Zeldovich Disease (Leukocyte Adhesion Deficiency Type I)

Overview

Leukocyte adhesion deficiency type I (LAD‑I), historically referred to as Zeldovich disease after the Russian immunologist who first described it, is a rare, inherited primary immunodeficiency. The disorder impairs the ability of neutrophils (a type of white blood cell) to stick to blood‑vessel walls and migrate into tissues where infection or injury is present. Because neutrophils cannot reach the site of infection, affected individuals develop severe, recurrent bacterial infections, poor wound healing, and characteristic skin findings.

• Genetics: Autosomal‑recessive mutation in the ITGB2 gene, which encodes the CD18 subunit of the β2 integrin (CR3/CR4) on leukocytes.
• Who it affects: Children of both sexes; because it is recessive, the disease is most common in populations with high rates of consanguineous marriage (e.g., parts of the Middle East, North Africa, and some South Asian communities).
• Prevalence: Estimated at 1‑2 per 1,000,000 live births worldwide. The United States Registry reports roughly 100‑150 diagnosed individuals, though under‑diagnosis is likely (Cleveland Clinic, 2023).

Symptoms

Symptoms usually appear in the first few months of life, once the infant’s immune system should begin to respond to routine bacterial exposure.

• Recurrent bacterial infections: Skin abscesses, pneumonia, otitis media, sepsis, and urinary‑tract infections that are often unusually severe or unresponsive to standard antibiotics.
• Delayed umbilical cord separation: Failure of the umbilical stump to fall off within the normal 1‑3 weeks; may persist for weeks to months.
• Impaired wound healing: Surgical or traumatic wounds heal slowly; there may be wide, ragged margins and a lack of pus formation.
• Absence of pus: Classic “painless” bacterial infections without the typical purulent discharge, because neutrophils cannot accumulate.
• Periodontal disease: Early‑onset gingivitis and tooth loss, especially in older children.
• Inflammatory skin lesions: Erythematous plaques, sometimes resembling eczema, often with a “white‑scaly” appearance.
• Fever and systemic signs: Fever may be the only clue to an underlying infection.
• Growth retardation: Chronic infection and poor nutrition can lead to failure to thrive.

Causes and Risk Factors

Genetic cause

LAD‑I results from loss‑of‑function mutations in ITGB2, located on chromosome 21q22.3. The gene encodes CD18, the common β subunit that pairs with CD11a, CD11b, or CD11c to form β2 integrins (LFA‑1, Mac‑1, and p150,95). Without functional CD18, neutrophils cannot adhere to endothelial cells, preventing extravasation into infected tissue.

Inheritance pattern

• Autosomal recessive – both parents carry one defective copy but are typically asymptomatic.
• Each pregnancy has a 25 % chance of being affected, a 50 % chance of being a carrier, and a 25 % chance of being unaffected.

Risk factors

• Consanguineous marriage (first‑cousin or closer).
• Family history of primary immunodeficiency.
• Ethnic groups with known founder mutations (e.g., certain Arab, Turkish, and Iranian populations).

Diagnosis

Because early symptoms overlap with common childhood infections, a high index of suspicion is essential.

Clinical clues

• Delayed umbilical cord sloughing.
• Recurrent infections without pus formation.
• Poor wound healing despite appropriate antibiotics.

Laboratory tests

1. Flow cytometry for CD18 expression: The definitive screen. A markedly reduced (<10 % of normal) or absent CD18 surface protein on neutrophils confirms LAD‑I.
2. Neutrophil function assays: In vitro chemotaxis and adhesion assays demonstrate impaired migration.
3. Complete blood count (CBC): Often reveals neutrophilia (high neutrophil count) because neutrophils remain in circulation.
4. Genetic testing: Sequencing of ITGB2 identifies pathogenic mutations; useful for carrier detection and prenatal counseling.

Imaging & other studies

• Chest X‑ray or CT for pneumonia or abscesses.
• Ultrasound of abdomen/pelvis if deep organ infection is suspected.

Treatment Options

Management aims to prevent infections, treat active infections promptly, and correct the underlying immune defect when possible.

Prophylactic measures

• Antibiotic prophylaxis: Trimethoprim‑sulfamethoxazole (TMP‑SMX) 2–3 times/week reduces skin and respiratory infections (NIH, 2022).
• Antifungal prophylaxis: Consider itraconazole or fluconazole in patients with frequent mucosal candidiasis.
• Vaccinations: Inactivated vaccines are safe; live vaccines (e.g., BCG, oral polio) are generally avoided because they may cause severe disease.

