Thrombotic thrombocytopenic purpura (TTP) secondary to Systemic Lupus Erythematosus (SLE)

We have reviewed the history provided and the laboratory data on this patient. The history is nicely outlined in the referring documentation. This patient presented with clinical syndrome of fever, fatigue, and diarrhea. Laboratory findings showed severe anemia with findings of microangiopathic hemolysis (schistocytes, hyperbilirubinemia, elevated LDH) and severe thrombocytopenia. He was later documented to have fluctuating ADAMTS13 activity that appeared to correlate with the hematologic abnormalities. He also had urinary findings of hematuria, moderate proteinuria, and creatinine as high as 1.4 mg/dL. Further lab evaluation included low complement levels, positive ANA of a high titer at 1:640 with negative double stranded DNA antibodies.

The patient was initially treated with steroids and intravenous immune globulin (IVIG) without improvement in his hematologic findings, which came only after the addition of plasma exchange. After later tapering his steroids, his hematologic parameters worsened with return of anemia and thrombocytopenia. At that time his creatinine was elevated to 1.4 as noted. He was treated again with steroids and plasma therapy. Rituximab was added with eventual remission.

A renal biopsy was obtained after treatment outlined above, which revealed glomerulonephritis with focal and segmental capillary necrosis on light microscopy. By immunofluorescence, granular deposits of IgA+, C3++, and IgM+ were seen in the mesangium level and capillary loops. (Of note, neither the original biopsy report nor the slides themselves were available for review). His creatinine later improved down to 0.9 mg/dL.
Based on the findings above, the patient likely has a unifying diagnosis of Systemic Lupus Erythematosus, supported by low complement, positive ANA, cytopenias, and renal abnormalities (hematuria, proteinuria, renal dysfunction). His cytopenias are also suggestive of Thrombotic Thrombocytopenia Purpura (TTP), also supported by the low ADAMTS13 activity in the presence of inhibitors. He has other auto-antibodies as well, including positive direct Coombs test for complement, and a positive lupus anticoagulant, the clinical significance of which are not clear but which support a diagnosis of underlying systemic autoimmune disease.

Regarding the specific questions posed:
1. The first and the second episode of TTP can be considered “secondary” to a systemic disease or the (likely) systemic disease is coexistent with the TTP?
We believe the TTP to be secondary to Lupus. The association of TTP with Lupus has been well described.

2. The antibody for ADAMTS13 was negative after 12 sessions of PEX (in total 15 were carried out), while it was positive after 3 dosages of Rituximab (in total 4 doses were administered). If a further TTP relapse would occur, do you deem it advisable to carry out (at least at first) the PEX or the administration of other doses of Rituximab? Vincristine is to be used?
The initial treatment for TTP acutely or in the setting of recurrence needs to focus on plasma exchange to remove the offending antibodies and replace deficient ADAMTS13 protein. Immunotherapy such as rituximab, cyclophosphamide, and corticosteroids generally do not work quickly enough to reverse the immediate, life-threatening hematologic and renal abnormalities associated with TTP. With respect to possibly repeating a course of rituximab, our practice is to follow the number and percentage of B-cells in the peripheral circulation by flow cytometry, which remain depleted for 6-9 months on average. This effect can last even longer if additional immunosuppression is used. We also monitor quantitative IgG levels monthly for several months after rituximab and consider repletion if levels are very low (under 400) to reduce the risk of serious infection. If the patient relapsed, there would be no rationale for a repeat course of rituximab if B cell levels remain very low or undetectable. We do not see a role for vincristine.

3. Do you think splenectomy could have a clinically positive role?
Splenectomy would only be considered if the patient remains refractory to all other forms of therapy, which would include repeated courses of Rituximab as outlined above.

