Clinical and Genetic Findings of the First Report of PAPA Syndrome in Brazil

Background. PAPA syndrome (MIM #604416) is a rare monogenic autoinflammatory disease genetically transmitted in an autosomal dominant trait that results from missense mutations in the proline-serine-threonine phosphatase-interactive protein 1 (PSTPIP1) gene located on chromosome 15 and is characterized by sterile pyogenic arthritis, pyoderma gangrenosum, and cystic acne. We describe the clinical and molecular findings of two related Brazilian patients with PAPA syndrome. Case Presentation. A 7-year-and-3-month-old boy with nonconsanguineous parents had had recurrent pyoarthritis since the age of 5 years and 8 months. During his last and long hospitalization, the lack of improvement with antibiotics, evidence of increased inflammatory activity, repeated arthrotomies, draining purulent fluid that had negative cultures, and the history of trauma, all on in a clinical background of pyoarthritis, led to the suspicion of an autoinflammatory syndrome. This was confirmed by the good clinical response to corticotherapy. Genetic sequencing confirmed the diagnosis of PAPA syndrome, with the pathogenic mutation c.688 G > A (p. Ala230Thr) in the PSTPIP1 gene present in the patient and in the mother. Conclusions. This case illustrates that in children with recurrent/recalcitrant sterile recurrent pyogenic arthritis/osteomyelitis, the possibility of an underlying immunological condition should be considered. In both, recurrent infections or recurrent inflammation, many genes involved in the inborn errors of immunity can be associated, and a correct and precocious diagnosis is necessary to avoid mobility and mortality. To the best of our knowledge, this is the first report of PAPA syndrome in Brazil.

Kidney Involvement in PSTPIP1 Associated Inflammatory Diseases (PAID): A Case Report and Review of the Literature

Pyogenic arthritis, pyoderma gangrenosum and acne (PAPA) syndrome, and the proline-serine-threonine phosphatase-interacting protein 1 (PSTPIP1)-associated myeloid-related proteinemia inflammatory (PAMI) syndrome are two distinct clinical conditions caused by heterozygous mutations of the PSTPIP1 gene. While skin and joint involvements are shared by both conditions, PAMI is characterized by hepatosplenomegaly, pancytopenia, and growth failure. Kidney involvement is exceptional in PSTPIP1-mediated disorders. The two missense PSTPIP1 variants associated with PAMI syndrome are p.E250K and p.E257K. Long-term treatment with interleukin (IL)-1 inhibitors is effective to control inflammatory manifestations and is usually well-tolerated. We report a case of a patient carrying the PSTPIP1 p.E250K mutation who developed a late-onset kidney involvement despite a long treatment with canakinumab and anakinra. Kidney biopsy showed focal segmental glomerulosclerosis that was treated with tacrolimus (0.1 mg/kg/day in two doses). A literature revision with the aim to assess the proportion and type of kidney involvement in PAMI syndrome revealed that heterogeneous nephropathies may be part of the clinical spectrum. Our study supports the importance of a periodic diagnostic work-up, including kidney laboratory tests and kidney biopsy, in individuals affected with PAMI syndrome. Kidney and liver functions may be impaired regardless of anti-cytokines treatments and additional therapy approaches (i.e., multi-drugs, hematopoietic stem cell transplantation) should be carefully considered.

Case Report: Pyogenic Arthritis, Pyoderma Gangrenosum, and Acne: A Single-Center Experience and Literature Review

ObjectivesThis study aims to describe the characteristics of patients diagnosed with pyogenic arthritis, pyoderma gangrenosum, and acne (PAPA) syndrome at a single center in China and provide an up-to-date literature review.MethodsThe clinical data and genotype of three Chinese Han patients were carefully documented and studied. We also conducted a systematic literature review on PAPA syndrome.ResultsA total of three patients were diagnosed with PAPA syndrome at our center from 2018 to 2020. Arthritis was observed in all three patients, while pyoderma gangrenosum (PG) was found in two patients and acne in one patient. Other manifestations included pathergy reaction, intermittent fever, oral ulcer, keratitis, proteinuria, and hematuria. The PSTPIP1 A230T mutation was identified in two patients, and a novel Y119C variation was revealed in a sporadic patient. A total of 76 patients with PAPA syndrome reported in 29 articles were included in our literature review. The classical triad of arthritis, PG, and acne was visible in only 16 (25.4%) patients, while 24 (38.1%) exhibited only one major symptom. Skin lesions were more commonly seen in patients with adult-onset disease than those with childhood-onset disease (100 vs. 83%), whereas arthritis was less common (50 vs. 98.1%). Steroid and/or biological agents were effective in most patients.ConclusionsThe rarity and phenotypic heterogeneity associated with PAPA syndrome make the diagnosis a huge challenge to physicians, especially in adult patients. A significant portion of patients did not exhibit the full spectrum of the classical triad. Accordingly, gene testing is critically helpful for diagnosis.

