PF4 and monoclonal gammopathy: Recently, however, chronic anti-PF4 disorders featuring potent VITT-like properties of monoclonal proteins (M-proteins) have been identified: this oftentimes treatment-refractory entity, named "VITT-like monoclonal gammopathy of thrombotic significance" (VITT-like MGTS), dramatically expands the clinical spectrum of recognized anti-PF4 disorders.