Clinical examinations and immunohistochemical markers
Of the 28 patients, five did not undergo ASST due to the impossibility of removing antihistamines; therefore, the analysis was performed separately. Regarding the ASST results, the comparison did not indicate significant differences between negative versus positive results, for any of the immunohistochemistry markers (for M1 or M2 phenotypes) evaluated (p > 0.05). The correlations between the immunohistochemical markers and PCR, D DIMMER, were all nonsignificant (p > 0.05) and did not reveal a direct relationship between the complementary tests and macrophage phenotypes.
The cutaneous expression of the two populations of macrophages, M1 represented by STAT1 and M2 represented by CD163, CMAF, and CD206, was compared. The descriptive results of these markers are illustrated in Figures 1 and 2 and Table 3.
No significant differences were found between the skin samples of patients with CSU and of the control population for the immunohistochemical markers CD163, CD206, and pSTAT-1 (Table 3 and Figure 1).
The expression of the immunohistochemical marker CMAF was significantly higher in the CSU patients compared to the controls of apparently normal skin (p < 0.001; Table 3 and Figure 1).
The skin expression of pSTAT-1 was significantly lower than CD163 (p < 0.001), CMAF (p < 0.001), and CD206 (p < 0.001) in patients with CSU, demonstrating a clearly M2 phenotypic pattern of macrophage response (Figure 2).
No significant difference was found between pSTAT-1 and CMAF in the skin of control individuals (p = 0.181). Images obtained from slides with immunohistochemical staining are depicted in Figure 3.
Table 3. Descriptive statistics by immunohistochemical markers and subpopulation of macrophages in patients with spontaneous chronic urticaria and control subjects.