Maria Luisa Lombardi

A case of diet-related pemphigus

An experimental investigation has lately shown that certain allyl compounds of garlic are able to provoke acantholysis in normal human skin cultured in vitro. The acantholytic effect has been more prominent in the samples from DR4+ donor. We here report a case of superficial pemphigus which appeared spontaneously in a DR4,14+, 49-year-old man and which ran a course that proved to be affected by dietary factors, in particular by the consumption of garlic. In the absence of a conventional treatment and on a garlic-free diet only, the disease ceased for several months. Soon after an unintentional dietary test with a strongly and presumable garlic-spiced fish meal, the pemphigus recurred. Nutritional factors should be added to the ever-growing list of exogenous factors capable of inducing or perpetuating pemphigus in genetically predisposed individuals.

ENALAPRIL: A POWERFUL IN VITRO NON-THIOL ACANTHOLYTIC AGENT

Drugs containing sulfhydryl groups (thiol drugs) (e.g., penicillamine, captopril, thiopronine) can induce pemphigus in vivo and provoke acantholysis in vitro. Enalapril, like captopril, is an angiotensin‐converting enzyme (ACE) inhibitor largely used as an antihypertensive drug; it has recently been reported to induce pemphigus, though it is not a thiol drug. In this study we investigated the possible in vitro acantholytic effect of enalapril on normal human skin from donors. The drug induced severe acantholytic changes of keratinocytes and complete suprabasal splitting at one tenth the concentration required by thiol drugs in similar experiments, even after a shorter period of culture. All skin samples from different donors was highly susceptible to the acantholytic effect of enalapril. In our experience, enalapril is the most powerful acantholytic drug in vitro.

The in vitro effect of hydroxychloroquine on skin morphology and transglutaminase

Background Antimalarials are some of the most notorious drugs which may induce psoriasis, with 25% of all reported cases being associated with them. Antimalarials do not induce psoriasis de novo, but trigger subclinical psoriasis. In a previous report, we suggested that antimalarials exert their effect by interfering with the epidermal transglutaminase (TGase) activity.

Imbalance between plasminogen activator and its inhibitors in thiol-induced acantholysis

Pemphigus may be an idiopathic disease or a syndrome induced by drugs, mainly thiol drugs. Autoantibodies, always present in the idiopathic form but often lacking in the drug-induced one, may cause acantholysis by activating endogenous proteolytic enzymes. Pathogenesis of drug-induced pemphigus when antibodies are absent has not been elucidated yet. Extracts of skin tissues cultured for 4 days with penicillamine, captopril or thiopronine were assayed for the presence of plasminogen activator (PA) and plasminogen activator inhibitors (PAI) on agar fibrin plates. Moreover, uPA, tPA, and PAI-1 were identified in the extracts by immunoenzymatic assay. The results have shown progressively decreasing amounts of PAI-1 in penicillamine, thiopronine and captopril-cultured tissue extracts, respectively. This suggests that the acantholytic potential of thiol drugs is directly correlated to their capability of reducing PAI-1 in the epidermal cells leading to increased PA activity. This PA-PAI imbalance may be itself the cause of intraepidermal splitting.

Increased serum concentrations of soluble HLA-class I antigens in hepatitis C virus related mixed cryoglobulinaemia

OBJECTIVE To investigate whether quantitative alterations of both β2microglobulin (β2μ) associated HLA class I heavy chains (sHLA-I) and β2 μ free class I heavy chains (sHLA-FHC) in sera of patients with hepatitis C virus (HCV) infection occur and whether they distinguish patients with mixed cryoglobulinaemia (MC). METHODS 83 HCV infected patients were studied and divided into three groups: (A) without cryoglobulinaemia (n=21), (B) with polyclonal MC (n=20), (C) with monoclonal MC (n=42). Serum sHLA-I and sHLA-FHC were measured by double determinant radioimmunoassay using monoclonal antibodies: TP25.99 as catching antibody, and NAMB-1 and HC-10 as revealing antibodies. Western blot identified HLA-I isoforms. RESULTS The serum concentrations of sHLA-I and of sHLA-FHC in HCV infected patients versus controls were respectively 1.3(0.5) μg/ml (mean (SD)) versus 0.8 (0.3) (p<0.001) and 13.9 (7.1) ng/ml versus 9.2 (5) (p<0.001). sHLA-I were 1.01 (0.4) μg/ml in group A, 1.04 (0.4) μg/ml in group B, and 1.47 (0.4) μg/ml in group C (p=0.001). Statistical analysis showed a significant difference versus controls for groups B (p<0.02) and C (p<0.001). sHLA-FHC were 12.8 (8.3) ng/ml in group A, 17.2 (7.1) ng/ml in group B, and 12.9 (6.2) ng/ml in group C (p<0.02). A significant difference versus controls for each group was found (p<0.02, p<0.001, and p<0.02, respectively). Different patterns of sHLA-I isoforms were observed. CONCLUSIONS Increased serum concentrations of sHLA-I and sHLA-FHC characterise HCV infected patients. The highest sHLA-I concentrations seem to distinguish patients with monoclonal MC. In this last condition sHLA could play a part in the HCV escape and in B cell proliferation. The significance of sHLA-FHC is still undefined.