4. After the first episode of TTP steroid was reduced until suspension (it was suspended in approximately 2 weeks before the 1st relaps). How is it advisable to reduce steroid now (after the 1st relapse)? Is it advisable to suspend it or do you suggest to keep a maintenance dose? (From the first 50 mg/a day, taken for about 1 and a half month, at present - he takes 25 mg/a day).
We would suggest tapering the steroids slowly over the coming months with ongoing monitoring of CBC, reticulocyte count, and LDH to evaluate for relapse. The presence of glomerulonephritis should also be considered, as the labs provided showed moderate proteinuria and hematuria. Complement levels should also be followed as another marker of Lupus activity to address further tapering of steroids. If tapering is unsuccessful, the addition of maintenance immunosuppression with mycophenolate could be considered to address the various manifestations of his Lupus.

5. Is it advisable to schedule the administration of Rituximab “pre-emptive?” If the answer is yes, based on which parameters?
We would not use Rituximab pre-emptively. Recurrence of TTP at this point is uncommon. As outlined above, we would suggest following B-cells via flow cytometry and only use additional Rituximab if there is recurrence and his B-cells have recovered.

6. How can the steady positive result of the direct Coombs test can be interpreted only for C3d?
We do not know the clinical significance of the positive Coombs test or whether this was contributing significantly to the hemolysis that he had. This may be just another autoantibody that the patient has in the setting of underlying autoimmune disease, and certainly red blood cell antibodies and autoimmune hemolytic anemia can be seen in the context of SLE. If the patient has a normal reticulocyte count, normal LDH and haptoglobin in the face of persistently positive Coombs test this supports this not being of clinical relevance at present. We have followed patients with chronically positive Coombs test who do not have clinical autoimmune hemolytic anemia and no treatment is warranted in this scenario. Coombs test can also be positive after red blood cell and plasma transfusions and this may be a contributing factor.

7. How can C3 and C4 depression be interpreted especially in the active moments of the disease?
The hypocomplemetemia is consistent with Lupus, and is often low in the setting of Lupus flares.

8. The suspect of an autoimmune disease is clear, mainly from the examinations carried at the time of the 1st relapse. Which autoimmune disease do you think we are dealing with? Is it possible to talk of LES or Lupus-like? Is it possible the presence of a congenital anomaly of the “complement?” (Anti-DNA antibodies are always negative).
As outlined above, we believe the patient has Systemic Lupus Erythematosus. The recovery of complement levels to normal after treatment speaks against a congenital complement deficiency.

9. How can the kidney biopsy be interpreted and in particular the immunofluorescence picture? Could it be possible this picture was modified from the intake of Rituximab + steroid when carrying out the biopsy?
The biopsy report describes glomerulonephritis with immunofluorescence positive for IgA, IgM, and C3. The classic pattern of Lupus Nephritis is the so-called “full house” pattern, which also includes positive staining for IgG and C1q. However, the patient had received various forms of immunosuppression prior to the biopsy, which may have modified the original histology. If electron microscopy was performed, the presence of tubuloreticular inclusions are also highly suggestive of Lupus Nephritis.

10. The therapy the young man (15 years) carried out will have negative effects on his growth? Do you deem it necessary to monitor any particular lab or clinical parameters?
Long term steroid use can certainly impact linear height but we would not expect the amount of steroids that he has had to date to have significant long-term sequelae. It is important to taper his steroids, however, as suggested, as chronic use (more than 6 months) of relatively high doses could adversely impact his growth and lead to other late effects such as osteonecrosis, risk of cataracts, osteopenia, etc. Monitoring his height and weight at this point should be sufficient and attempting to actively taper his steroids with a plan of introducing alternative immunosuppression (such as mycophenolate) if this is not possible.

11. The young man has a twin sister who is currently in good conditions (the main lab examinations are within normal limits). Is it advisable for her to undergo particular haematological or genetic surveys?
No specific studies are indicated for his twin sister who is presumably asymptomatic. We do not believe there is likely to be a significant inherited nature to this illness apart from the relatively minor increase in the incidence of systemic autoimmune disease that is seen in immediate family members.