What is the recommended management and treatment plan for a patient with Chediak‑Higashi syndrome, including hematopoietic stem‑cell transplantation and infection prophylaxis?

Management of Chediak-Higashi Syndrome

Hematopoietic stem cell transplantation (HSCT) is the definitive treatment for Chediak-Higashi syndrome and should be performed as early as possible, ideally before the onset of the accelerated phase (hemophagocytic lymphohistiocytosis), as this significantly improves survival outcomes. 1

Diagnostic Confirmation

The first step is examining a peripheral blood smear, which will reveal pathognomonic giant azurophilic lysosomal granules in all granulated cells (neutrophils, eosinophils, monocytes, and lymphocytes) 1. This finding, combined with the clinical triad of partial oculocutaneous albinism, recurrent pyogenic infections (primarily skin and respiratory tract), and neurological manifestations (photophobia, nystagmus, cognitive impairment), confirms the diagnosis.

Infection Prophylaxis and Supportive Care

While awaiting HSCT, aggressive infection management is critical:

• Antimicrobial prophylaxis for pyogenic bacterial infections affecting skin, respiratory tract, and other organs
• Dental care is essential given the high frequency of gingivitis, oral ulcerations, and periodontal disease 1
• Monitor for bleeding complications due to the mild coagulation defect that can worsen during the accelerated phase 1

Management of Accelerated Phase (HLH)

Approximately 85% of CHS patients will develop the accelerated phase (hemophagocytic lymphohistiocytosis), which presents with:

• High unremitting fever
• Hepatosplenomegaly
• Pancytopenia
• Elevated liver enzymes, ferritin, triglycerides
• Hypofibrinogenemia 1

If accelerated phase occurs, immediately initiate HLH-2004 protocol chemotherapy to induce remission before proceeding to HSCT 1, 2. The treatment principles for HLH in CHS are identical to other familial hemophagocytic lymphohistiocytosis contexts 1.

Hematopoietic Stem Cell Transplantation Strategy

Donor selection hierarchy:

1. HLA-matched sibling donor (preferred, best outcomes) 3
2. Unrelated donor (acceptable alternative when matched sibling unavailable) 3, 4
3. Umbilical cord blood transplantation (UCBT) (effective option, can restore hematologic and immunologic functions even with mixed chimerism) 5, 2, 4

Critical timing considerations:

• Transplant BEFORE accelerated phase onset whenever possible 3, 6
• If accelerated phase has occurred, achieve remission with chemotherapy first, then proceed to HSCT 2, 7
• Patients transplanted during active accelerated phase have significantly worse outcomes (only 4 of 11 survivors in one series) 3
• Early referral to transplant center is essential 3

The 5-year overall survival after HSCT is approximately 62% 3. Survival is highest in patients transplanted in remission and lowest in those with active accelerated phase disease at transplantation 3.

Important Caveats

HSCT corrects the hematologic and immunologic defects but does NOT prevent or reverse the neurological manifestations (neuropathies, cognitive impairment) or oculocutaneous albinism 1, 8. These progressive neurological symptoms will continue despite successful transplantation.

Conditioning regimens typically include busulfan, cyclophosphamide, antithymocyte globulin (ATG), and etoposide 4. Post-transplant monitoring should include chimerism studies, as mixed chimerism can occur but may still provide adequate immune reconstitution 4.

The window for successful intervention is narrow - without HSCT, the accelerated phase is usually fatal 1, 6. Even with adherence to HLH protocols, progression to septic shock and death can occur rapidly 6, making early diagnosis and prompt transplant referral life-saving priorities.