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Table 2 Summary of clinical studies on the effect of larch arabinogalactan on the immune system

From: Does larch arabinogalactan enhance immune function? A review of mechanistic and clinical trials

Article Extract Challenge (Vaccine) Subjects Day for the measures Parameters measured Results: effect of the extract on parameters
Udani et al. 2013 [32] ResistAid™
Proprietary larch arabinogalactan
1.5 or 4.5 g/day
For 60 days
Tetanus & influenza vaccines
Vaccination at day 30
75 healthy adults Day 0, 45 & 60 ➢ Tetanus IgG Group 1.5 g/day, day 60: significant rise in IgG levels compared to placebo (p = 0.008)
Group 4.5 g/day group, day 45 & 60: significant rise in IgG levels compared to baseline (p < 0.01) but not compared to placebo
➢ Influenza A & B IgG & IgM No effect
Riede et al. 2013 [30] ResistAid™
Proprietary larch arabinogalactan
4.5 g/day
For 84 days
None 199 healthy adults   Common cold episode Reduce the incidence of common cold infection (p = 0.055)
Reduce the number of subject affected (p = 0.038)
Increase of the severity of symptoms (p = 0.028)
No effect on the duration of the common cold episodes
Udani et al. 2010 [31] ResistAid™
Proprietary larch arabinogalactan
4.5 g/day
For 72 days
Streptococcus pneumonia
Vaccination at day 30
45 healthy adults Day 0, 51 & 72 ➢ Pneumococcal IgG (subtypes 4, 6B, 9 V, 14, 18C, 19 F & 23 F) Significant rise in IgG levels compared to placebo in 2 antibodies subtypes (18C & 23 F) at day 51 (p = 0.006 and p = 0.002) and day 72 (p = 0.008 and p = 0.041)
➢ Pneumococcal salivary IgA No effect
Day 0, 30, 31, 51 & 72 ➢ WBCa count No significant difference compared to placebo
At day 72, rise in WBC compared to baseline (p = 0.045)
No differences (clinically significant) in lymphocytes, neutrophils, monocytes or basophiles count
Significant rise of eosinophil count at day 30 (p = 0.006) and day 51 (p = 0.014)
➢ Inflammatory cytokinesa: ENA-78, eotaxin, GM-CSF, IFNγ, IL10, IL12P40, IL1RA, IL2, IL4, IL5, IL6, IL8, MCP-1, MCP-3, PDGF-BB & TNF-α Significant rise in IL6 between day 30 and 31 compared to placebo (p = 0.046)
➢ Complement C3 & C4 No effect
Nantz et al. 2001 [28] Arabinogalactan
4 g/day
For 42 days
None 51
healthy adults
Day 1, 21 & 42 ➢ Haematology: WBCa, RBCa, haemoglobin, hematocrit, neutrophils, lymphocytes, monocytes, platelets
➢ Count of CD19 B lymphocytes, CD4 T helper lymphocyte, CD8 T cytotoxic lymphocytes & NK1.1 natural killer cells
➢ PBMCa (lymphocytes) proliferation after exposure to PMA
➢ PMNa for oxidative burst activity
➢ Natural killer cells activity
➢ IgaG
Significant increase of % CD8+ cells at 6 weeks after arabinogalactan compared to control group (p = 0.005)
Significant increase in lymphocyte proliferation at 6 weeks compared to baseline in the arabinogalactan group (p < 0.05) only
Significant effect of group detected on proportion of monocytes in the lymphocytes fraction (p = 0.0497), though no significant groupatime effect detected (p = 0.602).
No significant change in IgG levels, respiratory burst activity of neutrophils, NK cell number and B cell number.
Kim et al. 2002 [27] Larch arabinogalactan (90 %)
1.5 g/day
For 28 days
None 48
healthy female adults
Day 0 & 28 ➢ Vital signs: blood pressure, radial pulse, respiration rate, temperature No effect
➢ Complete blood count: WBC, neutrophils, lymphocytes & monocytes No effect
➢ NK cells quantitative No effect
➢ Complement properdin No effect
➢ TNF-α Significant decrease (p = 0.044)
➢ EBV VCA IgG Ab
➢ CMV IgG Ab
No effect
No effect
Lactobacillus acidophilus stool culture
➢ Stool fungus culture for yeast
No effect
No effect
➢ Health related quality of life (SF-36) Increase of the bowel movement (75 % of the subjects affected)
Kim et al. 2002 [12] Larch arabinogalactan (90 %) – different concentration grades
1.5 & 4.5 g/day
For 28 days
None 21 healthy adults Day 0 & 28 ➢ Haematology: WBCa, RBCa, haemoglobin, hematocrit, monocytes No effect
➢ TNF-α
➢ IFN-γ
➢ IL6
No effect
No effect
No effect
➢ Stool culture No effect
➢ Health related quality of life (SF-36) No effect
  1. a ENA epithelial neutrophil activating peptide-78, GM-CSF granulocyte monocytes colony stimulating factor, IFNγ interferon gamma, IL interleukin, MCP monocyte chemotactic protein-1, MCP-3, PDGF platelet-derived growth factor-BB or TNF tumour necrosis factor-alpha, PBMC peripheral blood mononuclear cells, PMN polymorphonuclear neutrophils, PMA phorbol 12-myristate 13-acetate, WBC White blood cells, RBC red blood cells, Ig immunoglobulin, EBV VCA IgG Ab Epstein-Barr Virus viral capsid antigen IgG antibody, CMV IgG Ab Cytomegalovirus IgG antibody, Ab antibody