**2. The preclinical diagnosis algorithm and a new conceptual model of T1D etiology**

T1D is an autoimmune disease induced by a vast variety of triggering factors. In individuals with genetic predisposition to T1D, these factors initiate autoimmune processes culminating in the appearance of autoAbs and infiltration of the pancreas with self-reactive T cells. In its turn, progressive deterioration of pancreatic functional activity leads to systemic metabolic and immune failures. These processes show a tendency for self-acceleration, aggravation by associated diseases or numerous adverse factors and formation of new linkages between immunoregulatory and immunoeffector compartments within the immune system. T1D is also distinguished for alterations at the cellular level including pathological changes in cell to-cell interactions, incompatibility of packages of secreted humoral factors, and so on. Intracellular events provoked by specific uncongenial conditions in the cell environment also play a role. Therefore, humoral factors secreted at any (cellular, tissue or organic) level and pathological changes in any link of the metabolic cascade can be regarded as highly specific *biopredictors* and valuable tools for *preclinical diagnosis* of T1D.

In the course of the autoimmune process, T1D goes through a number of sequential stages, which differ from one another by the degree of severity of the underlying pathology, functional peculiarities of affected organs and clinical manifestations of the disease. A *personalized* therapeutic approach must be based on a detailed analysis of the immune status with special reference to the patient's genetic map and is prerequisite to the construction of

Preclinical and Predictive Algorithms in Monitoring

ophthalmopathies, nephropathies, etc.).

Patients with Autoimmune Diseases and Their Relatives-at-Risks 195

tissue injuries. These disturbances are usually concomitant with acute manifestations (coma) or form the basis for more distant pathologies (micro- and macroangiopathies, neuropathies,

Fig. 1. The pathogenesis of T1D. Genetic and environmental factors are key elements in the susceptibility to **T1D**. Susceptible individuals develop autoimmune insulitis, which is mediated by CTL against autoAgs of *beta* cells and is characterized by enhanced production

The first five stages are defined as preclinical pathology stages, while Stage VI is thought to represent a transient step. It is diagnosing T1D at stages I – V and the use of preventive treatment protocols that enable the physician to delay the progression of the underlying disease and to procure complete recovery. (Antonio Gonzalez at. al., 1996s; Matthias von

**3. The origin of genetic predisposition or "genomics: A base of preclinical** 

Our knowledge of pathological processes occurring in the human organism has progressed considerably in the past decades, but the mechanisms of many human diseases are still poorly understood. Recent developments in genomics made it possible to discover a wide variety of novel genes and genetic variations including clinically important ones. i.e., those triggering pathological processes in various body tissues and cells. Every year, the clinical diagnostic instrumentarium is supplemented with efficient analytical techniques for detecting single-nucleotide polymorphisms (SNP's) which determine the susceptibility of

of a vast array of antiinflammatory cytokins and free radicals triggering the death

(apoptosis) of *beta* cells as main targets in inflammation.

Herrath at al., 2007)

**medicine"** 

any early diagnosis protocol designed to indicate the pathology, to identify the stage of the autoimmune process and the functional status of the target organ and to develop, on their basis, a strictly individual treatment schedule. In addition, this approach entails early implementation of pharmacocorrective therapy and prediction of scenarios for disease progression. (Suchkov et al., 2010)

In order to follow the dynamics of T1D on the time scale and to estimate efficiency and sensitivity of innovative approaches to *preclinical diagnosis,* we developed a fundamentally new strategy of pathogenesis. Its major goal is crucial features of the disease with special emphasis on its diagnosis allowing the physician to implement adequate *preventive therapy*, to prolong the *preclinical* stage and to delay clinical manifestations of the disease.

**Stage I** is often defined as the "*genetic predisposition*" step. Its most salient feature is a repertoire of predisposition genes (predominantly, MHC class II) responsible for susceptibility to autoimmune diseases and direct initiation, gradation and exacerbation of immune pathologies.

**Stage II** is often referred to as the "intervention" step. At this stage, provoking exogenous or endogenous factors interfere with the normal functioning of immune mechanisms and deplete the functional reserves of the affected organs providing the formation of the autoimmune status (e.g., postinfective autoimmune syndrome).

**Stage III** represents an "ignoring" step where progressive disturbances in immune homeostasis are unaccompanied by direct attacks at target organs. Clinical manifestations of T1D and visible lesions in the pancreas architectonics are absent in this step, while the functional activity of the pancreatic gland is unimpaired. AutoAbs are either not produced or their titers are negligibly small.

**Stage IV** is characterized by termination of the ignoring step and initiation of autoimmune processes. The main participants at this stage are molecular factors (e.g., addressins) triggering autoimmune reactions specifically directed against islet cells. At this particular level, clonal ignoring collapses and organ infiltration occur.

**Stage V** is closely associated with the development of immunological disorders. Its central event is generation of autoAbs to insulin, GAD, β-cells, heat shock protein 60 (hsp60), zinc transporter and fogrin. AutoAbs can be specific against a single antigen (Ag) or several Ags.

**Stage VI** is defined as a "transition from uncontrolled violence to chaos". Here, minor systemic failures related to immunological disregulation progress to the extent of profound disorders. Clinical symptoms are still missing at this stage, but latent tolerance to glucose develops.

