NCT06573671

Histiocytosis in Injecting Drug Users

• Status: Enrolling By Invitation
• Phase: —
• Study type: Observational
• Enrollment: 30 (estimated)
• Sponsor: Tampere University Hospital · Academic / Other
• Sex: All
• Age: 18 Years – 70 Years
• Healthy volunteers: —

Summary

The goal of this observational study is to describe a new disease condition of histiocytosis related to injecting drug use, its preconditions, symptoms, signs, findings, and prognosis in a detailed and systematic patient series in one referral center. The main question\[s\] it aims to answer are: * to find specific histologic features in different tissues to help the differential diagnosis from other histiocytoses * to describe the value of chitotriosidase activity to screen this condition * to describe the value of various tissue biopsies in confirming the diagnosis * to describe the nature of polyvinylpyrrolidone accumulation in tissue macrophages by novel special microscopic techniques * to find new tandem mass spectrometry methodology to prove polyvinylpyrrolidone accumulation in macrophages * to show that polyvinylpyrrolidone treatment activates macrophages to histiocytes and causes povidone accumulation within the cells in in vitro experiments * to evaluate the pathology of macrophage activation to histiocytes by transcriptomics The patient history will be collected from the data produced by follow-up of cases followed up in a single center. A subgroup of participants will be given an opportunity to sign informed consent to give access to/donate blood and tissue samples to search for techniques to prove polyvinylpyrrolidone storage within histiocytes, and to search for transcriptomics signal(s) in histiocytes. Researchers will compare blood and tissue samples from the biobank as controls.

Detailed description

Comprehensive patient data (disease history, findings, complications, laboratory findings, histopathology, and imaging) will be obtained from patient records of a single university hospital. Coded histiocytosis-positive tissue samples will be compared to biobank samples from corresponding tissues from healthy and other histiocytosis tissue samples to show polyvinylpyrrolidone storage with novel methodologies. In addition, if a study participant who is followed up clinically, signs informed consent, monocytes are separated from a blood sample, differentiated to macrophages, and exposed to polyvinylpyrrolidone. Various novel methods will be utilized to explore polyvinylpyrrolidone within histiocytes.

Conditions

• Histiocytosis

Interventions

Type	Name	Description
DIAGNOSTIC_TEST	Chitotriosidase	The amount of patients with increased chitotriosidase, and the extent of elevation of chitotriosidase
DIAGNOSTIC_TEST	Mass spectrometry	to show polyvinylpyrrolidone presence in histiocytes of injecting drug users compared to controls
DIAGNOSTIC_TEST	scanning electron microscope with energy-dispersive X-ray spectroscopy	to show polyvinylpyrrolidone presence in histiocytes of injecting drug users compared to controls
DIAGNOSTIC_TEST	Fluorescence microscopy	to show polyvinylpyrrolidone presence in histiocytes of injecting drug users compared to controls
DIAGNOSTIC_TEST	Transcriptomics	To describe pathologic signals of polyvinylpyrrolidone-exposed in vitro histiocytes of injecting drug users compared to control samples

Timeline

• Start date: 2023-05-29
• Primary completion: 2030-12-31
• Completion: 2030-12-31
• First posted: 2024-08-27
• Last updated: 2025-09-10

Locations

1 site across 1 country: Finland