Background Troponin elevation is common in hospitalized COVID-19 patients, but underlying aetiologies are ill-defined. We used multi-parametric cardiovascular magnetic resonance (CMR) to assess myocardial injury in recovered COVID-19 patients. Methods and results One hundred and forty-eight patients (64 ± 12 years, 70% male) with severe COVID-19 infection [all requiring hospital admission, 48 (32%) requiring ventilatory support] and troponin elevation discharged from six hospitals underwent convalescent CMR (including adenosine stress perfusion if indicated) at median 68 days. Left ventricular (LV) function was normal in 89% (ejection fraction 67% ± 11%). Late gadolinium enhancement and/or ischaemia was found in 54% (80/148). This comprised myocarditis-like scar in 26% (39/148), infarction and/or ischaemia in 22% (32/148) and dual pathology in 6% (9/148). Myocarditis-like injury was limited to three or less myocardial segments in 88% (35/40) of cases with no associated LV dysfunction; of these, 30% had active myocarditis. Myocardial infarction was found in 19% (28/148) and inducible ischaemia in 26% (20/76) of those undergoing stress perfusion (including 7 with both infarction and ischaemia). Of patients with ischaemic injury pattern, 66% (27/41) had no past history of coronary disease. There was no evidence of diffuse fibrosis or oedema in the remote myocardium (T1: COVID-19 patients 1033 ± 41 ms vs. matched controls 1028 ± 35 ms; T2: COVID-19 46 ± 3 ms vs. matched controls 47 ± 3 ms). Conclusions During convalescence after severe COVID-19 infection with troponin elevation, myocarditis-like injury can be encountered, with limited extent and minimal functional consequence. In a proportion of patients, there is evidence of possible ongoing localized inflammation. A quarter of patients had ischaemic heart disease, of which two-thirds had no previous history. Whether these observed findings represent pre-existing clinically silent disease or de novo COVID-19-related changes remain undetermined. Diffuse oedema or fibrosis was not detected.

Chemokines may control the macrophage infiltrate found in many solid tumors. In human ovarian cancer, in situ hybridization detected mRNA for the macrophage chemokine monocyte chemoattractant protein-i (MCP-1) in 16/ 17 serous carcinomas, 4/4 mucinous carcinomas, 2/2 endometrioid carcinomas, and 1/3 borderline tumors. In serous tumors, mRNA expression mainly localized to the epithelial areas, as did immunoreactive MCP-1 protein. In the other tumors, both stromal and epithelial expression were seen. All tumors contained variable numbers of cells positive for the macrophage marker CD68. MCP-1 mRNA was also detected in the stroma of 5/5 normal ovaries. RT-PCR demonstrated mRNA for MCP-1 in 7/7 serous carcinomas and 6/6 ovarian cancer cell lines. MCP-1 protein was detected by ELISA in ascites from patients with ovarian cancer (mean 4.28 ng/ml) and was produced primarily by the cancer cells. Human MCP-1 protein was also detected in culture supernatants from cell lines and in ascites from human ovarian tumor xenografts which induce a peritoneal monocytosis in nude mice. We conclude that the macrophage chemoattractant MCP-1 is produced by epithelial ovarian cancer and that the tumor cells themselves are probably a major source. MCP-1 may contribute to the accumulation of tumor-associated macrophages, which may subsequently influence tumor behavior. (J. Clin. Invest 1995. 95:2391-2396

SUMMARY BackgroundAllergy and functional gastrointestinal disorders have been associated with eosinophilia in duodenal mucosa.

Chemokines promote tumour progression by enhancing proliferation and modifying the immune response. The purpose of this study was to test the hypothesis that CCL2 monocyte chemotactic protein-1 (MCP-1) contributes to the progression of colorectal cancer by influencing the number and distribution of tumour associated macrophages (TAMs). Chemokine expression was assessed in human colorectal adenocarcinomas by ribonuclease protection assay (RPA). Colonic adenocarcinoma cell lines were used to assess chemokine production by enzyme linked immunosorbant assay (ELISA), and Boyden microchemotaxis assays were performed to determine cell line supernatant monocyte chemotactic activity. CCL2 production was assessed in paraffin embedded tumour samples by immunohistochemistry. Finally, the number of macrophages and their distribution was determined in the same colorectal adenocarcinomas and compared with CCL2 expression and tumour stage. Results showed that CCL2 produced by cell lines induced monocyte chemoattraction, the expression of this chemokine in solid cancers increased with tumour stage (P < 0.05) and immunohistochemistry localized production to tumour cells. Analysis of the macrophage infiltrate showed that the accumulation was significantly greater in tumours than controls (P < 0.005) and within tumours it was greatest in necrotic regions (median 44,600 per mm(3)). Macrophage accumulation increased with tumour stage and correlated with CCL2 expression (r(s) = 0.8). CXCL8 interleukin 8 (IL-8), a potent angiogenic factor and growth factor, was expressed in all tumours and cell lines. It is concluded that CCL2 induces the accumulation of tumour promoting TAMs in human colorectal cancer and represents a therapeutic target to modify the macrophage response and direct immune mediated therapy.