Focal segmental glomerulosclerosis in a patient with prefibrotic primary myelofibrosis.

We report a case of 56-year-old man presented to us with chief complaints of frothy urine and leg swelling. A urinalysis revealed nephrotic-range proteinuria. Haematological investigations revealed thrombocytosis, leucocytosis and peripheral blood smear showed a leucoerythroblastic picture. JAK 2 mutation was positive. To confirm the diagnosis of myeloproliferative neoplasm, bone marrow biopsy was done, which was suggestive of primary myelofibrosis. The patient underwent kidney biopsy due to rapidly declining renal function and persistent proteinuria, which was suggestive of focal segmental glomerulosclerosis. Early glomerulopathy is rare in myeloproliferative neoplasm, and aggressive follow-up is required to prevent progression of kidney disease.

Investigation of calmodulin and basic fibroblast growth factor (bFGF) in idiopathic myelofibrosis: evidence for a role of extracellular calmodulin in fibroblast proliferation.

The urinary concentration of calmodulin and basic fibroblast growth factor (bFGF) was determined in a total of 53 patients with various chronic myeloproliferative disorders (CMPD), including 22 patients with idiopathic myelofibrosis (IMF). Calmodulin excretion was significantly elevated in IMF (0.29 +/- 0.04 microgram/mmol creatinine) (P < 0.001), when compared to polycythaemia vera (PV) (0.14 +/- 0.02), essential thrombocythaemia (ET) (0.13 +/- 0.04), chronic myeloid leukaemia (CML) (0.16 +/- 0.02), unclassified myeloproliferative disorders (UMPD) (0.11 +/- 0.02) and age-matched controls (0.1 +/- 0.02) (P < 0.001). In contrast, bFGF was slightly elevated in all CMPD conditions when compared to age-matched controls. A neutralizing antibody to calmodulin was demonstrated to significantly influence the in vitro proliferation of normal human fibroblasts, an effect dependent on both cell density and the presence of fetal calf serum (FCS). Essentially, the antibody reduced FCS-induced proliferation of low-density fibroblasts but had little or no inhibitory effect on high-density fibroblasts in the absence of FCS. In addition, extracellular calmodulin was shown not to interact with known fibroblast mitogens, namely, IFG-1, EGF, bDGF and PDGF. We conclude that extracellular calmodulin should be considered, in addition to PDGF, TFG-beta and EGF, as a potential mitogen involved in the stromal reaction of idiopathic myelofibrosis.

Raised urinary calmodulin levels in idiopathic myelofibrosis: possible implications for the aetiology of fibrosis.

Platelet growth factors (e.g. PDGF and TGF-beta) are thought to be pathogenetically important in the stromal reaction characteristic of idiopathic myelofibrosis (IM). We have investigated a possible pathogenetic role for a further platelet mitogen, calmodulin. Platelets are rich in calmodulin, of which 30-40% is releasable with a time course that differs from alpha-granule proteins. In IM urinary calmodulin concentrations were 3-fold those of the normals controls. We suggest that an abnormal release of calmodulin may occur from platelets/megakaryocytes in patients with IM, and that calmodulin should be considered, along with other growth factors, in the pathogenesis of marrow fibrosis.

Platelet-derived growth factor concentrations in platelet-poor plasma and urine from patients with myeloproliferative disorders.

Our enzyme-linked immunosorbent assay (ELISA) for measuring human platelet-derived growth factor (PDGF) detects nanogram quantities (ranging from 0.007 to 16 ng/100 microL) in purified PDGF standards. This assay is sensitive enough for studying plasma and urine. The range in normal volunteers was 0.6 to 2.3 micrograms/L for platelet-poor plasma and 1.4 to 3.3 micrograms/L for urine. We determined PDGF levels in the circulation (outside platelets) in patients with myeloproliferative diseases. Platelet-poor plasma and urine PDGF were significantly elevated in patients with myelofibrosis (6.2 +/- 2.0 micrograms/L for plasma; 7.8 +/- 2.4 micrograms/L for urine) and essential thrombocythemia (5.5 +/- 1.5 micrograms/L for plasma; 11.4 +/- 2.2 micrograms/L for urine), but not in patients with chronic myelogenous leukemia (2.1 +/- 0.4 micrograms/L for plasma; 2.8 +/- 1.2 micrograms/L for urine). Polycythemia vera produced an intermediate pattern: although plasma PDGF was within the normal range (2.1 +/- 0.2 micrograms/L), urine levels were increased (3.7 +/- 0.6 micrograms/L). These results show that PDGF is increased in the circulation in some but not all myeloproliferative diseases, and suggest that this is due to abnormal in vivo release from either megakaryocytes in the bone marrow or circulating platelets.