Effects of lithium carbonate (Li2CO3) on in‐vitro‐cultured normal human skin explants

The early morphological changes induced by lithium carbonate, a well‐known psoriasis‐provoking drug, were studied on cultured skin.

Are acantholysis and transglutaminase inhibition related phenomena

BACKGROUND The loss of intercellular cohesion among keratinocytes (acantholysis) may be considered the histologic marker of pemphigus. Many drugs, especially thiol drugs, proved to be able to provoke in vitro acantholysis by biochemical mechanisms interfering with the disulfide and thiol group balance. As to nonthiol drugs, the pathomechanism of acantholysis is still unexplained. OBJECTIVE To explain the molecular mechanism of enalapril-induced acantholysis a potential link between transglutaminase (TGase) activity and the effects of this drug was investigated. METHODS TGase activity in extracts from human breast skin cultured in the presence of thiopronine, captopril and enalapril were evaluated in vitro. The acantholytic potential of cystamine, a known TGase inhibitor, was also investigated. RESULTS Enalapril, the most powerful acantholytic drug in vitro, was found to inhibit both the purified enzyme and the TGase activity in the extracts from cultured human breast skin explants. Kinetic studies showed that enalapril inhibition was competitive with respect to the amino acceptor substrate and uncompetitive with respect to the amino donor substrate. Moreover, an acantholytic effect of cystamine on explants of normal human skin was shown. CONCLUSIONS These results suggest that acantholysis and the inhibition of TGase activity could be two related phenomena.

Crohn disease: susceptibility and disease heterogeneity revealed by HLA genotyping

Predisposition to Crohn disease (CD) seems to be genetically determined but, though several reports on the matter, the association between HLA antigens and the disease is still controversial. PCR-SSP high resolution typing in 107 CD patients, and in subgroups selected according to clinical features, showed a positive association with the rare haplotype DRB1*07, DQB1*0303 both in the overall patients (p = 0.002; pc = ns) and in the subgroup of nonfistulized patients (p = 0.0008; pc = 0.032). Moreover, the protective role of the haplotype DRB1*03, DQB1*0201 (p = 0.029) was confirmed also in Italian patients, whereas no strong association with HLA class I alleles has been found. In addition, variability of the HLA alleles frequency in CD subgroups was observed, supporting the hypothesis of a genetic heterogeneity of the disease and suggesting that HLA alleles distribution in selected groups may allow to identify patients with probably different prognosis or associated complications.

Paroxysmal nocturnal hemoglobinuria: Significant association with specific HLA-A, -B, -C, and -DR alleles in an Italian population

Paroxysmal nocturnal hemoglobinuria (PNH) is characterized by the expansion of a PIG-A mutated hematopoietic stem cell. An immune-mediated origin has been suggested for this disease. Because HLA genes represent a susceptibility factor for autoimmunity, we investigated HLA genotype in 42 Italian PNH patients compared with 301 control subjects of the same ethnic origin. A significantly increased frequency of the HLA class I alleles A*0201 (p < 0.05), B*1402 (p < 0.001), and Cw*0802 (p < 0.005), and of the HLA class II DRB1*1501 (p < 0.01) with the linked DQB1*0602 (p </= 0.05) and DRB1*01 (p </= 0.05) with the linked DQB1*0501 (p </= 0.01) alleles, has been observed. Notably, a fourfold increase of the haplotype B*1402, Cw*0802 (p < 0.0005) and a 15-fold increase of the Mediterranean haplotype A*33, B*1402, Cw*0802, DRB1*0102, DQB1*0501 (p < 0.005) was also revealed. This association may provide new insights into the autoimmune pathogenesis of PNH.

Implication of tissue transglutaminase and desmoplakin in cell adhesion mechanism in human epidermis.

The distribution patterns of both tissue and keratinocyte transglutaminases (TGase), as well as that of desmoplakin (DP), have been immunohistochemically investigated in human skin cultured in the absence or presence of cystamine and enalapril, two acantholytic agents. In the control samples, tissue TGase is predominantly expressed in lower layers of the epidermis and is located intercellularly. Conversely, in tissues cultured with cystamine or enalapril, a diffuse cytoplasmatic staining was observed. Similarly, DP, detected on the cell membrane in the control, shifts into the cytosol of the keratinocytes following treatment. The distribution pattern of the keratinocyte enzyme in the acantholytic epidermis was identical to that observed in the normal one. Since cystamine and enalapril are TGase inhibitors and DP was shown to act as a TGase substrate in vitro, we suggest that DP and tissue enzyme may participate in cell adhesion at the intraepidermal level.