A reader asked:
“I was wondering…have you done a blog post on probiotics that might help shift the Th1-Th2 balance?”
“T(H)2-cytokines increase the production of IgE and stimulate mast cells [aka histamine release] and eosinophils, whereas T(H)1-cytokines, such as IFN-gamma, may suppress IgE synthesis and stimulate the expression of the secretory piece of IgA.”
“Type 1 Th cells (Th1 cells) secrete IL-2, interferon-gamma (IFN-γ) and tumour necrosis factor (TNF), whereas type 2 Th cells (Th2 cells) produce IL-4, IL-5, IL-6 and IL-13. ” 
- Evidence for T-helper 2 shift and association with illness parameters in chronic fatigue syndrome (CFS) .
- Gulf War syndrome: is it due to a systemic shift in cytokine balance towards a Th2 profile?
IMHO, there will be limited literature. Much of the literature is for specific strains that are not available commercially.
- Probiotic Escherichia coli Nissle 1917 suppresses allergen-induced Th2 responses in the airways .
- “Soil-based organisms improve immune function: shift cytokine profile from TH2 to TH1.“ – i.e. Prescript Assist, General Biotics Equilibrium
- “B. breve diet …increased percentages of activated Th1 cells were observed in the spleen.””
- All bifidobacteria tested were able to induce full DC maturation but showed differences in the levels of cytokine production, especially IL-12, IL-10, TNFalpha and IL-1beta, suggesting that specific cytokine ratios could be used to predict the type of Th response that they may promote” 
- ” Lactobacillus plantarum strain 06CC2 may be a versatile oral adjuvant to activate Th1 immune response.” 
- “oral administration of strain 06CC2 was effective in inducing Th1 cytokine production activating the Th1 immune response associated with intestinal immunity in normal mice.” 
- “The relationship between modulation of gut microbiota and regulation of host immunity by different doses of probiotics is complex. LGG exerted divergent dose-dependent effects on the intestinal immune cell signaling pathway responses, with 9-doses Lactobacillus rhamnosus GG being more effective in activating the innate immunostimulating TLR9 signaling pathway than 14-doses” 
- “VSL#3-treated NOD mice modulate gut immunity by… reducing differentiation/expansion of Th1 and Th17 cells” 
- “Of ten LAB extracts, four (from L. acidophilus, L. bulgaricus, L. casei, and S. thermophiles) promoted both cell proliferating and TH1 cytokine production. 
- Surface-Displayed IL-10 by Recombinant Lactobacillus plantarum Reduces Th1 Responses of RAW264.7 Cells Stimulated with Poly(I:C) or LPS .
- “Analysis of the impact of these three strains on the T helper balance revealed different mechanisms of action. The Lactobacillus salivarius LA307 strain proved to block Th1 and Th2 responses, while the Bifidobacterium longum subsp. infantis LA308 strain induced a pro-Th1 profile and the Lactobacillus rhamnosus LA305 strain induced pro-Th1 and regulatory responses.” 
- Th1 Cytokine Production Induced by Lactobacillus acidophilus in BALB/c Mice Bearing Transplanted Breast Tumor .
- ” Lactobacillus paracasei V0151.. the T helper 1/T helper 2 (Th1/Th2) balance was also skewed toward Th1 dominance through the elevation of Th1 cytokine production.” 
- “L. salivarius CICC 23174 was the more effective strain at maintaining the Th1/Th2 balance” 
- “Enterococcus faecalis CECT7121 implants itself and persists in the murine gastrointestinal tract, and enhances and skews the profile of cytokines towards the Th1 phenotype in several biological models.” 
- “Lactobacillus casei variety rhamnosus (LCR35) … possibly through the modulation of Th1/Th2 balance and gut microbiota.” 
- ” B. infantis feeding reduced Th1-related cytokines” 
- “Lactobacillus kefiranofaciens M1… strongest response in terms of splenic Th1 cytokine IFN-γ and IL-12 production” 
- “Lactobacillus brevis HY7401…showed a tendency to induce Th1 cytokines and inhibit Th2 cytokines.” 
- Lactobacillus casei ssp.casei induced Th1 cytokine profile and natural killer cells activity in invasive ductal carcinoma bearing mice .
- Heat-killed lactic acid bacteria enhance immunomodulatory potential by skewing the immune response toward Th1 polarization .
- Lactobacillus plantarum strain YU from fermented foods activates Th1 and protective immune responses .
- “0.5 × 108 Bifidobacterium longum, 0.5 × 107 Lactobacillus bulgaricus, and 0.5 × 107 Streptococcus thermophilus…. could attenuate the deviated Th1/Th2 response induced by severe TBI.. Traumatic brain injury (TBI) is associated with a profound immunological dysfunction manifested by a severe shift from T-helper type 1 (Th1) to T-helper type 2 (Th2) response. ”  i.e. the above increased Th1 and reduced Th2.
- Treatment with Bifidobacterium bifidum 17 partially protects mice from Th1-driven inflammation in a chemically induced model of colitis .
- “in vitro studies on mouse spleen cells indicates that the VSL#3 preparation has the capacity to shift a polarized Th2 response to a Th1/T regulatory-type profile.” 
- Probiotic Bio-Three induces Th1 and anti-inflammatory effects in PBMC and dendritic cells .
- “L. crispatus KT-11 strain reduces allergic symptoms in NC/Nga mice via the adjustment of the type 1 helper T cell and type 2 helper T cell balance via TLR2, NOD1, and NOD2.” 
For most of the probiotics reported above, they induce TH1 and reduce TH2. Alternatively, the loss of these families of bacteria in CFS patients could explain the shift to TH2. The degree of shift each probiotic does varied greatly from strain to strain. In other words, if you favor the TH2 – shift hypothesis for CFS, then you should definitely be taking probiotics. There are a few probiotics that decreases TH1.. so “taking a probiotic” is not a magic formula.
The observed shift in CFS patients microbiome would explain the shift towards TH2 seen in CFS patients
Personally, I believe that the TH1/TH2 shift is a simplification that masks a lot of details on which cytokines are involved. For example, which one of the IL-4, IL-5, IL-6 and IL-1 are high? Only one may be — we should be treating the specifics and not doing a shotgun approach.