Hydroxyprolinuria and hypercalcaemia during immobilization in patients with idiopathic myelofibrosis.

Two of three patients with bone pains and hydroxyprolinuria due to idiopathic myelofibrosis developed hypercalcaemia during periods of immobilization. This responded rapidly to cytotoxic therapy with busulphan. Hydroxyproline excretion in the urine was increased compared to ambulant patients with the same disease. These previously unreported findings suggest that immobilization can produce rapid, generalized bone resorption in patients with myelofibrosis.

Urinary hydroxyproline excretion in the myelofibrosis-osteomyelosclerosis syndrome and related diseases.

The total urinary hydroxyproline excretion was assessed in 47 patients with chronic myeloproliferative disorders. Urinary hydroxyproline excretion was normal in 16 patients with idiopathic myelofibrosis and in 5 out of 6 patients with acute myelofibrosis. In patients with osteomyelosclerosis (n = 8) values for urinary hydroxyproline excretion were higher (median 202, range 54-652) than those in idiopathic myelofibrosis (median 139, range 84-216). This difference was not significant (p greater than 0.1). Elevated values for urinary hydroxyproline excretion were found in 10 patients (1 AMF patient, 3 OMS patients and 6 patients with CML in the accelerated phase of the disease). All but 1 of these patients had been treated, or were being treated, with cytotoxic agents at the time of investigation. These findings are compatible with impaired degradation of bone marrow collagen which, together with enhanced collagen synthesis from bone marrow fibroblasts, accounts for progressive accumulation of connective tissue in the bone marrow. This process appears to be influenced by cytotoxic treatment as reflected in increased urinary hydroxyproline excretion in those patients receiving cytotoxic agents.

Platelet factor-4 excretion in myeloproliferative disease: implications for the aetiology of myelofibrosis.

Experimental evidence suggests that the fibroblastic proliferation often associated with the myeloproliferative disorders is not part of the neoplastic process, but is secondary to an unknown stimulus. This stimulus may be a factor derived from platelets which promotes the proliferation of fibroblasts in vitro (PDGF). Platelet-derived growth factor is localized to platelet alpha-granules together with PF4 and beta-TG. As an indicator of alpha-granule release, we have measured PF4 levels in plasma, platelets and urine in 46 normal subjects and 49 patients with myeloproliferative disorders, secondary thrombocytosis and miscellaneous malignancies. All 11 patients with elevated urinary PF4 excretion exhibited myelofibrosis, whereas 11 of 22 patients with documented myelofibrosis had urinary PF4 excretion in the normal range. No correlation was seen between marrow fibrosis and plasma levels or the platelet content of PF4. The data are consistent with the possibility that release of mitogen(s) from platelet or megakaryocyte alpha-granules in some patients with myeloproliferative disorders is pathogenetically related to the development of marrow fibrosis.

Urinary hydroxyproline excretion in myelofibrosis.

Urinary hydroxyproline measurements were performed in a group of health volunteers as well as patients with cancer and myelofibrosis. Patients in whom there was no metastatic involvement of bone marrow excreted an amount of hydroxyproline not different from that of the control group. Those who had marrow metastasis produced elevated levels of hydroxyproline; the highest excretions were observed when marrow fibrosis was associated with metastasis. These results contrasted with those observed in agnogenic myeloid metaplasia patients whose excretions were equivalent to the control group. The result suggests differences in the pathogenesis of myelofibrosis and a technique potentially useful for distinguishing between patients who may otherwise be diagnostic problems.

Plasma cell leukemia with excretion of half-molecules of immunoglobulin A (alpha1 lambda1).

A patient with plasma cell leukemia and myelofibrosis excreted free immunoglobulin light chains and an abnormal monoclonal immunoglobulin (Ig) A in her urine. The IgA that was present in serum and urine had a sedimentation coefficient of 4.0 S. The molecule was comprised of both heavy and light chains but was antigenically deficient compared to normal IgA. As excreted in the urine, the protein appeared to be a half-molecule of IgA, with a partial deletion in the heavy chain, probably involving part or all of the C-terminal domain.