Chronic lymphocytic leukemia (CLL) is the most common adult leukemia in Western countries, accounting for approximately 30% of all leukemias. Infections are the main cause of morbidity and mortality in patients with CLL.
Agents used in the management of CLL, especially steroids, purine analogues, alkylating agents and anti-CD20 monoclonal antibodies, contribute to the decrease in T cells and B cells, resulting in defects in humoral and cell-mediated immunity.
More than 20% treatment naive patients treated with FCR chemoimmunotherapy (fludarabina, cyclophosphamide, rituximab) and relapsed/refractory (R/R) patients treated with the BCR inhibitors develop severe infections, a pneumonia in the majority of the cases. Streptococcus pneumoniae (pneumococcus) constitutes a major global public health problem and is the most common cause of pneumonia. Conditions associated with immune deficiency greatly increase the likelihood of contracting pneumococcal disease. Growing resistance of pneumococcus to conventional antibiotics underlines the urgent need for vaccines to be used to control pneumococcal disease. Currently, pneumococcal vaccine is recommended in many countries and in Italy for patients with hematologic malignancy receiving immunocompromising therapy. However, data on the clinical benefit of vaccination in CLL patients is very limited. The present observational study will be carried out to define the clinical benefit and the serological response in previously untreated patients with CLL who receive the pneumococcal vaccine after the front-line FCR regimen and in R/R patients treated with the kinase inhibitors.
Despite progress in the prevention and diagnosis, the development and use of antibiotic therapies, pneumonia remains a leading cause of morbidity, mortality, and economic burden worldwide.
Elderly are more susceptible to pneumonia than younger populations and the prevalence pneumonia increases with age.
The immunosenescence, the state of dysregulated immune function associated with increasing age, play an important contributory role towards the risk of infections. As life expectancy is increasing, many countries are experiencing an increase in older individuals and by the year 2030 people over 65-70 years are expected to account for more than 70% of all patients with cancer.
CLL is a disease of the elderly, with a median age of onset of ~ 70 years. Therefore, elderly with CLL constitute a growing proportion of subjects at risk of pneumonia.
Prevention strategies, such as pneumococcal vaccination, may be the most valuable in reducing not only the morbidity and mortality but also the costs associated with pneumonia.
Since 2012, the World Health Organization recommended high valency conjugate pneumococcal vaccine (PCV13) in the prevention of pneumoccocal infections in immunocompromised adults.
However, very limited information is available about the efficacy of vaccinations in patients with CLL.
The objective of this study is to define the protective effect of pneumococcal vaccination in CLL patients.
This is an important information as in CLL, a frequent leukemia in older sujects, and characterized by well-known defects in the
humoral and cell-mediated immunity, pneumonia is a common cause of morbidity and mortality.
Our results could also define whether clinical and biologic characteristics of CLL patients, as well as that of the administered treatment, may influence a different response to the pneumococcal vaccination.