Table 4.

Selected studies in aSyn-SAA and skin immunofluorescence/immunohistochemistry

Study	Assay	Sample	Subjects	PD duration	Results
aSyn-SAA
Fairfoul et al. [17]	0.1 mg/ml rec aSyn WT (Stratech)	BH and CSF	Discovery: DLB:29 PD:2 AD:30 PSP:2 CBS:3 ILBD:13 HC: 20 Validation: PD:20 HC:15 RBD: 3	Not provided	DLB v HC: Sns 0.92, Spc: 1.00 PD v HC: Sns 0.95, Spc: 1.00 3/3 RBD patients + aSyn-SAA
Shahnawaz et al. [19]	1 mg/ml rec aSyn WT + 6hist (local)	BH and CSF	PD: 76 OND: 65 NDG: 18 AD: 14	Not provided	PD v disease controls: Sns: 0.89 Spc: 0.94 Time to reach 50% maximum aggregation inversely correlated with HY stage
Groveman et al. [20]	0.1 mg/ml rec aSyn K23Q + 6hist (local)	BH and CSF	PD: 12 DLB: 17 Non-aSyn: 31	2.9y	PD and DLB v non-aSyn: Sns: 0.93, Spc: 1.00
Bargar et al. [174]	1 mg/ml rec aSyn WT (rPeptide)	BH, CSF, Saliva, Skin, colon	PD: 88 DLB: 58 Controls: 68	Not Provided	CSF: PD and DLB v controls: Sns 0.98, Spc 1.00 Sns and Spc not analyzed for other tissues
Iranzo et al. [169]	0.1 mg/ml rec aSyn WT (Sigma)	CSF	RBD: 52 HC: 40	NA	RBD v HC: Sns 0.90 Spc 0.90 During 7y follow up 32 photoconverted to PD or DLB (31/32 + aSyn SAA)
Siderowf et al. [197]	0.3 mg/ml rec aSyn WT + 6hist	CSF	PD: 545 HC: 163 SWEDD: 54	Sporadic PD 0.6y ± 0.5 LRRK2 PD 3.0y ± 2.1 GBA PD 3.5y ± 2.4	All PD cases v HC: Sns 0.88 Spc: 0.96 Sporadic PD v HC: Sns: 0.93, Spc: 0.96 LRRK2 PD v HC: Sns: 0.68, Spc: 0.96 GBA PD v HC: Sns: 0.96, Spc 0.96
Rossi et al. [168]	0.1 mg/ml rec aSyn WT	CSF	Clinical RBD: 18 PAF: 28 PD: 71 DLB: 34 OND: 135 Path-validated LB + : 21 LB-: 101	Clinical PD: 56.8 m ± 45.8	Neuropathologically validated cases with aSyn Sns: 0.95 Spc: 0.98 Clinical diagnoses aSyn v OND: Sns: 0.95, Spc 0.98 18/18 RBD + aSyn SAA, 26/28 PAF + aSyn-SAA
Russo et al. [167]	AbbVie RT-QuIC: 0.1 mg/ml rec aSyn WT (local), Caughey RT-QuIC: 0.1 mg/ml rec aSyn K23Q PMCA: 0.3 mg/ml rec aSyn WT + 6hist	CSF	PD: 30 HC: 30 SWEDD: 20	PPMI: 6.7 m ± 6.5 SAA: 9.0 m ± 8.4	PD v HC at baseline: AbbVie: Sns:0.89, Spc: 1.00 Caughey: Sns: 0.86, Spc: 0.97 Amprion: Sns: 0.96, Spc: 0.97 PD v HC Year 3 AbbVie: Sns: 0.93, Spc: 0.93 Caughey: 0.89, Spc: 0.97 Amprion: 0.96, Spc: 0.93
Poggiolini et al. [170]	1 mg/ml rec aSyn WT	CSF	PD: 74 MSA: 24 RBD: 45 HC: 55	PD 2.1y ± 1.4y	PD v HC: Sns: 0.89 Spc 0.96 No major correlations of kinetic parameters and clinical features in PD MSA v HC: Sns: 0.75 Spc 0.96 (longer T50, lower Fmax) Some correlations of kinetic parametiers and clinical features in MSA RBD v HC: Sns: 0.64 Spc 0.96 14/45 phenoconverted in the 0.2–7.9 y of followup. 9/14 + aSyn SAA at baseline
Kang et al. [166]	RT-QuIC: 0.1 mg/ml rec aSyn WT (Sigma) PMCA: 0.3 mg/ml rec aSyn WT + 6hist	CSF	PD: 105 HC: 79	8 (4–17)	RT-QuIC: PD v HC Sns: 0.95 Spc: 0.96 PMCA: PD v HC Sns 0.90 Spc: 0.82
Kuzkina et al. [172]	RT-QuIC Cleveland aSyn rec WT (rPeptide) RT-QuIC Wurzburg 5 mg/ml aSyn rec WT (in house)	Skin: 5 mm. C7, T12, thigh, lower leg	PD: 34 HC: 30	11.7y ± 6.9	Sns: 0.91, Spc 0.87 Κ = 0.86 for patient results between labs
