The importance of macrophage subtypes in determining the treatment response in idiopatic granulomatosus mastitis

Idiopathic granulomatous mastitis (IGM) is a disease that is common in our country and usually affects young women, has an uncertain response to current treatments, reduces the quality of life of patients, and is difficult to treat. In our study, we determined the numbers, averages and M1/M2 macrophage ratios of M1-M2 macrophages with IGM. Thus, we aimed to measure the importance of these values in determining the treatment response and to initiate the most appropriate treatment protocol for the patients in line with the results. Forty patients diagnosed with IGM who applied to our clinic between 2011 and 2019 and were followed up for at least 2 years after using systemic steroid therapy were included in the study. The patients were divided into two groups according to their response to the treatment. CD163/RBP-J and CD163/CMAF dual staining was performed on paraffin blocks and M1 and M2 macrophages were determined. Obtained data were analysed in SPSS 25.0 package program, independent t-test and One-Way ANOVA on parametric data. In the same time, Mann Whitney U test and Kruskal-Wallis H test were used for non-parametric data. In the examination of M1-M2 staining conditions, the area under the curve was calculated by drawing the ROC curve and the cut-off value was determined. The results were evaluated within the 95% confidence interval, and p<0.05 was defined as statistically significant. Although the ratio of M1 macrophages in IGM was found to be high in all cases, when evaluated according to the cut-off value, it was found that it did not have sufficient sensitivity and specificity alone in predicting the clinical response. The M1/M2 macrophage ratio was higher in the group with poor clinical response, and this ratio was considered sufficient to evaluate the clinical response. When the staining intensity was examined, it was found that lighter and less intense staining was observed in the group with poor clinical response. Based on these results, we think that the most appropriate treatment protocol will be selected for the patient by predetermining how the IGM will respond to steroid therapy.