Leukocyte adhesion deficiency type I (LAD-I)

Doctors usually suspect LAD-I because of early signs. The umbilical cord stump may stay on longer than 21 days or become infected (omphalitis). A routine blood test often shows a very high white blood cell count. Infections that form little or no pus, and wounds that heal slowly, also raise concern.

The key test is flow cytometry. This blood test measures CD18 and the related proteins CD11a and CD11b on neutrophils, a type of white blood cell. An international expert panel says a genetic test of the ITGB2 gene, together with flow cytometry, is the ideal way to confirm LAD-I.

When LAD-I is already known in a family, a newborn can be diagnosed before any symptoms. Doctors use flow cytometry plus a genetic test or the family history. Knowing the family’s gene change also makes testing possible in a later pregnancy.

Until a lasting treatment is possible, care focuses on infection. Children with severe LAD-I take preventive antibiotics and antifungals, and serious infections are often treated in the hospital with long courses of medicine and sometimes surgery. Many specialists also use ustekinumab, an antibody medicine that calms the extra inflammation in LAD-I; it is approved for other conditions, not for LAD-I.

A donor stem cell transplant replaces the blood-forming cells, so new white cells carry CD18. For severe LAD-I, an international expert panel recommends transplant as soon as possible after diagnosis, ideally by about 13 months of age, though older children can still be transplanted. In a European registry study, graft failure and graft-versus-host disease were the main problems, and transplants from a brother or sister had fewer serious complications than those from other donors.

Kresladi (marnetegragene autotemcel) adds a working ITGB2 gene to the child’s own blood-forming stem cells. The FDA gave it accelerated approval on March 26, 2026, for children with severe LAD-I who have no HLA-matched sibling donor. Continued approval depends on a confirmatory study. It requires full-strength (myeloablative) conditioning chemotherapy, and treated children are checked for blood cancer at least once a year for at least 15 years. In the main study of 9 children, the missing proteins rose in every child who could be measured, and none of the 9 needed a donor transplant afterward during about 4 years of follow-up.

The outlook depends most on how severe the disease is and on getting a lasting treatment early. Severe LAD-I is life-threatening in early childhood. An international expert panel agreed that a child who lives past age 2 without a lasting treatment still faces this danger every year. For most children, the risk grows year after year.

A donor transplant can give lasting protection. In the United States, gene therapy is another option for some children with severe LAD-I. In a European registry of people with LAD-I and LAD-III, age at transplant and donor type mattered. Those transplanted at 13 months or older, or from a donor who was not a brother or sister, had more serious graft-versus-host disease. They were also less likely to be alive without graft failure or serious graft-versus-host disease.

Experts have less experience with moderate LAD-I. It can get worse over time, so teams check on it regularly and decide on treatment case by case.