Manne et al. [21]	0.1 mg/ml aSyn rec WT	Skin	Frozen PD: 25 HC: 25 Formalin fixed PD: 12 HC: 12	Not described	Frozen Sns 0.96 Spc 0.96 Fixed Sns: 0.75 Spc: 0.83
De Luca et al. [177]	5 mg/ml aSyn rec WT	Olfactory Mucosa	PD: 18 MSA: 11 OND: 18	10.1y ± 5.1	PD Sns: 0.56 MSA Sns: 0.82 Spc: 0.83
Skin IF/IHC
Donadio et al. [138]	IF Zamboni pSer129 aSyn/PGP Cryosectoining CSF and skin RT-QuIC: 0.1 mg/ml rec aSyn WT (rPeptide)	3 mm C7, thigh, leg CSF	IF reproducibility PD: 4 MSA: 4 DLB: 1 OND: 12 IF v RT-QuIC PD: 17 DLB: 5 MSA: 8 PAF: 3 OND: 38 HC: 24	Not available	aSyn v non aSyn Skin IF: Sns: 0.90 Spc: 1.00 CSF RT-QuIC: Sns 0.78 Spc 1.00 Skin RT-QuIC: Sns 0.86 Spc 0.80
Gibbons et al. [15]	IF: Zamboni, pSer129 aSyn/PGP Cryosectioning	3 mm distal leg, proximal/distal thigh, forearm	PD: 28 HC: 23	PD nAF 4.3y ± 5.1 PD AF 8.6y ± 7.3	Sns 0.95 Spc 0.91
Wang et al. [133]	IF: Zamboni, pSer129 aSyn/PGP Cryosectioning	3 mm distal leg or distal/proximal thigh	PD: 29 HC: 21	5.5y ± 5.1	50 µm sections: Sns 1.00, 20 µm sections: Sns: .90, 10um sections: Sns:73 Spc: 1.00
Donadio et al. [124]	IF: Zamboni pSer129 aSyn/PGP Cryosectioning	3 mm C7 2 × or C7 and T12	PD: 28	15 patients unilateral symptoms 3y ± 2 13 patients bilateral symptoms 10y ± 6	Sns 1.00 from C7 Sns 0.62 from T12 site No differences in laterality in spite of lateralized motor symptoms
Donadio et al. [132]	IF: Zamboni pSer129 aSyn, PGP Cryosectioning	3 mm C8, thigh, distal leg	PD: 21 Other Parkinsonism: 20 HC: 30	PD: 13y ± 6	Sns 1.00 Spc 1.00
Doppler et al. [126]	IF: PFA 4% pSer129 aSyn PGP Cryosectioning	5 mm Proximal and distal leg, T12, C7	PD: 25 RBD: 18 HC: 20		PD Sns: 0.80, RBD Sns: 0.56 Spc:1.00
Doppler et al. [136]	IF: PFA 4% pSer129 aSyn, PGP. Cryosectioning	5 mm, proximal and distal leg, T12, finger	PD: 31 HC 35	9.0y (range 0.3–27)	PD v HC Sns 0.52 Spc: 1.00
Al-Qassabi et al. [137]	IF: FFPE pSer129 aSyn/PGP	3-5 mm Leg or C8	PD: 20 RBD: 28 Other parkinsonism: 10 HC: 21	PD 8.4y ± 4.4	PD Sns 0.70, RBD Sns: 0.82, Other parkinsonism 0.20. Spc 1.00
Chahine et al. [116]	IHC: FFPE aSyn. Proteinase K	3 mm C7-8, mid thigh	PD: 58 HC: 21	4.8y ± 4.6	Sns 0.24 Spc 1.00

For aSyn-SAA studies, the type of aSyn used for reactions is detailed and for skin immunofluoresence/Immunohistochemistry, basic aspects of these assays are reported along with biopsy sites and type

RT-QuIC real-time quaking induced conversion, PMCA protein misfolding cyclic amplification, rec aSyn recombinant alpha-synuclein, WT wild type, 6hist histidine tag, BH brain homogenate, CSF cerebrospinal fluid, PD Parkinson’s disease, DLB dementia with Lewy bodies, AD Alzheimer’s disease, PSP progressive supranuclear palsy, CBS cortico basal syndrome, HC healthy controls, OND other neurological disorders, NDG other neurodegenerative diseases, MSA multiple systems atrophy, Sns sensitivity, Spc specificity, HY Hoehn and Yahr stage, RBD REM sleep behavior disorder, PAF pure autonomic failure, IF immunofluorences, IHC immunohistochemistry, PFA paraformaldehyde, FFPE formalin fixed paraffin embedded, PGP neuron specific protein gene product