Several of these studies have focused on pediatric patient populations, and thus nephropathy may not have been able to manifest in such a short time. Thus, the appearance of increased proteinuria is more indicative that potential renal damage is occurring.
Gluten exposure in CD patients induces an inflammatory response that can have a wide range of downstream effects, including reduced insulin sensitivity. It is worth questioning whether the protective effect of a gluten-free diet experienced by these patients are strictly due to reducing their overall gut inflammation or if a more complex mechanism exists.
Interestingly, anti-gliadin antibodies may have an association with IgA nephropathy (Ups J Med Sci 2006;111:339-352). Case reports have found a gluten-free diet in CD patients to resolve nephrotic syndrome (Pediatr Nephrol 2009;24:1247-1250; Nephrol Dial Transplant 2009;24:3545-3548). In a cohort of IgA nephropathy patients, one study reviewed rectal mucosal reaction to gluten using through nitric oxide production as well as myeloperoxidase and eosinophil cationic protein (Nephrol Dial Transplant 2009;24:2476-2481).
Additionally, they reviewed serum IgG antigliadin antibodies as well as multiple IgA antibodies. One third of the patients demonstrated gluten sensitivity via the rectal measurements, but interestingly this did not correlate with serum measurements. This presentation of gluten sensitivity without the classical serum markers is now being referred to as non-celiac gluten sensitivity (NCGS). This affliction has been a growing area of interest due to the increasing awareness that intolerance of wheat products can present without small intestinal destruction or wheat allergy (Nutrients 2013;5:3839-3853).
Adherence to a gluten-free diet in CD individuals is critical for an array of health parameters. Although nephropathy does not appear to be as common as retinopathy or neuropathy in gluten-intolerant individuals, these disease processes are closely related.
For patients beginning to exhibit microvascular damage, a trial of a gluten-free diet presents no inherent risk. Because NCGS is only now being truly recognized, a temporary elimination diet may be the most appropriate approach to test for food intolerance until adequate standardized diagnostic criteria can assess NCGS.