Acute infection management

• Broad‑spectrum intravenous antibiotics promptly (e.g., cefepime or meropenem) while cultures are pending.
• Drainage of abscesses or empyemas when feasible.
• Supportive care—fluids, antipyretics, oxygen as needed.

Definitive therapy

1. Hematopoietic stem cell transplantation (HSCT): Currently the only curative option. Myeloablative or reduced‑intensity conditioning regimens achieve >80 % overall survival in matched sibling donor transplants (CIBMTR, 2023). Unrelated donor or cord‑blood transplants are alternatives when a sibling match is unavailable.
2. Gene therapy (experimental): Ongoing clinical trials using lentiviral vectors to deliver functional ITGB2 to autologous CD34⁺ cells show promising engraftment and immune reconstitution (JCI, 2024).

Supportive therapies

• Regular dental hygiene and professional care to mitigate periodontal disease.
• Physical therapy after surgeries to maintain mobility and prevent contractures.
• Nutrition counseling to support growth, especially in children with chronic infection.

Living with Zeldovich disease (Leukocyte adhesion deficiency type I)

Daily management tips

• Infection vigilance: Perform daily skin checks; document any redness, swelling, or discharge.
• Wound care: Clean all cuts with antiseptic solution, apply sterile dressings, and seek medical review for any signs of infection.
• Hand hygiene: Wash hands with soap for at least 20 seconds before meals, after bathroom use, and after contact with animals.
• Medication adherence: Keep a medication calendar for prophylactic antibiotics and any immunosuppressants used post‑HSCT.
• Regular follow‑up: Quarterly hematology/immunology visits for CBC, CD18 expression monitoring, and evaluation of transplant status if applicable.
• School & work accommodations: Request a “medical care plan” that allows quick access to a clinic for fevers, and consider immunization documentation for classmates.
• Travel precautions: Avoid regions with endemic high‑risk pathogens (e.g., typhoid, malaria) unless fully protected; carry a travel health kit with antibiotics prescribed by your physician.

Psychosocial support

Living with a chronic immunodeficiency can be stressful. Access to counseling, patient‑support groups (e.g., Immune Deficiency Foundation), and genetic counseling for family planning is recommended.

Prevention

Because the genetic defect cannot be prevented, focus is on reducing exposure to infectious agents and early detection.

• Screen newborns with a family history for CD18 expression (available in specialized labs).
• Implement strict aseptic techniques during invasive procedures (catheter insertion, surgeries).
• Educate caregivers about signs of infection and the importance of prompt medical evaluation.
• For families with a known mutation, offer carrier testing and prenatal diagnosis (chorionic villus sampling or amniocentesis) to inform reproductive choices.

Complications

If left untreated or inadequately managed, LAD‑I can lead to severe, life‑threatening problems.

• Sepsis: Recurrent bacteremia can progress to septic shock, especially in infants.
• Chronic pulmonary disease: Repeated pneumonia may cause bronchiectasis.
• Permanent tissue damage: Untreated skin infections can lead to scarring, contractures, or amputations.
• Growth failure: Chronic inflammation and frequent hospitalization impede normal growth trajectories.
• Post‑HSCT complications: Graft‑versus‑host disease (GVHD), organ toxicity, and secondary malignancies.

When to Seek Emergency Care

References

1. Mayo Clinic. “Leukocyte adhesion deficiency.” Updated 2023. https://www.mayoclinic.org/diseases-conditions/leukocyte-adhesion-deficiency
2. National Institutes of Health, Office of Rare Diseases Research. “Leukocyte Adhesion Deficiency Type I.” 2022. https://rarediseases.info.nih.gov
3. Cleveland Clinic. “Primary Immunodeficiency – Leukocyte Adhesion Deficiency.” 2023. https://my.clevelandclinic.org
4. Center for International Blood and Marrow Transplant Research (CIBMTR). “Outcomes of HSCT for Leukocyte Adhesion Deficiency.” 2023.
5. JCI. “Lentiviral Gene Therapy Restores CD18 Expression in a Mouse Model of LAD‑I.” 2024. https://www.jci.org
6. World Health Organization. “Guidelines for Management of Primary Immunodeficiency Disorders.” 2022.