Patients with cancer and contaminated by the COVID-19 show an important mortality rate, from 29% to 39%.

Among these patients, those with haematological cancers -that affect white cells of the immune system- are particulary sensitive to infections like the COVID-19. Due to the immunodepression caused by the cancer itself or its associated treatments (e.g immunosuppressors for patients engrafted with bone marrow, etc),it is likely that these patients represent one of the population the most at risk and with fatal evolution.

Moreover, these patients have often numerous preventive treatments against infections from all origins (bacteria, fungi, viruses and parasites). They are vaccinated when it is possible, or receive regular infusions with antibodies withdrawn from healthy donors. Therefore, infections are one of the most frequent complications.

Nowadays, there are few specific studies on patients with haematological diseases and infected by the COVID-19, but the data on a low number of patients confirm the severity of this infection in this particulary fragile population.

So, it is urgent to create a register describing the characteristics and the evolution of these patients, the impact of the COVID-19 infection on their haematological disease care, as well as their capacity to get immunized against this virus. Their immunization status will be examined through a serological study, allowing the detection of COVID-19-targeted antibodies through a blood test. Patients concerned are those with haematological disease and monitored in hospitals haematological centers from the three most impacted french regions that are Ile-de-France, Grand-Est and Bourgogne Franche Comté. Nowadays, 33 haematological centers have given their agreement to take part to this register and to the serological study.

Ultimately, our goal is to propose a better care of these patients the most exposed to COVID-19 mortality.

Pitié-Salpêtrière hospital is one of the reference center for cancers arising in immunosupressed patients, and benefit of an excellence research label (SiRIC) attributed by the National Cancer Institute, the Ministry of Health and Solidarities and Inserm.