Immunological repertoire linked to PSTPIP1-associated myeloid-related inflammatory (PAMI) syndrome

Background Mutations along PSTPIP1 gene are associated to two specific conditions, PAPA syndrome and PAMI syndrome, both autoinflammatory disorders associated to disturbances in cytoskeleton formation. Immunological aspects of PAMI syndrome has not yet been reported neither the clinical impact on therapeutical decisions. Methods Clinical data of patients records were retrospectively accessed. Genomic DNA were extracted and sequenced following standard procedures. Peripheral lymphocytes were quantified in T, B e FOXP3 phenotypes. Results We describe two related patients with PAMI syndrome harboring the usual E250K mutation. Anti-IL1 therapy could partially control the disease in the index patient. A broad spectrum of immunological effects as well as an aberrant expression of FOXP3 could be observed. Conclusions Here we report two related brazilian patients with PAMI syndromes harboring the E250K mutation in PSTPIP1, their immunological aspects and the therapeutical response to canakinumab.

Immunological repertoire linked to PSTPIP1-associated myeloid-related inflammatory (PAMI) syndrome

Background: Mutations along PSTPIP1 gene are associated to two specific conditions, PAPA syndrome and PAMI syndrome, both autoinflammatory disorders associated to disturbances in cytoskeleton formation. Immunological aspects of PAMI syndrome has not yet been reported neither the clinical impact on therapeutical decisions.Methods: Clinical data of patients records were retrospectively accessed. Genomic DNA were extracted and sequenced following standard procedures. Peripheral lymphocytes were quantified in T, B e FOXP3 phenotypes.Results: We describe two related patients with PAMI syndrome harboring the usual E250K mutation. Anti-IL1 therapy could partially control the disease in the index patient. A broad spectrum of immunological effects as well as an aberrant expression of FOXP3 could be observed.Conclusions. Here we report two related brazilian patients with PAMI syndromes harboring the E250K mutation in PSTPIP1, their immunological aspects and the therapeutical response to canakinumab.

Excess Serum Interleukin-18 Distinguishes Patients with Pathogenic Mutations in PSTPIP1

ABSTRACTObjectiveDominantly-inherited mutations in PSTPIP1 cause a family of monogenic autoinflammatory diseases epitomized by Pyogenic Arthritis, Pyoderma gangrenosum, and Acne (PAPA) syndrome. The connections between PSTPIP1 and PAPA are poorly understood, although in vitro evidence suggests increased activation of the pyrin-inflammasome. We sought to identify biomarkers of potential mechanistic, diagnostic, and therapeutic utility specific to autoinflammatory diseases.MethodsClinical and genetic data and sera were obtained from patients referred with concern for PAPA syndrome, as well as relevant disease controls. Serum Interleukin-18 (IL-18) and related biomarkers were assessed by bead-based assay.ResultsSymptoms in PSTPIP1 mutation-positive PAPA patients overlapped with those of mutation-negative PAPA-like patients, but the former were younger at onset and had more arthritis. We found uniform elevation of total IL-18 in PAPA patients at a level approaching NLRC4-associated Macrophage Activation Syndrome (MAS) and well beyond Familial Mediterranean Fever. IL-18 elevation in PAPA patients’ sera persisted despite fluctuations in disease activity. IL-18 Binding Protein (IL-18BP) was modestly elevated, and as such PAPA patients had detectable free IL-18. PAPA patients did not develop MAS, and CXCL9 (an indicator of Interferon-gamma activity) was rarely elevated in their sera.ConclusionPAPA syndrome is a refractory, and often disabling monogenic autoinflammatory disease associated with chronic elevation of serum IL-18, but not risk for MAS. This finding instructs our understanding of the origins of excess IL-18, its potential spectrum of pathogenic effects, and the possible role for IL-18 blockade in refractory PAPA syndrome.

Actin Remodeling Defects Leading to Autoinflammation and Immune Dysregulation

A growing number of monogenic immune-mediated diseases have been related to genes involved in pathways of actin cytoskeleton remodeling. Increasing evidences associate cytoskeleton defects to autoinflammatory diseases and primary immunodeficiencies. We reviewed the pathways of actin cytoskeleton remodeling in order to identify inflammatory and immunological manifestations associated to pathological variants. We list more than twenty monogenic diseases, ranging from pure autoinflammatory conditions as familial Mediterranean fever, mevalonate kinase deficiency and PAPA syndrome, to classic and novel primary immunodeficiencies as Wiskott-Aldrich syndrome and DOCK8 deficiency, characterized by the presence of concomitant inflammatory and autoimmune manifestations, such as vasculitis and cytopenia, to severe and recurrent infections. We classify these disorders according to the role of the mutant gene in actin cytoskeleton remodeling, and in particular as disorders of transcription, elongation, branching and activation of actin. This expanding field of rare immune disorders offers a new perspective to all immunologists to better understand the physiological and pathological role of actin cytoskeleton in cells of innate and adaptive immunity.