Chronic myeloproliferative neoplasm in adulthood in CBL syndrome harboring a splice-site CBL variant alongside a novel constitutional CSF3R variant.

Casitas B-cell lineage (CBL) syndrome is a rare RASopathy known to predispose to CBL-mutated juvenile myelomonocytic leukemia (JMML) in childhood. Adulthood acute myeloid leukemia arising out of a genetic aberrancies consistent with prior CBL-mutated JMML has been twice previously described, but chronic myeloproliferative neoplasia has not. We present a case of progressive myeloproliferative neoplasm in adulthood in the context of CBL syndrome alongside a novel CSF3R variant. We also review pathogenic splice-site mutations in CBL-mutated JMML.

Prolonged administration of low-dose cytarabine and thioguanine in elderly patients with acute myeloid leukaemia (AML) achieves high complete remission rates and prolonged survival.

The prognosis of AML in elderly patients is poor and research into novel therapeutic approaches is urgently needed. This study examined the use of low-dose chemotherapy with cytarabine and thioguanine administered in repetitive cycles in 62 elderly patients with newly diagnosed or relapsed/refractory AML. The overall response rate was 58% in the total cohort. Response rates (CR/CRi) were significantly higher in patients with newly diagnosed AML (74%) compared to patients with relapsed/refractory disease (25%, p = .0004). Kaplan-Meier estimate of overall survival was 289 days (95% CI; 183-395 days) with a relapse rate of 65.7%. The induction mortality rate was 16.1% with treatment successfully undertaken in the outpatient setting. Similar clinical outcomes were observed in a retrospective analysis of a second cohort of 25 AML patients treated at a different site. These results support the use of a sustained low intensity chemotherapy approach as a therapeutic option for elderly patients with AML.

Humoral immune failure defined by immunoglobulin class and immunoglobulin G subclass deficiency is associated with shorter treatment-free and overall survival in Chronic Lymphocytic Leukaemia.

Immune dysfunction attributed to hypogammaglobulinaemia is common in chronic lymphocytic leukaemia (CLL) and infection is a major contributor to morbidity and mortality. A higher incidence of multiple immunoglobulin and immunoglobulin G (IgG) subclass deficiency was associated with more advanced disease (P < 0·001 and P < 0·001, respectively) in a cohort of 147 CLL patients. Multiple immunoglobulin and IgG subclass deficiency were significantly associated with shorter treatment-free survival (TFS) (P < 0·001 and P = 0·006, respectively). The association between disease stage and immune dysfunction demonstrated by these data suggest aspects of immune deficiency correlate with disease severity and may be associated with shorter TFS in CLL.

Immunoglobulin G subclass deficiency and infection risk in 150 patients with chronic lymphocytic leukemia.

Hypogammaglobulinemia is a common complication of chronic lymphocytic leukemia (CLL), but the significance of immunoglobulin G (IgG) subclass deficiency is unknown. We analyzed the prevalence of immunoglobulins G, A and M, IgG subclass deficiency and infection in 150 patients with CLL. Low IgG, IgA and IgM levels were observed in 27.3%, 30.7% and 56.7% of patients, respectively. IgG subclass deficiency was frequent, with reduced IgG1, IgG2, IgG3 and IgG4 in 28%, 19.3%, 52% and 22.7% of patients, respectively. IgG subclass deficiency (total 64.6%) and hypogammaglobulinemia (27.3%) were more prevalent than clinically significant infection (16%). Recurrent or significant infections were seen in 24 patients (16%), of whom 50% had hypogammaglobulinemia but 100% had at least one IgG subclass deficiency, indicating that half the patients with infection had IgG subclass deficiency but normal total IgG level. Deficiencies of IgG3 and IgG4 were statistically associated with infection risk. Normal immunoglobulin and IgG subclass levels were seen in 26 patients (17%) and none had infections. IgG subclass deficiency is commonly observed in patients with CLL with both normal and reduced total IgG levels, and is associated with infection. Screening patients with CLL for IgG subclass deficiency may be a useful adjunct in stratifying their infection risk.