A new case report published in the International Journal of Hematology documents what researchers believe is the first confirmed instance of immune thrombotic thrombocytopenic purpura (TTP) complicating the course of systemic mastocytosis (SM).
The report describes a 69-year-old woman with advanced SMAdvanced SM In these subtypes of SM, mast cells begin to damage organs. Advanced SM includes the subtypes aggressive SM, mast cell leukemia and SM with an associated hematological neoplasm. who developed immune TTP, a life-threatening autoimmune disorder that occurs when the immune system attacks an enzyme called ADAMTS13. Without enough of this enzyme, dangerous blood clots can form in small blood vessels throughout the body, making rapid diagnosis and treatment essential.
The woman, who also had high blood pressure, an underactive thyroid and type 2 diabetes, was admitted after a brief episode of unresponsiveness and dizziness. Blood tests showed severe anemia and an abnormally low platelet count. A blood smear also showed fragmented, damaged red blood cells, a hallmark of TTP.
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Based on these findings, doctors immediately started plasma exchange, a process used to remove antibodies against the ADAMTS13 enzyme from the blood. Her doctors also gave her corticosteroids and rituximab, a treatment used in TTP to slow antibody production. After six cycles of plasma exchange treatments, her red blood cell destruction stopped, fragmented red blood cells disappeared from her blood smear and her platelet count returned to normal.
However, further testing showed that her SM had progressed, with markedly higher tryptaseTryptase A protein enzyme that is primarily produced by mast cells and stored in small pockets within the cells, known as granules. High levels of tryptase are a key indicator of SM. levels and a repeat bone marrow biopsyBone marrow biopsy A procedure to collect a sample of bone marrow using a needle. Often used to examine the characteristics of mast cells and diagnose SM. revealing widespread infiltration of abnormal mast cells. Doctors treated her with cladribine, but her disease did not respond and her TTP continued despite additional plasma exchange.
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The woman subsequently underwent an allogeneic bone marrow transplant from a partially matched related donor. Nearly a month after transplantation, testing showed successful donor cell engraftment, remission of her disease and normal tryptase levels.
The researchers said diagnosing TTP in people with SM can be difficult because both the underlying disease and some treatments can cause similar complications. In this instance, testing confirmed that the woman’s symptoms were caused by primary immune TTP rather than another form of thrombotic microangiopathy.
“To the best of our knowledge, this is the first reported case of immune TTP complicating the course of systemic mastocytosisMastocytosis Rare disease caused by the buildup of mast cells. Cutaneous mastocytosis primarily affects the skin and is more common in children, while systemic mastocytosis affects internal organs and is more common in adults. based on a comprehensive literature search of PubMed, Web of Science, and Scopus databases,” the study authors concluded.
