA-haploidentical HCT with PT-CY is a safe and effective option for patients with LAD-I when HLA-matched donors are unavailable.