DO WE NEED SUCH A MICROBIOME?

Individuals diagnosed with neurodevelopmental conditions such as autism spectrum disorder (ASD; autism) often experience tissue inflammation as well as gastrointestinal dysfunction, yet their underlying causes remain poorly characterized.

Autistic children are often suffering from CVID (Common Variable Immunodeficiency). It is a primary immunodeficiency disorder characterized by low levels of several immunoglobulin (antibody) classes, especially IgG, and often IgA and/or IgM, as well as a reduced ability to produce specific antibodies in response to infections or vaccinations.

Key Features:

• Impaired B-cell differentiation and antibody production.

• Often presents with recurrent infections, e.g., skin and systemic infections (often underdiagnosed).

• Autoimmune diseases are common (e.g., autoimmune cytopenia, thyroiditis).

• Granulomatous disease or lymphoid hyperplasia may occur.

IT LEADS TO THE PERTURBATION OF MICROBIOTA. MICROBIAL AND GASTROINTESTINAL PATHOLOGIES IN AUTISTIC CHILDREN

I. Microbial Dysbiosis

A. Bacterial Overgrowth / Pathogenic Species

• Clostridium spp.: C. bolteae, C. difficile, C. perfringens, C. tetani

• Staphylococcus aureus

• Streptococcus spp.: S. mitis, S. oralis

• Enterococcus faecalis

• Klebsiella, Proteus, Citrobacter, Morganella

• Helicobacter pylori

• Bacteroides fragilis (especially imbalanced or toxigenic strains)

B. Fungal Overgrowth

• Candida spp.: C. albicans, C. parapsilosis

• Aspergillus spp.

• Fusarium spp.

• Penicillium spp.

C. Parasitic Presence

• Blastocystis hominis

• Giardia lamblia

• Dientamoeba fragilis

D. Viral Persistence in the Gut

• Cytomegalovirus (CMV)

• Epstein-Barr virus (EBV)

• Human Herpesvirus 6 (HHV-6)

• Enteroviruses

• Rotavirus antibodies

• Norovirus or adenovirus exposure

II. Biofilm Formation

• Mixed microbial biofilms that protect pathogens from immune clearance and therapy

• Frequently seen in chronic Clostridia and Staph overgrowth

III. Metabolic and Enzymatic Abnormalities

• Low digestive enzymes: e.g., lactase, sucrase

• Low pancreatic elastase or exocrine pancreatic dysfunction

• Low secretory IgA: impaired mucosal immune defense

• Altered bile acid metabolism

• Elevated short-chain fatty acids (SCFAs): especially propionate

• Elevated neurotoxic organic acids: e.g., HPHPA, 4-cresol from Clostridia

IV. Inflammatory and Immune Pathologies

• Chronic low-grade colitis, ileitis

• Lymphonodular hyperplasia (LNH) in terminal ileum

• Elevated fecal calprotectin/lactoferrin

• Eosinophilic gastrointestinal disorders

• Autoimmune reactivity to gut epithelial antigens

• Mast cell activation in the GI tract

• Cross-reactivity between gut and brain immune responses

V. Structural / Functional Abnormalities

• Leaky gut (increased intestinal permeability, high zonulin)

• Delayed motility, often linked to autonomic dysfunction

• Visceral hypersensitivity

• Reflux esophagitis

• Non-H. pylori gastritis

• Mucosal architectural changes (e.g., blunting, lymphoid infiltration)

VI. Nutrient Malabsorption / Malnutrition

• Deficiencies in: zinc, iron, vitamin B12, folate

• Fat malabsorption (steatorrhea, pale stools)

• Amino acid malabsorption

• Oxalate overload

• Impaired methylation, glutathione, and detox pathways

VII. Food Intolerances / Sensitivities

• Non-celiac gluten intolerance

• Casein/dairy intolerance (often IgG-mediated)

• Histamine intolerance (due to DAO or microbiome disruption)

• Salicylate or phenol intolerance

• FODMAP sensitivity

• Delayed food reactivity (IgG4-related)

VIII. Gut-Brain Axis Disruption

Microbial byproducts that affect the central nervous system:

• Propionic acid: linked to seizures, anxiety, repetitive behavior

• 4-cresol, HPHPA: neurotoxic metabolites from Clostridia

• LPS (lipopolysaccharide): induces systemic inflammation and neuroglial activation

• Ammonia, tyramine, D-lactic acid: associated with mood instability, fog, aggression

THERE IS A WAY FORWARD

Many parents are understandably afraid of antimicrobial therapy. They worry about side effects, resistance, or further damaging the gut. However, in cases of deep-rooted dysbiosis and persistent infection, there is no other way to make a meaningful difference.

Probiotics alone cannot displace a gut colonized by biofilm-forming, neurotoxin-producing pathogens. Symptomatic treatments—such as laxatives, antacids, and dietary changes—may bring temporary relief, but they do not alter the microbiome terrain. If we want to restore the gut and the child’s health, we must recognize the truth: We are not dealing with a microbiome slightly off course but with a microbiome hijacked by disease.

The path forward must be a stepwise, controlled process:

• Target and reduce pathogenic microbes using selective antimicrobials, herbals, or bacteriophages.

• Disrupt biofilms to make the pathogens vulnerable.

• Support detoxification and barrier repair to protect the host during the die-off process.

• Continuously replenish beneficial flora using well-selected, immune-compatible probiotic species.

• Repeat and adapt—because rebuilding a functional microbiome takes time and precision.

We do not destroy microbiomes. We heal it by removing what does not belong and replacing it with what was lost.

The restoration of the gut in autism is not merely symptom relief—it is a rebuilding of the biological foundation that allows the child to thrive. We must no longer fear the process but embrace it with precision, science, and persistence.

Dr. Ken Alibek,

MD, PhD, ScD