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Global Translational Medicine AA amyloidosis in rheumatoid arthritis

1.6. Objective AA deposition values. A significance level of P < 0.05 was

This study aims to determine the prevalence and severity considered statistically significant.
of systemic AA amyloidosis (sAAa) in RA, assess the For comparisons between two datasets, the most
prevalence and extent of GI AA deposits (giAAa) in stringent statistical criteria in Microsoft Excel were
various tissue structures of the GI tract, and characterize applied, using a two-tailed distribution (parameter=“2”)
the progression of AA deposition within the GI tract. In and assuming unequal variance (not homoscedastic,
addition, this study seeks to evaluate the relationship parameter=“-3”).
between sAAa and giAAa, investigate the impact of sAAa The mean age of patients varied within the observed
and giAAa on mortality, and clarify the diagnostic value of minimum and maximum values, and the distribution of
GI biopsy in AA amyloidosis. AA deposits followed a normal (Gaussian) distribution,
characterized by a bell-shaped curve.
2. Methods
The correlation between sAAa and giAAa was assessed
2.1. Patients (autopsy population) using Pearson’s chi-squared (χ ) test. 51
2
At the National Institute of Rheumatology, 9,475 patients
died between 1969 and 1992. Among them, 161 had RA 3. Results
and underwent autopsy. 3 3.1. Demographics of patients with sAAa and/or
The clinical diagnosis of RA in these patients was giAAa
established based on the criteria of the American sAAa was identified in 34 (23.13%) of 161 patients with
College of Rheumatology. The patient histories and RA. Tissue blocks from at least one segment of the GI tract
44
clinical protocols were reviewed by co-author Ágnes (stomach, small intestine, or large intestine) were available
Apáthy, a rheumatologist and neurologist. Autopsies and for 31 (91.18%) of these 34 patients.
histopathological evaluations were conducted by Miklós In 29 of the 31 patients (93.55%) with available GI
Bély.
tissue, AA deposits were detected in branches of blood
2.2. Methodology vessels of varying calibers and various tissue structures of
the GI tract. In contrast, 2 (6.45%) of the 31 patients with
In this study, the term “GI tract” refers specifically to the sAAa did not exhibit histologically detectable AA deposits
stomach, small intestine, and large intestine; other sections, in the GI tract, and these cases were considered as latent-
such as the oral cavity, pharynx, and esophagus, were not stage giAAa.
evaluated separately.
A strong positive correlation was observed between
The presence and extent of sAAa and giAAa were sAAa (n = 34) and giAAa (n = 29) (c = 1.0, χ = 142.06,
2
determined histologically through a detailed examination P < 0.000). However, there was no significant difference
of eight organs (kidneys, heart, pancreas, GI tract, liver, between the average AA deposition in sAAa and giAAa
lungs, skin, and brain). (P < 0.386).

AA deposition in various tissue structures of these organs Table 1 summarizes the demographics, onset, and
was diagnosed histologically according to Romhányi’s duration of disease for the total study population (N = 161),
method, utilizing a modified and more sensitive Congo as well as for subgroups with sAAa (n = 34) and without
45
red staining technique. AA deposits were further sAAa (n = 127). In addition, it presents data for patients
46
identified in serial sections using immunohistochemical with giAAa (n = 31), categorized into latent (n = 2), mild
47
and histochemical methods. 48-50 (n = 17), and severe (n = 12) AA deposits in the GI tract.
2.3. Statistical analysis A comparison of age, sex, RA onset, and disease
duration at the time of death revealed no statistically
The demographic characteristics of different patient significant differences in survival time, disease onset, or
cohorts were analyzed using the Student’s (Welch) t-test disease duration between patients with sAAa (n = 34) and
to compare age, sex, disease onset, and disease duration at the total study population (n = 161) (P = 0.321, P = 0.376, P
the time of death between patients with and without sAAa, = 0.554). No significant differences were observed between
as well as between patients with giAAa with mild (<0.8 female patients (P = 0.800, P = 0.631, P = 0.682) and male
deposits/patient) or severe (≥0.8/patient) AA deposits. 51
patients (P = 0.348, P = 0.565, P = 0.688). Similarly, no
The threshold value of 0.8 for classifying mild and severe statistically significant differences were found between
cases was determined based on the Gauss distribution of patients with sAAa (n = 34) and those without sAAa

Volume 4 Issue 1 (2025) 106 doi: 10.36922/gtm.5325