**Stage VII.** This "complete overall imbalance" step occurs when β-cell destruction reaches a certain critical level (80%). This stage is characterized by hyperglucosemia and insufficient production of insulin. Metabolic processes fluctuate slightly within normal limits due to residual secretion of the C-peptide.

**Stage VIII,** often referred to not as a T1D stage, but, rather, as emerging complications, is defined as "total or genuine diabetes", since beta cell destruction is fully complete in this step. It is distinguished for steadily decreasing titers or complete disappearance of autoAbs, functional failure of the pancreas, high glucosemia and glycosylation of proteins (including hemoglobin) against the background of systemic hypoxia and metabolic collapse. Other manifestations include disturbances in water-salt metabolism, osmotic diuresis, dehydration, activation and acceleration of gluconeogenesis and ketogenesis, enhanced breakdown of proteins and lipids, impaired lipid metabolism (low HDL levels and high LDL levels) and elevation of osmotic blood pressure resulting in microvascular and nerve

any early diagnosis protocol designed to indicate the pathology, to identify the stage of the autoimmune process and the functional status of the target organ and to develop, on their basis, a strictly individual treatment schedule. In addition, this approach entails early implementation of pharmacocorrective therapy and prediction of scenarios for disease

In order to follow the dynamics of T1D on the time scale and to estimate efficiency and sensitivity of innovative approaches to *preclinical diagnosis,* we developed a fundamentally new strategy of pathogenesis. Its major goal is crucial features of the disease with special emphasis on its diagnosis allowing the physician to implement adequate *preventive therapy*,

**Stage I** is often defined as the "*genetic predisposition*" step. Its most salient feature is a repertoire of predisposition genes (predominantly, MHC class II) responsible for susceptibility to autoimmune diseases and direct initiation, gradation and exacerbation of

**Stage II** is often referred to as the "intervention" step. At this stage, provoking exogenous or endogenous factors interfere with the normal functioning of immune mechanisms and deplete the functional reserves of the affected organs providing the formation of the

**Stage III** represents an "ignoring" step where progressive disturbances in immune homeostasis are unaccompanied by direct attacks at target organs. Clinical manifestations of T1D and visible lesions in the pancreas architectonics are absent in this step, while the functional activity of the pancreatic gland is unimpaired. AutoAbs are either not produced

**Stage IV** is characterized by termination of the ignoring step and initiation of autoimmune processes. The main participants at this stage are molecular factors (e.g., addressins) triggering autoimmune reactions specifically directed against islet cells. At this particular

**Stage V** is closely associated with the development of immunological disorders. Its central event is generation of autoAbs to insulin, GAD, β-cells, heat shock protein 60 (hsp60), zinc transporter and fogrin. AutoAbs can be specific against a single antigen (Ag) or several Ags. **Stage VI** is defined as a "transition from uncontrolled violence to chaos". Here, minor systemic failures related to immunological disregulation progress to the extent of profound disorders. Clinical symptoms are still missing at this stage, but latent tolerance to glucose

**Stage VII.** This "complete overall imbalance" step occurs when β-cell destruction reaches a certain critical level (80%). This stage is characterized by hyperglucosemia and insufficient production of insulin. Metabolic processes fluctuate slightly within normal limits due to

**Stage VIII,** often referred to not as a T1D stage, but, rather, as emerging complications, is defined as "total or genuine diabetes", since beta cell destruction is fully complete in this step. It is distinguished for steadily decreasing titers or complete disappearance of autoAbs, functional failure of the pancreas, high glucosemia and glycosylation of proteins (including hemoglobin) against the background of systemic hypoxia and metabolic collapse. Other manifestations include disturbances in water-salt metabolism, osmotic diuresis, dehydration, activation and acceleration of gluconeogenesis and ketogenesis, enhanced breakdown of proteins and lipids, impaired lipid metabolism (low HDL levels and high LDL levels) and elevation of osmotic blood pressure resulting in microvascular and nerve

to prolong the *preclinical* stage and to delay clinical manifestations of the disease.

autoimmune status (e.g., postinfective autoimmune syndrome).

level, clonal ignoring collapses and organ infiltration occur.

progression. (Suchkov et al., 2010)

or their titers are negligibly small.

residual secretion of the C-peptide.

immune pathologies.

develops.

tissue injuries. These disturbances are usually concomitant with acute manifestations (coma) or form the basis for more distant pathologies (micro- and macroangiopathies, neuropathies, ophthalmopathies, nephropathies, etc.).

Fig. 1. The pathogenesis of T1D. Genetic and environmental factors are key elements in the susceptibility to **T1D**. Susceptible individuals develop autoimmune insulitis, which is mediated by CTL against autoAgs of *beta* cells and is characterized by enhanced production of a vast array of antiinflammatory cytokins and free radicals triggering the death (apoptosis) of *beta* cells as main targets in inflammation.

The first five stages are defined as preclinical pathology stages, while Stage VI is thought to represent a transient step. It is diagnosing T1D at stages I – V and the use of preventive treatment protocols that enable the physician to delay the progression of the underlying disease and to procure complete recovery. (Antonio Gonzalez at. al., 1996s; Matthias von Herrath at al., 2007)
