Case Report: Intestinal Nodular Lymphoid Hyperplasia as First Manifestation of Activated PI3Kδ Syndrome Due to a Novel PIK3CD Variant

[Activated phosphoinositide 3-kinase delta syndrome: report of seven cases]

OBJECTIVES

To summarize the clinical data of 7 children with activated phosphoinositide 3-kinase delta syndrome (APDS) and enhance understanding of the disease.

METHODS

A retrospective analysis was conducted on clinical data of 7 APDS children admitted to Hunan Provincial People's Hospital from January 2019 to August 2023.

RESULTS

Among the 7 children (4 males, 3 females), the median age of onset was 30 months, and the median age at diagnosis was 101 months. Recurrent respiratory tract infections, hepatosplenomegaly, and multiple lymphadenopathy were observed in all 7 cases. Sepsis was observed in 5 cases, otitis media and multiple caries were observed in 3 cases, and diarrhea and joint pain were observed in 2 cases. Lymphoma and systemic lupus erythematosus were observed in 1 case each. Fiberoptic bronchoscopy was performed in 4 cases, revealing scattered nodular protrusions in the bronchial lumen. The most common respiratory pathogen was Streptococcus pneumoniae (4 cases). Six patients had a p.E1021K missense mutation, and one had a p.434-475del splice site mutation.

CONCLUSIONS

p.E1021K is the most common mutation site in APDS children. Children who present with one or more of the following symptoms: recurrent respiratory tract infections, hepatosplenomegaly, multiple lymphadenopathy, otitis media, and caries, and exhibit scattered nodular protrusions on fiberoptic bronchoscopy, should be vigilant for APDS. Citation:Chinese Journal of Contemporary Pediatrics, 2024, 26(5): 499-505.

Systematic review of mortality and survival rates for APDS

Activated phosphoinositide 3-kinase delta syndrome (APDS) is a rare genetic disorder that presents clinically as a primary immunodeficiency. Clinical presentation of APDS includes severe, recurrent infections, lymphoproliferation, lymphoma, and other cancers, autoimmunity and enteropathy. Autosomal dominant variants in two independent genes have been demonstrated to cause APDS. Pathogenic variants in PIK3CD and PIK3R1, both of which encode components of the PI3-kinase, have been identified in subjects with APDS. APDS1 is caused by gain of function variants in the PIK3CD gene, while loss of function variants in PIK3R1 have been reported to cause APDS2. We conducted a review of the medical literature and identified 256 individuals who had a molecular diagnosis for APDS as well as age at last report; 193 individuals with APDS1 and 63 with APDS2. Despite available treatments, survival for individuals with APDS appears to be shortened from the average lifespan. A Kaplan-Meier survival analysis for APDS showed the conditional survival rate at the age of 20 years was 87%, age of 30 years was 74%, and ages of 40 and 50 years were 68%. Review of causes of death showed that the most common cause of death was lymphoma, followed by complications from HSCT. The overall mortality rate for HSCT in APDS1 and APDS2 cases was 15.6%, while the mortality rate for lymphoma was 47.6%. This survival and mortality data illustrate that new treatments are needed to mitigate the risk of death from lymphoma and other cancers as well as infection. These analyses based on real-world evidence gathered from the medical literature comprise the largest study of survival and mortality for APDS to date.

Follicular helper T-cell lymphomas: disease spectrum, relationship with clonal hematopoiesis, and mimics. A report of the 2022 EA4HP/SH lymphoma workshop

Follicular helper T-cell lymphomas (TFH lymphomas) were discussed in session V of the lymphoma workshop of the European Association for Haematopathology (EA4HP)/Society for Hematopathology (SH) 2022 meeting in Florence, Italy. The session focused on the morphologic spectrum of TFH lymphoma, including its three subtypes: angioimmunoblastic-type (AITL), follicular-type, and not otherwise specified (NOS). The submitted cases encompassed classic examples of TFH lymphoma and unusual cases such as those with early or indolent presentations, associated B-cell proliferations, or Hodgkin/Reed-Sternberg-like cells. The relationship between TFH lymphoma and clonal hematopoiesis was highlighted by several cases documenting divergent evolution of myeloid neoplasm and AITL from shared clonal mutations. The distinction between TFH lymphoma and peripheral T-cell lymphoma, not otherwise specified (PTCL, NOS), was stressed, and many challenging examples were presented. Various cases highlighted the difficulties of differentiating TFH lymphoma from other established types of lymphoma and reactive conditions. Cutaneous T-cell lymphoma expressing TFH markers, particularly when resulting in lymph node involvement, should be distinguished from TFH lymphomas. Additional immunophenotyping and next-generation sequencing studies were performed on various cases in this session, highlighting the importance of these technologies to our current understanding and classification of TFH lymphomas.

Characterization of the mucosal microbiota in patients with nodular lymphoid hyperplasia with concurrent irritable bowel syndrome compared to healthy controls

BACKGROUND

Nodular lymphoid hyperplasia (NLH) is known as a lymphoproliferative lesion in which multiple small nodules appear on the intestinal wall. It has been documented that patients who struggle with irritable bowel syndrome (IBS) are at greater risk of developing NLH. Here, we aimed to investigate the previously reported pathogens and the abundance of a selection of mucosal microbiota in IBS + NLH patients compared to IBS, and healthy controls.

METHODS AND RESULTS

Terminal ileum biopsies were collected from 37 IBS + NLH, 37 IBS, and 29 healthy controls. Bacterial culture and PCR was performed to detect the presence of pathogens in biopsies. A qPCR assay was applied to assess the abundance of a selection of bacterial taxa. Totally, five bacterial isolates including two enteropathogenic and one enteroaggregative Escherichia coli (EPEC, EAEC), one enterotoxigenic Staphylococcus aureus (SEA), and one Yersinia enterocolitica strains were detected among the IBS + NLH cases. The relative abundance of Bacteroidetes and Streptococcus spp. in IBS + NLH patients was significantly less than IBS and healthy controls. Firmicutes, Pseudomonas spp., Haemophilus spp., and Campylobacter spp. were notably more abundant in IBS + NLH than in IBS patients. The abundance of Verrucomicrobia was higher in NLH + IBS than in healthy controls. Actinobacteria was also significantly more abundant among NLH + IBS patients than the controls.

CONCLUSION

Our results demonstrated that mucosal microbiota composition in NLH + IBS patients slightly differs from that of IBS patients and healthy controls. Further research using large-scale cohorts are needed to enhance current understanding of the contribution of the mucosal microbiota to NLH pathogenesis with concurrent IBS.