Israel Medical Association Journal

Inborn errors of immunity (IEI), formerly known as primary immunodeficiencies (PID), comprise a diverse group of genetic disorders characterized by increased susceptibility to infections, autoimmunity, autoinflammatory conditions, allergies, and malignancies. These disorders exhibit a broad spectrum of clinical manifestations, including extra-hematopoietic manifestations, which may also present later in life. IEI diagnosis has significantly advanced, in line with the common use of next-generation sequencing-based genetic platforms, such as whole-exome and whole-genome sequencing. Treatment approaches have evolved beyond infection management to include curative therapies such as hematopoietic stem cell transplantation, gene therapy, and targeted pharmacologic treatments. In this review, we explore recent advancements in the understanding, diagnosis, and treatment of IEI, emphasizing the rapid progress in this expanding field.

Background: Late-onset pulmonary complications can occur following hematological stem cell transplantation (HSCT). In allogeneic HSCT these complications are often associated with chronic graft-versus-host disease (GVHD). Lung transplantation (LTx) often remains the only viable therapeutic option in these patients.

Objectives: To describe our experience with LTx due to GVHD after HSCT and to compare the long-term survival of this group of patients to the overall survival of our cohort of LTx recipients for other indications.

Methods: We retrospectively retrieved all data on patients who had undergone LTx for end-stage lung disease as a sequela of allogeneic HSCT, between 1997 and 2021, at Rabin Medical Center in Israel.

Results: A total of 15 of 850 patients (1.7%) from our cohort of LTx recipients fulfilled the criteria of LTx as a sequela of late pulmonary complication after allogeneic HSCT. The median age at the time of HSCT was 33 years (median 15–53, range 3–60). The median time between HSCT and first signs of chronic pulmonary GVHD was 24 months (interquartile range [IQR] 12–80). The median time from HSCT to LTx was 96 months (IQR 63–120). Multivariate analysis showed that patients transplanted due to GVHD had similar survival compared to patients who were transplanted for other indications.

Conclusions: LTx for GVHD after allogeneic HSCT constitutes an important treatment strategy. The overall survival appears to be comparable to patients after LTx for other indications.

Abstract

Background: Human herpes virus-6 (HHV-6) reactivation after hematopoietic stem cell transplantation (HSCT) is well known and has been linked with several clinical manifestations. The significance of HHV-6 viremia and related complications in this setting is still unclear.

Objective: To estimate the incidence of HHV-6 reactivation and associated morbidity in children undergoing allogeneic HSCT.

Methods: Blood samples obtained weekly (for cytomegalovirus surveillance) from children who underwent allogeneic HCST during the period January 2006–June 2010 were retrospectively tested for the presence of HHV-6 DNA using standard real-time polymerase chain reaction (PCR) assay. Clinical records were reviewed for correlation between viremia and clinical manifestations.

Results: Samples from 39 children were tested. Twenty patients had viral loads above 1000 copies/ml (51%) in at least one sample. Higher viral loads were seen in patients with primary immunodeficiency and in those with cord blood transplant. Attributable symptoms were present in 12 patients (60%) concurrently with positive PCR. Clinical manifestations spontaneously resolved without treatment in most cases, concomitantly with a decrease in viral load.

Conclusions: HHV6 reactivation during allogeneic HSCT is common. HHV-6 reactivation should be considered in patients with graft-vs-host disease-like rash, onset of CNS symptoms, delay in engraftment, and in patients after cord blood transplantation.

Objective: To assess the ability of TREC and KREC counts to identify patients with combined T and B cell immunodeficiency in a pilot study in Israel.

Methods: We studied seven children born in Israel during the years 2010–2011 and later diagnosed with SCID, and an additional patient with pure B cell immunodeficiency. TREC and KREC in peripheral blood upon diagnosis and in their neonatal Guthrie cards were analyzed using real-time quantitative polymerase chain reaction, as were Guthrie cards with dried blood spots from healthy newborns and from normal and SCID-like controls.

Results: The first features suggestive of SCID presented at age 3.1 ± 2.4 months in all patients. Yet, the diagnosis was made 4.1 ± 2.9 months later. Their TREC were undetectable or significantly low at their clinical diagnosis and in their originally stored Guthrie cards, irrespective of the amount of their circulating T cells. KREC were undetectable in six SCID patients who displayed B cell lymphopenia in addition to T cell lymphopenia. KREC were also undetectable in one patient with pure B cell immunodeficiency.

Conclusions: TREC and KREC quantification are useful screening tests for severe T and B cell immunodeficiency. Implementation of these tests is highly important especially in countries such as Israel where a high frequency of consanguinity is known to exist.